9UNP0196SD_Pete_Cohen_WordPress

- Welcome everybody to Wednesday Nite at the Lab. My name is Tom Zinnen. I work here at the Biotechnology Center of UW-Madison. I also work for UW-Extension, Cooperative Extension. And on behalf of the Wisconsin Alumni Association, welcome to Wednesday Nite at the Lab. We do this every Wednesday night, 50 times a year. Tonight I'm delighted to be able to introduce our speaker who is Pete Cohen. He's a long time Wednesday Nite at the Lab participant and he's tonight our presenter. He'll be talking about the first 25 years of the HIV/AIDS epidemic. Pete is an alum of the Wisconsin High School which stood on this very location. 

That building actually was torn down to make way for this building, so he spent a lot of time in this three-dimensional space here. It was a different building. And he graduated in 1958, so he's celebrating his 50th anniversary of high school graduation. In 1962, he graduated from Harvard with a degree in biochemical sciences. In '67 from Brandeis University with his PhD in Biochemistry and in 1975 he got an MD from the University of California at San Francisco. From 1978 to 2000 he was an associate professor at UCSF and from 2000 to 2004 he moved back to the Midwest and was on the faculty at Washington University. From 2004 to 2006 he lived in Portland, Oregon working at Providence Portland Hospital and then he retired and returned to Madison in 2006. During his time working on HIV he served as the editor of the AIDS Knowledge Base which is a textbook that runs to about 1,000 pages and ran through three editions. And he also helped initiate and was the first medical editor of HIV Insight website which is at HIVinsite.ucsf.edu. And so it's a great pleasure to be able to introduce Pete Cohen to you tonight who by the way last Wednesday got married to Jennifer. 

- Can you hear me? I understand I'm competing with Joe Biden tonight, so I'm not sure what kind of competition that is, but you can be the judge. So, I want to talk with the goals of giving you an understanding of the disease itself and also present to you some of the kinds of research and thinking that led to our current understand and then talk about some of the problems that exist. These are some institutions where I worked and we don't have to do anything with that. So let's get started. I don't know how much time I have to spend on this, but there is some basic stuff that you ought to know. Proteins for example are made up of a string of amino acids. There are twenty different amino acids and the code for the sequence in a protein is determined in the genetic material DNA, and in order to perform their function, these proteins fold up into a three-dimensional configuration and there are -- the proteins -- there are a number of different kinds of protein. One kind is an enzyme which is a catalyst. Catalysts make a reaction go faster and we -- the processes in our body for the most part are determined by enzymes which catalyze them and they would otherwise proceed at a rate too slow to be useful. 

So an important point about enzymes is that we can purify them and use them as tools and they've been important tools in this epidemic in understanding what's going on and other aspects of dealing with the disease. Another kind of protein is an antibody. Antibodies are proteins that are made by us, by our immune system and they are proteins which are made in a very broad repertoire, each one very much the same except for a little bit on the end which is an active site and as a result they can respond to many different kinds of foreign materials including infections. And they are not only important to us, but we can use them as tools and assays and I'll talk a little bit about that. Let's see, what did I want to do? Go back. And DNA and RNA are molecules in the class of nucleic acids, and the important things to know about them are that they have you could say four code letters which make up our genetic code, and they have the property that because they carry a specific code, they can be copied faithfully. That's how we pass our genetic material on and how other living things pass their genetic material on. And the enzymes that make these copies are also enzymes that we can purify and use as reagents in studies. And I think maybe that's all I have to say about that. 

So we're going to talk about the AIDS epidemic and I finished my internal medicine residency at the University of California-San Francisco in 1978. And the AIDS epidemic first became apparent in 1980. I by that time was a faculty member and attending physician at San Francisco General Hospital and by virtue of San Francisco general being the county and public hospital for the City of San Francisco and because San Francisco was a relatively, and still is, a relatively small city geographically. We ended up in the initial part of the epidemic probably having more AIDS patients in our hospital than any other hospital in the world for a time. And those of us who were there were in the middle of it, and there were a lot of different ways that people dealt with it. Some people got scared and left. Some people took it on as a challenge and it was quite an experience to have lived through. So the first publications on this epidemic were kind of summarized on this slide, and they described several gay men who had unusual conditions that were suggestive of a problem with the immune system, what's called immune deficiency. And there was no obvious reason known to that time why they should have this deficiency. And initially there were just a few cases reported. 

And the way these cases presented themselves was that the individuals who were affected had infections with organisms that usually don't occur unless somebody has a damaged immune system. This x-ray is an x-ray of a person with pneumocystis pneumonia. This is a man who has a kind of skin cancer and a cancer that can effect deeper structures in the body called Kaposi's sarcoma. And this is an example of somebody who has a yeast infection in the mouth, given the name thrush. And I'm not going to show very many clinical slides, but this is just a small sample of the kind of things that appear to us. And initially, nobody knew what was going on, and there were a lot of problems in figuring it out. One of the problems was that the people who were affected were gay men and intravenous drug users primarily. And because of that, a lot of people said "why do we care?" And initially the numbers were small. And eventually got larger and larger and people began to realize that heterosexual people could contract this disease and began to decide that they were going to try to do something about it. 

So these were some of the speculations. One of the common ones was that this was due to a drug that the gay, at least a minority of the gay population used to enhance sexual pleasure called ammal nitrate. It had the street name of "poppers." And some people suspected right away that this was an infectious agent. There were some suspicions that it was an infectious agent that had been known for a long time called cytomegalovirus that many of us actually have in our bodies but that really doesn't cause disease except in unusual circumstances. And there were the usual perhaps somewhat paranoid speculations that this might be a CIA plot or some biowarfare experiment that went awry and so how do you approach a disease under these circumstances? Well, if you want to study a disease, you need to have a way of deciding that somebody has the disease and not something else. You need what's called a case definition, and you make a case definition sort of like a Chinese menu. Remember that there's no blood test for this disease at this point. And you say okay if somebody has these conditions and these conditions but not these conditions, then we'll say they have AIDS. 

And we didn't say they have HIV because HIV was an unknown term at that time. What we were seeing were people who had AIDS, the immunodeficiency syndrome. And when you can have a case definition and start to look at who gets the disease, you can begin to make some conclusions and some hypothesis about what's causing it. So you want to ask questions like who gets the disease, how is it spread, how fast is it spreading and is there a way to prevent it? And the people, the group of people who made the initial contributions to answering these questions were epidemiologists, people who study the kind of questions that I just described. And then as clinicians, we were faced with a bunch of new problems that for the most part we hadn't seen before or saw very rarely and so our job was to start documenting what the clinical findings were in people who seemed to have this condition and to figure out how to treat them knowing that we really didn't know what the disease was but try to treat what seemed to me the immediate problem. For example, if somebody had pneumocystis pneumonia, we could give certain antibiotics to cure pneumocystis pneumonia and that would make the person better for a while, but they would eventually succumb to some other kind of condition and eventually to one that we really didn't have a treatment for. And one of the things you always want to know about a disease or a syndrome is what is the course of the disease over time. How does it begin? How long does it last? 

