title: Role of islet autoimmunity in the aetiology of different clinical subtypes of diabetes mellitus in young north Indians.
abstract: OBJECTIVE
  To determine the role of islet autoimmunity in the aetiology of different clinical subtypes of diabetes mellitus in young north Indian patients by measuring islet autoantibodies.
  
  
  METHODS
  In a cross-sectional study, 145 young patients with diabetes (onset < 30 years) were subdivided into the following categories: Type 1 diabetes (n = 83), malnutrition-modulated diabetes mellitus (MMDM, n = 31) and fibro-calculous pancreatic diabetes (FCPD, n = 31). MMDM subjects presented with emaciation and severe insulin-requiring but ketosis-resistant diabetes, while FCPD was associated with idiopathic chronic calcific pancreatitis. Antibodies to glutamic acid decarboxylase (GADA) and IA-2 (IA-2 A) were detected by immunoprecipitation of 35S-labelled recombinant antigens and cytoplasmic islet cell antibody (ICA) by indirect immunofluorescence.
  
  
  RESULTS
  GADA were present in a significant proportion (23%) of patients with MMDM. In contrast, IA-2 A was increased only among patients with Type 1 diabetes (22%), but not MMDM (3%, P < 0.05). Among patients with a duration of diabetes < 2 years, GADA and/or IA-2 A were found in 61% of Type 1 diabetic and 37% of MMDM patients (P < 0.01). MMDM patients who were positive for GADA had a shorter duration of diabetes, but did not differ in their age at onset of diabetes, body mass index, fasting plasma C-peptide, or frequency of thyroid microsomal and parietal cell antibodies. FCPD subjects had the lowest prevalence of autoantibodies: IA-2 and ICA were absent, while GADA were present in 7% (P < 0.05 vs. Type 1 diabetes).
  
  
  CONCLUSIONS
  GADA, though not IA-2 A, were present in a substantial proportion of patients with the MMDM variant of diabetes, suggesting that islet autoimmunity may play a role in its pathogenesis. In contrast, none of the islet antibodies was increased in subjects with FCPD, making it likely that it is a secondary type of diabetes.
authors.affiliation: Department of Endocrinology, Sanjay Gandhi Postgraduate Institute, Lucknow, India.
authors.forename: A K
authors.initials: AK
authors.lastname: Singh
authors.forename: E
authors.initials: E
authors.lastname: Bhatia
authors.forename: P
authors.initials: P
authors.lastname: Dabadghao
authors.forename: V
authors.initials: V
authors.lastname: Bhatia
authors.forename: S A
authors.initials: SA
authors.lastname: Gellert
authors.forename: P G
authors.initials: PG
authors.lastname: Colman
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001323:Autoantibodies / Q000097:blood*; D002096:C-Peptide / Q000097:blood; D002114:Calcinosis / Q000150:complications / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000145:classification / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007194:India / Q000453:epidemiology; D007515:Islets of Langerhans / Q000276:immunology*; D008297:Male; D009748:Nutrition Disorders / Q000150:complications / Q000453:epidemiology; D010195:Pancreatitis / Q000150:complications / Q000453:epidemiology
chemical_list: D001323:Autoantibodies; D002096:C-Peptide; C024211:islet cell antibody; D005968:Glutamate Decarboxylase