Development of insulin antibodies and changes in titers over a long-term period in patients with type 2 diabetes

Diabetic Ketoacidosis in a Pediatric Patient with Cystic Fibrosis-related Diabetes

Cystic fibrosis (CF), a genetic disorder caused by pathogenic variants in the CFTR gene, is associated with various complications including cystic fibrosis-related diabetes (CFRD). CFRD is an entity distinct from type 1 or type 2 diabetes. We report a rare case of diabetic ketoacidosis (DKA) in a pediatric patient with CFRD, occurring during a significant pulmonary exacerbation. The patient's management involved addressing fluid and electrolyte imbalances, careful monitoring of nutritional status, and correction of hyperglycemia with insulin. This case serves as a reminder to consider DKA in the differential diagnosis of patients with CF presenting with respiratory distress, even in the absence of typical symptoms such as polyuria and polydipsia.

Clinical, genetic, and proteomic characteristics of type 2 diabetes complicated with exogenous insulin antibody syndrome: a case-control study

AIMS

Insulin antibodies (IAs) are prevalent in insulin-treated patients with diabetes and may cause immunological dysglycemia, known as exogenous insulin antibody syndrome (EIAS). This study aims to elucidate the clinical, genetic, and proteomic characteristics of patients with concurrent type 2 diabetes (T2D) and EIAS.

METHODS

This was a case-control study with 177 IA-positive and 177 IA-negative T2D patients receiving insulin therapy. Among the IA-positive group, 46 patients with hypoglycemia and aberrantly elevated molar ratio of insulin to C-peptide (ICPR > 1) were identified as EIAS cases, followed with human leukocyte antigen (HLA) genotyping and plasma proteomic analysis by Olink platform.

RESULTS

Patients with EIAS exhibited greater glycemic variability than patients in other groups (IA-positive ICPR ≤ 1 or IA-negative). Higher ICPR was associated with increased glycemic variability in the IA-positive group. DRB1*0405-DQA1*03-DQB1*0401, DRB1*0803-DQA1*0103-DQB1*0601, and DRB1*1501-DQA1*0102-DQB1*0502 are the susceptible HLA haplotypes for EIAS. Additionally, nine differentially expressed proteins were identified in EIAS patients, with GALNT3, IL10, and CCL28 showing promising diagnostic performance.

CONCLUSIONS

IA-positive patients with remarkably elevated ICPR are prone to glycemic variability and should be evaluated for the diagnosis of EIAS. In this pilot study with limited sample size, EIAS is associated with unique HLA-DR-DQ risk haplotypes and enhanced immunoinflammatory response.

Interference from anti-drug antibodies on the quantification of insulin: a comparison of an LC-MS/MS assay and immunoassays

Aim: This study aims to compare the anti-drug antibody (ADA) interference in four pharmacokinetic (PK) assays across different platforms (AlphaLISA, Gyrolab, LC-MS/MS) and to devise a strategy for ADA interference mitigation to improve the accuracy of measured drug in total PK assays.Materials & methods: Spiked test samples, created to achieve different ADA concentrations in human serum also containing an insulin analogue, were analyzed alongside pooled clinical samples using four assays.Results & conclusion: Interference was observed in all platforms. A novel approach using the Gyrolab mixing CD, including acid dissociation in the PK assay, significantly reduced interference and thereby improved relative error from >99% to ≤20% yielding measurements well within the acceptance criteria. Clinical sample results reinforced findings from the test samples.

When discordant insulin and C-peptide levels lead to a medical diagnosis in a patient with transient hypoglycemia: Varying degrees of interference of insulin-antibody complexes on three insulin immunoassays

Background

Determining the cause of hypoglycemia partly relies on blood insulin and C-peptide assays. Although the pancreatic secretion of these peptides is equimolar, discrepancies in their concentrations may occur.

