Diabetes after SARS-CoV-2 Vaccination
A 43-year-old man who had malignant melanoma (pT3bN1bM0 stage IIIC) received nivolumab treatment (480 mg 1× every 4 wks) 12 months before admission. Fasting plasma glucose level was 94 mg/dL and glycated hemoglobin (HbA1c) 5.6% at treatment initiation. Plasma glucose and HbA1c were tested every 4 weeks. His range of plasma glucose was 90–123 mg/dL and that of HbA1c was 5.4%–5.7% (Figure). Positron emission tomography–computed tomography showed no metastasis or recurrence of the tumor 1 month before admission.Laboratory tests at admission showed severely impaired insulin secretion capacity; fasting C-peptide immunoreactivity (CPR) was 0.33 ng/mL, 24-hour urinary CPR 5.74 μg/day and 3.82 μg/day, and ΔCPR during the glucagon load test was 0.03 ng/mL (Table). Tests results for islet-specific autoantibodies against glutamic acid decarboxylase, insulinoma-associated antigen 2, and zinc transporter 8 were negative. Human leukocyte antigen typing identified no specific alleles, including DR4, known to be related to T1D (Table). Blood glucose decreased in response to continuous intravenous administration of insulin and saline. On the second day of hospitalization, we switched from intravenous to subcutaneous injection of insulin. The patient’s blood glucose level was ultimately controlled by intensive insulin therapy (degludec 9 U before dinner and lispro 24 U before breakfast, 5 U before lunch, and 15 U before dinner). Five months after discharge, the patient still requires multiple daily insulin injections for glycemic control.