Circulating Insulin Antibodies Research Articles

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

Insulin antibodies (IAs) affect blood glucose control in patients receiving insulin therapy. To investigate the relationship between different hypoglycemic treatments and IAs in patients with type 2 diabetes mellitus (T2DM). 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. 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). 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.

SAT173 Insulin Autoimmune Syndrome: A Rare Diagnosis With Unique Features

Abstract Disclosure: S. Naqvi: None. S. Syed: None. A.R. Kasireddy: None. S. Alshami: None. D. Edem: None. J.A. Henske: None. Introduction: Insulin Autoimmune Syndrome [IAS], or Hirata’s disease, is a rare cause of hypoglycemia. It is characterized by positive insulin autoantibodies in an insulin naïve patient and should be considered in the differential for post-prandial hypoglycemia. Case: A 48-year-old male presented with postprandial tremors, sweating, palpitations and episodes of incoherent speech and loss of consciousness at least 6 months prior to his presentation. He had no history of diabetes, however, was found to have severe symptomatic documented hypoglycemic episodes, with resolution of hypoglycemic symptoms upon treatment; fulfilling the Whipple’s triad. Outpatient workup for causes of his hypoglycemia ruled out insulinoma, use of diabetes medications or insulin, adrenal insufficiency, severe illness, infections, thyroid, liver or kidney dysfunction. He never had gastrointestinal or bariatric surgery. Given his symptoms and severity of hypoglycemic episodes, he was admitted for observation and 72 hour fast. Lab work during hypoglycemic episode revealed inappropriately elevated insulin and low to normal c-peptide levels, undetectable proinsulin, elevated beta-hydroxybutyrate, normal IGF-1, IGF-2, and a negative sulfonylurea screen. Importantly, his insulin: c-peptide ratio was more than 1 and his insulin antibodies were elevated, consistent with IAS. He denied any history of autoimmune disorders or use of any medications with sulfhydryl group. CGM sensor clearly showed the relationship between high glycemic index foods, glucose spikes, and drops in his blood glucose several hours later. Dietary counselling was provided, without much improvement. Trials of Acarbose and Octreotide were not tolerated due to side effects like rash. Prednisone 20 mg bid was started; Diazoxide was titrated to 200 mg tid with much improvement. He has been followed by our clinic, and tapered to prednisone 10 mg bid and Nifedipine 30 mg daily with resolution of his symptoms. Conclusions: Severe hypoglycemia in non-diabetic patients requires investigation utilizing a broad differential diagnosis and biochemical evaluation. The findings of post-prandial hypoglycemia and inappropriately high insulin, with low to normal c-peptide and proinsulin levels with an insulin: C-peptide [ICP] ratio &amp;gt;1 in a non-diabetic patient is consistent with IAS. An ICP ratio &amp;gt;1 is a clue that the half-life of insulin has been increased by circulating antibodies. Mechanistically, post-prandial hyperglycemia cause insulin secretion, however, circulating insulin antibodies neutralize its effect. Ongoing hyperglycemia leads to further high levels of insulin, followed by intermittent spontaneous decoupling of insulin-antibody complex and subsequent post-prandial hypoglycemia. IAS may spontaneously resolve over time but may require indefinite length of treatment and dietary modification until this occurs. Presentation: Saturday, June 17, 2023

Characterization of Insulin Antibodies by Surface Plasmon Resonance in Two Clinical Cases: Brittle Diabetes and Insulin Autoimmune Syndrome

