Finally, pretreatment of RA ECs with an excess of the CXCR4-specific inhibitor T134, which precludes CXCL12α binding to CXCR4 [20], did not affect the immunodetection of RA EC-bound CXCL12 (Figure 2a). This evidence concerns the gene CXCL12 and rheumatoid arthritis.