The diagnostic significance of IgG cow's milk protein antibodies re-evaluated.

The effect of different feeding regimens, notably the use of hydrolysed cow's milk formulas, on the development of allergic reactions and the development of cow's milk protein-IgG antibodies is still disputed. We prospectively compared the development of allergic manifestations and cow's milk protein-IgG antibodies in a total of 702 infants who were divided into six groups: 1. exclusively breast milk for at least 4 weeks (n=206). 2. Breast milk plus initial partially hydrolysed formula (n=104). 3. Breast milk plus extensively hydrolysed formula (n=50). 4. Breast milk plus initial conventional cow's milk formula (n=73). 5. Conventional cow's milk with or without breast milk throughout (n=187). 6. Extensively hydrolysed cow's milk formula for 2 months, followed by conventional cow's milk (n=82). Cow's milk protein antibodies were determined by an indirect immuno-fluorescent test. Antibody titres rose slowly in groups 1, 3 and 6. Children in group 5 showed two high peaks. There were no significant differences in the frequency and type of allergic manifestations between the groups. Introduction of cow's milk formula during the first trimenon resulted in elevated antibody titres in all breast fed infants compared with introduction at a later date. Conclusion: In contrast to a previous study from the same laboratory, there is no diagnostic significance of cow's milk protein-IgG antibodies for allergic manifestations. The occurrence of these antibodies is a physiological phenomenon: the shorter the breast feeding period and the earlier cow's milk formula is introduced, the higher the antibody levels.