Re: Re: Some Random Comments 30 October 2004
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Mark Bartlett,
CD Investigator

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Re: Re: Re: Some Random Comments

Follow-up to Peter Flegg and Nicholas Bennett:

First - thanks to both of you for your replies.

Peter said:

<<Some of the newer HIV assays do actually use undiluted whole blood, and are very accurate, a point consistently ignored by the “everyone tests positive for HIV” dissident lobby.>>

Which tests specifically are you referring to and have these tests been approved to diagnose HIV/AIDS by the FDA? If not, why?

Also - I am aware that many of the antibody tests do require **some** dilution to control for the confounders, however the comment I have heard re Giraldo's work and the ELISA he used, suggested 2 things: 1) The test had never been developed against a virus isolation gold standard (isolation) and 2) the amount of dilution for this type of test was inordinately high. I think it was diluted 400:1, if I recall. If I understood his point correctly, this amount of dilutution was highly unusual for this type of test. (See more below)

What other infectious Dx antibody tests (except hepatitis C) have NOT been developed from an actual isolate of the organism as a reference?

From Nicholas Bennett:

<<It's nothing astounding: in laboratory research antibodies are frequently diluted 1:100 or 1:10000 or whatever is needed to get a balance of sensitivity and specificity. Other serological tests also dilute the sample: a 5 minute google search brings up leishmania, RSV, influenza, measles... It's a standard laboratory technique. >>

I agree that for seological tests that measure antibody titres (for example paired titres for influenza, RSV, Parainfluenza l, ll ans lll etc.) that is the case. Typically a four-fold increase between acute and convalescent is considered positive. In all of those cases a positive rarely goes over 1:128 and none of them need to get anywhere near that to be positive. Typically you see 1:8 to 1:32; or 1:16 to 1:68. Is that what you are referring to here?

It is my sense that Giraldo was saying that there is so much background noise, even in the average person's blood, that the specificty is called into question. I have no doubt that he believes (as do I) the test is still a good indicator to determine who may get AIDS, but it is not necessarily measuring HIV, rather somethig else. At the end of the day, for clinical purposes, I guess it really does not matter except when it comes to assigning causation, and therefore treatment.

From Nicholas Bennett:

<<HIV itself causes some direct effects>>

What direct effects specifically to you assign to HIV?

From Peter:

<< There is no suggestion that HAART is in itself ineffective, merely that current risks of continuous therapy may outweigh current benefits.>>

Agree that this was the intent of their comment. I question the actual meaning of the CD4 count vis-a-vis treatment value and significance. I think it is widely acknowledged that CD4 counts no longer hold the same weight as to AIDS prognosis, as they did at one time. Indeed there are some people who seem to live quite happily and are healthy with low CD4 counts.

A final comment/question to both of you (and anyone else who would care to respond). I have heard it said that modern HIV treatments reduce levels of HIV to almost immeasurable levels -- if that is the case, do you believe that if you rid the body of every HIV particle, the immune system would return to a state of healthy homeosatis?

I appreciate this is quite a hypothetical question, but if Tx truly DOES reduce the numbers to almost immeasurable levels, and the outcome is still poor, will ZERO HIV be any different? I suspect I know both your answers, but nevertheless I'd appreciate your comments.

From Nicholas Benntet:

<<This is also perhaps a cautionary tale in getting info "passed on by a friend"!>>

Agreed that is why I am very selective about the info that is passed to me, in terms of source/reliability/interpretation.

Competing interests: None declared