SAT0637 THE DIAGNOSTIC VALUE OF SERUM IGG4 IN IGG4 RELATED DISEASES

Abstract

Background: IgG4--RD is a newly recognized autoinflammatory disease. Serum IgG4 is an important tool for the diagnosis of IgG4—RD. However, only a few articles have reported the value of serum IgG4 for the diagnosis ofIgG4--RD. Objectives: To explore the diagnostic value of serum IgG4 in IgG4-related diseases,Whether 1350 mg/L as the cutoff concentration is suitable for Chinese people to identify IgG4-RD and other rheumatic immune diseases. Methods: From October 2013 to December 2018,40 patients with IgG4-RD diagnosed in the rheumatic immunology department of people’s hospital of Xinjiang Uygur Autonomous Region were collected.We also reviewed the of 90 other CTD patients and 40 healthy controls.The age, gender, diagnosis, serum IgG4 concentration and other data were collected. The cut off levels were determined by receiver operating characteristic (ROC) curve analysis Results: The mean serum IgG4 concentration of 40 definite IgG4-RD was was significantly higher than that of other rheumatic immune diseases group and healthy control group. There was a significant serum IgG4 concentration difference between patients with IgG4-RD,Non-IgG4-RD and healthy control group(P 0.07 as the cut-off for normal and the sensitivity and specificity were 90.0% and 77.7%, respectively. The area under the curve (AUC) was 0.925(Figure 2). Conclusion: The high levels of serum IgG4 are sometimes observed in not only IgG4-RD but also other rheumatic,malignancy diseases and common diseases. The cut of serum IgG4 is 1440mg/L,The usual cut-off value of 1350 mg/Lis useful for diagnosing whole IgG4-RD.