Insulin antibodies and hypoglycemia in diabetic patients. Can a quantitative analysis of antibody binding predict the risk of hypoglycemia?

Exogenous insulin antibody syndrome (EIAS): a clinical syndrome associated with insulin antibodies induced by exogenous insulin in diabetic patients

Insulin has been used for diabetes therapy and has achieved significant therapeutic effect. In recent years, the use of purified and recombinant human insulin preparations has markedly reduced, but not completely suppressed, the incidence of insulin antibodies (IAs). IAs induced by exogenous insulin in diabetic patients is associated with clinical events, which is named exogenous insulin antibody syndrome (EIAS). The present review is based on our research and summarizes the characterization of IAs, the factors affecting IA development, the clinical significance of IAs and the treatments for EIAS.

Insulin autoimmune syndrome in a pregnant female: A rare case report

RATIONALE

Insulin autoimmune syndrome (IAS) is an uncommon disorder characterized by hyperinsulinemic hypoglycemia related to insulin-binding autoantibodies. To the best of our knowledge, we report the first case of a pregnant female with IAS.

PATIENT CONCERNS

The 26-year-old patient with Graves disease and 10 weeks pregnant developed IAS after approximately 6 months treatment with methimazole. The patient exhibited recurrent spontaneous hypoglycemia.

DIAGNOSES

On evaluation, laboratory findings detected both high fasting insulin (>1000 mIU/L) and insulin autoantibodies. An oral glucose tolerance test showed elevated insulin concentrations with disproportionately elevated C-peptide levels. The imaging study showed nomasslesionsinthepancreas,and the patient was clinically diagnosed with IAS.

INTERVENTIONS

The patient had an abortion, discontinued methimazole and switched to oral prednisone (30 mg once daily) and propylth- iouracil (100 mg 3 times daily) for 3 months.

OUTCOMES

At the 3-month follow-up visit, hypoglycemic episodes had disappeared and insulin antibody levels were no longer detectable.

LESSONS

We have described this case and reviewed the relevant literature concerning diagnosis and treatment of IAS. Importantly, this case indicates that clinicians should view pregnancy as another factor of hypoglycemia in IAS.

Two Sisters with Graves' Disease and Similar Clinical Features who Tested Positive for Anti-insulin Antibodies after Thiamazole Treatment

The older of a pair of sisters experienced hypoglycemia after the start of thiamazole (MMI) treatment. Based on a high insulin antibody level, she was diagnosed with insulin autoimmune syndrome (IAS). HLA-DNA typing identified DRB1*04:06. Although a 75-g oral glucose tolerance test (OGTT) showed biphasic insulin secretion, the secretion pattern became monophasic after discontinuation of the MMI. The younger sister was diagnosed with IAS after the start of MMI treatment. HLA-DNA typing identified DRB1*04:06. The 75-g OGTT showed biphasic insulin secretion, but it became monophasic after discontinuation of the MMI. According to the similar insulin secretion kinetics in the two sisters with IAS, we suspect that a genetic predisposition may be associated with the features of anti-insulin antibodies.

Insulin antibodies in patients with type 2 diabetic receiving recombinant human insulin injection: A report of 12 cases

We report 12 cases of patients with type 2 diabetic receiving recombinant human insulin injection, who had uncontrolled hyperglycemia or frequent episodes of hypoglycemia, high levels of serum insulin and positive insulin antibodies. The clinical characteristics and insulin antibodies pharmacokinetics parameters were analyzed. After administration of glucocorticoids, changing insulin formulations or discontinuing the insulin and switching to oral antidiabetic agents, the level of insulin antibodies decreased and the plasma glucose restored. Thus, we recommend to identify the presence of high insulin antibodies in patients with type 2 diabetes who experience unexplained high plasma glucose or frequent reoccurrence of hypoglycemia.

Immunological hypoglycemia associated with insulin antibodies induced by exogenous insulin in 11 Chinese patients with diabetes

AIMS

To investigate the characteristics of immunological hypoglycemia associated with insulin antibodies (IAbs) induced by exogenous insulin in Chinese patients with diabetes.

METHODS

The clinical data of patients with immunological hypoglycemia due to IAbs were retrospectively analyzed by screening patients with diabetes discharged from West China Hospital from 2007 to 2013.

RESULTS

A total of 11 patients (eight men and three women) were identified. Insulin-C-peptide separation was found in all patients via insulin and C-peptide release test. Previous insulin use was ceased after admission and was switched to oral hypoglycemic agents (OHAs) (8/11), lifestyle modification only (2/11), or regular human insulin (1/11). Hypoglycemia was ameliorated after a median of 20 days (interquartile range [IQR], 11-40), while IAbs turned negative after a median of 17 months (IQR, 4-19), and serum immunoreactive insulin (IRI) levels dropped substantially after a median of 22 months (IQR, 9-32) in these cases.

