Performance of classification and diagnostic criteria for IgG4-related disease and comparison of patients with and without IgG4-related disease.

IgG4-related disease (IgG4-RD) was recently described in Japan. It is characterised by extensive organ involvement with tissue fibrosis. We assessed the performance of the 2019 American College of Rheumatology and European League Against Rheumatism (ACR/EULAR) classification criteria and the 2020 revised comprehensive diagnostic (RCD) criteria as well as differences between patients with and without IgG4-RD. In this retrospective, single-centre study of 50 patients admitted with suspected IgG4-RD, we evaluated the sensitivity and specificity of both criteria. We also compared clinical characteristics and laboratory data of patients with IgG4-RD (n = 42) and patients without IgG4-RD (n = 8). The ACR/EULAR classification criteria had 88.1% sensitivity and 87.5% specificity for IgG4-RD diagnosis. The RCD criteria had 100% sensitivity and 50% specificity. Patients with IgG4-RD had significantly more affected organs (p = 0.002). Patients with a single affected organ and IgG4-RD had significantly higher serum IgG4/IgG ratios (p = 0.027), lower serum C-reactive protein levels (p = 0.020), and lower total haemolytic complement activity (p = 0.044) than those without IgG4-RD. The ACR/EULAR classification criteria have high specificity and the RCD criteria have high sensitivity for diagnosing IgG4-RD. The number of affected organs is important for diagnosing IgG4-RD.

Kogami M ，Abe Y ，Ando T ，Makiyama A ，Yamaji K ，Tamura N ... -  《Scientific Reports》

The external validation of the 2019 ACR/EULAR classification criteria for IgG4-related disease in a large cohort from China.

To externally validate the performance of the 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for IgG4-related disease (IgG4-RD) within a cohort from China and to compare the criteria with the 2020 revised comprehensive diagnostic (RCD) criteria for IgG4-RD. This study included 875 IgG4-RD and 302 non-IgG4-RD cases (213 mimickers and 89 patients with other diseases). Using expert clinical judgment as the gold standard for diagnosis of IgG4-RD, the performance (sensitivity, specificity, area under the curve (AUC) of the 2019 ACR/EULAR criteria for IgG4-RD was evaluated. We also compared it with the 2020 RCD criteria. The 2019 ACR/EULAR classification criteria had a sensitivity of 76.6% (95% CI: 73.8% to 79.4%) and a specificity of 98.0% (96.0%-99.4%), an AUC of 0.873 (0.857-0.889) in the overall cohort. Those false negative cases under the 2019 ACR/EULAR classification criteria had significantly lower levels of serum IgG4, and fewer had pathological information, with a higher frequency in the involvement of those uncommon organs compared with the true positive cases. The cases judged as negative by the 2019 ACR/EULAR classification criteria yet judged as "definite" by the 2020 RCD criteria had more involvement of uncommon organs. The 2019 ACR/EULAR classification criteria for IgG4-RD show outstanding specificity and good sensitivity in real-world clinical practice. The 2020 RCD criteria are helpful for the diagnosis of IgG4-RD in clinical scenarios where IgG4-RD presents as involving an isolated organ, especially the unusual sites.

Liu Z ，Nie Y ，Peng Y ，Lu H ，Zhang P ，Li J ，Sun R ，Li J ，Sun B ，He X ，Zhou J ，Fei Y ，Peng L ，Zhang W ，Zeng X ... -  《-》

The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-Related Disease.

IgG4-related disease (IgG4-RD) can cause fibroinflammatory lesions in nearly any organ. Correlation among clinical, serologic, radiologic, and pathologic data is required for diagnosis. This work was undertaken to develop and validate an international set of classification criteria for IgG4-RD. An international multispecialty group of 86 physicians was assembled by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). Investigators used consensus exercises, existing literature, derivation and validation cohorts of 1,879 subjects (1,086 cases, 793 mimickers), and multicriterion decision analysis to identify, weight, and test potential classification criteria. Two independent validation cohorts were included. A 3-step classification process was developed. First, it must be demonstrated that a potential IgG4-RD case has involvement of at least 1 of 11 possible organs in a manner consistent with IgG4-RD. Second, exclusion criteria consisting of a total of 32 clinical, serologic, radiologic, and pathologic items must be applied; the presence of any of these criteria eliminates the patient from IgG4-RD classification. Third, 8 weighted inclusion criteria domains, addressing clinical findings, serologic results, radiology assessments, and pathology interpretations, are applied. In the first validation cohort, a threshold of 20 points had a specificity of 99.2% (95% confidence interval [95% CI] 97.2-99.8%) and a sensitivity of 85.5% (95% CI 81.9-88.5%). In the second, the specificity was 97.8% (95% CI 93.7-99.2%) and the sensitivity was 82.0% (95% CI 77.0-86.1%). The criteria were shown to have robust test characteristics over a wide range of thresholds. ACR/EULAR classification criteria for IgG4-RD have been developed and validated in a large cohort of patients. These criteria demonstrate excellent test performance and should contribute substantially to future clinical, epidemiologic, and basic science investigations.

Wallace ZS ，Naden RP ，Chari S ，Choi H ，Della-Torre E ，Dicaire JF ，Hart PA ，Inoue D ，Kawano M ，Khosroshahi A ，Kubota K ，Lanzillotta M ，Okazaki K ，Perugino CA ，Sharma A ，Saeki T ，Sekiguchi H ，Schleinitz N ，Stone JR ，Takahashi N ，Umehara H ，Webster G ，Zen Y ，Stone JH ，American College of Rheumatology/European League Against Rheumatism IgG4-Related Disease Classification Criteria Working Group ... -  《-》

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

Immunoglobulin 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. This 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. A 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. This 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.

Spandorfer R ，Ahmad M ，Khosroshahi A 《-》

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

Martín-Nares E ，Hernández-Molina G ，Baenas DF ，Delgado de la Mora J ，Caeiro F ，Wurmann Kiblisky P ，Pimentel-Quiroz VR ，Ascuña Valdivia V ，Faz-Munoz D ，Saad EJ ，Cairoli E ，Elgueta Pinochet S ，Madariaga Charaja H ，Montante-Montes de Oca D ，Gallo JR ，Ugarte-Gil MF ，Neira O ，Burgos PI ，Paira S ，Grupo Latino Americano de Estudio de la Enfermedad Relacionada a IgG4 (GLAER-IgG4) ... -  《-》