PDCD1 and myositis disease: We found that exhausted CD4+ T cells were associated with CK (PD1+CD4+, r = 0.2833, P = 0.0283), CRP (CTLA4+CD4+, r = 0.3144, P = 0.0354), ESR (PD1+CD4+, r = 0.4108, P = 0.0142), myositis disease activity assessment visual analogue scale of muscle (MAYOACT) (PD1+CD4+, r = 0.3243, P = 0.0115), and myositis intention to treat activity index of muscle (MITAX) (TIM3+CD4+, r = 0.3294 P = 0.0102; LAG3+CD4+, r = 0.3066 P = 0.0172).