Abstract: Objective To investigate the expression of B7-H1 on peripheral blood mononuclear cells(PBMCs) from patients with systemic lupus erythematosus(SLE).Methods Immunofluorescent staining and flow cytometry assay were used to measure the expression level of B7-H1 on PBMCs from 30 SLE patients and 20 healthy controls.Results of laboratory examination of patients were collected.SLE disease activity index(SLEDAI) was used to evaluate the disease severity.Results The expression levels of B7-HI on monocytes,lymphocytes and granulocytes was markedly higher in active SLE group than those in control group(all P<0.01),respectively.The expression of B7-H1 on monocytes and lymphocytes was positively correlated with SLEDAI of patients(r₁=0.42,P₁<0.05; r₂=0.52,P₂<0.05),respectively.On the other hand,B7-H1 expression on lymphocytes was significantly higher in patients with positive anti-dsDNA antibody than that in parients with negative anti-dsDNA antibody(t=3.20,P<0.01).After three weeks' treatment with glucocorticoid,the level of B7-Hl was significantly decreased on the monocytes,lymphocytes and granulocytes of patients in comparison with that before treatment(t=10.00,6.75,4.33,respectively,all P < 0.01).Conclusions The expression of B7-H1 on PBMCs increased in active SLE,and there was positive correlation between B7-Hl expression and SLEDAI,which suggests that B7-Hl may be relevant to the pathogenesis of SLE.

Key words: Lupus erythematosus,systemic, Lymphocytes, Monocytes, B7-H1