Figure 2.

Increased percentage of programmed death-1 (PD-1)⁺ CD4⁺ T cells from the blood of patients with sarcoidosis. (A) Percentages of total peripheral CD4⁺ T cells expressing PD-1 from healthy control subjects (HC, n = 40) and patients with sarcoidosis (S, n = 77). PD-1 was determined by gating on the naive population (shaded) for each sample as shown in the representative histograms. Overlay represents one HC (gray line) and one subject with sarcoidosis (black line). (B) Distribution of CD4⁺ memory T-cell subsets and (C) the percentage of CD4⁺ memory T-cell subsets expressing PD-1 from healthy control subjects (n = 23) and patients with sarcoidosis (n = 47). Memory subsets were determined as shown in the representative dot plots. (D) Percent PD-1⁺ unstimulated CD4⁺ T cells from peripheral blood mononuclear cells (PBMC) of healthy control subjects (n = 7) and patients with sarcoidosis (n = 17). Additionally for the patients with sarcoidosis, PD-1 was measured on Tregulatory (n = 5) and CD4⁺IL-17A⁺ T cells from polyclonally activated PBMC (n = 17). Measurement was not performed on healthy control CD4⁺IL-17A⁺ cells due to low number of cells. *P < 0.0001; **P < 0.05. CM = central memory T cells; EM = effector memory T cells; N = naive T cells; TEM = terminal effector memory T cells.