In this study, we identified the OCP subset with a high level of CCR2 expression that is specifically induced by the mouse model of RA, being present in SPL (CD45+Ly6G-CD3-B220-NK1.1-CD11b+CD115+CCR2hi) and PBM (CD45+Ly6G-CD3-B220-NK1.1-CD11b-/loCD115+CCR2hi). This evidence concerns the gene ITGAM and rheumatoid arthritis.