Study on the apoptosis of T lymphocytes of peripheral blood in systemic lupus erythematosus (SLE) and the correlated pathogenesis.

Objective:To study the apoptosis of T lymphocyte subsets of peripheral blood in systemic lupus erythematosus(SLE) and the correlated pathogenesis.Methods:The percentages of T lymphocyte subsets,the positive expression rates of Fas/FasL on T lymphocyte subsets,and the apoptosis of T lymphocyte subsets were determined by three-colorflow cytometry.The level of serum IL-10 was analyzed by ABC-ELISA.IL-10 antibody and FasL antibody were added respectively into the 48 hours' culture of 10 SLE patients' PBMCs in vitro,whose serum IL-10 significantly increased,and then,the changes of T lymphocyte subsets of SLE PBMCs were determined by three-colorflow cytometry.Results:1) In SLE,mainly in hyperactive SLE,the apoptosis of CD4+ T lymphocytes increased significantly(P<0.05),and the ratio of CD4+/CD8+ decreased compared with normal controls,and the abnormal apoptosis of CD4+ T lymphocytes had a positive correlation with the increased expression rates of Fas/FasL on CD4+ and CD8+ T lymphocytes(P<0.05).2) The serum IL-10 level increased significantly in SLE(P<0.01),expecially in hyperactive SLE,and serum IL-10 had a positive correlation with the level of serum anti-dsDNA antibodies,CD4+/CD8+ ratio,and the positive expression rate of FasL on CD4+ T lymphocytes(P<0.05).3) According to a tracking experiment on two different groups of SLE patients,we found that:with the stabilization of the illness,the level of serum IL-10 decreased significantly,the positive expression rate of Fas/FasL on T lymphocytes,particularly on CD4+ T lymphocytes,reduced evidently,and the apoptosis of CD4+ T lymphocytes decreased(P<0.05).Conclusion:The abnormal activities of T lymphocytes,particularly of CD4+ T lymphocytes from patients with SLE,which lead to AICD,cause the percentage of CD4+ T lymphocytes and the ratio of CD4+/CD8+ to decrease,disorder immune response,and accelerate the process of SLE.As a key factor in modulating the positive expression rate of Fas/FasL on CD4+ T lymphocytes,IL-10 plays an important role in causing SLE.