Fourthly, not only the clinical effect was evaluated by DAS28, CRP, ESR, RF, anti-CCP antibody, Health Assessment Questionnaire and scores (49, 50, 53, 55), but also patients’ immune balance was evaluated by the ratio of Treg/Th17 cells, serum levels of TNF- α, IL-6, IL-10, and even anti-HLA antibodies (39, 49), which might account for mechanisms of the effect and adverse reactions of MSCs in RA treatment. This evidence concerns the gene IL6 and rheumatoid arthritis.