The interleukin-7 (IL-7)/IL-7 receptor α (IL-7Rα) system is an important regulator of T-cell homeostasis. We evaluated the IL-7/IL-7Rα system in a large cohort of HIV-infected patients, including a subset treated with intermittent IL-2.Methods:
IL-7 serum levels and CD127 (IL-7Rα) expression on T cells were evaluated in a cross-sectional study of 36 healthy volunteers, 151 HIV-infected patients, and 83 HIV-infected patients who had received IL-2 therapy. Multivariate regression models were used to determine predictors of CD127 expression.Results:
HIV-infected patients had higher IL-7 levels compared with healthy volunteers (P = 0.022) and IL-2-treated patients (P = 0.012). CD127 expression was significantly lower on CD4 and CD8 T cells of HIV-infected patients compared with healthy volunteers (P = 0.008 and P < 0.001, respectively), and CD127 median fluorescence intensity was lowest on CD4 T cells in IL-2-treated patients (P < 0.001 compared with HIV-infected patients). The proportion of naive and effector memory/effector T cells were significant predictors of CD127 expression on T cells. IL-2 immunotherapy led to the expansion of a CD25+/CD127-low subset of CD4 T cells.Conclusions:
CD127 expression on T cells remains low in HIV-infected patients despite antiretroviral therapy, reflecting persistent aberration in the subset composition of the T-cell pool.