EXPRESSION OF COSTIMULATORY MOLECULE CD80 ON PERIPHERAL-BLOOD T-CELLSIN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. To investigate the expression of costimulatory molecule CD8 0 on T cells of peripheral blood mononuclear cells (PBMC) in patients with systemic lupus erythematosus (SLE). Methods. Monoclonal antibodie s against CD80 were used for flow cytometry and expression of CD80 on PBMC was studied in 26 patients with SLE, 18 patients with rheumatoid arthritis (RA), 8 patients with mixed connective tissue disease (MCTD) , and 22 healthy controls. Results. CD80 was detected on CD3+ and CD19 + cells in patients with SLE and it was significantly higher than that of controls. In patients with SLE CD80 was expressed on CD4+ T cells (8.05 +/- 5.45%), significantly higher than in RA and controls, but wa s not highly expressed on CD8+ T cells (1.67 +/- 2.87%). CD80+CD4+ T c ell phenotype analysis revealed CD45RA-, CD45RO+, and CD25+, or HLA-DR + activated T cells. The percentage of CD80+ cells in CD4+ cells incre ased in the active stage of SLE, and was significantly correlated with the SLE disease activity index. Conclusion. CD80 can be expressed on activated CD4+ T cells in PBMC of patients with SLE in vivo and the ap pearance of these cells is associated with the disease activity in SLE .