A Unique Case of Atezolizumab-Induced Autoimmune Diabetes

ABSTRACT Objective Immunotherapy is a novel treatment that can cause autoimmune diabetes in rare cases. More cases occur following use of the inhibitor to the protein programmed cell death-1 rather than the inhibitor to programmed cell death-ligand 1. Methods We report a unique case of autoimmune diabetes following atezolizumab use. Results A 55-year-old, Aboriginal Australian female with no prior history of diabetes was commenced on atezolizumab for recurrent squamous cell lung carcinoma. Two months following its commencement, there was the onset of fatigue, polyuria, polydipsia, and new hyperglycemia. Subsequently she was found to have a borderline-low C peptide level of 0.6 nmol/L (reference range is 0.5 to 1.0 nmol/L), and positive zinc transporter-8 antibodies. Following the diagnosis of autoimmune diabetes, 5 units of glargine insulin was commenced which maintained euglycemia and resolved her symptoms of hyperglycemia. Conclusion There are few case reports of atezolizumab-induced autoimmune diabetes. We present the first case associated with zinc transporter-8 antibodies, and a unique case of autoimmune diabetes in a patient of Aboriginal Australian background.