[Cow's milk protein intolerance, the search for the antigen continues]

Cow's milk protein intolerance is one of the most common causes of food intolerances in early infancy. The clinical picture of the disease varies tremendously, and the diagnosis is based on clinical criteria alone, because the nature of the antigen is still unknown. Thus macromolecular uptake has been demonstrated depending on the age and maturity of the intestinal mucosa. However it remains to be established where the antigen is absorbed and how it is taken up. The seize and the conformation of the molecule which comes in contact with immunocompetent cells needs to be determined. The role of sIgA is unclear in man but it has been proposed that secretory antibodies to food antigens facilitate digestion by holding oligopeptides in contact with proteases at the intestinal epithelium. The composition of milk varies depending on the region and the breed of cows. In addition milk proteins differ from breed to breed. The determination of antibodies, immunocomplexes and specific IgE antibodies using RAST give inconstant results. Intestinal biopsies can demonstrate unspecific structural changes of the mucosa but they cannot be used as diagnostic tool.