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

SUMMARY 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.

Clinical implications of copy number variations in autoimmune disorders

Human genetic variation is represented by the genetic differences both within and among populations, and most genetic variants do not cause overt diseases but contribute to disease susceptibility and influence drug response. During the last century, various genetic variants, such as copy number variations (CNVs), have been associated with diverse human disorders. Here, we review studies on the associations between CNVs and autoimmune diseases to gain some insight. First, some CNV loci are commonly implicated in various autoimmune diseases, such as Fcgamma receptors in patients with systemic lupus erythemoatosus or idiopathic thrombocytopenic purpura and beta-defensin genes in patients with psoriasis or Crohn's disease. This means that when a CNV locus is associated with a particular autoimmune disease, we should examine its potential associations with other diseases. Second, interpopulation or interethnic differences in the effects of CNVs on phenotypes exist, including disease susceptibility, and evidence suggests that CNVs are important to understand susceptibility to and pathogenesis of autoimmune diseases. However, many findings need to be replicated in independent populations and different ethnic groups. The validity and reliability of detecting CNVs will improve quickly as genotyping technology advances, which will support the required replication.

Frequency of abnormal thyroid function tests in Kuwaiti Arabs with autoimmune diseases

The purpose of this study was to examine the frequencies of abnormal thyroid function tests and serum thyroid autoantibodies in healthy Kuwaitis and those with autoimmune diseases. Serum concentrations of sensitive thyrotropin, and free thyroxine were measured in 577 apparently healthy controls, 177 patients with rheumatoid arthritis [RA], 60 with systemic lupus erythematosus [SLE] and 25 with primary Sjogren's syndrome [pSS] using the immunochemiluminescent assay method on IMMULITE 1000. Serum microsomal and thyroglobulin auto-antibodies were also measured by passive hemagglutination assay. For analysis of the thyroid function tests, the subjects were classified into five categories: normal, sub-clinical hypothyroidism, overt hypothyroidism, euthyroid sick syndrome and biochemical hyperthyroidism. Subclinical hypothyroidism was seen in 1.7% of healthy controls, 10.2% of RA, 13.3% of SLE, and 16% of pSS patients. Among RA patients, the frequency of subclinical hypothyroidism in females [11.4%] was significantly higher than among males [5.4%; p < 0.01]. In SLE and pSS patients, all those with sub-clinical hypothyroidism were females. Overt hypothyroidism was seen in 1.4% of controls, 10.2% of RA, 8.3% of SLE, and 4% of pSS patients. Biochemical hyperthyroidism was seen in 0.2% of controls, 4.5% of RA, 5% of SLE and none of pSS patients. The euthyroid sick syndrome was seen in 0.4% of controls, 13.6% of RA, 16.7% of SLE and in none of pSS patients. Thyroid autoantibodies were present in 3.1% of controls, 12.4% of RA, 18.3% of SLE, and 12% of pSS patients. Our data show that abnormal thyroid function tests and thyroid autoantibodies occur frequently in Kuwaitis with autoimmune diseases. Therefore, ordering these tests in these diseases is recommended