High prevalence of diabetes-specific autoimmunity in first-degree relatives of Sardinian patients with type 1 diabetes.

Research paper by M M Incani, C C Serafini, C C Satta, L L Perra, F F Scano, P P Frongia, R R Ricciardi, C C Ripoli, M M Soro, A A Strazzera, S S Zampetti, R R Buzzetti, M G MG Cavallo, E E Cossu, M G MG Baroni

Indexed on: 12 Oct '16Published on: 12 Oct '16Published in: Diabetes/Metabolism Research and Reviews


The incidence of T1DM In Sardinia is among the highest in the world (44.8 cases/100,000 person-years). Recommendations of the Immunology of Diabetes Society (IDS) advise evaluating autoantibody positivity in first-degree relatives (FDR) of patients with T1DM, for their higher risk to develop the disease. The aim of this study is to determine the prevalence of beta-cell autoimmunity in first-degree relatives of T1DM patients in Sardinia.188 Sardinian families were recruited in collaboration between Diabetes and Paediatric Units of University and District Hospitals in Sardinia. The recruitment involved 188 patients with diagnosed T1DM and all their available FDR (n = 447). Autoantibodies (Aabs) against GAD, IA2, insulin and ZnT8 were measured in all subjects. HLA risk genotypes (HLA-DR and DQ loci) were analysed in 43 Aabs-positive FDR.The prevalence of Aabs (any type of autoantibody, single or multiple) in FDR was 11.9% (53/447). Of those with autoantibodies, 62.3% (33/53) were positive to only one autoantibody, 22.6% (12/53) had two, 7.55% (4/53) had three, and 7.55% (4/53) had all four autoantibodies. Typing of HLA-DR and DQ loci showed that 89% of FDR carried moderate- to high-risk genotypes, with only 5 FDR with "low-risk" genotypes.The prevalence of T1DM autoantibodies in first-degree relatives of T1DM patients was very high (11.9%) in the Sardinian population, higher than in other populations from USA and Europe, and similar to that observed in Finland. Autoantibody positivity strongly associated with HLA risk. This study provides evidence of the high risk of T1DM in FDR of T1DM patients in Sardinia, and warrants longitudinal follow-up to estimate the risk of progression to T1DM in high-risk populations.

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