How do you figure out where somebody is in that progression? And these were conditions that -- these were circumstances that we really couldn't address very well at this point. And in the laboratory, people were looking at what processes in the body and what kind of cells are affected by this disease. And to do so they had to examine blood and tissue from the patients. And there -- I think the most astute people involved in this came around pretty quickly to the notion that this had to be an infectious agent and so they were looking in these tissues and blood and samples from patients for evidence of an infectious agent. And this is kind of a summary of the Centers for Disease Control initial case definition on AIDS. And so it says a person having a disease that is at least moderately predictive of a defect in cell-mediated immunity. The person has no known cause for diminished resistance to that disease. And then a lot of the other verbiage in it is talking about things that can't be counted as HIV like somebody is on chemotherapy which can damage your immune system or they have a leukemia or some other disease that's known to damage your immune system. 
- When did the term AIDS come into usage? 

- Well the term AIDS came into usage pretty quickly around this time. And there were sort of more -- you could even say judgmental terms like "gay immunodeficiency disease" but Acquired Immunodeficiency Disease was known pretty quickly. What wasn't in existence at that time was the term HIV. And we'll get into that a little bit here. So what happened in the endeavors of these various groups of people? So epidemiologically, who has the disease? Well, it turned out that the groups that had it were men who have sex with men, promiscuous heterosexuals -- I seem to be losing the pointer here. I'm not sure what I have to do to sustain it. IV drug users, recipients of blood products for example hemophiliacs in the early part of the epidemic were devastated by this disease. And a curious phenomenon was that Haitians had a very high incidence of this disease. 

And it wasn't clear why that was. Now at kind of at the end of the talk I'll say why. So it was an observation that the cases were increasing in the groups that I mentioned above and these all suggest that -- well and what was equally important was who doesn't get the disease. And so people who lived in the same house but didn't do any of those things or have any of those risks didn't get infected. Those of us taking care of the patients didn't get infected or didn't have the disease. We didn't know it was an infection yet. Close friends, health workers caring for the patients. And so when you look at this and say what is a sensible explanation for it, it would be that there is an infectious agent that's transmitted when certain body fluids are transferred but not by just close physical contact or kissing or things like that. So, clinically we saw a number of different entities. I mentioned Kaposi's Sarcoma. 

We saw certain kinds of lymphomas, a number of infections that are called in a classification "opportunistic infections" meaning that they don't affect somebody with a normal immune system. And then an important observation was that there was a group of individuals who had the same kind of risks but didn't have these profound complications. And they typically would have symptoms like maybe fatigue or generalized swollen lymph nodes. Sometimes they would have the condition that I showed you called thrush which is the yeast infection in the mouth, and we began to suspect that this was related to AIDS, but these people weren't sick. They were people who were going to work and in some cases they didn't feel bad at all and in other cases they may have been tired and not quite felt normal. And so we suspected that this might be part of the same process. A lot of what went on during this time was organizing clinical trials to be able to test whether certain treatments for the problems like pneumocystis pneumonia were really effective and what the best drugs were for it. And in terms of learning the course of disease, what we observed was that usually when it became apparent that somebody had AIDS, they would die within two years of the diagnosis. And so this was the way kind of the spectrum of the disease looked in 1982. So we had a group of people who had AIDS and were very sick with these conditions and then we had these individuals who maybe had these other symptoms and we didn't know whether any of them would progress. 

We didn't even know for sure it was the same disease. If they progressed, we didn't know whether all of them would or only some of them would. And this is an example of what's called the "Wasting Syndrome" in a patient with AIDS. Not everybody with AIDS looks like this. Sometimes people look quite healthy when you just look at them, but in this condition, somebody develops profound weight loss, loses their lean body mass which is the muscle tissue. And there were a lot of sort of non-medical things going on during this period. There was obviously in San Francisco. In San Francisco in case anybody doesn't know has a huge population of gay men. And there was obviously tremendous interest in it, probably ahead of what existed in a lot of other cities and certainly ahead of what existed around the world at that time. There were some very profound examples of prejudice and discrimination. 

I talked to patients who had been abandoned essentially by their parents because of their having this disease. There were people who were quite fearful, and we would see in the regular medical clinic, somebody would come in and say "I've had several colds in the last month, and I sat next to somebody on the bus who I think had AIDS" and I'm wondering if I have it. And this was kind of a fairly common thing for somebody to bring up. And there's a very good book. I'll have a slide with a title on the end by Laurie Garrett called "The Coming Plague" that describes in great, well written detail the initial actions or non-actions of the government and the governmental agencies in coming to realize that this was a serious problem. And the mistakes that were made I think have been repeated in almost every country in the world in initially denying that it was a serious problem and then realizing when it was later than it should have been that they had to do something about it. Obviously somebody who found out they had this disease -- these were for the most part young men, obviously changed the way that they could look at their life and there was and I think continues to be a pretty irresponsible depiction in the media of casual sex which even at this time seemed pretty clear to be part of what was one of the mechanisms by which this disease could be communicated. And there were a number of reports in the newspapers about somebody would do something like take some cells in a tissue culture and they'd shine ultraviolet light on it after infecting the cells with the virus and they'd say that it killed the virus. And some reporter would write this up as if it was a promising cure when it's a totally unpractical thing to do to a person. And there were just a lot of things like this. 

On the other hand, there were some very positive things that happened and the gay community in San Francisco was extraordinary in the way they responded to this, and I say every time I talk about this that if this disease had come to us entirely among IV drug users, we would be at least 10 years behind where we are in understanding what's going on. Members of the gay community volunteered at the hospital, volunteered for clinical trials, produced publications that were very sophisticated publications about not only the disease phenomenon but the prevention messages about the risks of unsafe sex. And there were a number of support and service organizations developed in San Francisco. And this was going on in other places. I think we had you know in places like New York City for example, they probably had just as many cases but a much greater percentage of them were in intravenous drug users. And the cases were spread out among a lot more hospitals and so I think we had an advantage at this time, in terms of the thing that we could see and the things that we could do. And IV drug users really are not a very good group to enroll in a clinical trial where you have to come in on a regular basis and lead an organized lifestyle. So in the laboratory, it was noted pretty early that people who had AIDS had a very low level of a kind of blood cell called a CD4+ T lymphocyte, also called a T helper cell and sometimes when one is speaking in a context it's just called T cells, but this is not the only kind of T cell. This is the kind that was low and that they were somewhat low in these patients who had this kind of pre-AIDS type condition. But not as low as they were in people with AIDS. 

