The Role Of PD-1/PD-Ls In IgG4-RD And The Significance Of Hypersensitivity/eosinophilia In IgG4-RD

Objective:The pathogenesis of IgG4-related disease(IgG4-RD)remains unclear.Programmed cell death protein 1(PD-1)and its two ligands PD-L1(Programmed cell death 1 ligand 1)and PD-L2(Programmed cell death 1 ligand 2)are involved in the pathogenesis of a variety of autoimmune diseases.This study aims to investigate the role of PD-1 and its ligands in the pathogenesis of IgG4-RD.Methods:We recruited forty-three patients with IgG4-RD who were admitted to the Department of Rheumatology and Immunology of Peking Union Medical College Hospital from October 2017 to March 2019.At the same time,34 cases of gender and age-matched healthy control(HC)were enrolled.Plasma and peripheral blood mononuclear cells(PBMCs)were collected from 20-30 mL anticoagulated blood.Submandibular gland tissue from five cases of IgG4-RD patients,libial gland from five patients with primary Sjogren’s syndrome(pSS)were also collected.Concentration of soluble PD-1(sPD-1),soluble PD-L1(sPD-L1),soluble PD-L2(sPD-L2)in plasma were determined by enzyme-linked immunosorbent assay(ELISA).The expression levels of PD-1,PD-L1 and PD-L2 in tissues were detected by immunohistochemistry.The expression levels of PD-1,PD-L1 and PD-L2 on peripheral blood CD4+T cell subsets were analyzed by flow cytometry.Naive T cells in peripheral blood PBMC from IgG4-RD patients were sorted by magnetic beads.Naive T cells cultured in vitro were subjected to stimulation of recombinant human PD-L1(10 u g/mL)?recombinant human PD-L2(10 μ g/mL),anti-human PD-L1(10 μ g/mL),anti-human PD-L2(10 μ g/mL),cells were collected after 7 days and the proportion of CD4+CD25+Treg cells was detected by flow cytometry.Results:1.The concentrations of sPD-1,sPD-L1 and sPD-L2 in plasma of patients with IgG4-RD were significantly higher than those of HC.Plasm sPD-1 was positively correlated with serum IgG,IgGl,IgG3,IgG4,IgG4-RD RI and numbers of organs involved in IgG4-RD patients,and negatively correlated with serum IgM,IgA,C3 and C4.Plasm sPD-Ll was positively correlated with sPD-L2 and negatively correlated with C3.Plasm sPD-L2 was positively correlated with serum IgG1.Immunohistochemical detection showed that IgG4-RD patients had high expression of PD-1,PD-L1 and PD-L2 in the submandibular gland.The peripheral blood CD4+CD25+Treg cells in IgG4-RD patients were significantly increased.T-helper lymphocyte type-2(Th2)cells,T-helper lymphocyte type-1(Thl)and helper Th17 cells(Th17)did not differ significantly between the two groups.The expression of PD-1,PD-L1 and PD-L2 on the surface of Treg cells were all increased in IgG4-RD patients.Adding PD-L1 can promote the differentiation of in vitro cultured naive T cells from IgG4-RD patients into CD4+CD25+Treg cells.The stimulation of PD-L2 does not affect the differentiation of naive T cells into CD4fCDlS’Treg cells.However,under PD-L1 combined PD-L2 stimulation,the effect of PD-L1 on the differentiation of naive T cells to CD4+CD25+Treg cells disappeared.Conclusion:This study was the first to explore the role of PD-1 and its ligands in IgG4-RD.We found that plasm concentration of sPD-1,sPD-Ll and sPD-L2 were significantly increased in patients with IgG4-RD.The number of Treg cells in the peripheral blood increased significantly,and the expression of PD-1 and PD-L1/2 on the surface of Treg cells were upregulated.PD-1/PD-L1 can promote the differentiation of naive T cells into Treg cells and thus participate in the pathogenesis of IgG4-RD.The mechanism remains to be further studied.Background:IgG4-related disease(IgG4-RD)is a relatively newly defined disease entity,which can affect multiple organs and exhibit clinical heterogeneity.Recently,it has been reported that allergy was closely associated with the pathogenesis and clinical performance of IgG4-RD.As a consequence,large cohort study is needed to probe into the role of allergy in IgG4-RD.Methods:Three hundred and ninety newly diagnosed IgG4-RD patients who referred to Peking Union Medical College Hospital between January 2011 and April 2018 were enrolled.Using the definitions of the European Academy of Allergy and Clinical Immunology,we classified the subjects as either allergic or non-allergic.Clinical features of all the participants were collected and analyzed statistically.Results:We