Early Disease Control, Corticosteroid Sparing, and Relapse-Free Survival after Intravenous Immunoglobulin in Pemphigus: a Single-Center Retrospective Cohort

BACKGROUND:Intravenous immunoglobulin (IVIg) is used in refractory pemphigus, but data linking disease activity, corticosteroid reduction, remission, and post-remission durability are limited. OBJECTIVES:To evaluate early clinical response, corticosteroid exposure, post-IVIg complete remission on therapy (CRon), and relapse-free survival (RFS) in pemphigus treated with IVIg before rituximab. METHODS:In this single-center retrospective cohort study, patients with pemphigus vulgaris or foliaceus treated between 2010 and 2018 were screened. Outcomes were analyzed in those receiving IVIg before rituximab. Mucosal and cutaneous Autoimmune Bullous Skin Disorder Intensity Score (ABSIS) and prednisolone exposure, normalized to the initial maximum dose (100%), were assessed. CRon was counted only when first documented after IVIg initiation, and RFS was measured from the CRon date. Missing data were not imputed. RESULTS:Among 100 patients, 37 received IVIg and 36 entered the IVIg-before-rituximab cohort. Prednisolone exposure decreased from 65.59±34.65% at IVIg initiation to 27.55±27.32% at month 6. By month 3, mucosal ABSIS decreased from 17.22±9.17 to 5.96±8.60 and cutaneous ABSIS from 5.00±7.46 to 1.38±2.58 (all p < 0.001). Post-IVIg CRon was documented in 25/36 patients (69.4%). In the primary RFS set (n=21), 10 relapses occurred; RFS was 72.4% at 12 months and 60.8% at 24 months. CONCLUSION:IVIg use was associated with early disease improvement and reduced corticosteroid exposure. Post-remission control was durable among patients achieving post-IVIg CRon, but RFS estimates are conditional on remission. Because background therapy continued, the independent contribution of IVIg cannot be determined.