Fig. 2

Dynamics of CD38⁺HLA-DR⁺PD-1⁺CD8⁺ cells segregate H7N9 disease outcome. a Representative FACS plots of PD-1 expression within the CD38⁺HLA-DR⁺CD8⁺ T cells (in red) and the total CD8⁺ T cells (in blue) in patient a79 (recovered from H7N9) and patient a33 (died from H7N9). b Correlation between the frequency of CD38⁺PD-1⁺CD8⁺ T cells and a proportion of CD38⁺HLA-DR⁺CD8⁺ T cells, as measured by Spearman test. c Representative histograms of PD-1 expression within CD38⁺HLA-DR⁺CD8⁺ T cells (red) and the remaining non-CD38⁺HLA-DR⁺ CD8⁺ T cells (blue). d High and prolonged expression of PD-1 in patients who died, as triple-positive CD38⁺HLA-DR⁺PD-1⁺ and mean fluorescence intensity (MFI) of PD-1 expression within CD38⁺HLA-DR⁺CD8⁺ T cells and non-CD38⁺HLA-DR⁺CD8⁺ T cells for survivals and fatal cases (a standard two-tail Student’s t-test), with samples from individual patients being acquired on an LSR Fortessa on different days. e CD45RA and CD27 profiles on CD38⁺PD-1⁺CD8⁺ T cells (in red) and on total CD8⁺ T cells (in blue). f Similar to CD38⁺HLA-DR⁺CD8⁺ T cells, the frequency of CD38⁺PD-1⁺CD8⁺ T cells declined with time in the H7N9 survival group, which was maintained or increased in H7N9 patients who died. The frequency of CD38⁺PD-1⁺CD8⁺ T cells was also analyzed in g patients hospitalized with seasonal pH1N1 (5 patients; dotted lines, solid triangles), H3N2 (10 patients in dashed lines, open diamonds), influenza B (6 patients in dotted black lines, open triangles), non-influenza/non-viral hospitalized patients (5 patients; gray lines, open gray circles), and 1 H3N2 patient with fatal outcome (black line, solid black circle); and h healthy individuals during inactivated influenza vaccination in 2015 (18 individuals vaccinated with a trivalent (TIV) vaccine; black lines) and 2016 (27 individuals vaccinated with quadrivalent (QIV) vaccine; gray lines). i Frequency of CD38⁺PD-1⁺CD8⁺ T cells during the first (T₁) and last time-point (T_L) of hospitalization or vaccination in H7N9 survival cases, fatal influenza patients (3 H7N9, 1 H3N2); seasonal influenza survival cases, and seasonal influenza vaccinees. Means are shown as horizontal bars. Standard two-tail Student’s t-test was performed with indicated p values