A case of diabetes mellitus associated with anti-insulin autoantibodies without previous insulin injection

A Novel Type of Extreme Insulin Resistance: Nonhypoglycemic Insulin Autoimmune Syndrome

CONTEXT

Extreme insulin resistance is caused by genetic defects intersecting with the insulin action pathway or by the insulin receptor antibodies. Insulin autoimmune syndrome (IAS) is not considered one of the causes of extreme insulin resistance.

OBJECTIVE

This work aimed to expand the current knowledge of extreme insulin resistance and to propose the diagnostic criteria and management strategy of a novel type of extreme insulin resistance.

METHODS

A patient with IAS never experienced hypoglycemia but had persistent hyperglycemia and extreme insulin resistance with treatment with 200 U of intravenous insulin per day. Immunoreactive insulin (IRI), free insulin, and total insulin were measured. The ratio of free insulin to total insulin (insulin-free ratio, IFR) was calculated.

RESULTS

Extreme insulin resistance has not been reported to be caused by IAS. At admission, IRI and free insulin were undetectable in our patient; total insulin was more than 20 160 pmol/L; and the IFR was lower than 0.03% (control, 90.9%). After adding 500 U porcine insulin to the precipitate containing insulin antibodies, the IRI was still undetectable. Since the patient started glucocorticoid therapy, the free insulin has gradually increased to 11.16 pmol/L, his total insulin has decreased to 5040 pmol/L, and the IFR has increased to 18.26%. Intravenous insulin was stopped, with good glycemic control.

CONCLUSION

High-affinity insulin autoantibodies with a large capacity can induce a novel type of extreme insulin resistance characterized by extremely high total insulin and very low free insulin levels. The IFR can be used to evaluate therapeutic effects.

Clinical and Laboratory Aspects of Insulin Autoantibody-Mediated Glycaemic Dysregulation and Hyperinsulinaemic Hypoglycaemia: Insulin Autoimmune Syndrome and Exogenous Insulin Antibody Syndrome

Autoimmune glycaemic dysregulation and hyperinsulinaemic hypoglycaemia mediated by insulin autoantibodies is an increasingly recognised but controversial phenomenon described in both exogenous insulin naïve (insulin autoimmune syndrome) and exposed (exogenous insulin antibody syndrome) individuals. There has been a significant proliferation of case reports, clinical studies and reviews in the medical literature in recent years which have collectively highlighted the discrepancy between experts in the field with regard to the nomenclature, definition, proposed pathophysiology, as well as the clinical and biochemical diagnostic criteria associated with the condition. The essential characteristics of the condition are glycaemic dysregulation manifesting as episodes of hyperglycaemia and unpredictable hyperinsulinaemic hypoglycaemia associated with high titres of endogenous antibodies to insulin. Although the hypoglycaemia is often life-threatening and initiation of targeted therapies critical, the diagnosis is often delayed and attributable to various factors including: the fact that existence of the condition is not universally accepted; the need to exclude surreptitious causes of hypoglycaemia; the diverse and often complex nature of the glycaemic dysregulation; and the challenge of diagnostic confirmation. Once confirmed, the available therapeutic options are expansive and the reported responses to these therapies have been variable. This review will focus on our evolving understanding, and the associated diagnostic challenges - both clinical and laboratory - of this complex condition.

Effects of isomaltulose on insulin resistance and metabolites in patients with non‑alcoholic fatty liver disease: A metabolomic analysis

Insulin resistance is associated with a poor prognosis in non-alcoholic fatty liver disease (NAFLD) patients. Isomaltulose, a naturally-occurring disaccharide, is reported to improve glucose and lipid metabolisms in obese patients. The present study aimed to investigate the effects of isomaltulose on insulin resistance and various metabolites in NAFLD patients. Five male patients with NAFLD consumed 20 g isomaltulose or sucrose (control). Changes in insulin resistance and metabolites were evaluated by alterations of serum C-peptide immunoreactivity (CPR) and metabolomic analysis from baseline to 15 min after the administration, respectively. There was no significant difference in changes of blood glucose level; however, the CPR level was significantly decreased in the Isomaltulose group compared to the control group (0.94±0.89 vs. −0.12±0.31, P=0.0216). In a metabolomic analysis, a significant alteration was seen in 52 metabolites between the control and Isomaltulose groups. In particular, the taurodeoxycholic acid level significantly increased approximately 12.5-fold, and the arachidonic acid level significantly decreased approximately 0.01-fold. Together, it present study demonstrated that isomaltulose improved insulin resistance in NAFLD patients. It was also revealed that isomaltulose affects taurodeoxycholic acid and arachidonic acid. Thus, isomaltulose may have a beneficial effect on insulin resistance through alterations of bile acid and fatty acid metabolisms in NAFLD patients.

