CCL4 and rheumatoid arthritis: Evidence from a case-control study of 24 RA patients and 22 controls showed that the mean (±SEM) level of MIP-1b was higher in the synovial fluids of RA patients (738 ± 282 pg/ml), while it was lower in the serum of RA patients (189 ± 23 pg/ml), as compared to controls (39 ± 6 pg/ml in synovial fluids; 244 ± 68 pg/ml in serum) (Patel et al., 2001).