In this study, the characterization of insulin (auto)antibodies has been described, mainly in terms of concentration (q), affinity (Ka) and Ig (sub)isotypes by Surface Plasmon Resonance (SPR) in two particular clinical cases of individuals with severe episodes of impaired glycemia. Subject 1 suffers from brittle diabetes associated with circulating insulin antibodies (IA) due to insulin treatment. Subject 2 has insulin autoantibodies (IAA) associated with hypoglycemia in spite of not being diabetic and not having ever received exogenous insulin therapy. After conventional screening for IA/IAA by radioligand binding assay (RBA), we further characterized IA/IAA in sera of both patients in terms of concentration (q), affinity (Ka) and Ig (sub)isotypes by means of SPR technology. In both cases, q values were higher and Ka values were lower than those obtained in type 1 diabetic patients, suggesting that IA/IAA:insulin immunocomplexes could be responsible for the uncontrolled glycemia. Moreover, subject 1 had a predominat IgG1 response and subject 2 had an IgG3 response. In conclusion, SPR technology is useful for the complete characterization of IA/IAA which can be used in special cases where the simple positive/negative determination is not enough to achieve a detailed description of the disease fisiopathology.

Biosimilar Insulin and Insulin Antibodies

Biosimilar Insulin and Insulin Antibodies

Is there a relationship between genetically determined haptoglobin phenotype and insulin-dependent diabetes mellitus (IDDM)?

The possible relationship between genetically determined haptoglobin phenotype and insulin-dependent diabetes (IDDM), circulating insulin antibodies and the occurrence of microangiopathy was studied in 144 IDDM. There were no differences regarding the distribution of Hp-phenotypes in 144 patients in comparison with a control population (n = 1726). Irrespective of the Hp-phenotype, the degree and severity of diabetic complications (retinopathy and/or nephropathy) significantly increased with the duration of diabetes. There was no relationship between Hp-phenotype and diabetic microangiopathy (retinopathy, nephropathy). No association existed between Hp-phenotype and the percentage of insulin antibody binding. Regardless of the Hp-phenotype, the insulin antibody concentration decreased with increasing duration of diabetes. Insulin binding parameters (maximum binding capacity and equilibrium dissociation constant) were found to vary considerably with the Hp-phenotypes among IDDM. For a given duration of diabetes the equilibrium dissociation constant increased significantly in the range from Hp 1-1, Hp 2-1 to Hp 2-2 phenotype. There was a direct relationship between the logarithm of the equilibrium dissociation constant and the degree of metabolic control, i.e. the lower the dissociation constant the better the metabolic balance. In conclusion, the results do not provide support for a putative relationship between Hp-phenotype and IDDM. However, differences between insulin binding parameters, in dependence on the Hp-phenotype may be of clinical importance.

Circulating insulin antibodies during therapy with highly purified neutrally buffered insulins including desphe insulins. Report of a prospective study with 40 cases.

Circulating insulin binding capacity was studied for 10 to 24 months in forty diabetic patients who were being treated with insulin for the first time. They received either neutral highly purified pork insulin, bovine or porcine desphe insulin containing formulations, semisynthetic human insulin, or "conventional" acid chromatographed bovine surfen insulin over the entire duration of the study. In only 6 of the 23 patients on pork insulin, porcine desphe insulin, or human insulin were minimal antibody concentrations (less than or equal to 2 IU/l) observed. The bovine desphe insulin containing beef insulin, was markedly more immunogenic: only 3 out of 12 patients did not produce any antibodies. All five patients treated with bovine surfen insulin reacted with a strong antibody formation, which was, on average, six times as high as that in the patients on bovine desphe insulin (approximately 90 vs 14 IU/l). According to these results, bovine desphe insulins should be considered more valuable in insulin therapy than formulations of unmodified beef or of mixed beef/pork insulins.

Influence of Polyethylene Glycol (PEG) Extraction on the C-Peptide Determination in Sera from Insulin-Dependent Diabetic Patients with Circulating Insulin Antibodies*)

To investigate whether the unexpectedly high C-peptide levels in some insulin-dependent diabetic (IDDM) patients are due to co-determination of proinsulin bound to circulating insulin antibodies, 36 randomly selected sera from IDDM patients were assayed for C-peptide immunoreactivity (CPR) after polyethylene glycol (PEG) extraction, preceding incubation with proinsulin binding antibodies (LAB + PEG) or without pretreatment of the sera. Recovery of proinsulin was checked by addition of 1 nmol/l proinsulin to all sera. Recovery was found to be 101.5 +/- 4.0%. The mean values of concentrations were significantly lower (p less than 0.001) after treatment with PEG and IAB + PEG compared to the untreated sera. There was also a significant difference (p less than 0.05) between sera extracted with PEG alone or after IAB + PEG-treatment. However, no correlation (p greater than 0.1) was found to bound insulin (total minus free insulin) or to insulin binding capacity (IBC) of the sera. If an antiserum is not available with very low cross-reactivity with proinsulin to determine human C-peptide then sera should not be extracted with PEG alone but after additional incubation with a proinsulin binding antiserum. In spite of the extraction in some cases unexplicably high C-peptide levels may still be expected.

