Previous Question

 

The AIDS Physician and the Actuary  (Part I)

 

The Perth Group does not claim originality for the invention of heuristic discourses.  That belongs to Socrates and scientists such as Giordano Bruno and Galileo.

 

Doctor:  I am sorry to have to tell you but your antibody test has come back positive.

Patient:  Youíre telling me I have HIV?

Dr: Iím afraid so.

P: Couldnít the test be mistaken?

Dr:  Unfortunately not.  The tests we use are extremely sensitive and specific.  I have never known them to make a mistake.

P: Doctor can you please explain how this particular test can be so accurate?  And how it actually works?

Dr:  Certainly.  In simple terms the test has detected some antibodies to HIV in your blood.  The only way you can get those antibodies is to come into contact with HIV.

P: When you say the antibodies are Ďtoí HIV, what do you mean?

Dr: I mean they are directed against HIV.  When your body came into contact with HIV it registered the HIV proteins as something foreign.  As a result your immune system was switched on to produce a set of antibodies which specifically combine with these proteins.

P: How do you know these antibodies are actually there? In my body?

Dr : Because when we mix your blood with the proteins in the antibody test kits there's a reaction.

P: How do you know there's a reaction?

Dr:  Because when we add your serum to a solution containing the test kit proteins the solution changes colour. We can see that and we can even measure the amount of reaction by the amount of colour change.  We get out a number which makes it quite objective.

P: And when you say Ďreactioní do you mean a chemical reaction?

P: Yes.  There is a chemical reaction.  That's because the antibodies in your blood recognise the HIV proteins.  The shape of the antibodies and protein molecules are complementary.  They fit together perfectly.  Like a lock and key.  Thatís what specific means.

P: But this is not a test for the actual virus is it?  The virus particles?  You havenít found those in my body?

Dr:  No itís not the actual virus.  Itís an indirect test.  As I explained, itís a test that looks for antibodies that are manufactured in response to the presence of the virus proteins.  Thatís why we call them HIV antibodies.  But the virus is there all right.  Thereís no other reason why your body would produce such antibodies.

P: So if you looked you could also find the virus particles?

Dr: Maybe and maybe not.  Not necessarily in your blood.  That would be very hard to do because to see them you need millions and millions of particles.  In fact no one has ever managed to find HIV particles in a patientís blood.  But we could use your blood to culture the virus.  Outside your body.  Or we could do the same thing from a small piece of lymph node for example.  But these kind of tests are  technically demanding.  And expensive.  And quite unnecessary.

P: Where do you get the HIV proteins from?

Dr: From HIV.  They form the major part of the HIV particle.

P:  I presume these proteins donít occur anywhere else then?

Dr: No.  They belong to HIV.

P:  And nothing else you know of could induce my immune system to make these antibodies?

Dr:  The way the tests have been refined and interpreted, no.

P: So youíre sure my body has this virus in it?

Dr:  As sure as anyone can be.

 

A week later.

Patient:  Doctor Iíve done a literature search and Iíve looked up some articles in the University library.  Iíve made you some copies as well.

Dr:  I assume you have a few more questions then?  About what we discussed last time?  I know it's hard coming to grips with something like this.

P: To be perfectly honest Iím confused.  Iíd really like to know what you think.  For instance, last week you told me the HIV proteins, the ones used to test my blood for antibodies, donít occur anywhere else except in HIV.

Dr : Thatís right.

P:  Hereís a paper I found.  Itís called ďHIV proteins in normal human placentae.1  Itís written by a group of scientists who tested tissue from the placentas of several healthy, pregnant women using antibodies directed against four of the HIV proteins.  They found three HIV proteins in women who are not infected with HIV.  They were p18, p24 and p120. And hereís another article.  This oneís called ďMonoclonal antibodies to the human immunodeficiency virus p18 protein cross-react with normal human tissuesĒ.2  In this paper the HIV p18 protein was found in the thymus and tonsils and brains of people who are not infected with HIV.  Are you familiar with these papers?

Dr:  Iím sorry Iíve not seen these before.  And I would have to read them before passing comment.

