CXCR5 and rheumatoid arthritis: We depicted the level of CXCR5 DNA methylation and the proportion of haplotypes in the peripheral blood of RA patients, combined the methylation changes with clinical characteristics of RA patients for correlation analysis, explored the role of CXCR5 in RA from an epigenetic perspective, and helped to deepen the understanding of the pathogenesis of RA.