CD4 and rheumatoid arthritis: To investigate whether IL-25 has a similar capacity to suppress the Th1/Th17 responses involved in the pathogenesis of RA, CD4+ T cells from PBMCs of RA patients and HCs were isolated and stimulated with anti-CD3 (5 μg/mL) plus anti-CD28 (2 μg/mL) in the presence or absence of rhIL-25 (100 ng/mL).