Figure 5: PD-L1 expression on CD8+ T cells is associated with a decreased T cell proportion in patients with acute A(H1N1)pdm09 viral infection. Correlations between PD-L1 expression on the proportions of CD8+ and CD4+ T cells in PBMCs from pH1N1+ patients are shown. Correlations between PD-L1 expression on CD8+ T cells and the proportion of total CD4+ (a) and CD8+ (b) T cells in PBMCs in pH1N1+ patients are indicated. Spearman correlation () and values are shown in each graph. MFI: mean fluorescence intensity; pH1N1: A(H1N1)pdm09 virus.