P:  You might have to read quite a few.  Hereís another paper where blood from five patients who were HIV negative was cultured and again the p24 protein was found.  Iíve got another paper for p32.  And several other papers confirming what Iíve already said about the others.1-7 8  9-16  Iím no expert but it seems to me if the antibodies used in these experiments are the same antibodies that are in AIDS patients, or in me for instance, and they specifically recognise the HIV proteins, they should not register anything in HIV negative peopleís blood or tissues.  Doctor what is going on?

Dr:  Youíre jumping to the wrong conclusion.  The HIV proteins are not there.  It only looks that way.  As your second paper says in its title, the antibodies cross-react with some normal human proteins.  That occur in brain for example.

P: But arenít the antibodies they used in these experiments meant to be specific?  Donít they recognise HIV and nothing else but HIV?

Dr:  When I explained the test to you last week I did say I was giving you a simplified version.

P: All right but how come these antibodies react in normal people?  If there's not a simple answer is there a complicated answer?

Dr: What these papers are describing is not strange or mysterious.  And itís not a secret.  The problem is that antibodies arenít always exactly 100% specific.  Sometimes they can and will react with other things besides what theyíre meant for.  Thatís what cross-react means.

P: So youíre saying that HIV antibodies can react with things other than HIV?

Dr:  Yes.

P: So if an antibody reacts with something thatís not proof itís directed against that something?

Dr: It may not be.

P: Are HIV antibodies the only antibodies that can cross-react?

Dr:  No.  In theory itís possible for any antibody to cross-react.  Itís not a property confined to one type of antibody.

P:  Well if HIV antibodies can cross-react with proteins which are not HIV, like in the brain for example, then why canít non-HIV antibodies cross-react with the proteins you say do come from HIV?

Dr: In theory they can.

P: What about in practice?

Dr: Yes they can.  That is reported in the literature.

P:  So how do you know the antibodies in my blood, the ones that react in my test, are caused by HIV and not by something else?

 

A week later.

Dr:  I understand this must be causing you considerable distress.  So Iíve set aside some extra time to fully go over these tests.

P:  I appreciate that doctor.  We were talking about cross-reactions.

Dr:  I remember.  OK.  And let me know if I lose you in what I am about to say.  Sometimes antibodies to one protein do react with another, different protein.  That happens because the fit between the bit of the protein the antibody reacts with, and the antibody itself, although not 100% perfect, is still good enough for a reaction to take place.

P:  I understand.

Dr:  Now back in 1985, when the HIV tests were being designed, when HIV testing was in its infancy, it was discovered there are people who are not infected with HIV who have antibodies that react with one or even a couple of the HIV proteins.

P: But that wasnít an infection?

Dr: No, that was cross-reactions.

P: How many people does that affect doctor?

Dr  It varies depending on what papers you read.  But in one of the types of test we do, it's called the Western blot, can be as high as 25%.  Itís certainly at least 15%.  The 25% figure is from Australia.  From studies of healthy blood donors.

P: 25% of people can have a positive Western blot?

Dr:  No.  25% of people can have antibodies that react with one or perhaps two of the ten HIV proteins that are in the Western blot strips.

P:  But one or two is not enough to make you positive on the Western blot?

Dr: Correct.

P: How do you know one or two antibodies doesnít mean infection with HIV?  Thatís how it used to be.  Montagnier said an antibody to the p24 protein was enough.  Gallo said an antibody to p41 was sufficient.  How do you know one or two antibodies reacting in the Western blot arenít real HIV antibodies?

Dr:  Because these people donít belong to a risk group.  And theyíre healthy and they stay healthy.  They donít go on to develop AIDS.  And when they donate blood the recipients donít develop AIDS either.

P: And 25% of the population couldnít possibly be infected with HIV?

Dr: Exactly.  If they were I canít imagine how many hospitals we would need to treat them all.

P: And for HIV to get that common life would have to be one continuous orgy?

Dr:  A very good point.

P: But these antibodies must have come from somewhere?

Dr: Thatís true.  Something must be responsible.  And itís often hard to know exactly what.  Although it really isn't important to know that.  Perhaps theyíre caused by some other illness or some exposure to something in the environment.  But whatever it is, itís not HIV.

P: I understand.

Dr:  Now, I said before, we do have a way to sort out true HIV antibodies from all the others.