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.

Insulin Binding to Antibodies is a Risk Factor for Inexplicable Severe Hypoglycaemia in Children with Type-1 Diabetes Mellitus

Type-1 diabetic individuals differ with regard to both, the formation of circulating insulin antibodies, and the incidence of severe hypoglycaemia. To assess the association of insulin binding to antibodies with the incidence of severe hypoglycaemia. In a cross sectional study, 73 children with type-1 diabetes mellitus (median age 14 years, duration of diabetes 6 years) were investigated, 22 of whom had experienced severe hypoglycaemia during the past 18 months, and 51 had never experienced severe hypoglycaemia. Of the patients with severe hypoglycaemia 16 had experienced severe unexplained hypoglycaemias, and 6 had experienced severe hypoglycaemias which were explicable (by missed meals, unplanned physical exercise etc.). Insulin binding was measured in a blinded central laboratory by radioimmunoassay, and expressed as ratio bound/unbound insulin; a binding >15% was considered relevant insulin binding. A total of 38 patients displayed relevant insulin binding (17 of whom had experienced severe hypoglycaemia), and 35 patients did not (5 of whom had experienced severe hypoglycaemia; p=0.0055, Fisher's exact test). Patients with relevant insulin binding were younger (12.2 vs 14.5 years, p=0.006) than patients without relevant insulin binding. From the 16 patients with inexplicable severe hypoglycaemia, 15 displayed relevant insulin binding, compared to 2 of the 6 patients with explicable severe hypoglycaemia (p=0.009). The association of any severe hypoglycaemia, and of inexplicable severe hypoglycaemia, with relevant insulin binding was significant (odds ratio 4.8 (95%CI 1.5-15.2), and 22.1(95%CI 2.7-179.6), p<0.006). Patients with/without relevant insulin binding, or with/without severe hypoglycaemia, did not differ significantly regarding sex, duration of diabetes, number of insulin injections per day, HbA1c and C-peptide levels (ANOVA). Insulin binding to antibodies >15% appears to be a strong risk factor for inexplicable severe hypoglycaemias in type-1 diabetic children.

Impact of insulin antibodies on insulin aspart pharmacokinetics and pharmacodynamics after 12-week treatment with multiple daily injections of biphasic insulin aspart 30 in patients with type 1 diabetes

This study aimed to evaluate the impact of insulin antibodies on insulin aspart pharmaco-kinetics and pharmacodynamics after 12-week multiple daily injections of biphasic insulin aspart 30 (30% fast-acting and 70% protamine-crystallised insulin aspart, BIAsp30) in patients with type 1 diabetes. Twenty-three patients (8 women, 15 men) aged 44.8 (20.6-62.5) years (median and range) with diabetes duration of 19.5 (1.6-44.6) years and haemoglobin (Hb)A(1C) of 9.2% (8.1-12.3%) participated in the study, which consisted of 12-week treatment with multiple injections of BIAsp30. At the end of the treatment period, all patients attended two 24-h profile days 1 week apart for pharmacokinetic and pharmacodynamic assessments. HbA(1C) and insulin antibodies were also determined. Patients were stratified into two groups depending on whether the level of insulin binding to insulin antibodies was below or above 75% (moderate vs high (%, median and range): 62 (15-74) vs 80 (75-89)). High levels of insulin antibodies resulted in about threefold increase in AUC((0 - 24 h)) (the area under the concentration-time curve during 24 h) for total insulin aspart (analysis of variance, P < 0.05). The differences in free insulin aspart pharmacokinetics, insulin pharmacodynamics and HbA(1C) were not statistically significant between patients with different levels of insulin antibodies. Total daily insulin dosage was significantly lower in patients with high than moderate levels of insulin antibodies. In type 1 diabetic patients, high levels of circulating insulin antibodies result in elevated total, but not free, insulin aspart profiles. Consistent with the finding of similar insulin pharmacodynamics, the long-term glycaemic control is not significantly different between patients with different levels of insulin antibodies.

