title: Increased serum IL-10 in lupus patients promotes apoptosis of T cell subsets via the caspase 8 pathway initiated by Fas signaling.
abstract: We sought to investigate the expression of Fas and FasL on T cell surface and caspase 8 involvement in T cell apoptosis promoted by serum IL-10 in systemic lupus erythematosus (SLE) patients. Cells and sera were obtained from 35 SLE patients. Apoptosis of T cells in patients with SLE was increased and associated with the SLE disease activity index (SLEDAI). Elevated expression of Fas and FasL on T cell surface contributed to increased apoptosis of T cells. Increased IL-10 in the sera of SLE patients was capable of inducing Fas and FasL expression on CD4(+)T cell surface, promoting apoptosis of this cell subset. Decreased IL-10 serum levels and low expression of Fas were found in 5 patients of the first follow-up group after 2-month treatment. In another group with one-year treatment, the SLEDAI declined to inactive scores. Serum IL-10 was decreased significantly, and expression of Fas and FasL on T cells was also reduced. Declined apoptosis was predominant only in CD4(+)T cell subset. When sera with high level of IL-10 were used to culture PBMCs from healthy controls, activated caspase 8 was elevated in CD3(+)T, CD4(+)T and CD8(+)T cells. The study showed that serum IL-10 induced apoptosis of T cell subsets via the caspase 8 pathway initiated by Fas signaling. Increased apoptosis of T cells contributes to autoantigen burden, which is pathogenic in the development of SLE.
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Xiaofan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210036, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Yin
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Xiaole
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Microbiology and Immunology, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Ji
keywords: T cell; apoptosis; lupus erythematosus; systemic