P:  Yes I remember your saying that.  The wheat from the chaff.

Dr:  Thatís a good analogy.   Let me tell you what happens.  When we first test you we do whatís called an ELISA test.  That is known as a screening test.  In the ELISA we test your blood against all the proteins from HIV.  All mixed up together.  Thatís about ten proteins by the way.  So we have all the proteins in one test-tube and then we add a few drops of your blood sample.  Minus the red blood cells of course.  Otherwise we wouldnít see any colour except red.  So we add the serum, where the antibodies are dissolved, not the whole blood.  If thereís a reaction the solution changes colour.  We can see that.  As I said before, we measure the amount of the reaction by measuring the passage of a light beam through the solution.

P: With the spectrophotometer?

Dr: Yes.  Youíve obviously been doing a lot of study.

P: I also did two years of chemistry as an undergraduate.

Dr: OK.  But thereís a problem with the ELISA.  Itís not that specific.  Or at least itís not specific enough.  We canít do just one ELISA test then look you in the eye and say youíre infected.  That would not be considered best practice.

P: So why do you use this test?

Dr: Because it is the most sensitive antibody test.  By that I mean itís guaranteed to pick up every HIV single antibody anyone could ever haveóbut at a price.  It also has a tendency to pick up non-HIV antibodies as well.  To use your analogy, it picks up all the wheat OK, every single grain, but along with that some of the chaff.  By that I mean antibodies which are not HIV.

P: I still donít understand why you use it.

Dr : We use it to screen people.  The way it works is this:  If the ELISA is negative it hasnít picked up any antibodies.  HIV or non-HIV.  So the person is not infected.  In that case thatís as far as we need to go.  So itís a very useful first up test.  Itís used a lot for donating blood.  Most people who want to donate blood are negative on the ELISA.  In fact most people period are ELISA negative.  End of story.

P: And what if a blood donor is positive?

Dr: Then we have to dig deeper.  But for the blood bank it means they know straight away they can or canít use that personís blood.  Itís quick and easy.

P: But what happens to the blood donor who is positive on the ELISA?

Dr: If the blood bank find a positive they hand over the case to an approved laboratory for running further tests.  Such as our laboratory.  In fact thatís the law in this country.  Not just any person or laboratory is allowed to do the further tests.  Then itís really no different from what happened in your case.  We dig deeper by doing another test.  A test which is different from the ELISA.  In most parts of the world the second type of test is the Western blot.  The difference is that in the Western blot the ten HIV proteins are not mixed up together.  They have been separated from each another along a paper strip about half a centimetre wide.  That way we can identify precisely which HIV proteins are reacting.  Or if you like, we can tell which antibodies you have to which HIV proteins.

P:  How do you read the Western blot?

Dr:  By eye.  Every place where an antibody reacts with one of the HIV proteins the strip changes colour.  So you end up with a series of coloured dots along the strip.  We call those bands.  The lab technician looks at the strip and reports the names of the bands that light up.  Each band is named with a Ďpí for protein and then a number which is its molecular weight in thousands.  I think youíve already found that out.

P: How does the number of bands determine whether someone is infected or not?

Dr: Well you might have one band or you might have ten bands.  If you only have a couple of bands then youíre almost certainly dealing with cross-reactions.  But if you have four or more your test is positive and you are infected.  Or of course you might have no bands which means you are definitely negative and not infected.

P: So the Western blot is used to work out whether the ELISA is right or wrong?

Dr : Yes.  We say the Western blot is a Ďconfirmatoryí test.

P:  And knowing which bands a person has distinguishes real antibodies from cross-reactions?

Dr:  Yes.  We know that HIV antibodies cause particular patterns of bands to show up.  Kind of like a Lotto ticket.  Certain combinations invariably mean a prize and others donít.

P:  What does my Western blot test show?  Which antibody bands do I have?

Dr: You have antibodies to p41, p24, p32 and p18.  Thatís four bands and itís also one of the several possible band patterns that makes a positive test.

P: I still donít understand how you can know that some band patterns are caused by HIV and others are not.

Dr:  OK.  Tell me what you donít understand.

