Significantly higher values of MFI were observed in circulating CD4+ and CD8+ T cells from patients with RA (median 93.5, IQR 69.4–126.3; 114.0, IQR 87.5–143.0, respectively) than in those from HC (median 46.7, IQR 25.5–71.0; 54.0, IQR 30.5–82.8, both p < 0.05) (Fig. 1b, c). Here, CD4 is linked to rheumatoid arthritis.