And the CD4+ T lymphocytes are a component of what we call the cellular immune system. This is a picture of a lymphocyte and they are critical to being able to stave off infections. So, since it was observed that CD4+ T lymphocytes were diminished, scientists reasoned that what they could do is look for the virus in cultures that they could grow in the lab of lymphocytes, and they would inoculate them with the patients' blood and they'd look for an organism. And there's a kind of virus called a retrovirus that had been discovered and that infected lymphocytes. And there were a couple of the viruses that did this where termed HTLV or Human Tumor Lymphocytic Viruses and one of the researchers at least suspected that this was that kind of virus or at least that it was a ret -- and several of the researchers suspected that is was a retrovirus because these had been -- because retroviruses had been observed to affect lymphocytes. So what do we mean by a retrovirus? It's not this. What's sometimes called the central dogma of molecular biology is that you have DNA in your cells and enzymes copy the DNA in a process called transcription. They make RNA in the form of what's called messenger RNA and then messenger RNA carries the genetic information out into the cytoplasm of the cell where the nucleic acid code is translated into the code for the proteins, and that process is called translation. A retrovirus has another step. 

It actually instead of DNA as its genetic chromosome, it has an RNA chromosome and when it infects a cell, there is an enzyme called reverse transcriptase that converts the RNA chromosome into DNA and then the viral DNA uses the cellular enzymes and some of its own to produce viral proteins. So the reverse transcriptase is an enzyme that is characteristic of a retrovirus and so one of the ways that scientists looked for an infectious organism was to try to assay the cultures that they were growing for the presence of activity of this enzyme called reverse transcriptase. And just for some local color I guess, a professor at the University of Wisconsin, Howard Temin was actually you could say one of the co-discoverers of reverse transcriptase and received the Nobel Prize for the work he did with it, and he was very interested in HIV, but unfortunately died at a relatively young age and wasn't able to continue the work. So, a big breakthrough. There were three different labs that isolated this retrovirus, and they all claimed to be the first one, and they all gave it a different name. This really wasn't what they looked like. And Luke Montagne called the enzyme Lymphadenopathy Virus or LAV. Jay Levy's lab in San Francisco called it AIDS retrovirus or ARV and Robert Gallo's lab called it HTLV3 because he thought it was in the same family as the HTLV viruses. And eventually, everybody realized that it was a different virus and they agreed on a name "Human Immunodeficiency Virus" and I always say that whoever got them to agree on the name probably should be sent to the Middle East to negotiate between the Israelis and the Palestinians. And this kind of illustrates how they did it. 

These are pictures from each of the publications and you can see these dark black dots are the virus. And these are electron micrographs. So in addition to looking for reverse transcriptase activity, they could see evidence of the virus particles with electron microscopy. So we talked about the terminology and so HIV disease is now a name for the consequences of infection by HIV and HIV stands for Human Immunodeficiency Virus. And I'll sort of say in a minute why you could argue that we shouldn't even use the term AIDS anymore, but it's pretty engrained and we probably will continue to use it. So this is kind of a busy slide, but let me go through some of the points. So it's great to know kind of intellectually that you now have an agent that you know causes this condition. Actually not everybody agreed that just because it was there that it was the cause, but most people who were involved did. But what are some of the other things that having isolated a virus allows you to do. For one thing, you could test any person to see whether they were infected because if they were infected, their body would make antibodies to the virus and you could use an assay to look for antibodies to HIV and to this day that's the test. 

When somebody say's they're going for an AIDS test, that's generally what's done. And there are a number of varieties of that, but they're generally based on the same concept that they're looking for evidence of antibodies. You could also examine people who were in this earlier group that I call pre-AIDS and you could see whether they were infected and then you could follow them over time and you could see whether they in fact would progress to develop the conditions that we had called AIDS. And you could note how long it took and you could thus characterize kind of the full clinical course of the disease and you could get even more information about how the virus is transmitted and you could in fact trace if somebody was came in and they were infected and they were willing to disclose their contacts you could trace those contacts and test them and figure out a source person and you could do tests to see whether there were barrier methods that could prevent the passage of the virus so for example, condoms. And one of the hopes was that you know in instances like polio and influenza and things like that isolating a virus led to a vaccine and so everybody was very optimistic that within a short period of time, a vaccine would be available. Unfortunately, that has not been realized and is still very very problematic. But a very very important thing that you could do that probably affected a lot of people was that you could screen the blood supply. You could screen the blood that and blood products that hemophiliacs were getting and you could screen the blood that was being used for transfusions. And this tremendously diminished the rate of transmission of the virus through the blood supply. And you could also inform people who you knew were infected that they might transmit the virus and that they should take precautions and organize their life so that they didn't do it. 

And then in the basic science lab you could ask what's the life cycle of the virus, what's the chemical structure, what are the places in the virus that might be interrupted by drugs that we have already or that we could develop. And this is just basic stuff. I think everybody should know this about HIV that it's transmitted by inoculation into the blood stream which can happen if IV drug users share needles or a health worker gets a needle stick or a janitor gets a needle stick from a discarded needle in a bathroom or some place like that. Somebody who gets contaminated blood products and occasionally exposure of broken skin or an open wound to fluids from an infected person that have a high concentration of the virus. And inoculation of mucous membranes during sexual contact with a partner who's infected, occupational exposures from contaminated body fluids and then the unfortunately it became clear that the virus was transmitted from pregnant women who were infected to their offspring and that the transmission could occur either in utero, during the time that delivery was occurring, or after delivery through the milk of the mother who's nursing. And in 1986, so we're now -- so 1980 was the first cases and 1984 was really when the virus was isolated. 1986 people recognized a syndrome that is the early HIV infection syndrome and they did this because people were following individuals who weren't yet infected but were undergoing very high risk behavior and wouldn't stop and so it seemed likely that at some point they were going to get infected and then when they did it was observed that they would develop this syndrome. Not everybody develops it profoundly. Some people don't even realize they have it, just dismiss it as a kind of a cold or a virus because it's mild, and in its most obvious form it has been described as a mononucleosis like syndrome which means that they typically have swollen lymph nodes and a rash. And I always say to people who are practicing medicine that if they're ordering a test for mononucleosis they should be ordering a test for HIV. 