P:  Last week I asked how you know blood donors who have one or two antibodies arenít infected with HIV.  You told me itís because they arenít sick or in a risk group. 

Dr:  And they donít go on to develop AIDS.

P:  OK.  But if I had only one band on the Western blot youíd say that was not an HIV antibody?

Dr : You can have up to three bands not caused by HIV antibodies.  Or at least the chances are very slim.  Of course it might also be that you havenít produced all your antibodies yet.  Itís early days.  You are on the way but your infection was only a few weeks ago.  In some people it can take a couple of months for all their antibodies to show up.  The bands donít appear simultaneously.  Itís called the window period.

P:  I could have as many as three antibodies and not be infected?

Dr:  Yes.  As many as that.  And as long as you donít get any more.

P:  So I could have three bands and not have HIV while the next patient you see today could have the same three plus one extra band.  And that extra one produces a pattern  you say is caused by Ďrealí HIV antibodies.

Dr: Thatís quite possible.

P: Then the three bands he shares with me must be real HIV for him but not for me.  So that extra band makes all the difference?

Dr: Precisely.

P:  I donít get it.  Why should just one extra band be Ďrealí when the others on their own arenít?  How can a number or combination determine which antibodies are real and which arenít?  I mean if you have three pieces of fruit that arenít apples and then you add a fourth that is an apple, does that make four apples?

Dr: I agree but we have evidence.  I said it before.  We know which band patterns are caused by HIV because weíve analysed which groupings of bands distinguish people with AIDS from those who remain healthy.  Itís really not that difficult.

 

A week later

P: Iíve been thinking about what you told me.  Iím sorry but I still have problems.

Dr : Well we better keep talking.  Fire away.

P: I have a cousin in the US who works for a biotechnology company.  He sells antibody test kits to several New York hospitals.  He faxed me a packet insert for the ELISA and Western blot.  One of each.  Which I read last week.

Dr : And what did they say?

P: They confirmed what you said.  With the ELISA you can distinguish most people with AIDS from healthy people.  If you use a combination as you said, an ELISA followed by a Western blot, the distinction is almost perfect.

Dr: Then doesnít that put the matter to rest?

P: Maybe.  Maybe not.

Dr Whatís the difficulty?

P:  The biotechnology companies want their tests to be highly specific.  In other words, they donít want their tests to react in someone whoís not infected with HIV.  And neither I guess do the doctors.  And certainly not the patients.  So, as you said, they try their tests out on healthy blood donors.  To see how good they are.  They assume, quite rightly I suppose, those sorts of people donít have much chance of getting AIDS or being infected with HIV.

Dr : Thatís right.  Theyíre extremely unlikely to be infected with HIV.  Thatís been proven time and time again by millions of tests at the blood banks.

P: Yes doctor but when the biotechnology companies test their tests on blood donors they go further.  They actually define the blood donors as not infected.  The World Health Organisation does the same thing.

Dr:  Thatís correct.

P:  Well thatís one of the problems.  When I read about healthy blood donors, not being in a risk group and all the rest, I asked myself, who are these people?  Where do they live?  What kind of people are they?  What are their habits?  Where do they hang out?  And you know who it reminded me of?

Dr: No.

P: It reminded me of me.  Iím healthy.  My friends regularly tell me how well I look.  I only got HIV tested because I need life insurance.  Iím not gay, Iím not a haemophiliac, Iím never been a drug taker.  Iíve not been promiscuous.  I havenít been an angel but since getting married my only sexual partner has been my wife.  And because we were about to start a family, a couple of months ago, unbeknown to me, my wife had an HIV test.  And sheís negative.

Dr:  What point are you making?

P: Doctor I could easily be in a group of people the manufacturers of antibody tests use to determine how accurate their tests are.  And when they tested me Iíd be positive all right but they would have already defined me as non-infected.  To me thatís a false-positive.  Donít you agree?

Dr : To be perfectly frank I think you are somewhat in denial over this.  Believe me I'm not having a go at you but thatís what people often do when the news is not good.  You realise there are other tests we could do to settle this matter?

P:  You mean the viral load test?

Dr  Yes.

P: But according to my packet inserts, when biotechnology companies and the WHO investigate their tests, they donít do that.  They donít go checking the antibody positive people with viral load tests.  So why do it to me?

