Polyendocrine Autoimmunity and Diabetic Ketoacidosis Following Anti-PD-1 and Interferon α.

Immune checkpoint inhibitor (ICI) therapies are now first-line therapy for many advanced malignancies in adults, with emerging use in children. With increasing ICI use, prompt recognition and optimal management of ICI-associated immune-related adverse events (IRAEs) are critical. Nearly 60% of ICI-treated adults develop IRAEs, which commonly manifest as autoimmune skin, gastrointestinal, and endocrine disease and can be life-threatening. The incidence, presentation, and disease course of spontaneous autoimmune diseases differ between adults and children, but the pattern of pediatric IRAEs is currently unclear. We report a case of a pediatric patient presenting with new onset autoimmune diabetes mellitus and diabetic ketoacidosis during ICI treatment of fibrolamellar hepatocellular carcinoma (FLC). Distinct from spontaneous type 1 diabetes mellitus (T1DM), this patient progressed rapidly and was negative for known β cell autoantibodies. Additionally, the patient was positive for 21-hydroxylase autoantibodies, suggesting development of concomitant adrenal autoimmunity. Current guidelines for the management of IRAEs in adults may not be appropriate for the management of pediatric patients, who may have different autoimmune risks in a developmental context.