EXORPHINS DERIVED FROM COWS MILK CASEIN ELICIT PSEUDO-ALLERGIC WHEAL-AND-FLARE REACTIONS IN HEALTHY-CHILDREN

Beta-Casomorphin-7 and alpha-casein (90-95) are opioid peptides occurr ing in cow's milk casein digest products. We investigated the direct h istamine releasing properties of these peptides in vivo. Intracutaneou s skin tests were performed with-beta-casomorphin-7, alpha-casein (90- 95) and cow's milk extract in 25 children without any clinical indicat ion of cow's milk allergy or intolerance. immediate wheal reactions we re measured and compared with skin reactions to histamine and codeine. Tests were repeated after pretreatment with 10 mg cetirizine, a Hi-an tagonist. The opioid peptides induced wheat-and-flare reactions in all children. These were concentration-dependent and similar to those obs erved with histamine or codeine. Pretreatment with cetirizine inhibite d skin reactivity to both opioid peptides. With one exception, no skin reaction to cow's milk was found. Degranulation of skin mast cells wa s observed in a biopsy specimen taken from the skin area injected with alpha-casein (90-95). Beta-Casomorphin-7 and alpha-casein (90-95) cau sed pseudo-allergic immediate type reactions, apparently by direct his tamine release. This may be of relevance with regard to clinical react ions to cow's milk.