Compared with HCs, increased percentages of TIGIT+CD226+ CD4 T cells (22.76 ± 7.063% vs. 18.87 ± 5.604%, p = 0.0281) and decreased frequencies of TIGIT–CD226+ CD4 cells (20.96 ± 10.15% vs. 29.85 ± 7.492%, p = 0.0005) were observed in patients with DM. The gene discussed is CD4; the disease is dermatomyositis.