Case presentation

We report the case of a 73-year-old woman with type 2 diabetes mellitus (T2DM) and a history of gastric bypass. The T2DM was initially treated with insulin analogs, which were interrupted due to transient hypoglycemia episodes three years before hospitalization in our endocrinology department. During this hospitalization, the most common etiologies of hypoglycemia were excluded. Fasting insulin level was high (190 mIU/L, reference values (RV): 5-25) on Architect i2000 (an assay recognizing insulin analogs) despite normal blood C-peptide (4.5 μg/L, RV: 0.8-5.2) and slight hypoglycemia (4.5 mmol/L, RV: 4.6-6.1). Insulin level using the Elecsys assay (an assay with low sensitivity to insulin analogs) was very high (>1000 mIU/L, RV: 2.6-24.9). This pattern was observed on several samples, including some taken during a fasting test. Insulin level was only slightly increased using the Mercodia iso-insulin ELISA kit (an assay recognizing insulin analogs). These results excluded an exogenous insulin intake and were suggestive of an interference on insulin assays. To explore the latter possibility, free anti-insulin antibodies were measured and found strongly positive. The presence of interfering insulin-antibody complexes was further investigated using gel filtration chromatography, polyethylene glycol precipitation, and dilution test. Based on these findings, an insulin autoimmune syndrome (IAS) was suspected to cause the hypoglycemic episodes observed.

Conclusion

Although a discrepancy between blood insulin and C-peptide levels points to insulin analog intake, IAS should also be considered, particularly in a patient with transient hypoglycemia. IAS is characterized by the presence of insulin-antibody complexes, which can induce varying degrees of interference on insulin immunoassays and may lead to discordant insulin and C-peptide levels according to the insulin immunoassay used.

Association between glucose-lowering drugs and circulating insulin antibodies induced by insulin therapy in patients with type 2 diabetes

BACKGROUND

Insulin antibodies (IAs) affect blood glucose control in patients receiving insulin therapy.

AIM

To investigate the relationship between different hypoglycemic treatments and IAs in patients with type 2 diabetes mellitus (T2DM).

METHODS

This cross-sectional, retrospective study included 1863 patients with T2DM who were receiving exogenous insulin therapy. All patients received stable antidiabetic therapy in the last 3 months and IA levels were measured using an iodine-125 array.

RESULTS

A total of 1863 patients were enrolled. There were 902 (48.4%) patients who had positive IAs (IA level > 5%), with a mean IA level of 11.06% (10.39%-11.72%). IA levels were positively correlated with high fasting blood glucose (odds ratio = 1.069, P < 0.001). The proportion of positive IAs was lowest in patients using glargine only (31.9%) and highest in patients using human insulin only (70.3%), P < 0.001. The IA levels in patients using sulfonylureas/glinides (8.3%), metformin (9.6%), and dipeptidyl peptidase-4 inhibitors (8.2%) were all lower than in patients without these drugs (all P < 0.05).

CONCLUSION

Nearly half of patients on insulin therapy have positive IA antibodies, and IA antibody levels are associated with blood glucose control. Insulin glargine and a combination of oral glucose-lowering drugs were correlated with lower IA levels.

A clinical case of insulin autoimmune syndrome with monoclonal gammopathy of uncertain significance; complexity in management

Insulin autoimmune syndrome (IAS) is a rare cause of spontaneous hypoglycaemia. We discuss a 91-year-old Caucasian lady who presented with syncope and episodic adrenergic and neuroglycopenic symptoms. Despite significantly elevated insulin, C-peptide, and proinsulin levels with the presence of anti-insulin antibodies, a pancreatic mass was not identified. Serum immunoelectrophoresis demonstrated monoclonal gammopathy of undetermined significance (MGUS). Treatment involved high-dose steroids, diazoxide, corn starch and acarbose, however the patient passed away four months later due to worsening co-morbidities. The management of IAS in the setting of MGUS is challenging.

