Type 1 diabetes related to immune checkpoint inhibitors

Type 1 diabetes, in part, has been recently reported as a side effect of immune checkpoint inhibitors (ICIs). The frequency of type 1 diabetes related to ICIs is estimated to be ∼3.5%. However, type 1 diabetes related to ICIs often presents with diabetic ketoacidosis or ketosis within approximately 2 weeks after hyperglycemic symptoms, such as dry mouth, polydipsia, and polyuria, necessitating urgent diagnosis and insulin treatment. Endogenous insulin secretion is depleted within 3 weeks of the clinical onset of type 1 diabetes. Moreover, the positive rate for islet-related autoantibodies has been shown to vary from 5% to 50%, and exocrine pancreatic enzyme levels are mildly increased. Thus, the clinical course of type 1 diabetes associated with ICIs is similar to that of fulminant type 1 diabetes. In this review, we describe the clinical features of type 1 diabetes associated with ICIs.