Clinical Characteristics and Classification Criteria Performance in a Single-Center Cohort of 114 Patients With Immunoglobulin G4–Related Disease

Abstract

Introduction/ObjectivesImmunoglobulin G4–related disease (IgG4-RD) is a heterogeneous fibroinflammatory condition. The 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Classification Criteria for IgG4-RD were published to provide unified classification criteria in clinical research. The purpose of this study was to characterize demographics, disease manifestations, and treatments of patients with IgG4-RD and assess performance of the Classification Criteria in a heterogeneous cohort with a large population of Black patients.MethodsThis was a medical records review of all patients referred to a specialized IgG4-RD clinic. Demographics, serology, histopathology, disease manifestations, and treatment information were collected and analyzed. An ACR/EULAR Classification Criteria score for IgG4-RD was calculated to compare performance in definite diagnosis, probable diagnosis, and mimicker groups.ResultsA total of 198 patients were evaluated. Eighty-five (43%) were mimickers. Of the remaining 114, 58 (51%) were classified as definite, and 56 (49%) as probable cases by treating clinicians. Pancreatitis was the most common presentation (37%) among 28 different organ manifestations of IgG4-RD. In patients with definite clinical diagnosis of IgG4-RD, 84% met the IgG4-RD Classification Criteria (i.e., score ≥20) with mean score of 29. Only 9% of the probable cases met this threshold with an average score of 8. None of the mimickers met the Classification Criteria.ConclusionsThis study highlights the broad spectrum of IgG4-RD and validates the use of the ACR/EULAR Classification Criteria for IgG4-RD, including a large proportion of Black patients. As shown in this study, IgG4-RD is a heterogeneous disease and continues to represent a diagnostic challenge to clinicians.

Performance of the 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-Related Disease in a Latin American Cohort

“…In this Latin American cohort, 66.7% of the patients met the 2019 AECC for IgG4-RD, which is lower than the sensitivity reported in the Japanese, Chinese, Spanish, US (Atlanta), South Korean, and Norwegian cohorts, but higher than the United Kingdom, Turkish, and Milan cohorts (Table 3). [2][3][4][5][6][7][8][9][10][11][12][13] Consistent with the aforementioned studies, the main reasons for not meeting the 2019 AECC were the lack of biopsy, mono-organic and atypical presentations, and the presence of exclusion criteria. Importantly, many of our patients had disease-specific autoantibodies that prevented them from meeting the criteria, even without evidence of concomitant autoimmune conditions.…”

“…1 In this regard, the 2019 AECC accomplished this goal, as demonstrated by a specificity higher than 97% in the original derivation and validation cohorts, and a specificity of 100% in the Japanese, United Kingdom, Atlanta, and the present Latin American cohort. 1,6,7,9 Our study is not without limitations. First, its historical nature and the use of different diagnostic algorithms by investigators rather than a standardized approach may have led to variability in patient assessments, such as incomplete assessment of IgG4 serum levels or complement, absence of biopsies, or incomplete imaging studies.…”

“…1 Many studies in diverse populations have evaluated the performance of the 2019 AECC. [2][3][4][5][6][7][8][9][10][11][12][13] However, most studies have primarily focused on cohorts consisting of White and Asian patients.…”

“…For instance, Asian and Latin America patients are more prone to head and neck manifestations, White patients are more likely to have a pancreatohepato-biliary phenotype, whereas Black patients have a higher rate of retroperitoneal fibrosis. 9,[14][15][16] Therefore, the objective of our study was to assess the performance of the 2019 AECC for IgG4-RD in a cohort of Latin American patients.…”

“…Their exceptional test performance makes it an almost perfect tool for excluding conditions that mimic IgG4-RD, particularly for clinical trial participation 1 . Many studies in diverse populations have evaluated the performance of the 2019 AECC 2–13 . However, most studies have primarily focused on cohorts consisting of White and Asian patients.…”