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.

The Effects of Anti-insulin Antibodies and Cross-reactivity with Human Recombinant Insulin Analogues in the E170 Insulin Immunometric Assay / 대한진단검사의학회지

BACKGROUND: Insulin assays are affected by varying degrees of interference from anti-insulin antibodies (IAs) and by cross-reactivity with recombinant insulin analogues. We evaluated the usefulness of the E170 insulin assay by assessing IA effects and cross-reactivity with 2 analogues. METHODS: Sera were obtained from 59 type 2 diabetes patients receiving continuous subcutaneous insulin infusion and 18 healthy controls. Insulin levels were determined using an E170 analyzer. To investigate the effects of IAs, we performed IA radioimmunoassays, and analyzed the differences between directly measured insulin (direct insulin) and polyethylene glycol (PEG)-treated insulins (free, IA-unbound; total, IA-bound and unbound insulin). We performed in-vitro cross-reactivity tests with insulin aspart and insulin glulisine. RESULTS: In IA-positive patients, E170 free insulin levels measured using the E170 analyzer were significantly lower than the direct insulin levels. The mean value of the direct/free insulin ratio and IA-bound insulin, which were calculated as the difference between total and free insulin, increased significantly as endogenous IA levels increased. The E170 insulin assay showed low cross-reactivities with both analogues (< 0.7%). CONCLUSIONS: IAs interfered with E170 insulin assay, and the extent of interference correlated with the IA levels, which may be attributable to the increase in IA-bound insulin, and not to an error in the assay. The E170 insulin assay may measure only endogenous insulin since cross-reactivity is low. Our results suggest that the measurement of free insulin after PEG pre-treatment could be useful for beta cell function assessment in diabetic patients undergoing insulin therapy.

Asociación de la variante GHRd3 del receptor de la hormona de crecimiento con autoinmunidad en la diabetes tipo 1 / Association of GHRd3 variant of growth hormone receptor gene with autoimmunity in type 1 diabetes

Background: Growth Hormone Receptor (GRH) is expressed in the liver, pancreas, stomach and small intestine. A high expression of GHR mRNA in the mucosal gut suggests a possible role of this receptor on digestive and immune functions. Aim: To investigate the putative effects of the GHRd3 variants on the cytokine profile and distribution of auto-antibodies in children with type 1 diabetes (T1D). Material and Methods: Unrelated unaffected controls (n =192) and incident cases of children with T1D (n =127) were analyzed for GHRd3 polymorphism, cytokine profile and a panel of auto-antibodies. Results: The allele frequency for d3 was 24.8 percent in type 1 diabetics and 34.1 percent in controls (p =NS). Among type 1 diabetic children, the carriers of the GHRd3 polymorphism had significantly higher levels of interleukin-lB than homozygous for the wild type genotype (5.7 and 17.7, pg/ml respectively p <0.015). Carriers of d3 variant had a higher frequency of positive anti-insulin antibodies (anti-IAA) than children without this variant (39.6 and 17.7 percent respectively, p <0.01). Conclusions: The observed frequency of the GHR d3/d3 genotype was comparable to other reports. A relationship between d3 variant and anti-IAA antibodies and interleukin-1ß was observed.

Insulin autoimmune syndrome: case report

CONTEXTO: A síndrome da hiperinsulinemia autoimune (SHA, doença de Hirata) é uma causa rara de hipoglicemia nos países ocidentais. Ela é caracterizada por episódios de hipoglicemia, níveis elevados de insulina e presença de anticorpos anti-insulina. Nosso objetivo é relatar um caso da SIA identificado na América do Sul. RELATO DO CASO: Um homem caucasiano de 56 anos de idade começou a apresentar sintomas neuroglicopênicos durante hospitalização devida a trauma grave. A avaliação laboratorial confirmou hipoglicemia e níveis extremamente elevados de insulina. Os exames radiológicos convencionais realizados foram negativos para tumor pancreático. A remissão clínica da doença não ocorreu durante o uso de verapamil e corticóides. Desta forma, pancreatectomia subtotal foi realizada devido à ausência de resposta ao tratamento conservador e à impossibilidade de serem utilizados imunosupressores em razão da bacteremia persistente. O exame histopatológico revelou hiperplasia difusa de células beta. O paciente persiste apresentando níveis elevados de insulina porém praticamente não apresenta mais episódios de hipoglicemia.

