Is Aids a Myth

  • Thread starter Cyrus
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  • #26
-snip-

However, even medical science doesn't say that all people who are HIV+ will develop AIDS. We know of groups of people who have been HIV+ for years, yet are apparently just fine (even without antiretroviral drugs). These are known as "long-term nonprogressors," and are a group that's actively being studied to see just how they're holding the virus in check--what is it about them that keeps them OK, whereas other people succumb in just a few years if they're not treated?

-snip-
Long-term nonprogressors have been studied for years. Has there been any significant progress?
 
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  • #27
adrenaline
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Long-term nonprogressors have been studied for years. Has there been any significant progress?


Their cell-mediated immunity is somehow different. Scientists are studying HIV-specific CD4+ Th1 lymphocyte levels and activity, high levels of which seem to the best factor linked to protection in these long term non progressors . I have a small population of these long term non progressors ( Hiv + individuals who maintain a CD4 count of 600 and above without antivirals for at least five years.) One stayed HIV + without progression for 20 years ! All his freinds who went on antiretrovirals died many years before him! He progressed rather quickly to AIDS towards the end of the twenty years and died of herpes encephalitis. He also had crippling rheumatoid and lupus. Off hand I know of three others in my practice who have maintained non progression along with their autoimmune diseases.... almost as if their dysfunctional immune system that causes their body to attack their own organs ( lupus, rheumatid, ankylosing spondylitis, crohns disease etc.) simultaneously keeps their Aids virus in check! Interestingly, there is some data that genetic status such as HLA-B 27 individuals protect from AIDS rapid progression. (These HLA-B27 patients are also more prone to developing such autoimmune diseases that I have mentioned.)

I think right these non progressors are providing a wealth of information for those researchers working on vaccine development.

Anyway, back to the folks discrediting the Aids virus. What did they think was happening to these people's immune system that was making them die from things that just don't kill people with normal immunities, even under the most distressing physical conditions ( ie: starvation)? ( I'm talking about cryptococcal meningitis, toxoplasmosis, PCP pneumonia, etc.) Infections that were almost non existant until the AIDS epidemic. Of course they could try to argue about how these folks died from "normal infections" like cholera, streptococcal pneumonia, malaria etc which also kill non HIV infected folks, but how do they explain these opportunistic infections? MAC colitis ( Mycobacterium avium complex) diarrhea is almost unheard of in those with normal immune systems, and ok, maybe you can argue about chemotherapy induced immune dysfunction ( which predisposes these patients to some similiar opportunistic infections found only in HIV) but I doubt that that many Africans are getting chemotherapy!

What do you say in response to his claim of lots of false positive testing used by clinical researchers in populations that are highly prone to giving false testing results, or the that testing positive for AIDs varies from country to country?
I can't do better than Tara on this but let me throw in my measly input. First of all, out of the thousands of medical diagnostic tests out there to diagnose any medical problem, the Aids test ( Elisa followed by western blot which amplifies HIV DNA) is the most sensitive and specific test out there. Tara was right, it's a damn good test in fact,we were taught in medical school that many other diagnostic testing out there don't come close to surpassing the AIDS test in its accuracy! The serum tests that look for Lupus or rheumatoid arthritis or syphllis doesn't even come close to the accuracy of the AIDS test. Why no "conspiracy" about rheumatoid arthritis or lupus or syphillis?

The rapid ELISA test has a sensitvity and specificity of over 99%. (The sensitivities and specificities close to 100% really make the test very reliable in the right clinical setting.) I don't know of any other medical diagnostic serum testing that is so sensitive or specific. . And yes there are false postives and negatives. However, if you look at the fact that the most common malaria test has only a sensitivity of 88% and specificity of 95 %, the malaria testing has a much higher rate of false positives! Hot dang, there must also be a conspiracy about the malaria epidemic!
 
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  • #28
Thank you for the update.

For curiosity, what vectors are being considered for inducing cell-mediated immunity to HIV1? And have any vaccine candidates passed phase II yet?
 
  • #29
adrenaline
Science Advisor
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Thank you for the update.

For curiosity, what vectors are being considered for inducing cell-mediated immunity to HIV1? And have any vaccine candidates passed phase II yet?
You better let a biologist answer the first half. as for phase III trial one was done in 1993 that was not too promising ( efficacy of 20% and the vaccine consisted of 7 shots, ouch!) here are the details

http://www.medscape.com/viewarticle/452480

I haven't really heard of any new ones down the pipe. I'll ask my ID folks here and post later.
 