Dr: To reassure you?

P: Thereís a man I talked to this morning in the waiting room.  He told me heís had a positive antibody test since 1987.  He didnít have his first viral load test until 1992. In fact I know there were no such things as viral load tests in 1987.   And this man didn't have a viral load test to prove his antibody test is correct.  It  was to do with his drug treatment.  If that man didnít need a viral load test to diagnose him in 1987, why do I in 2004?

Dr : Because most of the people who come to this clinic have clearcut reasons for being infected.  Their cases are straight forward.  Iím sure from all your reading you wouldnít be surprised to know most of our patients are either gay or drug users.

P:  But doctor three weeks ago you told me I was infected with HIV.  You didnít say I was a difficult case.  You didnít tell me I would need another test to sort out my antibodies.  And if Iíd come to you fifteen years ago with a positive test, before there were viral load tests, surely you wouldnít have told me I wasnít infected.  Thatís not what happened to the man in the waiting room.  And if it wasnít for me and the Internet we wouldnít even be having this conversation.  And I understand what you are saying about gay men and drug users.  But to me that just makes the problem worse.

Dr : Iím beginning to think you must be reading some very unusual material.

P:  All Iíve read is whatís at PubMed.  To find the paper on HIV in the normal placenta I just entered ďHIV p24 proteinĒ.  Up it came.  Along with about 3000 others.  So it took a bit of work.  I assume PubMed is where doctors do their literature searches.  And Iím sure you know that PubMed only list journals which are indexed and the vast majority of those are peer reviewed.

Dr:  Yes but why do you say the problem is worse in gay men and drug users?

P:  Doctor Iím an actuary.  I have a PhD in mathematics.  From Oxford.  I came to Australia six years ago because my wife is a top notch forensic scientist.  She was head hunted by your National Crime Commission.  My field is statistics.  I understand probabilities and the like.  Thatís what Iím paid to do.  If you tell me a few things about yourself I can tell what chance you have of getting any disease you name and living to any age you care to say.  If you want to know the chance your wife will outlive you by a certain number of years I can also tell you that.

Dr: Iím not questioning your competence in your field.  But you seem bent on questioning me in mine.  Please tell me what problems do you see with gay men and drug users.

P:  You tell me any antibody molecule can cross-react.  It can pick off some protein itís not destined for.  So letís assume that each individual antibody molecule has some probability of a cross-reaction.  I have no idea what it is.  Do you?

Dr: No.  I donít think that kind of data is available.

P: OK but if healthy people with a normal number of antibodies have a ľ probability of reacting with one of the ten HIV proteins the probability canít be small.  If a healthy person has say ten thousand different antibodies, and a target of ten HIV proteins, you have a hundred thousand combinations to try.  Thatís a lot of locks and keys.  If you double the number of antibodies you have two hundred thousand combinations.  And thatís just on numbers.  I donít know how variety affects the maths.  So the more antibodies you have and the more things youíre exposed to and the more likely you will generate an antibody that can cross-react in these tests.  Or in any test for that matter.  And thatís the problem.  At least the way I see it.

Dr  Youíll have to explain.

P:  Letís ask ourselves, what kind of people are likely to have the greatest number and variety of antibody molecules?  In general.  Surely the people in the AIDS risk groups must head the list?  What about all the germs and foreign substances that gay men and drug addicts are exposed to?  And haemophiliacs who get infused with foreign proteins that come from thousands of blood donors.  And what about Africans?  Who have all manner of diseases such as TB and fungal and parasitic infections which also cause antibodies?  And the organisms that cause these diseases just happen to be representative of the commonest AIDS defining diseases in Western AIDS patients.  Who donít actually come from Africa.  So the groups of people with the greatest probability of having cross-reacting antibodies, antibodies that will confuse these tests, are the very groups in which you say the tests rarely make a mistake.  It just doesnít add up doctor.  Iíd say it would be a miracle if any of the antibodies in AIDS patients were genuinely HIV.

Dr: I honestly donít follow your logic.  You told me that the laboratory test inserts your cousin sent from America confirmed the antibody tests can separate patients with AIDS from patients who are healthy.  Isnít that right?

