New AIDS Insight Suggests Clinical Trials Approach

Two studies conducted by researchers at Stanford University in the USA have revealed new insights into the pathogenesis of HIV infection and AIDS, and suggest that the "conventional" wisdom that the disease is caused by loss of CD4 cells is too simplistic. The work is reported in two articles published in the Journal of Clinical Investigation (May 1995).

The new work suggests that in HIV-infected adults and children, there is a relatively early, selective loss of naive (unstimulated by antigen) CD4 and CD8 cells, compared to memory (antigen-challenged) subsets. The ratio of naive to memory cells has now been found to change markedly in response to HIV infection - for example, about 50% of CD8 cells in uninfected adults are naive cells, compared to less than 15% in most HIV-infected adults.

Children And Adults Tested The first study, in 266 HIV-infected adults and 44 uninfected controls, involved taking blood samples and testing them using flow cytometry for the relative proportions of CD4 and CD8 cells, as well as the ratio of naive to memory subsets. (The patients actually were selected from an ongoing screening program for a study of N-acetylcysteine, a candidate treatment for HIV infection - enrollment criteria for the NAC study were CD4 counts of less than 500, and no significant antioxidant, vitamin or mineral supplement usage). The second study tested 19 HIV-infected children (who were recruited for a separate study of glutathione levels) and 17 HIV-negative controls.