CCR1 and rheumatoid arthritis: Similarly, the small molecule CCR1 antagonist BX471 also blocked CCL5/RANTES-induced migration of RA monocytes (1 μg/ml, P = 0.0181; 5 μg/ml, P = 0.0015; 25 μg/ml, P = 0.0118 compared to CCL5/RANTES) (Fig. 4C).