Relationship between CD38 expression on peripheral blood T‐cells and monocytes, and response to antiretroviral therapy: A one‐year longitudinal study of a cohort of chronically infected ART‐naive HIV‐1+ patients

Abstract

Background: HIV‐1 infection has been associated with high expression of CD38 on peripheral blood (PB) CD8+ and CD4+ T‐cells, which has been related with poor prognosis in untreated HIV‐1+ patients. In turn, CD38 expression on PB monocytes from HIV‐1+ individuals and its behavior after starting antiretroviral therapy (ART) have been poorly studied. Methods: CD38 expression on PB CD8+ and CD4+ T‐lymphocytes and monocytes was prospectively analyzed in 30 ART‐naive HIV‐1+ patients, using a quantitative multiparameter flow cytometry approach. Patients were tested prior to therapy, and at weeks +2, +4, +8, +12, and +52 after ART. Results: Prior to ART, CD38 expression was significantly increased on PB CD8+ and CD4+ T‐cells and monocytes; despite a significant decrease after ART, CD38 expression remained abnormally high on PB CD8+ T‐cells and monocytes, even after one year of therapy, in the absence of detectable plasma viral load. The ART‐induced early changes on CD38 expression by PB T‐cells and monocytes differed among the cell subsets analyzed and patient groups, probably reflecting an interaction between the direct effects of therapy and a redistribution of the PB compartments of T‐cells and monocytes. Hierarchical clustering analysis showed that the overall pattern of changes in CD38 expression observed early after starting ART was predictive of a better response to therapy, not only for PB CD8+ T‐cells, but also for CD4+ T‐cells and monocytes. Accordingly, those HIV‐1+ patients, who experienced a more pronounced increase in CD38 expression on both PB CD4+ T‐cells and monocytes after 2 weeks of ART, showed a more rapid viral clearance, which might reflect decreased HIV‐1 replication in lymph nodes and other tissues, and a partial restoration of hematopoiesis. Conclusions: Combined quantitative measurement of CD38 expression on PB monocytes, and CD8+ and CD4+ T‐cells is a more useful tool for monitoring HIV‐1+ patients under ART, rather than quantitation of CD38 expression on PB CD8+ T‐lymphocytes alone. © 2006 International Society for Analytical Cytology