Prevalence of islet cell antibodies among 1021 relatives of type 1 diabetics

BACKGROUND: An immunological damage of beta cells in the islets of Langerhans, plays a role in the pathogenesis of type 1 diabetes. Recently, the identification of individuals in pre clinical phase and with high risk of developing type 1 diabetes, has become possible by means of the detection of immune markers such as islet cell antibodies (ICA) and the measurement of first phase response of insulin (FPRI). SUBJECTS AND METHODS: We studied 1,021 first degree relatives of type 1 diabetics, aged 4 to 35 years. ICA were measured using poly-IgG peroxidase in sections of human pancreas. In those subjects with positive ICA and normal oral glucose tolerance test, the FPRI was measured. FPRI was defined as the sum of insulinemias at minutes 1 and 3 after a three minutes 0.5 g/kg glucose load. RESULTS: Thirty subjects were ICA (+), defined as having more than 20 juvenile diabetes foundation units (prevalence of 2.9%). No differences in age, sex and closeness of familial relationship was found between ICA (+) and ICA (-) individuals. FPRI was measured in 24 subjects with normal oral glucose tolerance test and was normal in five. Seventeen subjects had a decreased response (between percentiles 1 and 5) and two had a response below percentile 1. No relationship between ICA levels and FPRI was found. CONCLUSIONS: The early detection of populations at risk of developing type 1 diabetes should be regarded as an important tool to better understand the natural history of the disease and to develop preventive programs in the future.