Dextran-Reactive Antibodies in Healthy Infants and Toddlers – Relation to Type of Feeding

The appearance of dextran-reactive antibodies (DRA) during the first 2 years of life was studied in 88 healthy newborn babies in an effort to provide information about the origin of DRA in normal persons. The results were related to type of feeding, immunizations and to blood group of infants and their mothers. No DRA were detected in cord sera by passive hemagglutination. At 3 months of age 42% had DRA, at 8 months 95 % and at 27 months 84%. The latter figure corresponds to previous reports of DRA in healthy adults. Peak titers were also seen at 8 months (mean 2 log titers at 3, 8 and 27 months; 2.1, 6.2 and 4.9, respectively). Breastfeeding influenced the time of appearance of DRA and the magnitude of the titers. Babies breast-fed at 3 months more often were DRA negative than those that had received cow’s milk-based formula at that time (p <0.005). However, in those breast-fed babies that were DRA positive the titers were higher than in the formula-fed infants (p <0.001). Other types of feeding e.g. juices did not influence the DRA levels. The appearance of DRA could not be explained by polyclonal stimulation of antibody production since changes of DRA titers in 11 tested patients could not be clearly related to similar changes of levels of antibodies to an unrelated hapten, trinitrophenyl. The study demonstrates that DRA appear during the first year of life, and that the appearance is influenced by exogenous factors. The most likely source of the antigen stimulation is the gastrointestinal flora which is altered by introduction of cow’s milk into the diet.