IL17A and rheumatoid arthritis: The median percentage of IL-17-positive CD4 T cells coexpressing IL-22 did not significantly differ between SFMC (7.90% (5.57 to 16.23)), RA PBMC (15.13% (3.36 to 26.76)) and PBMC of healthy donors (14.29% (9.37 to 23.85)) (Figure 3B).