Objective To investigate the changes of B lymphocyte subsets ( naive B cells, memory B cells and plasmablasts) in peripheral blood of patients with rheumatoid arthritis ( RA) and their correla-tions with the clinical manifestation and laboratory indexes.Methods Sixty-six patients with RA were di-vided into two groups including the group with active RA and the group with inactive RA according to the dis-ease activity score in 28 Joints (DAS28).A control group with healthy subjects was set up accordingly.The distributions of B lymphocyte subsets in peripheral blood samples were detected with flow cytometry analysis and their correlations with clinical manifestations and laboratory indicators were analyzed.Results ( 1 ) Compared with healthy subjevts, the mean fluorescence intensities ( MFIs) of CD19 and the percentages of memory B cells in peripheral blood of the patients with RA were significantly decreased, while the percenta-ges of naive B cells were increased (P<0.05).The percentages of plasmablasts in the patients with active RA were significantly increased as compared with those of healthy subjects and the patients with inactive RA (P<0.05).(2) The percentages of plasmablasts in peripheral blood of the patients with RA were positively correlated with the joint tenderness count, joint swelling count and joint swelling index (P<0.05).(3) A positive correlation was found between the MFIs of CD19 and the erythrocyte sedimentation rates ( ESRs ) among the patients with RA.The percentages of plasmablasts were positively correlated with C reaction pro-tein (CRP) and anti-cyclic citrullinated peptide (anti-CCP) antibody (P<0.05).(4) The percentages of plasmablasts were also positively correlated with the DAS28 among the patients with RA ( R2=0.343, P<0.01).Conclusion The distributions of B lymphocyte subsets varied among the patients in different stages of RA, which were related to the patient′s clinical symptoms and laboratory indexes.The study suggested that different subsets of the B lymphocytes might play an important role in the pathological process of RA.