title: Establishment of a serum IgG4 cut-off value for the differential diagnosis of IgG4-related disease in Chinese population.
abstract: OBJECTIVE
  This study was performed to better know diagnosis associated with serum IgG4 concentration, and to explore the possibility for development of a serum IgG4 for IgG4-related disease (IgG4-RD) in Chinese populations.
  
  
  METHODS
  We studied retrospectively 497 IgG4 serum subclass measurements from Peking Union Medical College Hospital during the four-year period, including 242 IgG4-RD, 130 other diseases and 125 healthy individuals.
  
  
  RESULTS
  Serum IgG4 concentrations were significantly higher in IgG4-RD than in other pathologies (1662.9 ± 3760.9 mg/L, p < 0.001) and healthy individuals (538.2 ± 458.6 mg/L, p < 0.001). There were no significant differences in serum IgG4 level between other pathologies group and healthy individuals (p = 0.075). Among the 242 IgG4-RD patients analyzed, serum IgG4 concentrations were normal in 46 patients (19.0%). We found 32 patients (24.6%) with elevated serum IgG4 levels among the 130 patients who suffered from other pathologies. There were seven (5.6%) with serum IgG4 over 1350 mg/L in healthy individuals. The ROC curve analysis revealed that the optimal sensitivity and specificity were 80.0% and 88.2%, respectively, at the concentration of 1575 mg/L for Chinese patients.
  
  
  CONCLUSIONS
  Our study demonstrated that serum IgG4 elevation was not specific of IgG4-RD. Further studies are needed to define the sensibility and specificity of IgG4 values for the diagnosis of IgG4-RD.
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Hua
authors.initials: H
authors.lastname: Chen
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Chuiwen
authors.initials: C
authors.lastname: Deng
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Ziyan
authors.initials: Z
authors.lastname: Wu
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Wei
authors.initials: W
authors.lastname: Lin
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zeng
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Wen
authors.initials: W
authors.lastname: Zhang
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Fengchun
authors.initials: F
authors.lastname: Zhang
authors.affiliation: a Department of Rheumatology and Clinical Immunology , Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education , Beijing , China.
authors.forename: Yongzhe
authors.initials: Y
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007154:Immune System Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D007074:Immunoglobulin G
keywords: Cut-off values; IgG4-related disease; Receiver operating characteristic; Serum immunoglobulin G4 concentrations; Standard deviation