And it turns out that this is a very important point in the HIV disease process and probably an awful lot of what happens that determines the eventual course of the disease occurs within even the first few days but certainly the first few weeks after somebody is infected. So this was described and then I mentioned that one of the things that people were doing was to follow the people who had these pre-AIDS conditions and watch them over time and see whether they progressed to AIDS and how many of them did and what became clear, and this is why I said the term AIDS could be abandoned is that AIDS is really the late stage of HIV infection. It's not a separate disease, it's a stage in HIV disease, really the end stage. AIDS patients die within two years, I mentioned that, and virtually everybody with very few exceptions which are certainly interesting and important studies for researchers trying to figure out how to control the disease, but with very few exceptions, infected people will progress to AIDS. They do it at different rates. Some very rapidly, some more slowly, and the mean or the median I guess is 10 years from the time of infection, so if you take all the people who have been infected and you follow them then half of them will take less than 10 years and half of them will take more and that means the median is 10 years. And the CD4+ T lymphocyte count goes down as the disease progresses. So this was what the disease spectrum looked like to us in 1986. The black line is HIV antibodies, and I mentioned that we use these to test for the disease, but you can see that once they appear which happens early in the disease, they pretty much stay the same throughout the disease, so they aren't very useful in figuring out how far along somebody is once you've used them to assess that somebody is infected. And this vertical gray rectangle represents the initial stage of infection. 

I don't know if you can see this clearly, but this is -- this axis is about six months and then this axis to here is about 10 years and then this axis is just two years. So these aren't really to scale, but what happens in early infection is that the CD4+ T cell count goes way down. Sometimes people can get very sick from this, they can get an encephalitis and really be profoundly ill, but most of the time, eventually what seems to happen is the immune system takes over and the virus is at least cleared from the blood. And the lymphocyte count rises and then over time the lymphocyte count can be used as a way to follow how much -- how far the disease has progressed. And by the time people get to AIDS, it's usually a normal lymphocyte count would be somewhere above 500 cells per cubic millimeter by the time they have AIDS it's usually below 200 typically and sometimes it's as low as 2 or sometimes even undetectable in a milliliter of blood. And one of the things to notice here is that when you try to look in the blood for virus, these red dots are the quantitation of the virus doing cultures, in other words taking samples of blood and growing them on plates and then counting the colonies that occur on the plates and it turns out that this is not a very good way to look at this, but the fact that you -- it didn't appear that there was really much virus in the blood led some people to say how do we really know that this virus is causing the disease. And you may all know that for much of the epidemic there have been sort of a small number of people, a few of them scientists who have asserted that they didn't believe that HIV was really the cause of this disease. And one of the perhaps worst consequences of this was that the premier, Mbeki of South Africa kind of bought into this and because of it was very slow to accept that his country had a serious problem and needed to have drugs. But so to the extent that these people had evidence, this would have been what they would hang their hat on. They would say well this causes the viral illnesses that we know about. 

There's a lot of virus in the blood so why should we think that this virus is causing the disease. And we'll talk more about that later. So part of what was known was that culturing the virus was not really a very reproducible and accurate way for quantifying it. And I guess I've already mentioned the problem of virus in the blood and let me just -- so one of the speculations was that here is this long period of time where people aren't really that sick and then the more virus appears when they get AIDS, so some people said gee maybe the virus really isn't very active at these early stages of disease and if we could only kind of keep it there then maybe that would be an approach. And as you'll see that hypothesis was wrong. So we're around 1987 now and there was a very important discovery or I guess creation of a method for analyzing DNA and RNA that was conceived in 1983 by a guy named Karry Mullis and within 10 years he had received the Nobel Prize for this. And the specific name for the process is the preliminaries chain reaction. I don't want to try and go through it in detail but to say that -- when you watch Crime Scene Investigation and they talk about looking for DNA, they're using a method like this to do it. And what this method does and what other methods that have since been based on it do is if you have a single molecule of DNA you take advantage of the property that is has a code that can be copied by enzymes. So you have a process whereby you do repeated cycles of making more and more copies of it until you have so many copies of the molecule that you can now analyze it with instruments whereas you couldn't see a single molecule with an instrument. 

And the general name for this is nucleic acid amplification. And this was being developed in parallel with the emergence of this epidemic and it became important in terms of our having methods to reliably quantify the virus. In 1987 the first drug for AZT -- I meant for AIDS became available. And it had several names over its career. Azidothymidine, Zidovudin, AZT, ZDV, Retrovir. And initially everybody was very excited about this. This was a -- and the drug acts by inhibiting the enzyme reverse transcriptase. So if you have a virus or a pathogen, you say what I'd like to do is find drugs that act on the enzymes that are not enzymes that humans have because that way it's not very likely to do something bad to the people who take it. And AZT seemed to fit that bill. And initially there was a lot of hope if you gave this drug to people who had AIDS, they lived a little bit longer. 

But then what happened was if you gave it to people at an earlier stage of the disease, they really didn't live any longer. And we now know that that's because if you use only a single drug, resistance develops very quickly and it may not have developed quickly enough to keep it from prolonging the life of somebody who didn't have much life left like the people with AIDS, but it certainly wasn't doing any good to somebody who maybe still had several years of life left. So this was very disappointing and as I'll talk about in a minute, AZT did have one major triumph, and I'll mention that. But I want to pause to talk about what was involved and what is involved in getting a drug to the point where people use it. I'm second to none in my belief -- in the belief that drug companies are a pernicious influence on our healthcare system, but they do some things that are important, it's just that I think they could do the important things without doing the pernicious things. And this is what they go through when they have to bring a drug to market. First of all they have compounds that they suspect, and in the case of AZT it was just something that was on the shelf because it had been tried many years before as a cancer drug. And so they just take these compounds off the shelf and they try them in a culture, and they see if they get inhibition of the reverse transcriptase and then they test it in animals. And then if it seems like it's not killing all the animals they test it in a small number of healthy adults and they test it partly to see -- do what's called pharmacokinetics, how much of the drug is absorbed and gets into the blood stream, how long does it last, what side effects if any are there. And then if the drug is tested in a small number of patients maybe of the order of 50 or 100 in a clinical trial where you would test it against a placebo or against non-drug and then if that works then you can test it with a larger number of patients. 

And when you do a clinical trial like this you have to design the trial with endpoints. You have to say how am I going to know whether this drug is really working better or not. So you have to say for example the endpoints that were available at this time were somebody with this pre-AIDS conditions develops AIDS so you could say that would be an endpoint, or you could say somebody with -- infected with this virus whether it's AIDS or earlier dies. So that's certainly an endpoint in more ways than one. But there really weren't kind of chemical tests that could be used as endpoints, and it means that you had to do trials for a long period of time like months and months, maybe even a year or more before you really understood whether there was a difference between the drug you were trying and the placebo. So that's what the situation was and then kind of from 1988 until 1993, at least from my point of view as a clinician, there were several kind of similar drugs that inhibited reverse transcriptase that became available. There was a lot of advances in treating the opportunistic conditions and in some cases giving people medicines in advance to prevent them. But there really wasn't what anyone would call a breakthrough except around this time somebody did a study that I think is on the next slide. I'll mention also that there were improvements in the assays to quantitate the virus using nucleic acid amplification. I guess I didn't have that yet. 

