In cartilage, natural log-transformed MIF mRNA level was significantly lower in OA patients than in controls (mean ± SD, logRQ = − 0.47 ± 0.32 vs. − 0.21 ± 0.35; p = 0.028) and RA patients (mean ± SD, logRQ = − 0.18 ± 0.28; p = 0.004). This evidence concerns the gene MIF and rheumatoid arthritis.