Positive disease-specific autoantibodies have limited clinical significance in diagnosing IgG4-related disease in daily clinical practice. (12th December 2020)

• Record Type: Journal Article
• Authors: Mizushima, Ichiro; Yamano, Takahiro; Kawahara, Hiroyuki; Hibino, Shinya; Nishioka, Ryo; Zoshima, Takeshi; Hara, Satoshi; Ito, Kiyoaki; Fujii, Hiroshi; Nomura, Hideki; Kawano, Mitsuhiro
• Is Part Of: Rheumatology. Volume 60:Number 7(2021)
• Page Start: 3317
• Page End: 3325
• Publication Date: 2020-12-12
• Subjects: IgG4-related disease -- classification criteria -- false-negative; Rheumatism -- Periodicals; Rheumatology -- Periodicals; 616.723005
• DOI: 10.1093/rheumatology/keaa783
• Languages: English
• ISSNs: 1462-0324

Abstract

Abstract: Objectives: The 2019 ACR/EULAR classification criteria for IgG4-related disease (IgG4-RD) have exclusion criteria including positive disease-specific autoantibodies, and these have been documented to have a high specificity. This study aimed to further validate these criteria as well as identify characteristics of patients showing false-negative results. Methods: We retrospectively analysed 162 IgG4-RD patients and 130 mimickers. The sensitivity, specificity and fulfilment rates for each criterion were calculated, and intergroup comparisons were performed to characterize the false-negative cases. Results: Both the IgG4-RD patients and mimickers were aged ≥65 years with male predominance. The final diagnoses of mimickers were mainly malignancy, vasculitis, sarcoidosis and aneurysm. The classification criteria had a sensitivity of 72.8% and specificity of 100%. Of the 44 false-negative cases, one did not fulfil the entry criteria, 20 fulfilled one exclusion criterion and 27 did not achieve sufficient inclusion criteria scores. The false-negative cases had fewer affected organs, lower serum IgG4 levels, and were less likely to have received biopsies than the true-positive cases. Notably, positive disease-specific autoantibodies were the most common exclusion criterion fulfilled in 18 patients, only two of whom were diagnosed with a specific autoimmune disease complicated by IgG4-RD. In addition, compared with the true-positive cases, the 18 had comparable serum IgG4 levels, number of affected organs, and histopathology and immunostaining scores despite higher serum IgG and CRP levels. Conclusions: The ACR/EULAR classification criteria for IgG4-RD have an excellent diagnostic specificity in daily clinical practice. Positive disease-specific autoantibodies may have limited clinical significance for the diagnosis of IgG4-RD.