P: Yes there we agree.  And we agree they do this very accurately.

Dr: Surely then if a positive antibody test distinguishes between AIDS and healthy people then HIV must be involved in one group, the AIDS patients, and not in the other group?  The healthy people.

P: Why?

Dr: Because HIV causes AIDS.  If the test distinguishes between AIDS and not having AIDS then it automatically distinguishes between having the cause of AIDS and not having the cause of AIDS.  Which is HIV.  Itís just another way of saying the same thing.  It doesnít matter which way around you say it.

P: No you cannot deduce that doctor.

Dr : Why not?  It canít be any other way.  Unless of course you say HIV is not the cause of AIDS.  Surely youíre not suggesting that?  Not seriously?  Have you been reading some of the dissident junk on the Internet?

P: Have you read any of that junk doctor?

Dr:  No of course not.  Look, this is getting out of hand.  There are important things we must discuss and the sooner the better.  We seem stuck on what really shouldnít be a problem at all.  I respect your right to ask questions and Iíve tried my best to answer them but obviously Iím not able to satisfy you.  Perhaps you would prefer to talk to one of my colleagues?

P: No that will not be necessary doctor.  I have every confidence in you.  And in this clinic.  Another doctor would only increase my confusion.  Letís call it a day.  Iíll try and come to come to grips with it next time.

Dr: Very well.  We certainly need to move on.

 

A week later.

P: Doctor I think Iíve worked out a way to explain my misgivings.

Dr: Iím glad to hear it.

P: Letís talk about tests in general terms.  What actuaries do for example.  Itís not too different from our last discussion.

Dr: OK.

P: Actuaries  are interested in how long people live.  Which is another way of saying when people die.  So we collect data about large groups of people who have something in common.  People who have say heart disease or diabetes.  We work out whether having or not having one of these diseases will affect a personís chances of being or not being alive at some future date.  In a statistical sense of course.

Dr: Go on.

P: So what we do is very similar to your antibody tests and AIDS.  Your take people with or without a positive antibody test and contrast that with the risk of having or getting AIDS or staying healthy.

Dr:  Yes.

P:  Now this is where I think the medical profession or the laboratory scientists or whoever decides these things have gone beyond their data.  The outcome actuaries seek is whether a person is dead or alive.  And one of the Ďtestsí we use, is what diseases they have or donít have at various times before they die.  So our tests are diseases and our outcome is death.  Clear and unambiguous.  Youíre either dead or youíre not.

Dr: Go on.

P: We donít use a substitute for dead bodies.  We donít count the numbers of death notices in the papers.  We donít tally up how much timber undertakers order.  Or how small the forests are becoming.  We donít ask Centre Link how many pensions theyíve cancelled.  We go straight to the real thing.

Dr OK.

P: When it comes to the antibody tests the medical profession doesnít deal with the real thing.

Dr: I donít follow.

P: You told me the antibody tests diagnose HIV infection.

Dr: Thatís right.

P: But you havenít produced any evidence for that.  What youíve described is a test for AIDS.  Or, more accurately, of diseases which the medical profession defines as AIDS.  None of these diseases are new.  Theyíre just been bundled together because in the early 1980s gay men in large Western cities started to get them more frequently than ever before.  Isnít that right?

Dr:  Yes, that is right.

P:  So itís AIDS that measure the antibodies against.  The biotechnology companies and the WHO say it too.  You say itís a test for HIV but you measure it against AIDS.

Dr: I already explained thatÖ

P:  I know.  You say you can use AIDS as a substitute for HIV.  And not having AIDS as a substitute for not having HIV.  Well I donít think you can do that.

Dr: Why not?

P: Several reasons.  First:  AIDS is not HIV.  Theyíre totally different.  AIDS is 30 diseases.  HIV is allegedly a virus.  Second:  The AIDS diseases have been around for hundreds, maybe thousands of years.  Long before we had AIDS.  Thereís an account of Kaposisí sarcoma in the Ebers papyrus.  From ancient Egypt.  Dating from 2500 BC.  So if HIV is really a virus and does cause the AIDS diseases itís not the only cause.  Itís not unique.  How about tuberculosis?  TB has been found in Egyptian mummies.  Would you use an Egyptian mummy as a substitute for HIV?

