Influence of breast feeding on the development of cow's milk protein antibodies and the IgE level.

In 48 infants unselected with regard to atopic heredity, the levels of serum IgG, IgA and IgM antibodies against native cow's milk proteins and IgG antibodies against beta-lactoglobulin were measured with ELISA and the total serum IgE concentration with Phadebas PRIST. Using multiple regression analysis the level of each type of antibody was related to the age at weaning, at first exposure to cow's milk and at sampling. The longer the infants were exposed to cow's milk protein without concomitant breast feeding and the younger they were at the introduction of cow's milk formula, the higher were the IgG antibody levels against native cow's milk proteins. The investigated variables explained only 17% of the variation of the antibody level, however. The IgG antibodies against beta-lactoglobulin showed significant negative correlations to the age at weaning and the age at first cow's milk exposure, explaining 8% of the variation. Specific IgA and IgM antibody levels an those of total serum IgE did not show any significant relation to the investigated independent variables.