Predictive value of immunologic and virologic markers after long or short duration of HIV-1 infection.

Laboratory markers that predict HIV-1 disease progression include plasma viral burden, CD4+ T-cell count, and CD38 expression on CD8 T cells. To better understand whether the predictive value of these markers is dependent on how long an individual has been infected, we analyzed data from the Multicenter AIDS Cohort Study early (median = 2.8 years) and late (median = 8.7 years) in the course of infection. Overall, we found that HIV RNA and CD38 levels were similarly predictive of AIDS early on compared with a relatively weaker CD4 cell count signal. Later in the course of infection, CD38 level remained the strongest predictive marker and CD4 cell count registered a marked increase in prognostic power. Among untreated individuals, there was little difference in prognosis (median time to AIDS) associated with given marker values regardless of infection duration. The prognosis given a specific viral load level tended to deteriorate late in the course of infection among those undergoing treatment with monotherapy or combination therapy, however. These data provide a unique historical look at the predictive value and prognostic significance of HIV-1 disease markers at different stages of infection in a large cohort, with direct relevance to current patients who are untreated or for whom treatment is ineffective.