PDCD1 and rheumatoid arthritis: We observed in vitro experiment that MtROS scavenging significantly downregulated the secretion of inflammatory cytokines IFN-γ and TNF-α, the cytotoxic molecules Perforin and Granzyme B (Fig. 5A), and transcription factors (T-bet, Eomes, BATF, and Blimp1) (Fig. S8) in RA CD4+PD-1+T cells.