CCR2 and rheumatoid arthritis: Statistical analysis showed that the expression levels of CXCL13 (P < 0.0001), CXCL6 (P = 0.0252), CCR5 (P = 0.0002), CXCR5 (P = 0.0033), CCR2 (P = 0.0073), CXCL3 (P = 0.0314), and CXCL10 (P < 0.0001) in the RA synovial tissue samples were significantly higher than those in the OA synovial tissue samples, while the expression level of SSTR1 (P = 0.0486) was significantly higher in the OA synovial tissue samples than in the RA synovial tissue samples (Figure 6).