IgG4-RD Treatment Outcomes

This study was conducted on patients with active IgG4-RD who were treated with immunosuppressants and had elevated serum IgG4 levels at a tertiary referral center in South Korea between January 2011 and December 2020. All patients met the 2011 IgG4-RD diagnostic criteria [7 (link)]: (1) a clinical examination with diffuse/localized swelling or masses in single or multiple organs; (2) an elevated serum IgG4 level; and (3) histopathologic findings of lymphoplasmacytic infiltration and fibrosis, > 40% IgG4-positive plasma cells, and > 10 IgG4-positive plasma cells per high-power field. Patients were also evaluated according to the 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for diagnosis of IgG4-RD [14 (link)]. Patients with pancreatic involvement were classified as definite or probable cases using the International Consensus Diagnostic Criteria (ICDC) for autoimmune pancreatitis [15 (link)]. We excluded patients with other rheumatic diseases, malignancy, or infection. Either glucocorticoid alone or glucocorticoid plus azathioprine were used as an initial regimen for remission and were maintained for at least six months and up to 24 months. To evaluate the factors associated with relapse, we classified patients into relapsed and non-relapsed groups.