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  • #30
Curious3141
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the Aids test ( Elisa followed by western blot which amplifies HIV DNA)
The ELISA detects antibodies to HIV +/- p24 Antigen (in the case of 4th generation assays). It is a highly sensitive and highly specific assay, but is capable of giving significant numbers of false positives in a low prevalence population (where the pre-test odds are low). This is a common pitfall : low prevalence compromises positive predictive value in any test with less than 100% specificity.

The Western Blot (or immunoblot) detects specific antibodies to weight sorted HIV-1 proteins belonging to the 3 classes (gag, pol, env). It is a less sensitive but more specific assay than the ELISA, and is often used for confirmation and disease follow-up. The Western Blot pattern can be positive, negative or indeterminate and there are different criteria for reading them (CDC/ASTPHLD, American Red Cross, CRSS etc.) The pattern can evolve with disease progression. HIV-2 specific WBs are available.

Nucleic acid tests are the most sensitive, most specific and most expensive. They are difficult to perform with expertise (if done improperly, false negatives due to sample matrix inhibition and false positives due to sample-sample carryover contamination abound). They are uncommonly used in routine clinical diagnosis and are generally reserved for screening blood products prior to human transfusion. They are also sometimes useful in testing neonates with vertically acquired maternal antibodies to HIV. You can test for viral RNA or proviral DNA (which is the form that integrates into human cells). You can use different assay methodologies (PCR for DNA, RT-PCR for RNA and bDNA (branched chain DNA assay)).
 
  • #31
adrenaline
Science Advisor
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The ELISA detects antibodies to HIV +/- p24 Antigen (in the case of 4th generation assays). It is a highly sensitive and highly specific assay, but is capable of giving significant numbers of false positives in a low prevalence population (where the pre-test odds are low). This is a common pitfall : low prevalence compromises positive predictive value in any test with less than 100% specificity.

The Western Blot (or immunoblot) detects specific antibodies to weight sorted HIV-1 proteins belonging to the 3 classes (gag, pol, env). It is a less sensitive but more specific assay than the ELISA, and is often used for confirmation and disease follow-up. The Western Blot pattern can be positive, negative or indeterminate and there are different criteria for reading them (CDC/ASTPHLD, American Red Cross, CRSS etc.) The pattern can evolve with disease progression. HIV-2 specific WBs are available.

Nucleic acid tests are the most sensitive, most specific and most expensive. They are difficult to perform with expertise (if done improperly, false negatives due to sample matrix inhibition and false positives due to sample-sample carryover contamination abound). They are uncommonly used in routine clinical diagnosis and are generally reserved for screening blood products prior to human transfusion. They are also sometimes useful in testing neonates with vertically acquired maternal antibodies to HIV. You can test for viral RNA or proviral DNA (which is the form that integrates into human cells). You can use different assay methodologies (PCR for DNA, RT-PCR for RNA and bDNA (branched chain DNA assay)).
very true which is why no medical test should be ordered unless the pretest probability for the disease is high and the local prevalence of the disease is taken into consideration. Ordering a HIV test in a virginal nun is probably not a good idea. ( ELisa with reflex western blot if positive). For that reason I don't order CA 125s at all for ovarian cancer screening, the sensitivey and specificity suck. However, compared to any singular medical diagnostic test I have yet to find any medical diagnostic test ( both serological as well as say, radiographic ( ex helical cat scan for pumonary embolism where senstiviites and specificities range from 57-95% and 78%-98% respectively depending on the study and type of cat scan) that comes close to the HIV test! There is no doubt under the right circumstance it can produce false positives and negatives but there is no other medical diagnostic test that I can recall offhand that has such a good specifcity and sensitvity ( Thus the potential to diagnose a blood clot in the lungs is fraught with much more false negatives and positives.) (I was sleep deprived yesterday so I meant to say DNA isolation vs amplification). Thats why this guy bringing up the rate of false positives and false negatives as the main thrust of his argument is way off base. He has no idea that almost all other medical diagnostic testing are far less sensitive and specific!
 
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  • #32
Curious3141
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(I was sleep deprived yesterday so I meant to say DNA isolation vs amplification).
The Western blot is an immunologic (antibody) test. It is not a nucleic acid (DNA/RNA) assay at all.

I agree with the rest of the stuff about sens/spec. etc.
 
  • #33
adrenaline
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The Western blot is an immunologic (antibody) test. It is not a nucleic acid (DNA/RNA) assay at all.

I agree with the rest of the stuff about sens/spec. etc.
you are right, i keep thinking of pcr and my lack of sleep is making me3 punchy.
 

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