Accordingly, we found that abatacept enhanced blood LAG3+ conventional (CD4+CD25+Foxp3+) and unconventional (CD4+CD25-Foxp3+) Tregs level as well as IL-35+IL-10+ producing Bregs (IL-35+IL-10+ cells within CD19+CD138+CD1d+) in RA patients. Here, CD4 is linked to rheumatoid arthritis.