CD19 and rheumatoid arthritis: The absolute number of circulating CD19+ cells was not different in RA patients with active or inactive disease as compared with controls (mean ± SEM, 86.65 ± 13.06 × 103 CD19+ cells/ml in RA-a versus 87.51 ± 15.78 in RA-r patients versus 86.70 ± 9.49 in HC).