It was found that, like TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-7, IL-10, IL-12, GM-CSF, IFN-γ, and MCP-1, IL-37 in the blood of RA patients was also positively correlated with the DAS28 disease activity score, suggesting that both proinflammatory and anti-inflammatory cytokines are highly produced in RA patients, especially in those with active RA. This evidence concerns the gene CCL2 and rheumatoid arthritis.