T-cell receptor repertoire and function in umbilical cord blood lymphocytes from newborns of type 1 diabetic mothers

Recent observations show that the development of the human fetal immune system is susceptible to conditions of the maternal immune system and vice versa. To investigate the impact of type I diabetes mellitus in pregnant women on the maturation of the immune system of their newborn infants. the umbilical cord blood (UCB) T-cell repertoire at birth was analysed for clonal or oligoclonal expansions and TCRBV gene usage. Quantitative PCR using TCRBV family-specific probes and the spectratyping method were used. The extent of oligoclonal expansions observed in cord blood was markedly lower than in peripheral blood of the diabetic mothers and health adults. Functional analysis revealed that UCB T cells from newborns of both type I diabetic and gestational diabetic mothers are mature and can be readily stimulated by superantigens and phytohemagglutinin in vitro. No significant differences of the clonal contingent and the TCRBV usage were found in newborns of type I diabetic mothers when compared to newborns of gestational diabetic mothers, independent from the presence or absence of islet autoantigens. Our findings indicate that the immune system of type I diabetic mothers has no major effects on the TCR repertoire of the newborn infants. In that respect, no evidence was found for superantigen-activated T cells. nor was chronic hyperplycaemia per se found to alter either T-cell repertoire or functional activity.