Immunophenotypic markers and antiretroviral therapy (IMART): T cell activation and maturation help predict treatment response.

To determine whether markers of T cell activation and maturation are independently predictive of the response to potent antiretroviral therapy, the Immunophenotypic Markers and Antiretroviral Therapy study applied a novel data-sharing strategy across 5 Adult AIDS Clinical Trial Group trials that counted naive and activated CD4(+) and CD8(+) T cells in 324 subjects. Regression models--adjustment for baseline CD4 cell count, human immunodeficiency virus (HIV) RNA, and study--revealed that high pretreatment CD8(+) T cell activation predicted virologic failure (P=.046). Additional models showed the greatest increase in CD4(+) T cell counts in subjects with highest pretreatment naive CD4(+) T cell counts (P<.0001), which was enhanced by high CD4(+) and low CD8(+) T cell activation. Total lymphocyte count also predicted a subsequent CD4(+) T cell change. These results document the utility of T cell markers in predicting treatment outcome and their potential value for the study and management of HIV-1 infection.