[Tissue-specific autoimmunity in patients with idiopathic diabetes]

According to the WHO classification, type 1 diabetes is divided into type 1A - autoimmune and type 1B - idiopathic. The pathogenesis of the latter remains unknown. Clinical observations confirm that type 1 diabetes is often associated with the presence of other organ-specific autoantibodies. Besides, the idiopathic type 1 diabetes is suggested as resulted form immune-related beta cell destruction with the defect of humoral response.

of the study was to verify the above-mentioned hypothesis by an evaluation of the prevalence of thyroid and coeliac antibodies in children with idiopathic diabetes.

The study groups consisted of 37 patients with idiopathic diabetes (group 1B) and 108 patients with autoimmune diabetes (1A). The examined groups were chosen from 569 children with newly diagnosed type 1 diabetes. Anti-islet antibodies (ICA) and antibodies to endomysium were detected by indirect immunofluorescence. Antibodies to tissue transglutaminase were measured by the immunoenzymatic method, whereas the measurement of autoantibodies to insulin, to tyrosine phosphatase and to glutamic acid decarboxylase was determined by radioimmunoassay.

Thyroid antibodies were detected in 5.9% of the examined patients from group 1B and 14.7% from group 1A. The frequency of the presence of tissue transglutaminase autoantibodies in both groups was similar (9.4% in 1B and 8.3% in 1A) and in case of endomysial antibodies it was slightly higher in group 1B (9.4% vs 4.8%, p=0.39).

Since the prevalence of tissue specific autoantibodies is similar in both presentations of type 1 diabetes it is unlikely that a humoral defect of immune response in idiopathic diabetes is observed in this group of patients.