Insulin autoimmune syndrome: a rare cause of spontaneous hypoglycaemia in non-diabetic individuals

Insulin autoimmune syndrome (IAS) is a rare cause of hypoglycaemia, characterised by recurrent hypoglycaemic episodes secondary to insulin autoantibodies in individuals who are not exposed to exogenous insulin. We are reporting a case of IAS in a 64-year-old gentleman, who presented with predominant postprandial hypoglycaemic episodes. On biochemical evaluation, he was found to have hyperinsulinemic hypoglycaemia. Localisation studies with MRI abdomen and endoscopic ultrasound (EUS) were negative for pancreatic tumour. Tests sent for insulin antibody levels were elevated. The patient was treated with frequent meals, acarbose and glucocorticoids. Patient condition improved and did not experience hypoglycaemia on follow-up.

Sensitive detection of multiple islet autoantibodies in type 1 diabetes using small sample volumes by agglutination-PCR

Islet autoantibodies are predominantly measured by radioassay to facilitate risk assessment and diagnosis of type 1 diabetes. However, the reliance on radioactive components, large sample volumes and limited throughput renders radioassay testing costly and challenging. We developed a multiplex analysis platform based on antibody detection by agglutination-PCR (ADAP) for the sample-sparing measurement of GAD, IA-2 and insulin autoantibodies/antibodies in 1 μL serum. The assay was developed and validated in 7 distinct cohorts (n = 858) with the majority of the cohorts blinded prior to analysis. Measurements from the ADAP assay were compared to radioassay to determine correlation, concordance, agreement, clinical sensitivity and specificity. The average overall agreement between ADAP and radioassay was above 91%. The average clinical sensitivity and specificity were 96% and 97%. In the IASP 2018 workshop, ADAP achieved the highest sensitivity of all assays tested at 95% specificity (AS95) rating for GAD and IA-2 autoantibodies and top-tier performance for insulin autoantibodies. Furthermore, ADAP correctly identified 95% high-risk individuals with two or more autoantibodies by radioassay amongst 39 relatives of T1D patients tested. In conclusion, the new ADAP assay can reliably detect the three cardinal islet autoantibodies/antibodies in 1μL serum with high sensitivity. This novel assay may improve pediatric testing compliance and facilitate easier community-wide screening for islet autoantibodies.

Insulin autoimmune syndrome induced by exogenous insulin injection: a four-case series

Background Insulin autoimmune syndrome (IAS) is a rare cause of hypoglycemia and is characterized by the presence of insulin autoantibodies. Patients with IAS usually complain of hypoglycemia without any previous insulin received. Glucocorticoids and immunosuppressants are used to treat IAS. Case presentation We report four patients with diabetes who were diagnosed with non-classical IAS and describe the treatment of these patients. Moreover, the differential diagnosis with hyperinsulinism is discussed. Conclusion High levels of insulin autoantibodies, as well as hyperinsulinemic hypoglycemia, are found in patients with diabetes mellitus and prior exogenous insulin exposure. This situation that we classified as non-classical IAS should be attached importance to.