Objective Autoantibodies and corresponding immune complexes involved directly in the development of rheuma -toid arthritis ( RA) .The effect of anti-mutated citrulline vimentin antibodies contained immune complex ( AMCV-IC) on the function of fibroblast-like synoviocytes ( FLSs) is still unclear .The aim of the study was to investigate the effect of AMCV-IC in serum of RA pa-tients on the proliferation of RA-FLSs. Methods Serum samples of RA , SLE ( systemic lupus erythematosus ) and healthy people were collected from outpatients and hospitalized patients in Nanjing General Hospital of Nanjing Military Region from March 2012 to March 2013 , including 20 RA patients ( 10 patients with serum AM-CV+and 10 patients with serum AMCV -) , 10 SLE patients and 10 healthy people .Serum AMCV of SLE patients and healthy people was negative .Serum IC was extracted by affinity chromatography with im-mobilized protein G and was divided into AMCV +-IC group,AMCV--IC group,SLE-IC group, and control group.The levels of AMCV were detected by ELISA .We cultivated RA patients'arthral FLSs in vitro .FLSs were stimulated with AMCV +-IC,AMCV--IC, SLE-IC and CON-IC (50,100,200,and 400μg/mL),respectively.And the effect of IC on RA-FLSs was detected by CCK-8. Results Compared with AMCV --IC group (1.37 ±0.86, 1.31 ±0.10),SLE-IC group (1.36 ±0.06, 1.38 ±0.03) and CON-IC group (1.08 ±0.02, 1.04 ±0.06),the A values of AMCV +-IC group (1.53 ±0.11, 1.58 ±0.05) were obviously higher after stimulating RA-FLSs with 50 and 100μg/mL IC for 24 h (P<0.05);Similarly, compared with AMCV --IC group (1.32 ±0.04, 1.38 ±0.07), SLE-IC group (1.31 ±0.10, 1.29 ±0.01) and CON-IC group (1.13 ±0.06, 1.03 ±0.09),the A values of AMCV +-IC group (1.53 ±0.16, 1.57 ±0.06) were obviously higher after stimulating RA-FLSs with 200 and 400μg/mL IC for 24 h (P<0.05). Meanwhile , the A values of AMCV --IC group and SLE-IC group were obviously higher than CON-IC group under different concentra-tions of IC(P<0.05). Conclusion AMCV+-IC can stimulate the proliferation of RA-FLSs more effectively compared with AM-CV--IC, SLE-IC and CON-IC under different concentrations of IC and involve in the pathogenesis of RA .