Figure 4.

PD-1 upregulation in sarcoidosis CD4⁺ T cells. PBMC isolated from the whole blood of healthy control, and sarcoidosis subjects were stained using anti-CD3, anti-CD4, anti-CCR7, anti-CD45RO, and anti-PD-1 antibodies. (a) Representative flow cytometry histograms to illustrate PD-1 gating in the population of CD4⁺ T cells from healthy control and sarcoidosis progressor and resolver subjects. For comparison, the healthy control histogram (black trace) was overlayed with the sarcoidosis progressor and resolver histogorams. (b) Plot of the percentages of sarcoidosis PD-1⁺CD4⁺ T cells relative to healthy controls. Statistical analysis was performed using the Mann–Whitney U test. (c) Plot of PD-1⁺CD4⁺ T cells present during sarcoidosis disease progression and resolution relative to healthy controls. Statistical analysis was performed using one-way ANOVA with Tukey's HSD. Horizontal lines indicate mean percentages of PD-1⁺CD4⁺ T cells. ^∗p < 0.05 and ^∗∗∗p < 0.001. NS: not significant.