Flow cytometry analyses demonstrated that OX40 expression on CD3+, CD4+, and CD8+ T cells in PBMC samples was less frequent in patients with T1D than HCs (14.34 ± 1.02% vs. 22.47 ± 1.87%, p = 0.003; 18.78 ± 1.31% vs. 24.85 ± 1.87%, p = 0.093; and 7.94 ± 0.66% vs. 15.9 ± 1.87%, p < 0.001; respectively) (Figures 1(a) and 1(b)). The gene discussed is TNFRSF4; the disease is type 1 diabetes mellitus.