Fig. 7
From: Effect of age and sex on immune checkpoint expression and kinetics in human T cells
Effect of sex on PD-1 expression frequencies. Sex effects on PD-1 expression were determined by flow cytometric staining of whole blood. Graphs show the frequencies of PD-1+ cells in older males and females within different CD4+ fractions (a), and in young and older males and females in fraction 3 (b) and fraction 4 (c). Horizontal bars reflect median percentages. Dashed line divides conventional memory and naive fractions from regulatory fractions. For the comparison of 4 groups, a Kruskal-Wallis test was performed and found to be statistically significant in fraction 3 and 4 (p = 0.019 and p = 0.005). Each group consisted of n = 9 (males) and n = 11 (females) participants. The Mann-Whitney U test was used for comparison between two groups. P-values are indicated in the graphs