Clinical Investigation On Characteristics Of IgG4-related Autoimmune Pancreatitis And Efficacy Of Glucocorticoids And Immunosuppressive Therapy

Background:IgG4-related disease（IgG RD）is a chronic fibroinflammatory disease mediated by autoimmunity with increased serum IgG4 level.The disease can involve multiple organs and systems,mainly including bile duct,salivary gland,lacrimal gland,pancreas and so on.IgG4-related autoimmune pancreatitis（IgG4 AIP）is the most common in IgG4-RD.IgG4-AIP is a special type of chronic pancreatitis mediated by autoimmunity and characterized by pancreatic enlargement and irregular stenosis of pancreatic duct.The main histopathological features were a large number of lymphocyte infiltration with storiform fibrosis,and a large number of IgG4 positive cell infiltration.At present,the pathogenesis is not completely clear,the epidemiological data in China are not perfect,the clinical manifestations and imageology are mostly nonspecific,the onset is hidden,and the rate of missed-diagnosis and the rate of misdiagnosis of the disease are very high.At present,glucocorticoids are the main therapeutic method of AIP,but there is no unified standard for the treatment of AIP.Therefore,we should summarize the clinical characteristics of the disease and the the clinical effects of glucocorticoids and immunosuppressive agents to strengthen the understanding of the disease and improve the level of clinical diagnosis and treatment.Objectives:The aims of this study were to analyze the clinical characteristics of 165 cases of IgG4-AIP.and the clinical efficacy of glucocorticoids and immunosuppressive agents（azathioprine）in the treatment of autoimmune pancreatitis.Materials and methods:We collected the data of 165 patients with IgG4-AIP who hospitalized in the first hospital of Jilin University from January 2011 to December 2021 to analyze the general data（gender,age）,clinical symptoms,laboratory indexes and treatment.According to different treatment methods during hospitalization,the patients were divided into 108 cases in the glucocorticoids group,14 cases in the combination of glucocorticoids with immunosuppressive agents（azathioprine）and 12 cases in the azathioprine group.We analyzed the laboratory indexes（AST,ALT,γ-GT,ALP,serum amylase,lipase,IgG4,IgG,Ig A,Ig M,Ig E,C3 and C4）to see whether there were statistical differences.Results:165 patients with IgG4-AIP in this study were mostly over 50 years old（76.4%）and mainly male（69.9%）.Among 165 patients,80.5% were treated with glucocorticoids alone,which was significantly higher than that in glucocorticoids combined immunosuppressive drugs group（10.4%）and immunosuppressive drugs group alone（8.1%）.The main clinical symptoms of IgG4-AIP were yellow staining of skin and sclera（39.5%）,abdominal pain（42.6%）,diarrhea,swelling of salivary gland,pancreatic mass and other rare symptoms.There were significant differences in ALP and C4 baseline levels before treatment among steroid group,azathioprine group and the combination of two agents,but there were no significant differences in amylase,lipase,AST and other parameters.Glucocorticoids and immunosuppressive drugs have certain curative effects,but we should be vigilant about their related adverse reactions.Of 165 cases of IgG4-AIP,CT tomography showed 43.6%（72/165）in diffuse swelling pancreatitis,38.9% in focal mass pancreatitis,13.69% in multifocal pancreatitis.Of the focal mass pancreatitis,pancreatic head was mainly invovled（60.9%）.The effective rates in steroid therapy,azathioprine treatment and the combination of both agents were 86.1%,100% and 92.8%,respectively,with no significance among them.Conclusions:The incidence rate of IgG4-AIP is more common in elderly male patients over 50 years old.The main clinical manifestations are obstructive jaundice,abdominal pain,fatigue,pancreatic space occupying,etc.Focal mass pancreatitis isn’t uncommon which is difficult to differentiate from pancteatic ductal adenocarcinoma.The clinical diagnosis of the disease should be made through comprehensive examination,including histology,imagy,serology,other organ involvement and response to glucocorticoid treatment.Glucocorticoids or azathioprine have a certain curative effect.Meanwile,we should be alert to the adverse reactions of glucocorticoids and immunosuppressive drugs.