Engineering Antigen-Specific Tolerance to an Artificial Protein Hydrogel

Artificial protein hydrogels are an emerging class of biomaterials with numerous prospective applications in tissue engineering and regenerative medicine. These materials are likely to be immunogenic due to their frequent incorporation of novel amino acid sequence domains, which often serve a functional role within the material itself. We engineered injectable "self" and "nonself" artificial protein hydrogels, which were predicted to have divergent immune outcomes in vivo on the basis of their primary amino acid sequence. Following implantation in mouse, the nonself gels raised significantly higher antigel antibody titers than the corresponding self gels. Prophylactic administration of a fusion antibody targeting the nonself hydrogel epitopes to DEC-205, an endocytic receptor involved in Treg induction, fully suppressed the elevated antibody titer against the nonself gels. These results suggest that the clinical immune response to artificial protein biomaterials, including those that contain highly antigenic sequence domains, can be tuned through the induction of antigen-specific tolerance.

The clinical implications of fasting serum insulin levels in patients with insulin-treated type 2 diabetes: a cross-sectional survey

Objective

This study aimed to investigate the clinical implications of fasting serum insulin (FINS) levels in subjects with type 2 diabetes who were receiving insulin therapy.

Methods

A total of 1,553 subjects with type 2 diabetes [774 subjects who had never received insulin treatment (N-INS) and 779 subjects who were receiving insulin therapy (constant insulin treatment, C-INS)] admitted to the Department of Endocrinology and Metabolism of Peking University People's Hospital were enrolled in this study. Their FINS levels were measured and those with hyperinsulinemia were identified. The underlying mechanisms of hyperinsulinemia were revealed by measuring insulin antibodies (IAs) and analyzing changes in FINS levels before and after polyethylene glycol (PEG) precipitation. In addition, the clinical characteristics of patients with different types of hyperinsulinemia were compared.

Results

Higher FINS levels and a higher incidence (43.8%, 341/779) of hyperinsulinemia (FINS > 15μIU/mL) were observed in subjects with C-INS than in subjects with N-INS. Among subjects with C-INS and hyperinsulinemia, 66.9% (228/341) were IAs positive, and the incidence of IAs was found to be positively associated with FINS level. By performing PEG precipitation, we found that all subjects without IAs (i.e., those with real hyperinsulinemia) and 31.1% of subjects (71/228) with IAs (i.e., those with both real and IAs-related hyperinsulinemia) still had hyperinsulinemia after PEG precipitation, whereas FINS levels in the other 68.9% of subjects (157/228) with IAs were normal (IAs-related hyperinsulinemia) after PEG precipitation. Comparisons between the groups showed that subjects with real hyperinsulinemia showed more obvious insulin resistance characteristics, including higher lipid levels, BMIs, and homoeostasis model assessment2-estimated insulin resistance (HOMA2-IR) index, and were more likely to have hypertension, obesity, and metabolic syndromes (p < 0.05). However, the risk of hypoglycemia and glucose variability increased significantly in subjects with IAs compared with those without IAs. A cutoff of FINS to serum C-peptide ratio (≥ 9.3μIU/ng) could be used to screen IAs in clinical practice with 83.3% sensitivity and 70% specificity.

Conclusions

It is necessary to measure FINS in subjects with C-INS to distinguish between types of hyperinsulinemia, which should help to tailor treatment regimens.

Alpha-Lipoic Acid and Glucose Metabolism: A Comprehensive Update on Biochemical and Therapeutic Features

Alpha-lipoic acid (ALA) is a natural compound with antioxidant and pro-oxidant properties which has effects on the regulation of insulin sensitivity and insulin secretion. ALA is widely prescribed in patients with diabetic polyneuropathy due to its positive effects on nerve conduction and alleviation of symptoms. It is, moreover, also prescribed in other insulin resistance conditions such as metabolic syndrome (SM), polycystic ovary syndrome (PCOS) and obesity. However, several cases of Insulin Autoimmune Syndrome (IAS) have been reported in subjects taking ALA. The aim of the present review is to describe the main chemical and biological functions of ALA in glucose metabolism, focusing on its antioxidant activity, its role in modulating insulin sensitivity and secretion and in symptomatic peripheral diabetic polyneuropathy. We also provide a potential explanation for increased risk for the development of IAS.

