Analysis of activated CD8⁺ T cells in peripheral bloods of scrub typhus patients.

PBMCs were stained with antibodies against CD8 and PD-1 or IL-7Rα and then analyzed on a flow cytometer. A and B. Representative histograms show the frequencies of IL-7Rα^low cells (A) and PD-1^high cells (B) within CD8⁺ T cells. Gray histogram, isotype control. C. The frequency of IL-7Rα^lowCD8⁺ T cells from healthy controls (HC, n = 9, open circle) is compared with that of scrub typhus patients at acute phase (AP, n = 7, gray circle) or convalescent phase (CP, n = 8, black circle). D. The frequencies of PD-1^highCD8⁺ T cells were compared among healthy controls (n = 9) and the patients (AP, n = 13; CP, n = 15). Red bars indicate the mean value and p values were obtained using the Mann-Whitney U test or Wilcoxon signed-rank test. Statistically significant p values (<0.05) are shown in bold.