Insulin Autoimmune Syndrome Accompanied by Multiple Myeloma

Resolution of dysglycaemia after treatment of monoclonal gammopathy of endocrine significance

In very rare cases of monoclonal gammopathy, insulin-binding paraprotein can cause disabling hypoglycaemia. We report a 67-year-old man re-evaluated for hyperinsulinaemic hypoglycaemia that persisted despite distal pancreatectomy. He had no medical history of diabetes mellitus or autoimmune disease but was being monitored for an IgG kappa monoclonal gammopathy of undetermined significance. On glucose tolerance testing, hyperglycaemia occurred at 60 min (glucose 216 mg/dL) and hypoglycaemia at 300 min (52 mg/dL) concurrent with an apparent plasma insulin concentration of 52 850 pmol/L on immunoassay. Laboratory investigation revealed an IgG2 kappa with very high binding capacity but low affinity (Kd 1.43 × 10-6 mol/L) for insulin. The monoclonal gammopathy was restaged as smouldering myeloma not warranting plasma cell-directed therapy from a haematological standpoint. Plasma exchange reduced paraprotein levels and improved fasting capillary glucose concentrations. Lenalidomide was used to treat disabling hypoglycaemia, successfully depleting paraprotein and leading to resolution of symptoms.

Insulin Autoimmune Syndrome: A Systematic Review

Insulin autoimmune syndrome (IAS) is a rare endocrine disorder characterized by recurrent episodes of severe hypoglycemia, markedly elevated serum insulin, and positive insulin autoantibodies. In recent years, various countries have reported it one after another. It can be seen that we must pay attention to this disease. The diagnosis of IAS is challenging, requiring a careful workup aimed at excluding other causes of hyperinsulinemic hypoglycemia. High levels of insulin autoantibodies are found in patients, and C-peptide is not parallel to insulin, which could be diagnostic. IAS is a self-limiting disease with a good prognosis. Its treatment mainly includes symptomatic supportive treatment, such as adjusting the diet and using acarbose and other drugs to delay the absorption of glucose to prevent hypoglycemia. For patients with severe symptoms, available treatments may include drugs that reduce pancreatic insulin secretion (such as somatostatin and diazoxide), immunosuppressants (glucocorticoids, zaprin, and rituximab), and even plasma exchange to remove autoantibodies from the body. This review provides a comprehensive analysis of the epidemiology, pathogenesis, clinical manifestations, diagnosis and identification, and monitoring and treatment management of IAS.

Comparison of patient characteristics between East Asian and non-East Asian patients with insulin autoimmune syndrome

OBJECTIVE

Insulin autoimmune syndrome (IAS) is the third most common cause of spontaneous hypoglycaemia in Japan but very rare in the rest of the world. We aimed to identify factors, which are associated with the occurrence of IAS and which may differ between East Asian and non-East Asian patients.

DESIGN

A PubMed search using the search terms 'insulin autoimmune syndrome' and 'Hirata disease' revealed a total of 287 reports of IAS cases, including one previously unpublished own case.

RESULTS

Mean age (±standard deviation) was 52 ± 19 years in East Asian and 54 ± 21 years in non-East Asian patients (p > .05). In both groups, there were more females. Mean body mass index was lower in East Asian than in non-East Asian patients (23.0 ± 4.3 vs. 27.1 ± 5.6 kg/m² , p < .0001). Postprandial hypoglycaemia was more common in non-East Asian patients (p < .05). East Asian patients took more frequently antithyroid medications and non-East Asian patients angiotensin-converting enzyme (ACE) inhibitors (both p < .0001). Graves' disease and other autoimmune diseases were more frequently observed in East Asian patients (both p < .01). Parameters of glucose metabolism were comparable in both groups, independent of diabetes diagnosis (p > .05), except for insulin that was higher in East Asian compared to non-East Asian metabolically healthy patients (p < .01). Human leukocyte antigen (HLA)-DRB1*0406 was the most frequent HLA-type in East Asian patients (p < .0001), whereas DRB1*0403 and *0404 were more frequent in non-East Asian patients (both p < .05). Non-East Asian patients received more secondary treatments, including plasmapheresis and rituximab, whereas medication discontinuation was more common in East Asian patients (all p < .05). Outcome was similar in both groups (p > .05).