Insulin antibody as a biomarker to monitor the development of type 2 diabetes in county hospitals in China

Background

The significance of insulin antibody (IA) detection in type 2 diabetes mellitus (T2DM) has received scant attention from county hospitals in China. We aimed to introduce exogenous IA positive rate and its relative factors in T2DM treated with insulin in Xiangshan County of Ningbo City, analyzing the immunogenicity of different kinds of insulin.

Methods

Patients who were residents from the Danxi community and six towns (Dongchen, Xizhou, Maoyang, Sizhoutou, Juexi, and Qiangtou) in Xiangshan County and diagnosed with T2DM and treated with insulins at Xiangshan Hospital of TCM Medical and Health Group between August 2019 and June 2020 were identified. Those who met the eligibility criteria were included and assigned to the IA-positive or IA-negative group. The immunogenicity of different insulins was compared between the two groups.

Results

Among 992 patients, 781 were eligible for IA detection, and 40.2% of them were IA positive. Blood IA was closely associated with fasting and 2-h glucose, insulin, and C peptide levels and higher insulin dosage. Patients receiving basal insulin treatment showed significantly lower blood IA than those treated with mixed human insulin, premixed human insulins, rapid-acting analogs, or a combination of basal and rapid-acting analogs.

Characteristics of OGTT and Correlation Between the Insulin to C-Peptide Molar Ratio, HOMA-IR, and Insulin Antibodies in T2DM Patients

PURPOSE

The purpose of our study was to analyze the characteristics of OGTT and the correlation between the insulin to C-peptide molar ratio (ICPR), HOMA-IR and insulin antibodies (IAs) in T2DM patients.

PATIENTS AND METHODS

A total of 77 T2DM patients were included and divided into the IA+ group (25 patients) and IA- group (52 patients). The values of serum glucose, insulin, and C-peptide testing during 2-h OGTT were summarized comparatively, and ROC was made to analyze the predictive value of ICPR for IAs.

RESULTS

At each time point of OGTT, there was no significant difference in serum glucose and C-peptide changes (p>0.05). Serum insulin levels in positive patients were elevated or not at different time points of the OGTT but ICPR was significantly different (P<0.05) in the two groups. Spearman correlation coefficient analysis showed that the presence of insulin antibodies was correlated with ICPR, but not with HOMA-IR, and ICPR-2h had a better prediction capacity (AUC=0.735, the optimal cutoff-point=0.11, Se=0.760, Sp=0.635).

CONCLUSION

T2DM patients with IAs showed no difference in serum glucose and serum C-peptide changes, but elevated or not insulin levels on the OGTTs, compared with negative patients. ICPR-2h can be a preliminary diagnostic index to timely predict IAs in T2DM patients.

EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA), Turck D, Castenmiller J, de Henauw S, Hirsch‐Ernst KI, Kearney J, Knutsen HK, Mangelsdorf I, McArdle HJ, Naska A, Pelaez C, Pentieva K, Siani A, Thies F, Tsabouri S, Vinceti M, Cappellani D, Ijzerman R, Van Loveren H, Titz A, Maciuk A. Scientific opinion on the relationship between intake of alpha-lipoic acid (thioctic acid) and the risk of insulin autoimmune syndrome