Influence of maternal metabolic control and insulin antibodies on neonatal complications and B cell function in infants of diabetic mothers

Circulating insulin antibodies at birth and the degree of maternal metabolic control were measured in 68 infants of insulin-treated diabetic mothers. Their correlation with neonatal B cell function and with the clinical features of the infants was evaluated in order to better understand their influence on fetal outcome. Maternal metabolic control was assessed on the basis of blood glucose levels, glycosuria and the occurrence of hypoglycemia and/or ketonuria. All infants were clinically evaluated for gestational age, macrosomia, hypoglycemia, hyperbilirubinemia, hypocalcemia, and respiratory distress syndrome. Cord blood plasma glucose, C peptide, and IgG insulin antibodies were also measured. It was shown that poor maternal metabolic control was associated with a higher prevalence of fetal morbidity as well as with signs of B cell hyperfunction. Also the presence of circulating insulin antibodies correlated well with higher C peptide levels and with several neonatal complications. B cell hyperfunction, indicated by high C peptide levels in the infants of diabetic mothers, may possibly play a causal role in the pathogenesis of fetal morbidity. In conclusion, a good fetal outcome in insulin-treated diabetic pregnancies was associated with and may have depended upon: (1) good maternal metabolic control, and (2) absence or low levels of circulating insulin antibodies.

Glycerol-insulin raises circulating insulin antibodies in type I diabetic patients treated with permanently implanted devices

The instability of insulin in the reservoirs of implantable insulin delivery devices has been a major obstacle in implementing this form of therapy. To overcome the problem of precipitation, a glycerol-insulin preparation has been used in large-scale long-term clinical trials. The aim of this study was to evaluate the stability of the glycerol-insulin solution and its effects on circulating insulin antibodies in eight type I diabetic patients who were implanted with an Infusaid pump (Infusaid Corporation, Norwood, MA) and followed for 1 year or more. Total insulin requirement did not change throughout the observation period. Plasma free insulin was higher during treatment with glycerol-insulin than with the standard insulin treatment ( P < .02). Insulin antibodies increased in all patients ( P < .05). High-performance liquid HPLC analysis of insulin samples from the pump reservoirs showed the generation of insulin modification products at a daily rate of 1.84%, reaching 40% to 50% of the total reservoir content 3 weeks after refilling; among these products, high molecular weight species accounted for about 15%. It is concluded that glycerol-insulin is not an adequate insulin preparation for use in implanted devices. Insulin deteriorated in the pump reservoirs, and insulin antibody concentration increased in the treated patients. It is believed that this antibody production is favored by circulating insulin fragments and polymers of insulin generated inside the pump reservoirs.

Prolonged Action of Regular Insulin in Diabetic Patients: Lack of Relationship to Circulating Insulin Antibodies*