A Case of Autoimmune Hypoglycemia Complicated with Diabetic Ketoacidosis

Autoimmune hypoglycemia is characterized by hyperinsulinemia, fasting hypoglycemia, and the presence of insulin auto- antibodies without previous exposure to exogenous insulin. We experienced a case of autoimmune hypoglycemia without diabetes mellitus or any evidence of insulinoma. The insulin auto-antibody and insulin receptor auto-antibody were present. We diagnosed the patient as having autoimmune hypoglycemia and treated with glucocorticoid. After treatment, the hypoglycemic symptoms were resolved. However, four months later, the patient was readmitted with transient diabetic ketoacidosis. After recovery, he showed no signs of diabetes mellitus. We believe that insulin auto-antibodies may play a role in autoimmune hypoglycemia and diabetic ketoacidosis, but its role and mechanism are not precisely known. Further studies are needed to define the action mechanisms and the functions of insulin auto-antibodies: here we present case with a relevant literature.

Frequency of islet cell autoantibodies (IA-2 and GAD) in young Brazilian type 1 diabetes patients

Type 1 diabetes, as an autoimmune disease, presents several islet cell-specific autoantibodies such as islet cell antibody (ICA), anti-insulin, anti-glutamic acid decarboxylase (GAD) and the antibody (Ab) against tyrosine phosphatase (PTP)-like protein known as ICA-512 (IA-2). In order to determine the frequency of the anti-GAD and anti-IA-2 autoantibodies in Brazilian type 1 diabetes patients we studied 35 diabetes mellitus (DM) type 1 patients with recent-onset disease 12 months and 37 type 1 diabetes patients with long-duration diabetes 12 months who were compared to 12 children with normal fasting glucose. Anti-GAD65 and anti-IA-2 autoantibodies were detected with commercial immunoprecipitation assays. The frequency of positive results in recent-onset DM type 1 patients was 80.0 percent for GADAb, 62.9 percent for IA-2Ab and 82.9 percent for GADAb and/or IA-2Ab. The long-duration type 1 diabetes subjects presented frequencies of 54.1 percent for GADAb and IA-2Ab, and 67.5 percent for GAD and/or IA-2 antibodies. The control group showed no positive cases. Anti-GAD and IA-2 assays showed a high frequency of positivity in these Brazilian type 1 diabetes patients, who presented the same prevalence as a Caucasian population

Auto Anticorpos anti-ilhota e anti-insulina em diabéticos do tipo 1 de diagnóstico recente e parentes de primeiro grau brasileiros / Autoantibodies anti-islets and anti-insulin in patients with recently dianosed type I diabetes and in Brazilian first degree relatives

