| Objective:Systemic lupus erythematosus (SLE) is a complex connective tissue autoimmune diseases that are associated with multi-system involvement, mostly occurring in women of childbearing age, and performance manifest as multiple target organ damage including kidney damage, which may even develop into the end-stage renal disease and need to rely on life-sustaining renal replacement therapy.Therefore, people show much attention on the the pathogenesis of lupus nephritis as long. It has been recognized that the functional changes and imbalances of B cell subsets are closely related to the pathogenesis of SLE.Regulatory B cells have relationship with a variety of autoimmune diseases. It is not only related to the secretion of autoantibodies, but also plays a role in immune regulation by secreting IL-10, TGF-? and other cytokines, and especially has an important role in regulatory T cell-mediated immunity. However, how does the regulatory B cells play its regulatory roles in autoimmune diseases remains controversy. This study will investigate the expression and distribution of regulatory B cells in SLE. Besides, the important signaling pathways of the B cells in regulation will also be evaluated.Methods:Part 1:The enrolled SLE patients were initial or recurrent (stopping the treatment of hormones and other immunosuppressive agents more than six months) patients who visited to our hospital between 2012.01 to 2013.01, and their SLEDAI score all were greater than 5 points. Blood samples were collected with a part for conventional biochemical tests, a part for retention of serum, the rest for flow cytometric analysis. Then, we compared the biochemical indicators and the pathological indicators and evaluated whether the score of the SLEDAI and BILAG is agreeable.Part 2:Using the flow cytometry to analyze peripheral blood of patients and healthy controls in the following aspects:1)the cell subset distribution of CD19+CD24hiCD38hi and CD19+CD24hiCD38low2)the distribution of CD40 and CD40L on T and B cells. sCD40L concentrations from patients and the healthy controls were analyzed using the ELISA method.Part 3:Normal human peripheral blood lymphocytes were isolated and cultured with treatment of IL-21, CD40L, lupus serum, aCD40L and IL-21RFcy respectively. Then, using the flow cytometry method, the redistribution of cell subsets with CD19+CD24hiCD38hi were evaluated.Results:Part 1:The enrolled patients showed a fairly agreeable in the SLEDAI and BILAG score.Part 2:1)The CD 19+CD24hiCD38hi cell subsets of regulatory B cells in SLE patients were increased compared with the healthy controls (P<0.05).2)CD19+CD24hiCD38low cell subsets in SLE patients were decreased as compared to healthy control group.3) The expression of CD38 and the serum concentrations of sCD40L was positively correlated (P<0.05).Part 3:1) The regulatory B cell expression from the healthy people were increased when co-cultured with serum of SLE patients on IL-21 (P<0.05).2) CD40L monoclonal antibody could block the upregulated regulatory B cells from the healthy control treated with SLE serum (P<0.05).Conclusion:1) Evaluating the disease activity of SLE needs reliable and sensitive evaluation system.The score of the SLEDAI and BILAG on the enrolled patients is fairly agreeable. The combination of these two evaluating systems can better evaluate clinical conditon. In addition,we find BILAG-2004 has a better correlation with 24 hours urinary protein compared with SLEDAI-2000.2) Compared to the healthy controls, the ratio of regulatory B cells in active SLE patients is significantly increased, and has a positive correlation with sCD40L. CD40L monoclonal antibody can reverse the proliferation of regulatory B cells in SLE patients, indicating that there is a close link between the regulatory B cells and SLE, and such links may be regulated by IL-21/IL-21R and CD40/CD40L signaling pathway. |
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