SAT0637 THE DIAGNOSTIC VALUE OF SERUM IGG4 IN IGG4 RELATED DISEASES
Authors: Xue Wu, Lijun Wu, Cai Nan Luo, Ya Mei Shi
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> 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. <h3>Objectives:</h3> 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. <h3>Methods:</h3> 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 <h3>Results:</h3> 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&lt;0.05)(Figure 1). By the ROC curves of serum IgG4 levels in 170 patients. The optimal cutoff value of serum IgG4 for a diagnosis of IgG4-RD was 1440 mg/L, and the sensitivity and specificity were 90.0% and 80.8%, respectively. The area under the curve (AUC) was 0.926. When We using a ratio &gt;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). <h3>Conclusion:</h3> 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. <h3>References</h3> [1] Kamisawa T, Funata N, Hayashi Y, et al. A new clinicopathological entity of IgG4-related autoimmune disease[J]. Journal of Gastroenterology, 2003, 38(10):982 [2] Takahashi H, Yamamoto M, Suzuki C, et al. The birthday of a new syndrome: IgG4-related diseases constitute a clinical entity.[J]. Autoimmunity Reviews, 2010, 9(9):591-594 SSadlerR,ChapmanRW,SimpsonD,etal.The diagnostic significance of serum IgG4 levels in patients with autoimmune pancreatitis: a UK study. Eur J Gastroenterol Hepatol. 2011;23:139–45. Umehara H, Okazaki K, Masaki Y, et al. Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011[J]. Nihon Naika Gakkai Zasshi the Journal of the Japanese Society of Internal Medicine, 2012, 101(3):795. Stone JH, Zen Y, Deshpande V.IgG4-related disease[J].N Engl J Med, 2012, 366(6):539-551. Yamamoto M, Tabeya T, Naishiro Y, et al. Value of serum IgG4 in the diagnosis of IgG4-related disease and in differentiation from rheumatic diseases and other diseases[J]. Modern Rheumatology, 2012, 22(3):419-425. Zen Y, Nakanuma Y. IgG4-RD: a cross-sectional study of 114 cases. Am J Surg Pathol 2010, 34:1812–19. Carruthers M N, Khosroshahi A, Augustin T, et al. The diagnostic utility of serum IgG4 concentrations in IgG4-related disease.[J]. Annals of the Rheumatic Diseases, 2015, 74(1):14. Masaki Y, Kurose N, Yamamoto M, et al. Cutoff values of serum IgG4 and histopathological IgG4+ plasma cells for diagnosis of patients with IgG4-related disease. Int J Rheumatol 2012;2012:580814. <h3>Disclosure of Interests:</h3> None declared