In RA patients, the synovial sRANKL concentration correlated with the synovial MIF concentration in RA patients (γ = 0.6; P < 0.001; Figure 1a), but the serum sRANKL concentration did not correlate with serum MIF concentration (γ = 0.13; P = 0.5, data not shown). The gene discussed is MIF; the disease is rheumatoid arthritis.