Specific antibodies in infants with gastrointestinal intolerance to cow's milk protein.

Antibodies of various immunoglobulin classes against cow's milk proteins were studied in infants and children with cow's milk protein intolerance, gluten-sensitive enteropathy and acute gastroenteritis. Their IgE, IgG, IgM and IgA antibody levels determined with the enzyme-linked immunosorbent assay (ELISA) and the IgE antibodies also determined with RAST, were compared with reference groups of children and adults. IgE, IgT or IgA antibodies against unseparated cow's milk proteins, alpha-lactalbumin, beta-lactoglobulin, alpha-casein and beta-casein were present in many of the studied samples, but did not discriminate between the individuals with and without intolerance symptoms. As a group, the infants with late reactions to cow's milk showed increased levels of IgE and IgG antibodies detected with the ELISA, while patients with gluten-sensitive enteropathy had significantly increased levels of IgG and IgA antibodies of cow's milk proteins compared to the reference group. By combining the findings of antibody increases in various immunoglobulin classes, an individual discrimination could be reached. Thus, 8 of 9 of the patients with late reactions to cow's milk had increased levels of IgE or IgG + IgA antibodies as compared to 3 of 22 in the reference group. Serodiagnosis with the ELISA may, therefore, be of some use in patients with a suspicion of cow's milk protein intolerance.