Prevalence and fate of type 1 diabetes-associated autoantibodies in cord blood samples from newborn infants of non-diabetic mothers

Background Cord blood samples were collected from 1002 consecutive births at Turku University Hospital to study the prevalence and fate of type 1 diabetes-associated autoantibodies in newborn infants of unaffected mothers. Methods The samples were analysed for cytoplasmic islet cell antibodies (ICA), autoantibodies to the 65 kD isoform of glutamic acid decarboxylase (GADA), autoantibodies to the protein tyrosine phosphatase related IA-2 antigen (IA-2A), insulin autoantibodies (IAA) and HLA DQB1 genotypes. Results ICA were detected in 27 cord blood samples (2.7%), with a median of 6 (range 4-34) JDF units. GADA were found to be positive ( greater than or equal to6.6 RU) in six samples (0.6%), with a median of 66 (range 19-125) RU. IA-2A ( greater than or equal to0.43 RU) were observed in three samples (0.3%), with a median of 1.3 (range 0.8-57) RU, while only one cord blood sample (0.1%) tested positive for IAA (greater than or equal to1.56 nU/ml) with a value of 5.4 RU. Maternal or gestational age, sex and birth weight of the infant were not related to antibody prevalence or titres. Altogether there were 29 infants with antibody positivity in their cord blood (2.9%). Five of these (0.5%) tested positive for two antibodies (ICA and GADA), and one was positive for all four antibodies measured. All nine infants from whom follow-up samples were available became antibody negative by the age of 15 months, and in all but one case inverse seroconversion occurred by the age of 9 months. Conclusions Around 3% of infants of non-diabetic mothers in Finland have diabetes-associated autoantibodies at birth, and these antibodies disappear at the latest by the age of 15 months. Copyright (C) 2002 John Wiley Sons, Ltd.