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the relationship between alpha-lipoic acid (ALA) and the risk of insulin autoimmune syndrome (IAS). The Panel was also asked to advise on the dose below which ALA added to foods is not expected to cause IAS. A review of all possible adverse effects associated with consumption of ALA was not requested. This mandate refers to the procedure under Article 8(2) of Regulation (EC) No 1925/2006 on addition of vitamins, minerals and certain other substances to foods. No pre-established rule exists for the evaluation of the safety of foods when classical toxicity tests cannot be used, e.g. for autoimmune diseases. Published scientific evidence was retrieved through comprehensive literature searches, particularly 49 case reports in which IAS developed following ALA consumption. In all cases, IAS resolved after a few weeks to months when ALA was discontinued. No publication linking the intake of ALA naturally occurring in foods to IAS was identified. The Panel concludes that the consumption of ALA added to foods, including food supplements, is likely to increase the risk of developing IAS in individuals with certain genetic polymorphisms, who cannot be readily identified without genetic testing. The plausible mechanism of such an effect has not yet been fully elucidated. The incidence of IAS in Europe is low and likely lower than in Japan where it has been estimated to be 0.017 per 100,000 inhabitants in 2017-2018. Considering the limited data available, the risk associated with the development of IAS following ALA consumption cannot be quantified precisely. An ALA dose below which IAS is not expected to occur is likely to vary between individuals and cannot be determined from the available data.

Recurrent Diabetic Ketoacidosis and Extreme Insulin Resistance Due to Anti-Insulin Antibodies: Response to Immunosuppression and Plasma Exchange

Anti-insulin antibodies (IAs) in patients with insulin-treated diabetes, though common, correlate poorly with glycemic control, insulin requirement, and insulin resistance. We are hereby reporting the clinical course and challenges in the management of a 70-year-old man who had severe insulin resistance as evidenced by recurrent diabetic ketoacidosis and poor glycemic control despite treatment with >9 U of insulin/kg body weight per day. He was found to have anti-IAs and responded clinically to plasmapheresis and immunosuppression with mycophenolate mofetil and prednisolone. Improved glycemic control correlated well with falling titers of antibodies. This case emphasizes that clinicians should be alert to the possibility of insulin resistance due to anti-IAs and the role of immunosuppression and plasmapheresis in such cases.

Insulin Autoimmune Syndrome (Hirata Disease): A Comprehensive Review Fifty Years After Its First Description

Insulin autoimmune syndrome (IAS), also named Hirata's disease, is a rare condition characterized by hypoglycemic episodes due to the presence of high titers of insulin autoantibodies (IAA). IAS is a form of immune-mediated hypoglycemia, which develops when a triggering factor (ie, a medication or a viral infection) acts on an underlying predisposing genetic background. IAS pathogenesis involves the formation of insulin-IAA complexes that induce glycemic alterations with a double-phase mechanism: IAA prevent insulin to bind its receptor in the postprandial phase, possibly resulting in mild hyperglycemia; thereafter, insulin is released from the complexes irrespective of blood glucose concentrations, thus inducing hypoglycemia. The diagnosis of IAS is challenging, requiring a careful workup aimed at excluding other causes of hyperinsulinemic hypoglycemia. The gold standard for the definitive diagnosis is the finding of IAA in a blood sample. Because IAS is frequently a self-remitting disease, its management mostly consists of supportive measures, such as dietary modifications, aimed at preventing the development of hypoglycemia. Pharmacological therapies may occasionally be necessary for patients presenting with severe manifestations of IAS. Available therapies may include drugs that reduce pancreatic insulin secretion (somatostatin analogues and diazoxide, for instance) and immunosuppressive agents (glucocorticoids, azathioprine and rituximab). The purpose of this review is to provide a comprehensive analysis of the disease, by describing the burden of knowledge that has been obtained in the 50 years following its first description, took in 1970, and by highlighting the points that are still unclear in its pathogenesis and management.

Oral Pharmacotherapy as Alternative Treatment for Type 2 Diabetes Mellitus in a 61 Year Old Ethnic Filipino Man with Insulin Allergies

Allergy to insulin occurs in approximately 2% of patients treated with insulin. However, major guidelines fail to emphasize this serious adverse effect. In this article, we report on a 61 year old ethnic Filipino man who developed urticaria and pruritus with a swollen tongue, which necessitated a visit to the emergency department. His clinical diagnosis was confirmed by a high titer of anti-insulin antibodies. His condition was successfully managed by discontinuing insulin and by treatment with oral hypoglycemic agents, with no additional adverse reactions. At the most recent follow-up visit, his antibody titer had fallen; however, that titer has not normalized. Also, the patient currently does not have uticaria.

