No differences in percentages of CD4+IL-17+ and IL-22+ T cells were seen within PsA SFMCs as compared to RA SFMCs (1.9% vs. 1.3%, P > 0.05, and 0.66% vs. 0.45%, P > 0.05) (Figures 5C and 5D). Here, CD4 is linked to rheumatoid arthritis.