Abstract
A 72-year-old man with type 2 diabetes mellitus with good glucose control for 20 years and maintained on oral hypoglycaemic agents was diagnosed with Hodgkin's Lymphoma (HL) and started on insulin glargine for glycaemic control. Despite increased doses of insulin, his blood glucose levels went up dramatically. The anti-insulin antibody test proved to be positive, and Scatchard plot analysis showed 2 binding sites with relatively low-affinity constants: K (1) = 0.0032, K (2) = 0.0002 (10(8)/M); and high binding capacities: R (1) = 98.4, R (2) = 372 (10(-8) M), which were compatible with the features of antibody of insulin autoimmune syndrome (IAS). However, hypoglycaemia was not noted throughout the course of treatment. Since the insulin binding ratio of the antibody decreased from 87.3% to 62% after the termination of insulin treatment, it was suggested that the antibody reacted mainly to exogenously injected insulin. Switching insulin preparations or introducing insulin secretagogues did not improve elevated blood glucose levels. The initiation of brentuximab vedotin (BV), a therapeutic agent for relapsed HL, resulted in a remarkable improvement in glycaemic control despite the absence of insulin therapy and partial remission of HL. This case suggested that HL triggered anti-insulin antibody production, which resulted in poor glycaemic control, and that BV could be a new treatment option for autoimmune diseases associated with HL. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13340-021-00550-1.