We previously reported that in insulin-treated diabetic subjects the time course of action of regular insulin injected sc is different from that reported in standard textbooks. The present studies evaluated the role of insulin antibodies (Abs) in the altered pharmacokinetics of regular insulin by comparing the time course of insulin action in 10 patients receiving chronic insulin therapy and having insulin Abs with that in 15 previously untreated patients without detectable Abs. After an overnight fast, the patients were given an infusion of 5% dextrose in water at 100 ml/h. Regular insulin (15 U) was then injected sc in the deltoid region of the arm. The onset of action of sc insulin, as indicated by a 10% fall in serum glucose, was similar in both patient groups [1.9 +/- 0.1 (+/- SEM) hour in Ab-negative and 1.8 +/- 0.1 h in Ab-positive patients]. The peak effect of insulin action, as determined by the nadir of serum glucose, was 4.6 +/- 0.2 h in the previously untreated patients, not significantly different from the value in the diabetic patients with insulin Abs (5.2 +/- 0.4 h). The duration of action of insulin was also similar in both groups (14.7 +/- 0.7 vs. 14.4 +/- 1.0 h). No significant correlations were found between insulin Ab levels and any of these 3 parameters of insulin action. However, the peak effect and total duration of insulin action were significantly correlated with the baseline serum glucose levels. A possible role of insulin Abs was evaluated in these patients by repeating the studies over a 2-year period. During this time, the previously untreated patients were treated with highly purified pork insulin, to which they developed low titers of insulin Abs. The diabetic patients who had been chronically treated with insulin were changed from less purified insulin to highly purified pork insulin, and all had a significant reduction in their Ab titers. No changes in insulin pharmacokinetics were found in either group. These studies demonstrate that the prolonged action of sc injected regular insulin in diabetic patients is not related to the effect of circulating insulin Abs.

Failure of ultracentrifugation as a means of separating plasma free insulin from immunoglobulin fraction prior to radioimmunoassay

It has been reported that ultracentrifugation of plasma will allow direct measurement of free insulin in the serum of diabetic subjects with insulin antibodies. To validate this method, we determined recovery of immunoreactive insulin and immunoglobulin G from the plasma of normal individuals after ultracentrifugation. The upper and middle fractions of plasma after ultracentrifugation were evaluated at several combinations of time and temperature (4°C, 25°C, or 37°C for 3, 4 or 5 hours). None of these conditions effectively removed all immunoglobulin G without causing concomitant loss of insulin. We conclude that ultracentrifugation of plasma prior to radioimmunoassay cannot be used to reliably determine free insulin concentration in the plasma from subjects with circulating insulin antibodies.

Insulin Autoimmunity as a Cause of Hypoglycemia

"Autoimmune" hypoglycemia is a syndrome consisting of fasting hypoglycemia, hyperinsulinemia, and insulin-binding antibodies in a patient who has never been exposed to exogenous insulin. The stimulus for insulin-antibody formation and the mechanism of the hypoglycemia in this condition remain unknown. Three patients with this rare syndrome had severe hypoglycemia of limited duration. Two had received a drug containing a sulfhydryl group (methimazole and penicillamine) as treatment for an autoimmune disorder (Graves' disease and rheumatoid arthritis, respectively). A third patient who underwent surgery for a suspected insulinoma was found to have pancreatic beta cell hyperplasia. Drugs containing a sulfhydryl group may have a role in the etiology of the syndrome. Additionally, our findings suggest a relationship between circulating insulin antibodies and beta cell hyperplasia.

Insulin pharmacokinetics.

Where adjustments of diet, physical activity, and dosage of insulin are well known to diabetologists and diabetic patients, present-day knowledge of factors of importance to the pharmacokinetics of insulin is frequently ignored. The pharmacokinetics of insulin comprise the absorption process, the distribution including binding to circulating insulin antibodies, if present, and to insulin receptors, and its ultimate degradation and excretion. The distribution and metabolism of absorbed insulin follow that of endogenous insulin. The distribution and metabolism cannot be actively changed, except in the case of circulating insulin antibodies, which in rare cases also may cause insulin resistance. The use of insulin preparation of low immunogeneity will avoid or reduce this course of variation in action. The absorption process, the detailed mechanisms of which are still unknown, is influenced by many variables where some can be controlled, thereby reducing the intrapatient variability in insulin absorption, which may reach 35%, causing a corresponding metabolic lability. Besides the known differences in timing among different preparations, the size of dose, the injected volume, and the insulin concentration are determinants of absorption role. Fortuitous injection technique contributes to variance, as do changes in blood flow of the injected tissue. This may be induced by changes in ambient temperature, exercise of injected limb, or local massage. Regional differences are also due to differences in blood flow. Serum insulin peaks may peak up to 1 h after injection of soluble insulin into the thigh versus into the abdominal wall. Local degradation of insulin seems of less importance but may, in rare cases, be the cause of high insulin "requirements." Available evidence is reviewed and the importance of implementing the consequences in the daily care of the insulin-treated patient is emphasized.