Dr  This is beginning to sound ridiculousÖ

P:  You can use AIDS as an HIV substitute if and only if the sole cause of these 30 diseases is HIV.  Which it isnít.  Thereís no way around that.  If you want to say AIDS can be substituted for HIV then actuaries can substitute death for the number of cancelled pensions.

Dr  Hold onÖ

P: The other faulty piece of logic is to use an antibody test as part of the AIDS diagnosis.  If a positive antibody test is part and parcel of having AIDS it stands to reason there will be a perfect correlation between these antibodies, wherever they come from whatever they are, and AIDS.  But that would be a man made correlation.

Dr: Look we may diagnose AIDS with an antibody test now but that was not what we did when the HIV tests were developed.  They were verified against AIDS.  A clinical diagnosis of AIDS.  By that I mean history and examination.  Plus a few test like X-rays.  But not antibody tests.  But when we did an antibody test, as an experiment if you like, thatís when we discovered all AIDS patients have these antibodies.  And if you donít have these antibodies you donít have AIDS.  And that has been found time after time.  Thatís why an antibody test is now part of the diagnosis.

P: Doctor that doesnít prove the antibodies are caused by HIV.  It just proves that AIDS patients have some antibodies which react with these proteins in the test kits.  Which you say could be cross-reacting and therefore not HIV.  So what you have is a blood test for AIDS. Or a blood test that predicts an increased likelihood you will get sick from certain diseases.  Thatís fine if thatís what you want.  But thatís not the same thing as proving the antibodies are caused by a virus.

Dr:???

P: Thereís more doctor.  Third:  A couple of weeks ago I suggested I was a false positive.  You didnít agree.  That means you want to have things both ways.  If youíre a biotechnology company you want to use people like me as stand ins for being HIV free.  You can read it in their inserts.  The one I have says ĎRandom donors are assumed to have a zero prevalence of HIV antibodyĒ.   So thatís the rule.  Once you set up the rules you canít break them.  Which means anyone in this group whoís positive must be recorded as a false positive.  But the same person sitting in your clinic the next day is truly infected.  That could easily apply to me.

Dr: I really think all your reading has made you quite confused.

P: What I understand doctor is this:  If biotechnology companies and the World Health Organisation are quite happy to use people without AIDS including healthy people as HIV-free substitutes to verify their tests then there can be no epidemic of HIV.

Dr: How on Earth do you come to that conclusion?

P: Because most people on Earth with a positive antibody test donít have AIDS and in fact most are healthy.

Dr: Youíre telling me all those people, millions of them, 30% of some African countries, arenít infected with HIV?  Theyíre all false positives?

P: Itís not me saying that doctor.   Iím only drawing a conclusion based on the rules you and the WHO recommend and approve.  I donít make up the rules.  Iím just saying you should stick to them.

Dr: Is there anything else?

P: Have you ever read a packet insert?

Dr : No.  I donít do the tests.  Theyíre done by the laboratory staff.

P: Do they read the packet inserts?

Dr:  I donít know.

P: Donít the agencies that approve the tests read them?

Dr: I donít know that either.

P: Can I read you something else from my packet insert?

Dr: Sure.

P: Both my packet inserts say ďAt present, there is no recognized standard for establishing the presence or absence of antibodies to HIV in human bloodĒ.  Whatís your opinion on that statement doctor?

Dr: Iíd like to hear your opinion.

P: OK.  My opinion is that biotechnology companies employ a lot clever people.  And if a biotechnology company was developing a pregnancy test someone in the organisation would know the recognised standard for pregnancy is whether or not a woman has a baby.  So itís not rocket science to know that the recognised standard for a test to diagnose HIV is whether or not the person has HIV.  If thatís what the test is for thatís what it should judged against.  Which means the biotechnology companies know these tests are not being judged against HIV itself.  Otherwise their lawyers wouldnít be telling them to put that sentence into the test kit packet inserts.

Dr: So you do not accept what I explained before?

P: Doctor Iím commenting on a packet insert.  Iím offering my opinion that the biotechnology companies must know HIV is the gold standard method for validating the antibody tests but that itís not being used.  Why this is so I donít know.  And why test manufacturers repeatedly warn whoever reads their packet inserts about this I donít know either.  But Iím going to try and find out.

