CCR2 and rheumatoid arthritis: On T/NK lymphocytes, CCR1 was expressed in four RA patients (the mean of the positive cells was 14.8%; range: 5.4%–24.3%), but CCR2 was expressed in 11 out of the 15 RA patients (the mean of the positive cells was 11.7%; range: 5.3%–29.2%).