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Hypoglycemia due to an Insulin Binding Antibody in a Patient with an IgA-κ Myeloma
Context: Autoantibodies to insulin have been described to cause spontaneous hypoglycemia in nondiabetic subjects. There have been occasional reports of spontaneous hypoglycemia due to monoclonal anti-insulin antibodies. We present the first report of a patient with an IgA-κ myeloma in whom frequent...
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Published in: | The journal of clinical endocrinology and metabolism 2007-06, Vol.92 (6), p.2013-2016 |
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Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Context: Autoantibodies to insulin have been described to cause spontaneous hypoglycemia in nondiabetic subjects. There have been occasional reports of spontaneous hypoglycemia due to monoclonal anti-insulin antibodies. We present the first report of a patient with an IgA-κ myeloma in whom frequent hypoglycemia resulted from the ability of the monoclonal IgA-κ to bind insulin.
Objectives: The aim of this study was to describe the occurrence of profound hypoglycemia in a patient with IgA-κ myeloma, characterize biochemically the nature of the IgA:insulin complex present, and place this case in the context of the published literature on hypoglycemia resulting from autoantibodies to insulin.
Design: A case study was performed.
Patients: A single case of profound hypoglycemia associated with IgA-κ myeloma was studied.
Intervention: There were no interventions.
Main Outcome Measures: A case study was performed.
Results: Polyethylene glycol precipitation and gel filtration chromatography were used to demonstrate high-molecular weight insulin immunoreactivity in the patient’s plasma. This was characterized as an insulin binding IgA-κ paraprotein present at 4200 mg/dl (42 g/liter) with a relatively high insulin dissociation constant of 0.32 μm/liter using radiolabelled insulin binding studies.
Conclusions: We present the first case of hypoglycemia due to IgA binding insulin antibodies in a patient with an IgA-κ paraprotein myeloma. The hypoglycemia was associated with high-plasma insulin levels and relatively low C-peptide levels. A plausible mechanism for the hypoglycemia is the delayed clearance of insulin. This case broadens the spectrum of monoclonal gammopathies that have been associated with anti-insulin reactivity and spontaneous hypoglycemia. |
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ISSN: | 0021-972X 1945-7197 |
DOI: | 10.1210/jc.2007-0075 |