CONCLUSIONS

In insulin-treated patients with unexpected and refractory hypoglycemia even after insulin therapy was gradually reduced or even withdrawn, IAbs induced by exogenous insulin should be considered, and insulin withdrawal might be promptly needed. The course of immunological hypoglycemia was benign and self-limited.

Hypoglycemic coma due to insulin autoimmune syndrome induced by methimazole: A rare case report

Insulin autoimmune syndrome (IAS) is a rare cause of hypoglycemia characterized by the presence of insulin-binding autoantibodies and fasting or late postprandial hypoglycemia. The number of reports on the association of human leukocyte antigen (HLA) genotype with this disease in adolescents in China is limited. This is the case report of a 17-year-old female patient with Graves' disease who was treated with methimazole (MTZ). After 4 weeks of continuous MTZ treatment, the patient suffered an episode of unconsciousness during the late postprandial phase and was admitted to the hospital, where the blood glucose level was found to be 2.88 mmol/l. The symptoms were relieved following intravenous glucose administration. Imaging studies of the pancreas were unremarkable, but the laboratory investigations on admission revealed high serum levels of total insulin, associated with relatively low levels of free insulin and markedly elevated insulin autoantibody (IAB) levels. HLA testing revealed DRB1*0406/0901 and the patient discontinued MTZ and was prescribed propylthiouracil. During the long-term follow-up, the total insulin and IAB levels gradually declined. There was no other episode of hypoglycemia. Therefore, in adolescents with Graves' disease receiving antithyroid treatment with MTZ who experience hypoglycemia, the IAB levels should be assessed to exclude or confirm IAS as the underlying cause.

Frequent reoccurrence of hypoglycemia in a type 2 diabetic patient with insulin antibodies

BACKGROUND

Insulin antibody (IAb) may be produced in patients receiving long-term, animal-derived insulin, leading to insulin resistance or hypoglycemia. There have been very few reports of hypoglycemia caused by IAb in patients taking recombinant human insulin.

CASE REPORT

We report the case of an 82-year-old male patient with type 2 diabetes mellitus who suffered repeated episodes of severe hypoglycemia-related symptoms (including coma) prior to admission. The patient had been taking Novolin 30R, a premixed human insulin. The patient's IAb level was markedly elevated, and hypoglycemia caused by recombinant human insulin treatment-induced IAb production was diagnosed. Acarbose and metformin were prescribed, and the patient recovered uneventfully. The patient ceased taking these medications, and he was subsequently treated with recombinant human insulin to combat hyperglycemia. This was followed by reoccurrence of hypoglycemic coma. The patient was advised to avoid taking recombinant human insulin for the rest of his life and to control hyperglycemia with acarbose and metformin.

CONCLUSIONS

Although rare, hypoglycemia caused by recombinant human insulin-induced IAb production should be considered in patients with type 2 diabetes who experience repeated episodes of hypoglycemia.

The importance of anti-insulin antibody in patients with type 1 diabetes mellitus treated with continuous subcutaneous insulin infusion or multiple daily insulin injections therapy

To investigate the influence of two insulin administration modalities, continuous subcutaneous insulin infusion (CSII) and multiple daily insulin injections (MDI) therapy with insulin analogues, on the development of insulin antibodies (IAs) in patients with type 1 diabetes mellitus and to assess the impact of IAs on glucose control and hypoglycaemia. 96 patients with type 1 diabetes mellitus treated with CSII (n = 48) or MDI (n = 48) were included in the study. Age, duration of diabetes, A1c, preprandial and postprandial blood glucose and hypoglycaemic events were compared between IA positive and negative patients. IA levels were higher in the CSII group (% 24.6 ± 14.2) than the MDI group (% 13.2 ± 9.9). Duration of diabetes and age were not associated with IA positiveness. While A1c, preprandial blood glucose and the frequency of hypoglycaemic events were similar in two groups, postprandial blood glucose was lower in IA positive group (P = 0.03). Patients with type 1 diabetes mellitus treated with CSII with insulin analogues had higher IA levels when compared to MDI therapy. However, the development of IAs did not impair the glycaemic control.

Inhaled insulin: overview of a novel route of insulin administration

Diabetes is a chronic disease characterized by inadequate insulin secretion with resulting hyperglycemia. Diabetes complications include both microvascular and macrovascular disease, both of which are affected by optimal diabetes control. Many individuals with diabetes rely on subcutaneous insulin administration by injection or continuous infusion to control glucose levels. Novel routes of insulin administration are an area of interest in the diabetes field, given that insulin injection therapy is burdensome for many patients. This review will discuss pulmonary delivery of insulin via inhalation. The safety of inhaled insulin as well as the efficacy in comparison to subcutaneous insulin in the various populations with diabetes are covered. In addition, the experience and pitfalls that face the development and marketing of inhaled insulin are discussed.