Insulin autoimmune syndrome in an occidental woman: a case report and literature review

Insulin autoimmune syndrome (IAS, Hirata's disease) is a rare hypoglycemic disorder characterized by spontaneous hypoglycemia associated with extremely high circulating insulin levels and positive anti-insulin antibody results. Thus far, most cases have been reported in Asian countries, notably Japan, with few cases reported in western countries. As a possible cause, it is associated with the use of drugs containing sulfhydryl radicals, such as captopril. This report refers to a 63-year-old female Brazilian patient with a history of postprandial hypoglycemia. After extensive investigation and exclusion of other causes, her hyperinsulinemic hypoglycemia was considered to have likely been induced by captopril. Most cases of IAS are self-limiting. However, dietary management, corticosteroids, plasmapheresis, and rituximab have already been used to treat patients with IAS. In our case, after discontinuation of captopril, an initial decrease in insulin autoantibody levels was observed followed by improvement in episodes of hypoglycemia. Although it is a rare disease, IAS should be considered in the differential diagnosis of endogenous hyperinsulinemic hypoglycemia. Patients with suspected IAS must be screened for autoimmunity-related drugs for insulin. Initial clinical suspicion of IAS can avoid unnecessary costs associated with imaging examinations and/or invasive surgical procedures.

Insulin Detection Using a Corona Phase Molecular Recognition Site on Single-Walled Carbon Nanotubes

Corona phase molecular recognition (CoPhMoRe) is a technique whereby an external, adsorbed phase around a colloidal nanoparticle is selected such that its molecular conformation or interaction recognizes a specific target analyte. In this work, we employ a high-throughput screening of a library of poly(ethylene glycol) (PEG)-conjugated lipids adsorbed onto near-infrared fluorescent single-walled carbon nanotubes to discover a corona phase selective for insulin. We find that a C₁₆-PEG(2000 Da)-ceramide causes a 62% fluorescent intensity decrease of the (10,2) chirality nanotube in the presence of 20 μg/mL insulin. The insulin protein has no prior affinity toward the C₁₆-PEG(2000 Da)-ceramide molecules in free solution, verified by isothermal titration calorimetry, and the interaction occurs only upon their adsorption onto the single-walled carbon nanotube scaffolds. Testing a panel of proteins originating from human blood as well as short 7 amino acid fragments of the insulin peptide rules out nonselective recognition mechanisms such as molecular weight, isoelectric point, and hydrophobicity-based detection. Interestingly, longer fragments of isolated α- and β-peptide chains of insulin are detected by the construct, albeit with lower affinity compared to that of the intact insulin protein, suggesting that the construct recognizes insulin in its native form and conformation. Finally, the insulin recognition and the quantification of its solution concentration were demonstrated both in buffer and in blood serum, showing that the CoPhMoRe construct works in this complex environment despite the presence of potential nonspecific adsorption. Our results further motivate the search for nonbiological synthetic recognition sites and open up a new path for continuous insulin monitoring in vivo with the hope of improving glycemic control in closed-loop artificial pancreas systems.

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.

Rapid decline in insulin antibodies and glutamic acid decarboxylase autoantibodies with ibrutinib therapy of chronic lymphocytic leukaemia

WHAT IS KNOWN AND OBJECTIVE

Ibrutinib is inhibiting the Bruton's tyrosine kinase (BTK), thereby influencing B-cell development. We describe an unexpected side effect of ibrutinib in two patients with chronic lymphocytic leukaemia concerning the vigorous decrease of two different diabetes-associated antibodies.

CASE DESCRIPTION

Two weeks after onset of ibrutinib therapy, patient A frequently noticed symptoms of hypoglycaemia such as dizziness and blurred vision. Blood glucose declined to 35-40 mg/dL. He had to lower his insulin dose step by step. High levels of insulin antibodies which had developed during insulin therapy were detected. Seven weeks after start of ibrutinib, his insulin antibodies level had dropped by 54.6%. Patient B had a 54.1% decrease in his glutamic acid decarboxylase autoantibodies level after 7 weeks.