Therapeutic plasma exchange normalizes insulin-mediated response in a child with type 1 diabetes and insulin autoimmune syndrome

BACKGROUND

Insulin autoimmune syndrome (IAS), characterized by glycemic dysregulation and life-threatening hypoglycemia, can occur in patients with type 1 diabetes (T1D). Diagnostic confirmation is complex but important in order to ensure timely initiation of definitive therapy.

AIMS

We aimed to quantitate the degree of immunoglobulin-insulin complex (IIC) formation and its effects on glycemic control in a patient with T1D and IAS compared with T1D and non-T1D controls and before and after therapeutic plasma exchange (TPE).

MATERIALS & METHODS

The prospective descriptive study was conducted between June 2015 and December 2015 in a quaternary children's hospital in Brisbane, Australia. Percent Free "Immunoreactive" Insulin (%FII) as assessed by polyethylene glycol precipitation studies and its relationship to plasma glucose and serum insulin concentration.

RESULTS

Samples from the patient with T1D and IAS demonstrated lower mean %FII compared to T1D (23.8 ± 2.0 vs 52.0 ± 6.7; P < .0001) and non-T1D (23.8 ± 2.0 vs 102.9 ± 2.7; P < .0001) controls. This was associated with loss of glycemic predictability and frequent severe hypoglycemia. TPE increased %FII (23.8 ± 2.0 before TPE vs 83.6 ± 2.5 after TPE, P < .0001) and reestablished plasma glucose responsiveness to exogenous insulin.

DISCUSSION

IAS should be considered in T1D patients with unexplained glycemic instability and hypoglycemia. The laboratory plays an integral diagnostic role.

CONCLUSION

TPE is an effective method for removing IICs and normalizing insulin-mediated glucose responses.

Imaging of the buffering effect of insulin antibodies in the autoimmune hypoglycemic syndrome

Insulin autoimmune hypoglycemia is characterized by recurrent hypoglycemia and high levels of immunoreactive insulin in the presence of insulin autoantibodies. The mechanisms inducing hypoglycemia are largely unknown. An [123I]insulin scintigraphic scanning was performed to directly demonstrate the effect of antibodies on insulin biodistribution in one patient with this syndrome both before and after treatment. The patient had insulin autoantibodies IgG3 lambda, which had a single site dissociation constant (Kd = 10(-7) mol/L, by Scatchard analysis), a very fast dissociation rate of immune complexes, and a very rapid association of [125I]insulin. Insulin receptors on red blood cells were down-regulated. The [123I]insulin scintigraphic study imaged the buffering effect of antibodies on insulin bioavailability. [123I]Insulin was not removed from the blood, and no liver or kidney uptake of the hormone occurred. The frequency and severity of hypoglycemic episodes required treatment. Insulin antibody levels decreased and [123I]insulin biodistribution improved after treatment with plasmapheresis and prednisone. Improved hormone bioavailability was further evidenced by the reduction in the hypoglycemic delay after i.v. insulin from 90 min before any treatment to 60 min after plasmapheresis and 30 min after steroid administration. Glucose tolerance was normal after treatment. Plasmapheresis followed by steroid treatment can lower the insulin antibody concentration, abolish severe hypoglycemia, and improve insulin biodistribution and glucose tolerance in insulin autoimmune hypoglycemia.

An unusual case of recurrent hypoglycaemia: 10-year follow up of a child with insulin auto-immunity

We report the case of a child with hypoglycaemia due to insulin auto-immunity. Insulin auto-immunity is the third most frequent cause of hypoglycaemia in Japan where the first cases were described. The child has been followed for the past 10 years with recurrence of hypoglycaemic symptoms and high titres of insulin antibodies.