Circulating insulin antibodies: influence of continuous subcutaneous or intraperitoneal insulin infusion, and impact on glucose control

The purification of animal insulin preparations and the use of human recombinant insulin have markedly reduced the incidence, but not completely suppressed, the development of anti-insulin antibodies (IAs). Advances in technologies concerning the mode of delivery of insulin, i.e. continuous subcutaneous insulin infusion (CSII), continuous peritoneal insulin infusion (CPII) and more recently inhaled insulin administration, appear to significantly increase circulating levels of immunoglobulin G (IgG) anti-IAs in diabetic patients. However, the increase is usually moderate and mostly transient as compared to previous observations with poorly purified animal insulin preparations. The clinical impact of these circulating anti-IAs remains unclear. Nevertheless, several studies have suggested that antibodies could retard insulin action, leading to a worsening of postprandial hyperglycaemia and/or serve as a carrier, thus leading to unexpected hypoglycaemia. CPII may be associated with more marked and sustained increase in IAs levels, possibly related to the use of an unstable insulin and the formation of immunogenic aggregates of insulin. The possible clinical consequences of these high levels of IAs remain to be evaluated because a low-glucose morning syndrome or severe insulin resistance with ketone bodies production have been reported in some cases. In conclusion, even if CSII and CPII may promote the development of circulating IAs, this increase does not lead to immunological insulin resistance, compared to that previously described with animal non-purified insulin preparations, and seems to have only marginal influence on blood glucose control or complications in most diabetic patients.

Immunological responses to exogenous insulin

Regardless of purity and origin, therapeutic insulins continue to be immunogenic in humans. However, severe immunological complications occur rarely, and less severe events affect a small minority of patients. Insulin autoantibodies (IAAs) may be detectable in insulin-naive individuals who have a high likelihood of developing type 1 diabetes or in patients who have had viral disorders, have been treated with various drugs, or have autoimmune disorders or paraneoplastic syndromes. This suggests that under certain circumstances, immune tolerance to insulin can be overcome. Factors that can lead to more or less susceptibility to humoral responses to exogenous insulin include the recipient's immune response genes, age, the presence of sufficient circulating autologous insulin, and the site of insulin delivery. Little proof exists, however, that the development of insulin antibodies (IAs) to exogenous insulin therapy affects integrated glucose control, insulin dose requirements, and incidence of hypoglycemia, or contributes to beta-cell failure or to long-term complications of diabetes. Studies in which pregnant women with diabetes were monitored for glycemic control argue against a connection between IAs and fetal risk. Although studies have shown increased levels of immune complexes in patients with diabetic microangiopathic complications, these immune complexes often do not contain insulin or IAs, and insulin administration does not contribute to their formation. The majority of studies have shown no relationship between IAs and diabetic angiopathic complications, including nephropathy, retinopathy, and neuropathy. With the advent of novel insulin formulations and delivery systems, such as insulin pumps and inhaled insulin, examination of these issues is increasingly relevant.

Acute liver dysfunction complicated with uncontrollable glycemia due to insulin antibody: successful treatment with glucocorticoid and lispro insulin

Here, we report a case of acute liver dysfunction complicated with uncontrollable glycemia due to insulin antibody. The patient was admitted to our hospital due to diabetic ketoacidosis. He was administered insulin immediately, however, his fasting plasma glucose level remained unstable despite the insulin treatment. Blood biochemistry revealed severe liver dysfunction, although no markers including hepatitis virus or autoantibodies associated with autoimmune liver diseases were detected. The 125I-insulin binding rate was high (54%). The characteristics of insulin antibody in this patient were similar to the antibodies of IAS patients, therefore we administered oral glucocorticoid against insulin antibody. The reduction in the 125I-insulin binding rate and the binding capacity of the high affinity site of insulin antibodies were balanced after oral glucocorticoid therapy. In addition, preprandial subcutaneous regular insulin was switched to lispro insulin. Postprandial plasma glucose levels were relatively improved by lispro insulin. The etiology of acute liver dysfunction was unknown, however, we believe that the combination of oral glucocorticoid and lispro insulin was suitable and useful for preventing recurrent liver dysfunction in this patient.

Autoimmune hypoglycemia

Autoimmune hypoglycemia is a rare but fascinating syndrome of hypoglycemia caused by the interaction of endogenous antibodies with insulin or the insulin receptor. Awareness of autoimmune hypoglycemia is important because the syndrome may produce severe neuroglycopenic symptoms and may be confused with the presence of an insulinoma. A correct diagnosis is important to avoid unnecessary surgical intervention in patients who are best treated with conservative support, watchful waiting, or in some cases, immunosuppressive therapy.