C17orf99 and rheumatoid arthritis: In patients with RA, synovial fluid IL-40 significantly correlates with the number of synovial fluid neutrophils (r=0.375, p=0.017) and with the synovial fluid levels of chemokines IL-8 (r=0.539, p=0.004) and MIP-1α (r=0.537, p=0.002), (Figures 3C, D).