For RA PB the MFI (mean ± SD) for CCR1, CCR2, CCR5 and CXCR4 was 46 ± 13, 92 ± 20, 14 ± 10 and 17 ± 6, and for healthy PB 41 ± 17, 94 ± 40, 10 ± 4 and 11 ± 8 respectively. Here, CXCR4 is linked to rheumatoid arthritis.