Susceptibility markers in Tunisian first-degree relatives of patients with type 1 diabetes

To identify the profile of anti-pancreas autoantibodies and elucidate the HLA DRB1, DQB1 polymorphism in Tunisian first-degree relatives of patients with type I diabetes, we recruited 96 relatives from 21 families with at least one diabetic child. Islet cell antibodies (ICA) were detected by it immunofluorescence on monkey pancreas, glutamate decarboxylase (GADA), IA2 (IA2-A) and insulin (IAA) antibodies were measured by RIA. HLA class 11 DRB1 and DQB1 alleles were typed by PCR-SSP. ICA, GADA, IA2-A and IAA were found in respectively 11.5, 4.2, 5.2 and 8.3% of relatives. Twenty-two out of 96 had at least one antibody and 20 out of these 22 had a susceptibility allele (DRB1*03, DRB1*04 DQB1 *02 or DQB1*0302) with or without protective allele (DRB1 *11, DR-B1 *13, DRB1 *15 or DQB1 *06). All of the 5 relatives having 2 autoantibodies or more carried the DRB1 *04-DQB1 *0302 susceptible haplotype. In conclusion, this observational study confirms in a Tunisian population known epidemiological data and demonstrates the usefulness of follow-up to determine the predictive value of studied markers. (c) 2007 Publie par Elsevier Masson SAS.