Clinical manifestations, clinical course, and outcomes of immunoglobulin G4-related disease.

BACKGROUND: Immunoglobulin G4-related disease (IgG4-RD) is an uncommon chronic systemic autoimmune disease, pathologically characterized by lymphoplasma cell and IgG4 plasma cell infiltration with storiform fibrosis. IgG4-RD is a new disease and is not yet widely recognized. The aim of this study was to describe the clinical manifestations and outcomes in Thai patients with IgG4-RD. METHODS: This multicenter retrospective cohort study included patients aged ≥ 18 years who were diagnosed with IgG4-RD, according to the 2011 comprehensive or consensus diagnostic criteria, between 2000 and 2019 in four academic centers in Thailand. Baseline characteristics, laboratory and pathologic findings, treatments, and outcomes were systematically reviewed. RESULTS: The study included 110 patients (71% male) with a mean age (SD) of 59.6 (13.3) years and median disease duration (interquartile range [IQR]) of 28.8 (14.6-53.5) months. Single organ involvement was observed in 60 patients (54.5%). Most patients (96%) had an IgG4 level of more than 135 mg/dL at presentation. Also, most (92%) were treated with corticosteroid (CS) alone or in combination with immunosuppressive agents. The most commonly used immunosuppressive agents were azathioprine (47%) and methotrexate (11%). Additionally, 20% required surgery, and 6.4% underwent stent insertion. One-quarter (26%), 37%, and 29% were in remission with successfully tapering CS, complete and partial response. Nevertheless, 22% relapsed, with a median time to relapse (IQR) of 22.2 (12.8-41.1) months. CONCLUSION: IgG4-RD is a chronic systemic autoimmune disease with diverse manifestations, response to treatment, and outcomes. Most patients responded well to treatments but with a notable relapse rate.