Search

During HIV infection, the destruction of naive T cells apparently occurs at a faster rate than the destruction of memory T cells. This was demonstrated in a study that analyzed the changes in blood levels of specific subsets of CD4 and CD8 T lymphocytes in 116 people with asymptomatic HIV infection. The CD45RO+ subsets of both CD4 and CD8 lymphocytes increased while the CD45RO-CD45RA T cell levels decreased. Levels of CD11b- subsets of CD8 lymphocytes declined while levels of CD11b+ subsets increased.

The concentration of beta2-microglobulin in the blood may be a useful indicator in identifying HIV-infected patients with an increased risk of developing AIDS. Researchers analyzed the blood of 130 HIV-positive intravenous drug users and found that the strongest predictor of progression to AIDS was a low CD4+ cell count at the start of the study. Increases in blood levels of beta2-microglobulin, which indicates stimulation of the immune system, predicted how soon patients would develop AIDS. The predictive value of beta2-microglobulin was significant when CD4+ cell counts exceeded 500. The study followed participants for 67 months. Study findings of this group of injection drug users agreed with previous findings among HIV-infected homosexuals.

Monocytes produce more prostaglandin E2 (PGE2), interleukin-1-beta (IL1B) and tumor necrosis factor-alpha (TNF-A) in HIV-positive injection drug users when compared with their HIV-negative counterparts and with healthy volunteers. Monocytes are white blood cells that play a key role in cell-mediated immunity. This monocyte activity shows that the production of PGE-2 increases throughout the course of HIV disease, not just when the infection becomes severe and complications occur. HIV itself might cause increased production of these substances, collectively known as cytokines. Also, T-helper cell levels were inversely related: the higher the PGE2 and IL1B counts were, the lower the T-helper counts. The subjects with high cytokine counts and low T-helper cell counts also registered a low immune response to pokeweed mitogen. Further research is needed to clarify how these results illuminate immune system disruption caused by HIV.