Changes Of IL-27 In Peripheral Blood Of Patients With Sjogren's Syndrome And Its Regulation On B Cells

Background:Sjogren’s syndrome (SS) is an autoimmune disease with immune system imbalance. Autoantibodies existed in the peripheral blood of SS patients participate in the pathological process, which is secreted by B cells.Objective:To testify dysfunction of B lymphocytes and the possible factors involved in SS.Methods:Five milliliters anticoagulant peripheral blood was obtained from SS patients and healthy controls. Peripheral blood mononuclear cells (PBMCs) were isolated, and B cell activation, proliferation, differentiation and apoptosis of CD19+B cells, as well as the percentages of T follicular helper cells (Tfh) were tested by flow cytometry. Serum levels of immunoglobulin (Ig) G and cytokines including interleukin (IL)-27, IL-4and IL-10were examined by Enzyme linked immunosorbent assay (ELISA). To detect the effect of IL-27on B cells, PBMCs from SS patients and healthy controls were cultured with or without the stimulation of50ng/ml IL-27.72or96hours later, cells were collected and the B cell functions as well as Tfh percentages were tested by flow cytometry. Concentrations of cytokines in the culture supernatants were detected by ELISA.Results:Compared with healthy controls, SS patients had enhanced B cell activation, proliferation, apoptosis and plasma cell differentiation, along with increased Tfh cell percentages. However, the differentiation ability of B cells into CD27+memory B cells were reduced. Serum levels of IL-27in SS patients were elevated, especially in those with high concentration of ANA or with anti-SSA, anti-SSB antibodies. In vitro study showed that B cell activation, proliferation, plasma cell differentiation, IgG secretion and the percentages of Tfh cells were all improved after adding IL-27to the culture system of PBMCs from SS patients. Cytokines related to B cell functions such as interferon (IFN)-y, IL-4and IL-10were increased and positively correlated with IL-27levels in SS patients in vivo. Meanwhile, levels of IFN-y, IL-4and IL-10in the supernatants were upregulated by IL-27stimulation.Conclusion:High concentration of serum IL-27in SS patients could participates in the regulation of B cell functions including activation, proliferation and differentiaion in which cytokines such as IFN-y, IL-4and IL-10may be involved.