Based on the foregoing, the main purpose of this study was to evaluate whether recombinant human MIF (rhMIF) promotes the secretion of IL-25, IL-31, and IL-33 in peripheral blood mononuclear cells (PBMC) from control subjects (CS) and RA patients and to recognize the possible relationship between these four cytokines and their role in RA. The gene discussed is IL33; the disease is rheumatoid arthritis.