WHAT IS NEW AND CONCLUSION

The inhibitory effect of ibrutinib on the levels of insulin antibodies and glutamic acid decarboxylase autoantibodies is a novel finding and may have implications for diabetes care.

Development of Insulin Detemir/Insulin Aspart Cross-Reacting Antibodies Following Treatment with Insulin Detemir: 104-week Study in Children and Adolescents with Type 1 Diabetes Aged 2-16 Years

BACKGROUND

To study the long-term development (104 weeks) of insulin antibodies during treatment with insulin detemir (IDet) and insulin aspart (IAsp) in children with type 1 diabetes aged 2-16 years.

METHODS

A 52-week, two-arm, randomized trial comparing IDet and neutral protamine Hagedorn insulin, both in combination with IAsp, was followed by a one-arm, 52-week extension trial of the IDet + IAsp arm. The present analysis was conducted in children who completed the randomized trial and entered into the extension trial.

RESULTS

Of the 177 children randomized to IDet treatment, 146 entered the extension trial. IDet-IAsp cross-reacting antibodies peaked within the first 39 weeks of treatment before gradually declining. A similar pattern was seen for IDet-specific and IAsp-specific antibodies. At end of trial (EOT), no correlation was observed between the level of IDet-specific or IAsp-specific antibodies or IDet-IAsp cross-reacting antibodies and either glycated hemoglobin (HbA1c) or basal insulin dose. Mean HbA1c was stable during the treatment period, with a slight increase over time from 8.41% (68.4 mmol/mol) at baseline to 8.74% (72 mmol/mol) at EOT. Mean IDet dose increased from 0.43 U/kg at baseline to 0.66 U/kg at EOT. Mean IAsp dose increased from 0.46 U/kg to 0.51 U/kg at EOT.

CONCLUSION

Although treatment with IDet and IAsp is associated with development of specific and cross-reacting antibodies, no correlation between insulin antibodies and basal insulin dose or HbA1c was found.

FUNDING

Novo Nordisk A/S. ClinicalTrials.gov identifiers: NCT00435019 and NCT00623194.

Hyperinsulinemic hypoglycemia associated with insulin antibodies caused by exogenous insulin analog

Insulin antibodies (IA) associated with exogenous insulin administration seldom caused hypoglycemia and had different characteristics from insulin autoantibodies (IAA) found in insulin autoimmune syndrome (IAS), which was first described by Dr Hirata in 1970. The characteristic of IAS is the presence of insulin-binding autoantibodies and related fasting or late postprandial hypoglycemia. Here, we report a patient with type 1 diabetes mellitus under insulin glargine and insulin aspart treatment who developed recurrent spontaneous post-absorptive hyperinsulinemic hypoglycemia with the cause probably being insulin antibodies induced by exogenous injected insulin. Examinations of serial sera disclosed a high titre of insulin antibodies (33%, normal <5%), high insulin concentration (111.9 IU/mL) and undetectable C-peptide when hypoglycemia occurred. An oral glucose tolerance test revealed persistent high serum levels of total insulin and undetectable C-peptide. Image studies of the pancreas were unremarkable, which excluded the diagnosis of insulinoma. The patient does not take any of the medications containing sulfhydryl compounds, which had been reported to cause IAS. After administering oral prednisolone for 3 weeks, hypoglycemic episodes markedly improved, and he was discharged smoothly.

LEARNING POINTS

Insulin autoimmune syndrome (IAS) or IAS-like situation should be one of the differential diagnosis in patients with hyperinsulinemic hypoglycemia.Although less reported, insulin antibodies (IA) caused by exogenous insulin analog should be considered as the cause of hypoglycemia.Patients with suspected insulin autoimmune syndrome (IAS) should be screened for drugs related to autoimmunity to endogenous insulin.