CONCLUSIONS

Factors associated with IAS markedly differ between East Asian and non-East Asian patients, with autoimmune disorders, particularly Graves' disease, antithyroid medications, and HLA-DRB1*0406 more prevalent in East Asian patients and cardiovascular and plasma cell diseases, ACE inhibitors and HLA-DRB1*0403 more prevalent in non-East Asian patients.

Polysaccharide from Patinopecten yessoensis Skirt Boosts Immune Response via Modulation of Gut Microbiota and Short-Chain Fatty Acids Metabolism in Mice

Polysaccharide from marine shellfish has various bioactivities. In this study, the effects of polysaccharide from Patinopecten yessoensis skirt (PS) on boosting immune response in mice were evaluated, and the potential mechanisms were explored. The results showed that PS administration effectively increased the serum IgG and IgM levels, implying that PS had immune response-boosting properties. Moreover, PS administration could modulate the composition of the gut microbiota, and significantly improve short-chain fatty acids (SCFAs) metabolism, especially butyrate metabolism. Of note, the expression of the Tlr2, Tlr7, MyD88, Tnfa, and Il1b genes in toll-like receptor (TLR) signaling pathway was significantly increased. In summary, PS could boost immune response by modulating the gut microbiota and SCFAs metabolism correlating with the activation of the TLR signaling pathway. Therefore, PS can be developed as a special ingredient for functional product.

[Hypoglycemic syndrome in patients with monoclonal gammopathy]

One of the reasons for the development of hypoglycemia is the synthesis of autoimmune antibodies to insulin or its receptor &ndash; insulin autoimmune syndrome (IAS). The largest number of cases of this syndrome is described in the Japanese population. The antibodies to insulin are most often polyclonal immunoglobulins. In monoclonal gammopathy of undetermined significance and multiple myeloma secreted pathological monoclonal immunoglobulin may have an affinity for human insulin, which induces the development of IAS. The prolonged persistence of episodes of hypoglycemia of unknown origin requires the exclusion of the monoclonal nature of secreted antibodies to insulin. Often the presence of pathological secretion for a long time is not recognized due to the absence of other manifestations of the disease. The manifestation of gammopathy is represented by a wide range of symptoms and syndromes requiring the collaboration of doctors of various specialties. This review summarizes the literature on IAS in patients with monoclonal gammopathy, whose disease debuted from episodes of spontaneous hypoglycemia. When hemoblastosis remission is achieved (when the secretion of the pathological protein is minimal or not determined), the glucose, insulin, and antibodies levels of insulin normalize, and when multiple myeloma recurs, episodes of hypoglycemia resume. The onset of the disease from the IAS can be considered as a new criterion for symptomatic multiple myeloma, dictating the need for the initiation of specific therapy.

Management of Insulin Autoimmune Hypoglycaemia: Single-centre experience from Western India with systematic review of world literature

BACKGROUND

Awareness about Insulin Autoimmune Hypoglycaemia (IAH) and its management remains limited.

METHODOLOGY

We describe two cohorts: Cohort 1 (n = 7) included patients with IAH from a tertiary care centre in India and Cohort 2 (n = 294) included systematic review of published English literature from PubMed. They were compared with our insulinoma patients (n = 41).

RESULTS

Cohort 1 included seven female patients where two had drugs (carbimazole and thiocolchicoside) as triggering factors. Except for one patient requiring oral prednisolone, others had spontaneous remission. The unique features from our series are being first case series of IAH from India and reporting of second case of thiocolchicoside triggered IAH. Cohort 2 had 294 patients identified from 149 publications. Mean age was 54 ± 19 years. Thirty-five different triggers were identified from 160 cases. Antithyroid drugs were most common triggers in Japanese patients and most common HLA allele was DRB1*0406, while it was alpha-lipoic acid and HLA DRB1*0403 in non-Asians. Serum Insulin >100 µIU/mL and insulin to C-peptide molar ratio (ICMR) >0.25 had specificity of 100% and 97.5%, respectively, for IAH as compared to insulinoma. 56% patients had remission with complex carbohydrate diet and trigger removal while 43% required immunosuppressants. 70% achieved remission within 6 months.

CONCLUSIONS

Middle age remains most common age group. Sulfhydryl drugs are most common triggers. Serum Insulin >100 µIU/mL and ICMR > 0.25 in critical sample are good predictors for diagnosis of IAH, which needs to be confirmed by IAA. Conservative management with dietary modification and trigger removal usually suffices in majority. Rests need immunosuppressants.