Although the numbers of the B-cell CCR1-positive and B-cell CCR2-positive persons did not differ between the cohorts, the frequency (the mean %) of the CCR1- and CCR2-positive B cells was considerably higher in RA patients, 2.1- and 4.3-fold, respectively, relative to the OA and HC groups. This evidence concerns the gene CCR1 and rheumatoid arthritis.