Comparison of porcine and semisynthetic human insulins using euglycemic clamp-derived glucose-insulin dose-response curves in insulin-dependent diabetes

In order to compare the biologic effectiveness of porcine and semisynthetic human insulins, a euglycemic clamp method was used in eight insulin-dependent diabetic subjects. Each subject was tested for each insulin on separate days. In order to derive glucose-insulin dose-response curves for both insulins, sequential but constant insulin infusion rates of 0.2, 0.5, 1.0, and 2.0 mU/kg/min were performed. Plasma glucose levels attained during the euglycemic clamp were 96 ± 3 mg/dL. At each insulin infusion rate, the steady-state glucose infusion rate required to maintain euglycemia was measured. At each increment of insulin infused, steady-state glucose infusion rates for porcine insulin were 1.12 ± 0.22, 1.90 ± 0.59, 4.28 ± 0.61, and 9.37 ± 0.66 mg/kg/min compared with 1.27 ± 0.42, 2.38 ± 0.20, 4.25 ± 0.43, and 8.87 ± 0.67 mg/kg/min for semisynthetic human insulin. By ANOVA, no significant difference was noted between the two insulins. Because insulin infusion rates may not result in predictable circulating free insulin levels in subjects who have circulating insulin antibodies, free insulin levels were determined. When steady-state glucose infusion rates were compared with free insulin levels achieved at the four insulin infusion rates, dose-response curves for both porcine and semisynthetic human insulins were virtually identical. These data suggest that semisynthetic human insulin has equivalent biologic effects on overall glucose metabolism compared with porcine insulin in insulin-dependent diabetes.

Decrease of Circulating Insulin Antibodies in Two Patients Treated with Continuous Subcutaneous Infusion of Human Insulin (recombinant DNA)

Circulating insulin antibodies (CIA) were measured in two patients treated with continuous subcutaneous infusion (CSII) of human insulin (recombinant DNA). CIA were determined by a kinetic equilibrium assay after pretreatment of the serum to remove bound and free insulin. We observed that by changing from either purified bovine or purified porcine insulin to human insulin given by CSII, there is a gradual decrease in CIA detectable after 3 wk and more pronounced 3 mo after changing. These findings suggest that human insulin in combination with the improved metabolic control by CSII considerably reduces the antibody formation in patients with IDDM.

Factors affecting enzyme-linked immunosorbent assay (ELISA) for insulin antibodies in serum.

We have evaluated the factors affecting an enzyme-linked immunosorbent assay (ELISA) for circulating insulin antibodies. Dilutions of patients' sera were incubated in polystyrene tubes coated with procine insulin. The second incubation was with alkaline phosphatase-conjugated anti-human Fab. Each of these reactions was complete after 4 h. Specificity of the reaction for insulin antibodies was demonstrated by removal of anti-insulin activity after preincubation with insulin, but not with glucagon at similar concentrations. Sensitivity of the ELISA system, assessed by performing the reaction with affinity-column purified insulin antibodies, was 10 microgram of specific antibody per liter. Using this system, we examined sera from 22 patients who had been determined by radioimmunoassay to have insulin antibodies, and sera from 23 normal individuals. The ELISA results correlated reasonably well with those of RIA (r = +0.84). Besides detecting insulin antibodies in diabetic patients who are being treated with insulin, we use this ELISA test as a screening procedure to be certain insulin antibodies are not present when we use indirect immunofluorescence methods of fixed pancreatic substrate to detect islet-cell antibodies.

Metabolic control in diabetic patients. Effect of insulin-secretory reserve (measured by plasma C-peptide levels) and circulating insulin antibodies

Metabolic control in diabetic patients. Effect of insulin-secretory reserve (measured by plasma C-peptide levels) and circulating insulin antibodies