Os autoanticorpos contra as células pancreáticas têm sido utilizados para caracterizar e determinar o risco de evoluçao para o diabetes mellitus do tipo 1 (DM1) autoimune. No entanto, a maioria desses estudos foram realizados em populaçoes norte-americanas, européias ou asiáticas. No presente estudo foram avaliadas, em brasileiros, as prevalências dos autoanticorpos anti-ilhota (ICA) e anti-insulina (IAA) em normais (N), DM1 com início recente - menos de 6 meses de diagnóstico (DM1ir) e parentes de primeiro grau de DM1, nao diabéticas (PGDM1). Os métodos utilizados foram: imunohistoquímica (imunoperoxidade-proteína A) para os ICA e radioensaio supersensível para os IAA. A prevalência dos ICA isoladamente foi: N= 2,1 por cento (1/48), PGDM1= 5,6 por cento (3/54), DM1ir= 68 por cento (50/74) e dos IAA: N= 0 por cento (0/17), PGDM1= 18,7 por cento (27/144), DM1ir= 47,5 por cento (29/61); e de ambos. ICA+IAA, foi: N= 0 por cento (0/17), PGDM1= 1,8 por cento (1/54), DM1ir= 36 por cento (9/53). A positividade dos ICA (p<0,001), dos IAA (p<0,001) e de ambos (p<0,001) foi mais prevalente nos DM1ir. OS ICA foram mais prevalentes nos DM1ir entre 5 e 15 anos do que naqueles com idade superior a 30 anos por ocasiao do diagnóstico (p=0,003). Há uma correlaçao inversa (rS= -0,42, p<0,001) entre os níveis de IAA e a idade ao diagnóstico. Os níveis de IAA nos DM1ir (165,9+33,7 nU/ml; X+EPM) foram maiores do que nos N (22,3+2,5 nU/ml;p<0,001) e nos PGDM1 (508,7 nU/ml; p=0,03). Esses resultados mostram uma alta prevalência de autoimunidade nos DM1 da populaçao brasileira. A prevalência dos ICA e a distribuiçao dos IAA entre as faixas etárias dos DM1ir foram semelhantes às encontradas em populaçoes pareadas de outros países. Assim, também no nosso meio, os ICA e os IAA podem ser utilizados para o diagnóstico do DM1 autoimune. Estudos longitudinais de crianças com ICA ou IAA positivos sao necessários no nosso país para se determinar o valor preditivo destes anticorpos para a doença manifesta.

Associaçäo entre auto-anticorpos anti-pro-insulina e anti-insulina com diabetes mellitus do tipo I / The association between insulin and proinsulin autoantibodies with tipe I Diabetes Mellitus

O presente trabalho compara a incidência de auto-anticorpos anti-insulina (IAA) e anti-pró-insulina (PAA) em diabéticos do tipo I de início recente e em seus parentes de primeiro grau. Foram estudados 33 indivíduos normais (grupo I), 16 diabéticos do tipo I de início recente (grupo II) e 141 parentes em primeiro grau de diabéticos do tipo I (grupo III). Os IAA e PAA foram determinados pelo método de radioensaio, sendo considerados anormais níveis de IAA acima de 0,584 pmol/L e de PAA acima de 0,441 pmol/L. Näo foram observadas diferenças significantes quanto a idade e sexo entre os 3 grupos. Nos indivíduos normais os níveis de PAA foram significantemente menores do que os de IAA. Entre os diabéticos de início recente foi encontrada uma incidência de IAA de 37,5 por cento e de PAA de 25,0 por cento, näo ocorrendo, entretanto, diferenças significantes entre os níveis destes dois anticorpos. Entre os parentes em primeiro grau a incidência de IAA foi de 3,5 por cento e de PAA de 7,8 por cento, näo ocorrendo também diferenças entre os dois testes. Houve uma correlaçäo significante entre os níveis dos IAA e dos PAA no grupo de diabéticos de início recente (r=0,64; p < 0,05). Os IAA e PAA parecem estar dirigidos contra o mesmo determinante antigênico e, portanto, têm o mesmo valor preditivo para o DM tipo I

Anti-insulin antibodies and retinopathy in juvenile onset type-1 diabetes.

Juvenile diabetics have severe loss of beta cell function and require replacement therapy with insulin. Insulin antigenicity can produce anti-insulin antibodies resulting in allergic reactions and insulin resistance. The role of insulin-anti-insulin antibody complexes in the development and progress of chronic diabetic complications like microangiopathy is not very clear. In the present study, there was statistically a significant trend of higher insulin antibody binding levels in IDDM patients who developed retinopathy. Though there was a trend of higher insulin antibody in IDDM patients with retinopathy, there was no association between insulin antibody and HLA antigen which some authors have reported.