Recurrent hypoglycemic coma and diabetic ketoacidosis caused by insulin antibody: a rare case of type 1 diabetes mellitus / Hipoglicemia hiperinsulinémica causada por anticuerpos antiinsulina: informe de un caso

ABSTRACT Insulin antibodies (IAs) induced by exogenous insulin rarely cause hypoglycemia. However, insulin autoantibodies (IAAs) in insulin autoimmune syndrome (IAS) can cause hypoglycemia. The typical manifestations of IAS are fasting or postprandial hypoglycemia, elevated insulin level, decreased C-peptide levels, and positive IAA. We report a 45-year-old male with type 1 diabetes mellitus (T1DM) treated with insulin analogues suffering from recurrent hypoglycemic coma and diabetic ketoacidosis (DKA). His symptoms were caused by exogenous insulin and were similar to IAS. A possible reason was that exogenous insulin induced IA. IA titers were 61.95% (normal: 300 mU/L and < 0.02 nmol/L when hypoglycemia occurred. Based on his clinical symptoms and other examinations, he was diagnosed with hyperinsulinemic hypoglycemia caused by IA. His symptoms improved after changing insulin regimens from insulin lispro plus insulin detemir to recombinant human insulin (Gensulin R) and starting prednisone.

Los anticuerpos contra la insulina (AI) inducidos por la insulina exógena raramente causan hipoglucemia. No obstante, los autoanticuerpos contra la insulina (AIA) en el síndrome autoinmune de insulina (SAI) pueden causar hipoglucemia. Las manifestaciones típicas del SAI son la hipoglucemia en ayunas o posprandial, niveles elevados de insulina, la disminución del nivel de péptido C y AIA positivos. Presentamos un paciente hombre de 45 años con diabetes mellitus de tipo 1 (DMT1) tratado con análogos de insulina, que sufría comas hipoglucémicos recurrentes y cetoacidosis diabética (CAD). Sus síntomas fueron causados por la insulina exógena y fueron similares al SAI. La posible razón fue que la insulina exógena indujo AI. El título de AI era del 61,95% (Normal: 300 mU/L y < 0,02 nmol/L cuando se producía la hipoglucemia. Basados en sus síntomas clínicos y otros exámenes, se le diagnosticó hipoglucemia hiperinsulinémica causada por la AI. Sus síntomas mejoraron después de cambiar el régimen de insulina de lispro más insulina detemir a insulina humana recombinante (Gensulin R) y de empezar a tomar prednisona.

Marcadores inmunológicos de diabetes tipo 1: análisis de 4.164 perfiles en un centro de salud de Chile / Analysis of 4, 164 type 1 diabetes antibody profiles in a Chilean health centre

Background: Previous studies have assessed the role of Type 1 diabetes (DM1) antibodies as predictors of the natural history of disease. Aim: To determine the frequency and combinations of positivity for DM1 antibodies in patients with DM1 and the relationship between antibody positivity and the age of the patient. To explore the relationship between history of insulin therapy or diabetic ketoacidosis (DKA) at the onset of the disease with antibody positivity in a subsample. Material and Methods: Data was gathered from every sample processed for DM1 antibodies in our laboratory between January 2015 and September 2019. Medical records from 84 patients who tested positive for at least one antibody were revised to study the relationship between insulin therapy or DKA at the onset of the disease with antibody positivity. Results: Forty percent of DM1 antibody tests were positive. Among positive tests, 1, 2, 3 or 4 DM1 antibodies were detected in 48%, 33%, 17% and 3% of cases, respectively. The likelihood of testing positive was inversely related with age for ICA, GAD, IA-2, ZnT8 and directlyproportionalforIAA (p= −0,012; −0,013; −0,014; −0,009; 0,005 respectively). An association between DKA at the onset of the disease and IA-2 positivity was observed (Odds ratio (OR) 5.38 95% confidence intervals (CI) 1.79 − 16.16, P < 0.01). No association was found between IAA positivity and history of insulin therapy (OR 2.25 95%CI 0.63 − 7.90, P = 0.2403). The results obtained from this study represent a novel local profile of DM1 antibody data, highlighting a relationship between antibody positivity and age.

Use of cross-reactivity immunoassay to orient insulin replacement in diabetic patients with high levels of insulin antibodies.

The prevalence and high levels of anti-insulin antibodies (IA) have frequently been associated with brittle diabetes, lipodystrophy in the areas where the insulin is injected and/or poor metabolic control. When this happens the usual criterion adopted is the empirical change of insulin type and/or formulation intending to diminish the IA level and then to decrease the undesirable side-effects. Here, we present a rational two step radiometric method consisting in: A) a first-line radioligand binding assay (RBA) to assess IA in sera of these patients and detecting those with high levels. B) applying a displacement assay (RIA) to determine the in vitro cross-reactivity parameters (affinity constants and selectivity ratios) that quantify the relative degree of interaction between antibodies and alternative insulin analogs. From these results we conclude that conventional criteria for selection of insulin analogs, in terms of pharmacokinetic and pharmacodinamic parameters, should be complemented with an appropriate test to assess affinity parameters when high IA title is demonstrated. •This manuscript introduces a rational method to determine the appropriated insulin replacement when high insulin antibodies levels are present.•This protocol provides instructions and details in mathematical tools and laboratory processes for the analysis of serum samples.•This method proved to be successful in a single case and requires confirmation using a large group of patients.

Síndrome de hipoglicemia autoinmune: Primeros casos en Chile / Insulin autoimmune syndrome: Report of two cases

Insulin autoimmune syndrome (IAS) is characterized by spontaneous hypoglycemia with extremely high insulin levels and the presence of circulating autoantibodies against insulin, in patients who have never been exposed to exogenous insulin. We report two patients with the syndrome. A 36 years old male presenting with hypoglycemia in the emergency room had an oral glucose tolerance test showed basal and 120 min glucose levels of 88 and 185 mg/dl. The basal and 120 min insulin levels were 2,759 and 5,942 μUI/ml. The presence of an insulin secreting tumor was discarded. Anti-insulin antibodies were positive. He was successfully treated with a diet restricted in carbohydrates and frequent meals in small quantities. A 65 years old female presenting with hypoglycemia in the emergency room had the fasting insulin levels of 1,910 µUI/ml. No insulin secreting tumor was detected by images and anti-insulin antibodies were positive. The polyethylene glycol precipitation test showed a basal and after exposition insulin level 1,483 and 114 µUI/ml, respectively. She responded partially to diet and acarbose and required the use of prednisone with a good clinical response.