Insulin Aspart in the Management of Diabetes Mellitus: 15 Years of Clinical Experience

Limiting excessive postprandial glucose excursions is an important component of good overall glycemic control in diabetes mellitus. Pharmacokinetic studies have shown that insulin aspart, which is structurally identical to regular human insulin except for the replacement of a single proline amino acid with an aspartic acid residue, has a more physiologic time-action profile (i.e., reaches a higher peak and reaches that peak sooner) than regular human insulin. As expected with this improved pharmacokinetic profile, insulin aspart demonstrates a greater glucose-lowering effect compared with regular human insulin. Numerous randomized controlled trials and a meta-analysis have also demonstrated improved postprandial control with insulin aspart compared with regular human insulin in patients with type 1 or type 2 diabetes, as well as efficacy and safety in children, pregnant patients, hospitalized patients, and patients using continuous subcutaneous insulin infusion. Studies have demonstrated that step-wise addition of insulin aspart is a viable intensification option for patients with type 2 diabetes failing on basal insulin. Insulin aspart has shown a good safety profile, with no evidence of increased receptor binding, mitogenicity, stimulation of anti-insulin antibodies, or hypoglycemia compared with regular human insulin. In one meta-analysis, there was evidence of a lower rate of nocturnal hypoglycemia compared with regular human insulin and, in a trial that specifically included patients with a history of recurrent hypoglycemia, a significantly lower rate of severe hypoglycemic episodes. The next generation of insulin aspart (faster-acting insulin aspart) is being developed with a view to further improving on these pharmacokinetic/pharmacodynamic properties.

Flying under the radar: treatment of refractory hyperglycemia

Clinicians are often presented with the scenario of what to do when one medication in a drug class has failed a therapeutic trial on a patient. We encountered a patient who developed profound resistance to glargine, aspart and regular insulin, but had a rapid and sustained response to detemir. The mechanism of the increased sensitivity to detemir is unclear, but may be related to an additional carbon chain on detemir shielding it from an antibody response. This case highlights the profound impact that subtle differences in molecular structure can have on biological activity and thus patient outcomes.

LEARNING POINTS

Subtle differences in molecular structure can have a profound impact on biological activity, and thus patient outcomes.Poor outcomes with one medication in a drug class should not be used to rule out the efficacy of all related medications.Detemir has been shown to be less immunogenic than other insulins, and should be considered in patients with insulin resistance.

Macro TSH in patients with subclinical hypothyroidism

OBJECTIVE

TSH is a sensitive indicator of thyroid function. In subclinical hypothyroidism, however, serum TSH concentrations are elevated despite normal thyroid hormone levels, and macro TSH is one of the causes. This study aimed to clarify the prevalence and nature of macro TSH in patients with subclinical hypothyroidism.

DESIGN

We conducted a 2-year cross-sectional observational study.

PATIENTS

We included 681 patients with subclinical hypothyroidism and 38 patients with overt hypothyroidism (controls).

MEASUREMENTS

Macro TSH was screened by polyethylene glycol (PEG) method and analysed by gel filtration chromatography and bioassays.

RESULTS

Among 681 serum samples, 117 exhibited PEG-precipitable TSH ratios greater than 75% (mean + 1·5 SD in controls) and were subjected to gel filtration chromatography. TSH was eluted at a position greater than 100 kDa in 11 patients with subclinical hypothyroidism (1·62%); these patients were diagnosed with macro TSH. The nature of macro TSH included eight anti-TSH autoantibodies of IgG class, two non-IgG-associated and one human anti-mouse antibody (HAMA). Macro TSH showed low bioactivity.

CONCLUSIONS

Macro TSH was heterogeneous, but it is mostly comprised of TSH and anti-TSH autoantibodies. When PEG-precipitable TSH exceeds 90% in serum samples with TSH above 10 mU/l, clinicians should strongly suspect the presence of macro TSH and confirm it by gel chromatography. Because macro TSH exhibited low bioactivity, thyroid hormone replacement therapy may not be required in patients with subclinical hypothyroidism due to macro TSH except for those with high serum free TSH levels.

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.