Objective:To investigate the possible deficiencies in the transcription,secretion,and expression of regulatory T cells(Treg) associated TGF-β in patients with systemic lupus erythematosus(SLE). Methods:Peripheral blood mononuclear cells(PBMC)and CD4+ CD25+ T cells were isolated from patients with SLE and health controls. The cells were cultured and stimulated with anti-CD3 and anti-CD28 for 48 hours. Three-color flow cytometry was performed to detect CD4+CD25+LAP+T and CD8+CD25+LAP+T cells; Q-RT-PCR was used to detect TGF-β mRNA level; ELISA was performed to detect the levels of total TGF-β1 and free active TGF-β1 in the supernatants of the cell cultures. Results:The ratios of LAP+/CD4+ T,CD25+ LAP+/CD4+ T and LAP+/CD4+CD25+ in fresh PBMCs,or in cultured cells stimulated with anti-CD3 and anti-CD28,from active SLE patients were both significantly higher than those from health controls (P < 0.05),but there were no significantly correlations between the abnormally increased LAP expression and SLE disease activity index (SLEDAI). Whether stimulated or not,mean fluorescent intensity (MFI) of LAP in CD4+CD25+LAP+ cells from patients with SLE was also higher than that from health controls(P < 0.05). With the stimulation,CD4+CD25+ T cells from the patients secreted less TGF-β1,both in the forms of total TGF-β1 and free active TGF-β1 (P < 0.05). Furthermore,CD4+CD25+ T cells from active SLE patients displayed less TGF-β mRNA level than those from health controls did. Conclusion:In CD4+CD25+ T cells from SLE,there are deficiencies in the transcription and secretion of TGF-β1,and in the production of free active TGF-β1,although the expression of LAP on the cell surface is increased,which may reflect the abnormal activation of T cells and a proliferative respond of CD4+CD25+ LAP+ Treg to auto-antigens. These deficiencies in TGF-β expression of CD4+CD25+T cells in active SLE patients probably weaken the function of Treg cells.