Dr: So what would actuaries have us do?

P: I can only speak for this actuary doctor.  Youíve already told me that cross-reacting antibodies can react in the HIV test.  You said that in the Western blot one or two antibodies are most likely caused by cross-reactions and not HIV.  When I asked how you know that you said itís because of the band patterns the antibodies form.  I donít see how patterns or numbers distinguish between real and cross-reacting antibodies.  I donít believe you can know what something is just because thereís more of it.  Thatís why I said maybe all antibodies in these tests are cross-reacting and not HIV.  Or maybe they really are all HIV.  Well thereís an easy way to find out.

Dr: And whatís that?

P: Use the virus.  Do an experiment comparing the antibodies against the virus itself.  After all, thatís what the test is for.  Itís a test for HIV.  Itís not a test for AIDS.

Dr: And how would you do that?

P: Take say a thousand people.  Some with AIDS, some with other diseases like AIDS, some with diseases which are not AIDS and some healthy people.  You canít restrict your choice of non-AIDS people to those who are healthy.  If you do youíll be avoiding the problem of cross-reacting antibodies.  The non-AIDS group must include sick people because these are the people who are likely to have generated increased amounts of different antibodies that might confound the test.  If you only use healthy people you donít expose the test to enough cross-reacting antibodies.  Then you compare having or not having a positive antibody test with having or not having HIV.  As proven by virus isolation.  But, as the test manufacturers tell us in a round about way, this has not been done.  And it should have been done long before the tests were used on the general population.

Dr: Well what are you going to do about your tests?

P: For the next three months Iím going to try and forget I have a positive test.  Actually Iím encouraged by something else I read in the packet insert.  ďThe risk of an asymptomatic person with a repeatedly reactive serum sample developing AIDS or an AIDS-related condition is not knownĒ.  So it seems no one is very sure what a positive test means outside a risk group.  Meantime Iíll go to my GP to make sure I havenít got TB or something else that might set these tests off.  I got immunised for Ďflu and tetanus about three months ago.  Maybe thatís the reason.  I know I could be wrong so my wife and I will put off having a baby and weíll use condoms.  And Iím going to spend a lot of my spare time in the library.  Working out a few things.  Including why the HIV proteins occur in normal, healthy people.  In fact Iím going to read all the original papers on HIV isolation and find out exactly what evidence international scientists published to prove there is a virus called HIV.  Then Iím going to ask you to repeat my test.

Dr: And what if your test is still positive?

P: Then whatever caused it must still be operative.  But that wonít prove itís HIV.

 

TO BE CONTINUED

Next question

 

ENDNOTES

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3. Chassagne J, Verelle P, Fonck Y, Legros M, Dionet C, Plagne R, et al. Detection of the lymphadenopathy-associated virus p18 in cells of patients with lymphoid diseases using a monoclonal antibody. Annales de l Institut Pasteur - Immunology 1986;137D:403-8.

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11. Henderson LE, Sowder R, Copeland TD. Direct Identification of Class II Histocompatibility DR Proteins in Preparations of Human T-Cell Lymphotropic Virus Type III. J Virol 1987;61:629-632.

12. Pearce-Pratt R, Malamud D, Phillips DM. Role of cytoskeleton in cell-to-cell transmission of human immunodeficiency virus. J Virol 1994;68:2898-2905.

13. Orentas RJ, Hildreth JEK. Association of host cell surface adhesion receptors and other membrane proteins with HIV and SIV. AIDS Res Hum Retroviruses 1993;9:1157-1165.

14. Sasaki H, Nakamura M, Ohno T, Matsuda Y, Yuda Y, Nonomura Y. Myosin-actin interaction plays an important role in human immunodeficiency virus type 1 release from target cells. Proceedings of the National Academy of Sciences of the United States of America 1995;92:2026-2030.

15. Pinter A, Honnen WJ, Tilley SA, Bona C, Zaghouani H, Gorny MK, et al. Oligomeric structure of gp41, the transmembrane protein of human immunodeficiency virus type 1. J Virol 1989;63(6):2674-9.

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