Knee OA patients (n = 9) also had a lower level of MIF mRNA than controls and knee RA patients (n = 12) (mean ± SD, logRQ = − 0.40 ± 0.38, − 0.21 ± 0.35, and − 0.21 ± 0.30, respectively), but the differences were not statistically significant (p ≥ 0.2). This evidence concerns the gene MIF and rheumatoid arthritis.