Islet cell autoimmunity in youth onset diabetes mellitus in Northern India

We characterised a consecutive cohort of 132 youth onset diabetic individua ls (age at onset < 30 years, mean duration of disease 5.5 +/- 6.0 years) fr om North India, by serological determination of the determination of the is let cell autoantibodies, GAD(65) and IA2, and clinically for coexisting aut oimmune thyroid disease, malnutrition and pancreatic calcification. Five ty pes of diabetes were delineated: Type 1 (37%), ketosis resistant (32%), Typ e 2 (13%). fibrocalculous pancreatopathy (11%) and autoimmune polyglandular syndrome (7%). C-peptide response to glucagon was assessed in a representa tive subset of 50 patients with Type 1, ketosis resistant, and autoimmune p olyglandular syndrome. A total of 22.4% of Type 1 and 30% of autoimmune pol yglandular syndrome subjects showed both GAD(65) plus IA-2 autoantibody pos itivity, significantly more than the 4.7% positivity shown by the ketosis r esistant type. However, GAD(65) antibody positivity alone was seen in 38% o f ketosis resistant subjects which was significantly more than the 14.2 and 10% positivity seen in Type 1 and autoimmune polyglandular groups, respect ively. The fibrocalculous pancreatopathy group showed GAD(65) plus IA-2 aut oantibody positivity in 14.2% and GAD(65) autoantibody alone positivity in 7.1%. 26 and 60%, respectively, of the Type 1 and autoimmune polyglandular syndrome groups had thyroid microsomal autoantibody positivity. Type 1 show ed significantly less C-peptide response to glucagon when compared to the k etosis resistant and autoimmune polyglandular syndrome groups. The controls and Type 2 diabetic individuals tested negative for islet cell autoimmunit y markers. These findings demonstrate a role of islet cell autoimmunity in the pathogenesis of four out of the five clinical types of youth onset diab etes seen in North India. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.