So here are some things that everybody knew. HIV does its damage by not only destroying the immune system but it also evades it in a number of ways that I really don't have -- they're very interesting in terms of molecular biology, but I don't have time to talk about them all and it just indicates how many different ways and that's not even a complete list. It was known that when a single virus particle infects somebody within some period of time, there are a variety of virus particles that are closely related but not identical meaning that there are mutations that occur and so what develops in an infected person is what has been called a quasi species. They don't really have one pure virus with completely identical RNA sequences. They have a whole population of viruses. But what wasn't known at this time was how fast this occurs and in many ways it wasn't really clear what the implications of it were but there was certainly suspicion that this was part of what led to resistance. And this is a picture of the virus. These are -- each virus particle contains two RNA chromosomes. The reverse transcriptase is actually in the virus and there are several other viral enzymes that I probably am not going to talk about very much that are also encapsulated in the particle and the virus coat is actually made by the virus budding off from the cell it infects and it actually makes the coat from the membrane of the cell itself. But it puts its own proteins in it. 

This is an electron micrograph and you can see that there is kind of a similarity between the electron micrograph and this cartoon of the virus. And that's the genome of the virus in a diagrammatic form. And this is a depiction of the life cycle of the virus and so the virus is a virus particle. It attaches to cell surface receptors. It then is taken into the cell. Its coat is removed and the process -- it's in removing the coat the RNA chromosomes are released into the cell and then they are reverse transcribed by the reverse transcriptase into DNA and then the DNA is actually incorporated into the DNA of the cell. And then it uses the cell machinery to produce RNA which then produces proteins for the virus and then these assemble at the cell wall and they bud off using part of the cell wall and produce a new virus particle. And we now just -- well I won't do that for now. So I said AZT had one major triumph and it was in prevention of transmission of virus from mother to child. This was a study that was published in 1994 and the observation was that if you gave AZT to the mother at the time she was delivering and you gave it to the infant after delivery, that you could reduce anywhere from 25-40% of the time infants being infected down to 1% or less -- in this trial it was 8% but since then centers that do this can have the incidence be as low as 1% or less. 

And part of it depends on the mother obviously making herself available and taking the drugs without complications. So some new ideas or new questions: where is all the virus? We didn't have ways to measure it well quantitatively and most of it is not in the blood. It turns out that when people started examining lymph nodes from patients who were infected that huge quantities of virus were present in the lymph nodes and were actively replicating in the lymph nodes. And that eliminating virus from the blood was really not eliminating the virus from the body at all. And that was a new concept. And it also became clear that the virus can infect a number of different sites in the body and this is just a cartoon that indicates a number of the different sites. Probably the site with the greatest population of virus particles is the lymph system that includes the thymus, the spleen, lymph nodes and what I think was not widely appreciated at the time but certainly has turned out to be important is that a huge amount of the lymph tissue in the body is actually in the gut. If you think about it we take in stuff that's foreign material all the time and we don't get sick or have reactions from it and that's because we have a good lymph system in the gut. So people -- and another observation in examining the lymph nodes of people who were infected earlier in the disease was that there was a lot of damage to the structure of the lymph nodes. 

So this top picture shows what you could I think appreciate as quite a regular structure. It's called a lymph follicle and there are three of them evident on this slide. And this is from a normal lymph node. And this is from somebody who is infected with a virus, and you can see that this normal architecture is pretty much ablated and this -- without going into details, the follicular structure is really quite crucial in our bodies' dealing with infection and presenting foreign materials to cells that can destroy them in promoting the development of antibodies. And then observation that this occurred early in the disease began to make clear to people that this idea that if we could only keep the virus being real quiet was not a very good idea because it wasn't clear that the virus was being quiet in the early stages of the disease. So in 1993 this was kind of the way the disease looked. And well this was the way the virus looked during the course of the disease, so I've talked about the limits of plasma culture and here's a comparison of the quantitation that you get when you do it by culturing and the quantitation and the dotted line that you get when you do it using the nucleic acid amplification techniques and you can see that there is really much more virus in the body than previously -- than previously thought. So that was an important advance. And this was the slide that -- so now we have this picture using these nucleic acid amplification techniques. The red line indicates the number of copies of viral chromosome and therefore the number of virus particles in the blood goes way up during acute infection just like the CD4+ T cell count goes way down and then it kind of levels off and stays not too variant during this clinically quiescent period but certainly is significant in quantity. 

This is actually a log scale and I can't read it myself from here, but I can read it on the screen, so we're talking about 10,000 copies per milliliter of virus. And then late in disease the virus in the blood goes way up. So this is a pretty good -- one way I think of this disease is in three stages I guess you could say. The acute infection during which much of the stuff that determines the eventual course of the disease happens and unfortunately it's very unusual to identify somebody in this stage of the disease. And then there's the middle stage of the disease which is where most people are when we identify them and they get tested. And then there's the late stage of which we -- which was all we recognized in the initial part of the epidemic and we called it AIDS because we didn't know about any of the other stuff and so that's why I say that you could argue that you don't really even need the term AIDS anymore it's just a name for the late stage of HIV. So then an experiment was done that changed the way -- really changed the way people thought about this disease. And I'll just take, indulge you in a few slides here to try to talk about it. So imagine that you have somebody standing on the ground. There's a couple buried water tanks and the level of the water that you can see is relatively constant but you don't know whether it's being fed at a very rapid rate and leaves at a very rapid rate or whether it's being fed at a very slow rate and leaves at a very slow rate. 

What you could say if the level is constant is that the rate at which it is leaving is the same at which it's being produced. Otherwise the level wouldn't stay the same. So this is what's called a steady state. So since those rates are the same, if you could interrupt the rate at which something was flowing into this tank and measure the rate at which the level went down, then you would know the rate at which the stuff was coming into the tank. So this was the experiment that was done except that instead of water in the tank, it was HIV chromosomes in the blood. It was impossible to do this experiment until this time because there wasn't really a drug that would dramatically cut off HIV replication, so when those drugs became available, this experiment was done and you could -- you observed that -- I'm having trouble with this -- this is the time, this axis is time. And this vertical axis is the quantity of virus in the blood and you can -- the drug is given to the patient at this time and then you take blood samples and you can plot the results out on a curve and they diminish like this. And if you use some algebra that isn't really too complicated and you assume that this is a first order rate, you can calculate rates and calculate rates of viral production and what was discovered was that about 10 billion virus particles are produced every day in an individual and this was a big surprise. And these are the two publications that were published in the same journal that reported this experiment. And what they did among other things was to test people at all stages of disease and got pretty much the same result for people at every stage and so these results made it clear first of all that virus was reproducing much more rapidly than people had imagined and it's now been seen for a number of other viruses. 

