Characterization of CD57 expression in CD4 T cells. a The replicative senescence of the whole CD4 T-cell compartment was defined by the frequency of CD57+CD28− cells. b In addition, the expression of CD57+ cells was evaluated in the different CD4 T cell subsets by analyzing the frequency of CD57+ cells. c The relationship between levels of spontaneous CD4 T-cell death and replicative immunosenescence is shown. Plots shows data from immunodiscordant (n = 23, red), low nadir immunoconcordant (n = 17, dark green) or high nadir immunoconcordant individuals (n = 16, light green) with color-coded linear regression for each data set. Linear regression for the global data is shown in black lines. Correlation coefficients and p
values of Spearman’s test for the global analysis are shown. a, b also show data from HIV uninfected individuals (n = 11, blue bars).