PD-1, HLA-DR, and CD38 together identify an effector memory CD4 T cell subset elevated in HIV-1 infection.

<p>(A) Identification of CD4 T cells co-expressing PD-1, HLA-DR and CD38 in HIV-1 infected and uninfected subjects. (B) Box and whisker plots showing the median and 10–90 percentile percentage of CD38, HLA-DR and PD-1 triple-expression in CD4 T cells in HIV negative (n = 40) and HIV positive (n = 103) subjects. (C) In order to assess the phenotype of the activated CD4 T cells, PBMC were analyzed by flow cytometry for the expression of CD45RO, CCR7, CD28, and Ki67. Filled line represents CD4 cells triple-positive for CD38, HLA-DR, and PD-1, while dashed line represents data from the overall CD4 compartment and empty filled line is the fluorescence minus one (FMO) control for that channel.