CD14highCD16+ Rather Than CD14lowCD16+ Monocytes Correlate With Disease Progression in Chronic HIV-Infected Patients

OBJECTIVE: CD14(+)CD16(+) monocytes are an important cellular target for HIV-1 entry and expand in the peripheral blood of HIV-infected individuals. Because CD14(+)CD16(+) monocytes are a heterogeneous population and consist of CD14(high)CD16(+) and CD14(low)CD16(+) subsets, we evaluated the effects of HIV infection on distinct subsets of CD16(+) monocytes. METHODS: Untreated HIV-infected patients were recruited to investigate the relationship between the proportions of monocyte subsets with plasma viral loads and CD4(+) T-cell counts. Patients receiving highly active antiretroviral therapy (HAART) were followed up in a cross-sectional and a longitudinal study. RESULTS: Compared with CD14(low)CD16(+), CD14(high)CD16(+) monocytes showed higher levels of CD64 and HLA-DR antigens, which imply that these 2 distinct subsets have different immunoregulatory phenotypes. In HAART-naive patients, elevated proportions of CD14(high)CD16(+) monocytes were correlated with increased viral loads and decreased CD4(+) T-cell counts, whereas CD14(low)CD16(+) monocytes did not show such correlation with disease progression. Of importance, HAART recovered the proportion of CD14(high)CD16(+) monocytes, whereas CD14(low)CD16(+) monocytes did not decrease during 1 year of antiviral therapy. CONCLUSIONS: Taken together, our observations elucidate distinct immune responses of monocyte subsets during HIV infection and antiviral therapy and provide new insight into the roles of innate immunity in HIV-related pathogenesis.