두 종류의 항체를 보유한 자가면역성 저혈당 1예

Abstract

Autoimmune hypoglycemia is rare kind of autoimmune disease caused by either anti-insulin antibodies (insulin autoimmune syndrome, IAS) or anti-insulin receptor antibodies (type B insulin resistance, type-B IR). We experienced an extremely rare case of the IAS accompanied by type-B IR. A 73-year-old woman presented with recurrent severe hypoglycemic symptoms at dawn for one month was admitted to the Severance hospital. She had several medical histories including 30 years of hypertension, 15 years of type 2 diabetes, and 4 years of coronary artery disease before admission. She had never received an insulin injection. Hypoglycemia was diagnosed at 10 hours in the 72-hour fasting test with glucose, insulin, and C-peptide levels of 42 mg/dL, 280.31 μU/mL, and 7.70 ng/mL, respectively. The insulin autoantibody titer was 130 μU/mL and quantitative assay for insulin receptor antibody was positive. Insulinoma was ruled out by imaging techniques and calcium stimulation test. She has no evidence of other diseases associated with altered immunity. Despite of treatment with prednisolone, symptomatic hypoglycemic events persisted at fasting state. Early induction of 300 mg cyclophosphamide therapy resulted in remission of hypoglycemia accompanied by suppressed antibody titer. The changes in autoantibodies might result in alleviation of the symptoms of hypoglycemia and improvement in insulin and C-peptide levels