found that 47.95%(187/390)of our patients had a history of allergy.Allergic patients showed elevated incidence of salivary glands,paranasal sinus,and skin affection,while non-allergic patients had more large artery involvement and retroperitoneal fibrosis.Allergic patients also exhibited sig1ificantly up-regulated eosinophil,senam IgG4,IgE levels and IgG4/IgG ratio,while non-allergic patients presented with increased ESR,CRP,IgG1 levels,IgG1/IgG ratio,and higher incidence of anemia.The recurrence rate during follow-up showed no difference in the two groups.Conclusion:Clinical study put forward that allergic station did relate to different characteristics in IgG4-RD patients,therefore,basic research is needed to clarify the potentially related mechanism.Background:It has been reported that patients with IgG4-related disease(IgG4-RD)showed elevated incidence of eosinophilia.We aim to explore the clinical patterns of IgG4-RD patients with and without eosinophilia.Patients and methods:Four hundred and twenty-five IgG4-RD patients who referred to Peking Union Medical College Hospital between January 2011 and August 2018 were enrolled.Blood eosinophil counted higher than 0.5×109/L were defined as eosinophilia.Clinical features of all the participants were collected and analyzed statistically.Results:Eighty-seven patients(20%)with eosinophilia were found.As compared to patients with normal range of blood eosinophil count,male predominance,longer disease duration,increased prevalence of dacryadenitis,sialadenitis,lymphadenopathy and skin rash,higher IgG4-RD responder index,more organ involvement,higher levels of peripheral WBC,ESR,IgG,IgG1,IgG3,IgG4,IgE and IgG4/IgG ratio,while lower levels of serum IgA,IgG2 and C4 were found in patients with eosinophilia.There was no significant difference in the incidence of allergic disease between the two groups.Correlation analysis revealed that peripheral eosinophil counts were positively correlated to disease duration,numbers of organs involved,IgG4-RD responder index,peripheral WBC,HGB,ESR,IgG,IgG1,IgG3,IgG4,IgE and IgG4/IgG ratio,whereas inversely correlated to IgA,IgM,IgG2 and C4.Higher recurrence rate during follow-up period were found in patients with eosinophilia.Conclusion:IgG4-RD patients with eosinophilia exhibited different clinical pattern from patients without-Eosinophilia appeared independent of allergies in IgG4-RD.Our findings paved a way of identifying the role of eosinophil in the pathogenesis of IgG4-RD.Objectives:IgG4-related disease(IgG4-RD)and Castleman’s disease(CD)share similar clinical manifestations.When the histopathology coincides with the diagnosis of both IgG4-RD and CD,it is hard to depart the two disease entities utterly,here we call it IgG4-CD provisionally.In this study,we aim to review the clinical features of IgG4-CD.Methods:This study is based on a retrospective analysis of a prospectively acquired database.IgG4-CD was defined histopathologically in patients who fulfilled the diagnosis of both IgG4-RD and CD.Forty-five definite IgG4-RD and 16 multicentric CD(MCD)patients were recruited as controls.Clinical features including organ involvement,serum IgG4,IgG,IgE,ESR,CRP and IL-6 levels were collected and analyzed.Results:Fifteen patients(2.8%)out of 534 patients with IgG4-RD in China5s largest prospective IgG4-RD and Mimicry cohort fulfilled the definition of IgG4-CD.There were 14 males and 1 female,whose mean age was 47±18 years old,and the median disease duration before diagnosis was 12(1-132)months.Eight patients have allergic disease history.IgG4-CD patients had more lymph node involvement(100%vs 57.8%,P<0.01),while IgG4-RD patients had more submandibular(33.3%vs 77.1%,P<0.01)and parotid gland(13.3%vs 40.9%,P<0.05)affected.IgG4-CD patients had significantly higher levels of ESR,CRP,IgG,IgG1,IgG3,IgG4,and IgE than IgG4-RD patients.Compared with MCD patients,IgG4-CD patients showed higher incidence of salivary gland and paranasal sinus involvement,higher hemoglobin,eosinophil count,serum IgG4 level and IgG4/IgG ratio,and lower CRP,IL-6 levels and IgG1/IgG,IgG2/IgG ratio.All patients with IgG4-CD exhibited relatively favorable outcomes.Conclusions:Both IgG4-RD and CD can involve multiple organs.There are a small group of patients who had clinical and pathological characteristics of both CD and IgG4-RD showed better clinical outcome.