So it isn't anymore considered unusual, but it was dramatic at the time. But in addition that this was happening in the early stages of disease as well as the late states of disease and so what was happening was tremendous production of virus particles. In the early stages of the disease, the body produced tremendous numbers of CD4+ T lymphocytes to compensate for it and eventually it just couldn't do it anymore. But what are some consequences of this rapid replication. You can imagine in the context of what I told you earlier that in everybody who is infected there is a diverse set of strains of the virus. So a quasi species, so what you have in any infected person is a little Darwinian environment in which mutations are occurring, a diverse population arises as a result and so the virus evolves. And the virus population evolves would really be a more accurate way to say it. And so you get -- and there's an argument about whether and to what extent this is because the reverse transcriptase doesn't copy faithfully, but the point is that if you assume a mutation rate, you can calculate that within even a matter of hours it's very probable that one mutation would occur in any virus particle. And so many of these will be mutations that are incompatible with the life of the virus. But some of them won't, so you of all viruses which are resistant to immune recognition, resistant potentially to a vaccine which has to -- which is usually constructed to recognize certain viral structures. 

And if there is a diversity of those structures, the vaccine may work for one strain but not for some of the other variants. You of all viruses that are more fit to replicate, ones that are more pathogenic in terms of promoting the disease process and perhaps viruses that are more easily transmitted and viruses that may infect different cells. So all of these things are possible and have been observed and with this knowledge, as difficult as this problem is, it kind of put things on the verge of what you could call the HAART Era, and HAART is an abbreviation for Highly Active Anti-Retroviral Therapy. It's really a name for the combination of drugs that are used to treat somebody with this disease. Some people don't like the term, but it's easier than saying "highly active anti-retroviral therapy" every time you want to talk about it. So there were four things that really put us into the era of being able to use HAART and one of them was the knowledge that the virus replicates very rapidly, so that tells us why AZT didn't work very long because almost certainly mutations develop and if you assume as a very crude kind of example that one mutation makes it resistant to HIV and that has a certain probability then if you use two drugs then it took two mutations and that makes it an even lower probability and if you have three drugs then it would take three different mutations to confer resistance and so that makes it an even lower probability. But the point is, we realized that we had to use these drugs in combination or the virus would very rapidly become resistant. And obviously what we needed to do this was the drugs. And the pharmaceutical companies by this time, by 1996 had developed some new drugs that acted not just to inhibit reverse transcriptase but to inhibit at least one other enzyme and subsequently several other active sites but we had enzymes that inhibit -- drugs that inhibit an enzyme called the protease which acts late in the replication cycle of the virus. And then every bit as important was that the ability to quantitate HIV RNA was critical, not just understanding the path of physiology of the disease but if you're a clinician and you give somebody these drugs and you want to figure out if they're working, you can't wait until they reach an endpoint like death or even just developing AIDS. 

That's really not very useful, but if you have an assay like this you can say okay, when I gave them this drug they had this level of virus in their blood. I'll test them after they've been taking these drugs for three weeks or six weeks or whatever, and I would expect that the virus in the blood will be almost undetectable if not undetectable. So within a matter of weeks you could figure out whether what you were treating somebody with was actually working. And just as important is that when you were trying to evaluate new drugs you didn't have to do a trial for a year or more to see what an endpoint was and how many people reach the endpoint. You could do even at six weeks and six months and sometimes it can be misleading to see that something works early and then it may not continue to work later on, but for the most part this made doing clinical trials and bringing new drugs to market much much easier. And in addition to that it was our knowledge of how to use these drugs in combination to overcome the mutation rate of the virus. And this is using a similar type graph. This is ideally what would happen if you give somebody a drug at some point. The viral load which is a name for the RNA assay of the virus chromosomes goes down, becomes undetectable and what I think was probably surprising in a wonderful way to everybody was it wasn't just that these drugs interrupted the progression of the disease, but people actually got better. And they got better in quite dramatic ways. 

They got better by the kind of laboratory measurements of the components of their immune system, but they also got better because not only did they not get opportunistic infections, but in many cases, the opportunistic conditions that they had actually went away. So this is an example of -- this was taken from a article in a New England journal, but I've had this happen with patients I've treated. This is a patient who had AIDS and wasting and then this on the right is the patient -- I guess it's a year later after being on anti-retroviral therapy. So this is pretty dramatic and you don't have to imagine very hard to imagine how it changed not just the approach to life for people who were infected but also the feeling as a clinician instead of just treating people who you knew eventually were going to die, and they knew that they were going to die that now you really had something that could actually make them better. And so we have now drugs that act at this point where the virus attaches, the reverse transcriptase we have several kinds of drugs that act -- the protease inhibitor actually acts after the virus has budded off, there's a protease that cleaves some of the pre-protein structures in the particle and we have drugs that inhibit at that stage, so there's quite an extensive armamentarium at this point. This is a list; I think this is fairly up to date of the existing drugs and I don't want to spend time talking about them. I did -- one of the recent ones that I missed was there's now just in the last year a drug that blocks this step which is the integration of the viral DNA into the chromosome. So, we're now in an era where we have recognized a lot of limitations of HAART. We're continuing to try to develop new drugs in hopes that there will be an even better paradigm because as I'll say in a minute, HAART has some serious problems. And there is an impressive amount of basic research that's going on characterizing any number of aspects of this disease and the virus and there are attempts to address all of the sociologic issues which I really haven't talked about and then again what I haven't talked about is really this is not a disease that's under control in my opinion in the United States, but it's just running rampant in many other countries in the world. 

So what are the limitations of HAART. Well if I've done a good job of explaining to you why we have to use combinations, you can understand that if you miss doses of this drug and the virus is replicating very rapidly then when the drug is missing from your blood or it falls to a lower level the rapid replication rate of the virus allows it to develop mutations that are resistant to the drug that you missed the dose of. And this could in theory happen even missing a single dose. And there's a lot of studies that have been done on people and it's very clear that people who have very poor adherence -- the people that don't take the drugs at all don't develop resistance because they don't select for a resistant virus. The people who take the drugs very faithfully meaning at least greater than 90% of the time have a much lower rate of developing resistance. And it's the people who are kind of in between, they take them sometimes and they miss them sometime and they take them sometime. And when that happens the drugs, eventually the regimen they're on stops working and you have to try another regimen. And eventually you run out of regimens. And of course these drugs are not a cure. And I don't have a lot of time to go into why that is, but I'll say briefly that a certain small percentage of the viruses that infect a person and integrate their DNA into the cell, that DNA stays there in some of the cells and doesn't do anything at all, it just -- we call it, we say it stays latent. 

