Finally, we compared the MIF mRNA expression and the MIF serum levels according to both MIF polymorphisms to examine the effect of these genetic variants on MIF gene regulation; this analysis showed no association between any of the alleles, genotypes, or haplotypes and the MIF serum levels or the amount of mRNA in total leukocytes of patients with RA or CS. The gene discussed is MIF; the disease is rheumatoid arthritis.