The Role Of Tfh And Tfr Cell Ratio Disorder In The Pathogenesis Of Autoimmune Hepatitis

Objective:Autoimmune Hepatitis(AIH)is a chronic inflammatory liver disease characterized by circulating autoantibodies and elevated levels of serum immunoglobulin.Study found that in autoimmune diseases,the survival and differentiation of autoreactive B cells and the production of pathogenic antibodies are caused by the imbalance of Follicular helper T cells(Tfh cells)and Follicular regulatory T cells(Tfr cells).This study examined the ratio of Tfh and Tfr in peripheral blood of patients with AIH and healthy controls and also detected the expression of IL-21 in peripheral blood.Then analyzed the effects of the imbalance Tfh cells on the spleen germinal center reaction,plasma cells and memory B cells in AIH patients,to explore the potential role and mechanism of imbalance Tfh cell in the pathogenesis of AIH.Methods:Serum samples were collected from 20 treatment na?ve AIH patients who were admitted to the Department of Gastroenterology,General Hospital of Tianjin Medical University from January 2018 to September 2018 were enrolled.All subjects were excluded from other autoimmune diseases and malignancies.Age-and sex-matched healthy controls(n=15)were obtained from physical examination centers.Peripheral blood mononuclear cells(PBMC)were isolated from the venous blood of each group.Moreover,the proportion of Tfh cells and Tfr cells in peripheral blood of the subjects were analyzed by Flow cytometry.The correlation between Tfh cells and clinical indicators was calculated.The expression of IL-21 in peripheral blood of AIH patients and healthy controls were analyzed by RT-PCR.The spleen tissue was obtained from six AIH patients,three patients with HBV and two patients with traumatic spleen rupture.Hematoxylin-eosin staining and immunofluorescence were used to observe the changes in the germinal center and the expression of CD4~+CXCR5~+T cells in each patient.The changes in immune status after splenectomy were analyzed.Flow cytometry was used to detect the expression of plasma cells and memory B cells in peripheral blood of AIH patients and healthy controls,and to analyze their correlation with Tfh cells and clinical indicators.Flow cytometry was used to detect the expression of plasma cells and memory B cells in peripheral blood of AIH patients and healthy controls.The correlation between plasma cells and memory B cells and Tfh cells and clinical indicators was analyzed.Results:1.The proportion of CD4~+CXCR5~+T cells and Tfh cells in the circulation of AIH patients was significantly higher than that of healthy controls(P<0.05),and the expression level of IL-21 was increased(P<0.01).At the same time,the proportion of Tfr cells in AIH patients was lower than that in healthy controls(P<0.05).Correlation analysis showed that Tfh cells in peripheral blood of patients with AIH were positively correlated with serum IgG(r=0.6020,p=0.0174),but not correlated with ALT,AST,ALP,GGT and IgM in serum;2.HE staining of spleen tissue showed that the volume of germinal center in AIH patients increased,the number increased,and the shape was irregular.At the same time,the proportion of CD4~+CXCR5~+T cells in spleen tissue of patients with AIH patients was significantly increased.After spleen resection,serum IgG levels were significantly reduced in AIH patients;3.The levels of plasma cells and memory B cells in peripheral blood of AIH patients were significantly higher than those in healthy controls(P<0.01).Correlation analysis showed that the number of plasma cells in AIH patients was positively correlated with serum IgG(r=0.6393,p=0.0107)and IgM(r=0.5822,p=0.0228),but no correlation with ALT,AST,ALP,and GGT.The correlation between plasma cells and memory B cells and Tfh cells were found to be positively correlated with the proportion of Tfh cells in the peripheral blood of AIH patients.Conclusion:The imbalance of Tfh cells and Tfr cells in peripheral blood of AIH patients further led to abnormal amplification of spleen germinal center reaction.Also,Promotes excessive differentiation of plasma cells and memory B cells.The imbalance of Tfh cells and Tfr cells may be the primary cause of the production of autoantibodies and hyperimmunoglobulinemia in AIH patients,and one of the essential mechanisms of the pathogenesis of AIH.