And when that cell is activated for whatever reason, a virus can emerge. So you can have somebody in whom they have no detectable virus by the assays that we use in the blood, but if you stop the drugs, eventually the virus will reemerge from the latent population of cells even though they're a small number. And so curing this disease will be very difficult and there are things that have been tried but so far they haven't really worked. These drugs cost a lot of money. Many patients don't have access to them, not only in Africa but in the United States, or don't have access to the best possible combinations. And there's a lot of discussion about when is the best time to start treatment. But the biggest problem in my mind is these drugs have a lot of side effects. And not everybody experiences the side effects, but usually the people who are on a regimen like this can tell that they're on it. And they would feel better if they weren't on it, but it may not be enough to really make a big difference. But for some people it's really profound. 

And in addition, some of the side effects are really much more I guess nasty. The drugs can cause anemia, they can cause neuropathy which means that you get numbing of the nerves in the hand and feet. They can cause accumulation of cholesterol and lipids and probably can speed the development of cardiovascular disease. And so there is a lot of unresolved issues in these drugs although they are a wonderful advance over what we had before, and many people are alive who would have been dead 10 or 15 years ago. They are not a place to stop. These drugs became widely available in 1996, so that's 12 years ago. And we don't know yet whether people on these drugs will be able to live a normal life span because it hasn't been long enough to tell. This is one example of side effects of the drug. The drugs can affect the disposition of lipids in the body and this is a condition that's called a dorsocervical fat pad where lipids are deposited in this area. And then a common condition is a loss of subcutaneous fat from the face making somebody look very gaunt. 

And so if you're a young person who's concerned about your physical appearance, this is quite disturbing. And there are a number of other examples of this, so this can be quite profound. So why is this continuing to be a problem. Governments have not done everything they could. Infected persons may not feel sick for many years, so they don't get tested. And it's estimated in the United States that a quarter of the people who are infected have never been tested and don't know they're infected. Sex and drugs are things that people want to do and other indulgences like drugs and alcohol lead to sex. IV drug use transmits it. Drug resistant strains are being transmitted and this is increasingly a problem that now people who have been on the drugs and then transmit the virus in their bodies to other individuals, the person who gets the virus from that person now has a resistant strain of virus, so even though they've never taken drugs before, some of the drugs won't work. There are a lot of cultural behaviors that I don't really have time to go into that make it difficult for people to take precautions or even to go to get tested. 

There's a lot of denial and then if -- when you work as a physician or maybe in some other places, maybe you don't have to even do that to realize that in every population and in every segment of the population there are always a few irresponsible individuals who no matter what you tell them and what they know, they'll continue to behave irresponsibly. And so a cure and a vaccine are really not in sight. The latest vaccine trial that was called the step-trial was terminated because actually the people taking the vaccine actually did worse. There have been a number of articles in scientific journals about, as well as in the popular press about how the vaccine approach needs to go back to kind of square one and start over again with some new approaches because the things that have been tried up to now really just haven't worked. Now, if you indulge me for a couple more minutes, I think this is kind of interesting. There is a woman named Beatrice Hahn who did a lot of studies comparing viral strains and made some -- was able to get some evidence about where this virus came from. And she's not the only one who did the studies, but she was kind of the principle. So, if you -- there is a virus that affects monkeys call the Simian Immunodeficiency Virus and it's very similar to HIV and it has been known for a long time. And if you collect strains of Simian Immunodeficiency Virus, I'll call it SIV so I don't stumble over it. If you collect strains of SIV from a lot of different monkeys, you can look at the nucleic acid chromosome and compare how closely related they are and how many mutations occurred between this strain and the next strain and you can construct trees and you can make some conclusions about if you make some assumptions about how certain portions of the genome have a mutation rate that occurs over a certain period of time you can actually put the relationship in these trees within a time frame. 

And SIV is a virus that has been researched very carefully in monkeys and has actually contributed a lot to our understanding of the disease. But what Beatrice Hahn and her co-workers did is they went to areas of Africa and they collected feces from places where the monkeys hung out. They didn't have to catch the monkeys and take blood from them, they just collected the feces and then they could take the feces and use these techniques that I described like nucleic acid amplification and obtain enough of the material from the nucleic acid of the viruses to really figure out where they belonged in these trees. And these viruses are very closely related to HIV and they could actually show a progression to a virus that appeared to be HIV and they could make an estimate that HIV originated in the southeast corner of Cameroon in an area called the Thai Forest and that somewhere, probably around 1920, but you can't pin it down that precisely, a virus that we now know as HIV mutated from an SIV and infected a human. And exactly, obviously we don't know how it did that, but you can see by the relationship of the strains that that's what occurred, and you can construct a timeline. In her initial studies she said it was around 1930 you would guess, but some other studies suggest maybe it was a little earlier than that. And then the nearest big city to Cameroon is Kinshasa which is in the Democratic Republic of the Congo, and that is kind of right down here. And in around 1994, this infection was probably transmitted, brought to Kinshasa where it probably infected a number of people. 
- You said 1994, did you mean 1954? 
- 1954, I'm sorry. 

Thank you. 1954 it moved to Kinshasa. I'm glad you were paying attention. And there were Haitian workers who were doing I guess sort of social work and volunteer work and some kind of work in Kinshasa and then they went back to Haiti. And you can follow the strains and you can supplement this with other blood tests from Haitian patients who were identified in the early part of the epidemic and probably around 1966 the virus was brought to Haiti. So, Haiti had an HIV epidemic more than 10 years before it appeared in the United States which is really why a whole lot of Haitians seemed to be infected when we first identified the virus. And then the virus was carried to the United States and then by the sequences that can be determined it was just a single strain of virus and that became -- that strain gave rise to the viruses that were spread to most of Europe and North America. So I think it's pretty remarkable what you can do with this kind of technique and I would -- you know certain Haitian functionaries have taken offense at this, but I don't see that it reflects on Haitians, and for all we know it was not a Haitian who brought it to the United States. It could have been an American who went to Haiti and anyway. Now it's all over the world and these are the 2006 statistics. 

