The diagnostic significance of antibodies to various cow's milk proteins (fluorescent immunosorbent test).

Abstract

Antibodies of various immunoglobulin classes to different cow's milk proteins were studied with the fluorescent immunosorbent test in 601 newborns, infants, children and adults (A). The antibody levels, expressed as the geometric mean (gm) of four antibody titres to casein, β-lactoglobulin, α-lactalbumin and bovine serum albumin, showed a clear dependence on age. They were compared with the antibody levels in children with cow's milk protein intolerance (C), other gastrointestinal disorders (B) and coeliac disease (D). The 20 children with cow's milk protein intolerance clearly differed (significance level 2×10-11) from those of the two control groups (A, B) insofar as the criterion adopted was not the titre against a single protein but the gm of the four antibody titres, and insofar as allowance was made for the age of the patients. All patients with cow's milk protein intolerance also showed elevated gm titres of IgE, IgA and IgM antibodies. However, since a number of children in the control groups also showed higher values, particularly with regard to IgE antibodies, the determination of the IgE, IgA and IgM antibodies adds little to the diagnosis and at best provides a further discriminatory aid. Although antibody titres fall immediately after placing the child on a milk-free diet, it is a matter of months before they become negative (titre <1∶20). After challenge titres rise again. In a longitudinal study of 25 children with acute gastroenteritis (E) it was shown that the antibody titres remained unchanged during and after the attack. This contradicts the often expressed opinion that the cow's milk antibodies frequently observed in healthy infants are induced as a consequence of gastroenteritis. In contrast to the other groups, all 26 children with proven coeliac disease (D) had antibodies to gliadin, irrespective of whether their gm cow's milk antibody titre was high or low.