TreatmentUpdate 74 - Volume 8, No 10; December 1996
Sean Hosein

In late 1994 two teams of virologists were studying the effect of anti-HIV drugs, specifically changes in CD4+ cell counts and levels of HIV. Working together with scientists trained in mathematics, the teams developed some ideas about the interaction between HIV and the immune system, and came to a number of conclusions:

* "As many as 10 billion new HIVs are produced each day"

* Within 6 hours, 50% of these viruses are removed from the blood

* 2 billion CD4+ cells are produced each day as the body attempts to replace the ones destroyed by HIV infection. Once CD4+ cells are infected, 50% of them die in about 1.5 days

* It takes HIV 2.5 days to infect a CD4+ cell, turn it into a virus factory and have one of the new viruses made by that cell infect another cell.

The virologists evoked the image of a huge battle in which the production of 2 billion CD4+ cells was seen as a response by the immune system to fight HIV. The researchers compared changing CD4+ levels to water flowing into a sink and out again through a drain to illustrate their findings. Now results from two studies raise questions about the virologists' explanation of the interplay between HIV, the immune system, and the effect of anti-HIV drugs.

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Copyright © 1996 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284  http://www.catie.ca