Surprisingly, the proportion of CD38+CD4+ T cells were significantly elevated in RP-ILD group compared to C-ILD group, non-ILD group and HCs, respectively (Figure 3A, RP-ILD vs. C-ILD, P = 0.0429; RP-ILD vs. non-ILD, P = 0.0119; RP-ILD vs. HC, P < 0.0001). This evidence concerns the gene CD4 and retinitis pigmentosa 1.