CCR5 and rheumatoid arthritis: According to the qRT-PCR validation, the expression levels of CXCL13, CXCL6, CCR5, CXCR5, CCR2, CXCL3, and CXCL10 in the RA synovial tissue samples were higher than that in OA synovial tissue samples, while the expression of SSTR1 showed the opposite trend.