Summary Accumulating lines of evidence have suggested that regulatory T cells (Tregs) play a central role in T cell+ FoxP3 + T cells was significantly higher in patients with type 1A diabetes with detectable C-peptide but not in patients with type 1A diabetes without it and with fulminant type 1 diabetes. A proliferation suppression assay showed that a-Tregs were functionally impaired both in fulminant type 1 diabetes and in type 1A diabetes. In conclusion, a-Tregs were functionally impaired, related to residual insulin-secreting capacity and may be associated with the development of type 1 diabetes.

abstract. Fulminant type 1 diabetes, established in 2000, is defined as a novel subtype of diabetes mellitus that results from remarkably acute and almost complete destruction of pancreatic beta cells at the disease onset. In this study, we aimed to clarify the pathogenesis of fulminant type 1 diabetes with special reference to insulitis and viral infection. We examined pancreatic autopsy samples from three patients who had died soon after the onset of disease and analyzed these by immunohistochemistry and in situ hybridization. The results were that both beta and alpha cell areas were significantly decreased in comparison with those of normal controls. Mean beta cell area of the patients just after the onset was only 0.00256 % while that of normal control was 1.745 %. Macrophages and T cells-but no natural killer cells-had infiltrated the islets and the exocrine pancreas. Although both of them had massively infiltrated, macrophages dominated islet infiltration and were detected in 92.6 % of the patients' islets. Toll-like receptor (TLR) 3, a sensor of viral components, was detected in 84.7±7.0 % of macrophages and 62.7±32.3 % of T cells (mean±SD) in all three patients. TLR7 and TLR9 were also detected in the pancreas of all three patients. enterovirus RNa was detected in beta-cell positive islets in one of the three patients by in situ hybridization. In conclusion, our results suggest that macrophage-dominated insulitis rather than T cell autoimmunity contributes to beta cell destruction in fulminant type 1 diabetes.

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Background Since serum albumin is glycosylated more rapidly than hemoglobin, it is possible that the glycated albumin (GA) to HbA1c ratio (GA: HbA1c ratio) is potentially a more sensitive indicator of blood glucose excursion than HbA1c. The aim of the present study was to assess the clinical usefulness of GA: HbA1c ratio as a marker of daily glucose excursions in patients with type 1 diabetes according to the subtypes; acute onset type 1A, fulminant and slowly progressive type 1 diabetes. Methods Fifty-six outpatients with type 1 diabetes [16 fulminant, 20 acute-onset type 1A and 20 slowly progressive (SPIDDM)] were recruited consecutively. Each patient performed self-monitoring of blood glucose at seven points a day. The associations among the daily profile of glucose and GA, HbA1c, GA: HbA1c ratio were examined across and within the subtypes of type 1 diabetes. Results GA and GA: HbA1c ratio were each independently correlated with mean amplitude of glucose excursion (MAGE) in patients with type 1 diabetes (F=27.53, p<0.001 and F=13.02, p<0.001, respectively). GA: HbA1c ratio was significantly higher in fulminant type 1 diabetic patients than in SPIDDM patients (3.5 ± 0.2 vs. 3.2 ± 0.5, p=0.015) and it was independently associated with MAGE within fulminant type 1 diabetes (F=21.2, p<0.001). Conclusion In conclusion, the present study demonstrated that GA: HbA1c ratio could be a better marker for glycemic variability than HbA1c in type 1 diabetes, especially in fulminant type 1 diabetes.

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