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.