The Clinical Significance Of T Follicular Helper Cells And Its IL-29 Receptors In Rheumatoid Arthritis

Background:Rheumatoid arthritis(RA)is a systemic autoimmune disease which is related to abnormal immune response.Its etiology and pathogenesis are not very clear.At present,it is considered that RA is related to immune,genetic,environmental and other factors.Immune disorder is the main pathogenesis of RA.It has been found that RA patients'blood and synovium have abnormal proportion or functions'T,B lymphocyte,macrophage,neutrophil and other immune cells.They sustain to produce a large number of cytokines and inflammatory molecules,promoting the occurrence and development of RA.At present,abnormal activation of T lymphocytes and T cell-dependent B cell response are the main causes of RA.Among them,the large infiltration of CD4~+T cells are the key factor.Peripheral blood follicular helper T cells(Tfh cells)are one of the subgroups of CD4~+T cells which was found in recent years.They not only stimulate the proliferation and differentiation of B cells and eventually form germinal center(GC),but also play an important role in maintaining the maturation and proliferation of B cells and promoting the transformation of immunoglobulins.Previous studies:Tfh cells influence the pathogenesis of RA through assistanting B cells to promote the production of anti-CCP antibodies.Serum IL-29 levels in anti-CCP antibody positive RA patients are significantly positively correlated with disease activity.However,there are few reports on whether Tfh cells are involved in RA joint destruction,RA disease activity and its relationship with anti-CCP antibodies;the level of IL-29 receptors on Tfh cells in RA patients is not clear;whether Tfh cells are involved in RA pathogenesis under the action of IL-29 is not clear,and the correlation between Tfh cells and disease activity and various clinical and laboratory indicators has not been reported.Therefore,the study of the expression level of follicular helper T cells and IL-29 receptors in rheumatoid arthritis patients and their correlation with various clinical and laboratory indicators will help to further reveal the role of Tfh cells and IL-29 in the pathogenesis of RA,and provide new targets for the prevention and treatment of RA.Objective:Flow cytometry was used to detect the RA patients'expression of IL-29 receptorsin peripheral blood Tfh cells.The correlation between themwith clinical and laboratory indexes was analyzed.The role of Tfh cells and IL-29 receptors expression on the surface of Tfh cells in the pathogenesis and progression of RA was discussed.Patients and Methods:This study involved 30 RA patients fulfilling 1987 American College of Rheumatology(ACR)classification criteria or 2010ACR and European League Against Rheumatism(EULAR)classification criteria.They were diagnosed and hospitalized in the Department of Rheumatology and Immunology of the Hospital of Jilin University,from January 2017 to May 2017.30 age and gender matched healthy volunteers were enrolled as healthy controls(HC).Clinical indicators(including the name,sex,age,course of disease,morning stiffness time,patient health assessment questionnaire(HAQ),rheumatoid factor(RF),erythrocyte sedimentation rate(ESR),anti-cyclic citrullinated polypeptide antibody(CCP),C-reactive protein(CRP),serum immunoglobulin level(IgA,IgG,IgM),serum complement level(C3,C4),joint X-ray plain film,joint color Doppler ultrasound,swelling related factors,Segments(SJC),tender joints(TJC),etc.According to the joint X-ray plain film of RA patients,the joint destruction was evaluated and divided into joint bone erosion group(15 cases)and no joint bone erosion group(15 cases).Flow cytometry was used to detect CD3-PerCP,CD4-PerCP,CXCR5-APC,ICOS-PE,PD-1-PerCP,CD40L-FITC,OX40-FITC-labeled Tfh cells and IL-28R-PE,IL-10R-FITC-labeled CD4~+CXCR5~+Tfh cell in 30patients with RA and 30 patients with HC.The difference between the level of IL-29receptor on Tfh cells and its correlation with clinical and laboratory indexes were analyzed.Results:(1)In the peripheral blood,the percentage ofCD4~+CXCR5~+,CD4~+CXCR5~+ICOS~+,CD4~+CXCR5~+OX40~+,CD4~+CXCR5~+CD40L~+Tfh cells in CD4~+Tfh cells of RA patients(n=30)group were significantly higher than that of HC patients(n=30)group(p<0.05).(2)In the peripheral blood,the levels of IL-28Rand IL-10R in CD4~+CXCR5~+Tfh cells were significantly higher than that of HC patients(n=30)group(p<0.05).(3)The percentage of CD4~+CXCR5~+,CD4~+CXCR5~+OX40~+,CD4~+CXCR5~+CD40L~+Tfh cells in CD4~+Tcells and the level of IL-10R in CD4~+CXCR5~+Tfh cells were positively correlated with DAS28(ESR)(r=0.533,p=0.002;r=0.594,p=0.001;r=0.440,p=0.015;r=0.423,p=0.02).The percentage of CD4~+CXCR5~+,CD4~+CXCR5~+OX40~+,CD4~+CXCR5~+CD40L~+Tfh cells in CD4~+Tcellswere positively correlated with anti-CCP antibodies(r=0.406,p=0.026;r=0.401,p=0.028;r=0.429,p=0.018).(4)In this study,RA patients were divided into groups according to whether there was joint bone erosion or not.The results of correlation analysis showed that in RA patients without joint bone erosion,Tfh cells were positively correlated with ESR,HAQ,number of swollen joints and morning stiffness time(p<0.05).Conclusion:(1)The level of Tfh cells in RA patients increased significantly,and Tfh cells mainly participated in the immune response when the disease was highly active,suggesting that the level of Tfh cells in peripheral blood of RA patients may be one of the reference indicators for evaluating the severity of disease in RA patients.(2)The expression level of Tfh cell surface markers in RA were different,suggesting that Tfh cells can participate in the occurrence and development of RA through a variety of ways.(3)In peripheral blood of RA patients,we first found that the level of IL-29 receptors on CD4+CXCR5+Tfh cell surface of RA patients were significantly higher than that of HC group,and the level of Tfh cells were positively correlated with the level of anti-CCP antibody,suggesting that IL-29 may bind to the IL-29 receptors on Tfh cell surface of RA patients and participate in the production of RA autoantibody.(4)In peripheral blood of RA patients,we first found that the level of IL-29 receptors on CD4+CXCR5+Tfh cells were positively correlated with disease activity,and the level of Tfh cells in non-articular bone erosion group were positively correlated with disease activity index,suggesting that IL-29 may affect the disease activity of RA patients in the early stage of disease progression by acting on the IL-29 receptors on the surface of Tfh cells.