Re: More on CD4s 30 September 2004
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Peter J Flegg,
Blackpool, UK FY3 8NR

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Re: Re: More on CD4s

I thank the Perth Group for responding to my plea for evidence that in each of the 10 references they cited human CD4 cell counts can drop below 50/microlitre in the absence of HIV infection. However, they have not given what I asked for (an indication for each of the studies in question where it is explicitly stated that this is the case). Why not? Could it really be that their references say nothing of the sort, and the Perth Group were being economical with the truth?

They do now give references showing instances where low CD4 counts (<300/microlitre) have occurred in the absence of HIV, and then tag on the suggestion that: “If something decreases the CD4 counts to "less than 300/mcl", there is no reason why it should not decrease then to 50 per microliter.” Hmmm… how often would that happen, I wonder? Since I am a physician, I am also meant to know that “if a drug, X, causes an effect, Y, then the magnitude of Y will depend on the dose, the frequency and the duration to which the patient is exposed to X.” Well as a physician, I can say very few things in my experience of the human physiological response operates in such a simple, dose-dependent, linear manner, and there are clear limits for most parameters. (If a diuretic can make my serum sodium drop from 130mmol/l to 115mmol/l, will twice the dose make it drop to 100mmol/l, and four times the dose drop it to 70mmol/l?). I am however pleased to have been afforded this insight to the reasoning processes of the Perth Group, as it helps me understand some of their other deductions and conclusions.

I am grateful at least for the one new reference to a human CD4 count less than 50/microlitre in someone without HIV. (One of 53 patients acutely unwell in an ITU had a count <50). The same journal has also published a study indicating that severe acute illness results in a broad lymphopenia, rather than an isolated CD4 drop as is usual with HIV infection (1). Perhaps the Perth Group missed that one.

Finally, the Perth Group asks me questions about Montagnier’s work in the 1980s, even though these have been conclusively addressed previously by Chris Noble. I refer them to his very competent reply to the topic, which I assume they have not read or understood. I do not have any haemophiliac patients with HIV infection, but if I did, I would certainly tell any with CD4 count below 50/mcl that HIV was the cause.

(1) Collazos J, Mayo J, Ibarra S, Martinez E. The primary deficiency resulting from acute severe illness in nonimmunocompromised patients is not the CD4+ subtype, but the total number of lymphocytes. Arch Intern Med. 2001; 161(5):771-2.

Competing interests: None declared