And it's spreading really rapidly and there are countries where between the ages of 16 and 40 maybe 40% of the people will be infected. And I think that's all I want to say about it. This is a statement that I won't read it, but I gave a handout when I gave lectures at Washington University to the second year medical students, and this was the introduction I gave to their handout, so you can read it if you want to. Thank you for listening for so long. 
- I am wondering if you ever had an opportunity to meet UW-Madison Professor Howard Temin who we all know won the Nobel Peace Prize for his research here. 
- I don't -- If I met him it was briefly because I don't remember it. I was not in Madison during most of the epidemic, but you may remember I did have a slide that had a picture of him on it, and he certainly deserves to be acknowledged, and I think was a great loss to the scientific community. 
- There's some other books that have alternative theories about the origin of AIDS. There's the River and then there's The Band Played On. I'm wondering, do you think any of those theories have validity, or is this theory that you've presented more likely? 

- Well I think that there's much better objective evidence in this theory than in the others and I would tend to believe it in contrast to the other ones. These are two very interesting books, and there's a lot of books that have been written about it. But The Coming Plague: Newly Emerging Diseases in a World Out of Balance by Laurie Garrett is just very well written and it describes among other things it describes a lot about kind of plagues in general and our preparation for it. And really does a very detailed description of the first few years of the epidemic in the United States and which government agencies and which individuals thought what and it talks a little bit about the scientists who were involved in the discovery of the virus. And then this book called No Place to Bury the Dead by Nicole Itano. She went to South Africa and spent a lot of time with three different families and describes in each of the families in some cases stayed in their homes and at least stayed in their villages where she was in very close contact with them. And it's a very revealing book about what the conditions are and she describes it during the period that the epidemic was emerging in South Africa and gives you an idea of what the problems are in an undeveloped country in terms of controlling this disease and she does it also while at the same time describing the emergence of the epidemic, so I recommend these. And there certainly may be other books that I'm not familiar with. 
- Is there -- of what may cause this disease? 
(inaudible)

 
- You mean as opposed to monkeys? 
- Yeah. The variation has come to monkeys from people but we're killing off the cells that are there is one way of going. But the other is keeping the -- into it as much. Is there a way to -- is there any research done on what causes DNA, what causes -- to be more susceptible to human beings and to what parts of the human being -- does it run in blood? 
- The question I think is why are human beings susceptible to this virus when it was originally a monkey virus, is that what you're asking. 
- Part of it. And is there a way of treating the AIDS by getting at what allows it to develop in human beings. Are certain human beings more susceptible than others? 

- Okay, so I think what you're saying is there are some people, a very few, who get infected and they don't progress, and so studying those people we would hope to learn something about why can they control the disease and other people can't. And in fact, that's a very active area of study and there are some things that are known about it. In some cases it's -- I mean there are some very specific genetic I guess you could say sequences that can make people less likely to get infected and make them progress more slowly and what I think is not really still very clear is why these people who -- there are a few individuals, they are often called long term non-progressors who have undetectable viral loads despite being infected. And beyond saying that they seem to have the very exuberant production of a certain kind of lymphocyte that's not a CD4+ but a CD8+ lymphocyte and probably lymphocytes with a little bit different specificity. But how to translate that into a therapy is really pretty unclear. One of the hopes is you could look at what the specificities are that control the virus and then try to reproduce it by eliciting them with a vaccine. People have tried to do that but it hasn't really worked very well yet. There is something known about one difference between humans and monkeys in a protein that seems to keep monkeys from -- monkeys don't get infected very well with HIV now. They get infected with SIV but not with HIV and so clearly there has been a change. And there is at least one protein that has an analog in monkeys and in humans, and it's different in each of the species and it seems to play a role in controlling the infection. 

But again, how to translate that into a therapy is not very clear. Yes. 
- Do mothers who give -- who are HIV positive and at birth their babies aren't protected, are they advised not to nurse? 
- The problem is that in many of the underdeveloped countries they were initially advised not to nurse. And what happened in a lot of instances was that because nursing was a major source of nutrition, not nursing, and not having other sources of nutrition led to a worse outcome than if they had nursed. And so it has really depended on what the resources are in a particular place, what the options are. What I think people would advise these days is that the mother be on therapy and the infant be on therapy if they're going to nurse, but I mean that has a lot of problems associated with it including the cost of the drugs and the availability of the drugs. And even the drugs that get, for example, to Africa, not all of the drugs, they're not really even the best drugs necessarily. I mean they're pretty good, but they're not good. So the answer to your question is that it's a measurement of the risk of malnutrition from not nursing versus risk from getting infected if they nurse. 

- Monkeys who are infected with SIV. Do they follow the same course of progression with that virus as humans do with HIV? 
- Well there is some fascinating things about monkeys. If you -- Rhesus Macaque monkeys can be infected with SIV and they will get AIDS in the way that people do. Sooty Mangabee monkeys when you infect them with SIV they have very high levels of SIV in their blood and they don't get sick. And this is obviously a fascinating and intriguing area of research and exactly why it is there's some speculation. But I don't think the complete answer is in on it yet, so it depends on the species, but it's definitely a case that the right strain of SIV can produce AIDS and create a similar course in the species of monkeys that are susceptible to it. 
- Another question or two? 
- Tom. Are there restrictions or limitations to broad production of the HIV drugs by patent protections and such or is it... 

- Well I mean that's -- they definitely are under patent and there have been -- I don't know that I can tell you the precise -- the question was to what extent to patents restrict the availability of the drugs? And this is an ongoing battle and several countries have just said we're going to produce the drugs. And usually when they do that the drug companies make some sort of deal with them and rather than lose all their revenue they give them some kind of license. And I don't know what the terms of the license are. Probably that the drug companies get some revenue but not what they would do if they had sole control over it. So India and Brazil are the two that come to mind as countries that are producing HIV drugs. I'm not sure at all that they're the only ones. 
- What about the US? 
- I don't think there's been any real challenge to the patents in the US that has gone anywhere. 
- And do the drugs continue to be very expensive? 

- They continue to be very expensive, but they are -- most people have them because they either have insurance that covers them or there are government programs that provide money to give the drugs. So you could say in a way that it's a way that your taxes are paying the drug companies. But they are expensive if you have to buy them. I mean they're very expensive. I don't have off the top of my head, but it would be thousands and thousands of dollars for a years worth of drugs. 
- One last question in the back. 
- Early on there were some orphan drugs that were effective. Is there any new ones or are those drugs no longer being used? 
- Tell me what you have in mind. 
- Well it's a company called Lifomed. 

It was bought by Fuji -- that had an orphan drug that was used for AIDS. 
- So the question is are there orphan drugs that never really got into large scale production but were effective in treating this disease? I'm not aware of any that have really proven to be effective. There have been a lot of claims of people that they had drugs that would work, including alternative remedies and drugs from African countries. There continue to be claims like that as there have been for cancer and other diseases. I am not aware of one that really worked and was abandoned. But I'd be happy to learn about it. 
- If not, thank you very much. 
- Thank you.