An oral screening procedure to determine the sensitizing capacity of infant feeding formulae

Authors


Professor R. R. A. Coombs, Division of Immunology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge.

Summary

Allergy to cows' milk is an important and frequent cause of cows' milk protein-intolerance in infants. Many infants within days of birth are fed cows' milk or cows' milk-based formula feeds. It is thought desirable to have a test available that would indicate the allergenic potency per os of milk formulae and of milk substitutes intended for infant feeding.

Such a test, based on the finding that guinea-pigs drinking cows' milk become anaphylactically sensitized to milk proteins, is described. After drinking pasteurized milk for only 4 days, 88% of guinea-pigs were susceptible to fatal anaphylaxis on intravenous challenge on the 22nd day; drinking milk for 8 days resulted in 100% of guinea-pigs becoming sensitive to fatal anaphylaxis. Following milk drinking for 7 days, a subsequent interval of 7 days was required before anaphylactic sensitivity could be shown in 100% of animals. With this information the effect of heat on the per os allergenic potency of cow's milk could be examined; likewise the allergenic potency of supposedly hypo-allergenic infant feed formulations.

Pregestimil induced no anaphylactic sensitivity even after 37 days of drinking, and no anaphylactic antibodies, detectable by PCA, were formed to the milk proteins β-lactoglobulin and casein. In contrast, AL110 likewise drunk by guinea-pigs for 37 days resulted in 90% fatal anaphylactic reactions in animals challenged with the same product. Anaphylactic antibodies were found to casein but not to β lactoglobulin.

Comminuted Chicken and Prosobee (a soya milk), two alternative ‘hypo-allergenic’ cows' milk substitutes, rendered approximately 50% guinea-pigs anaphylactically sensitive to the product fed, but neither product stimulated cross-reactive anaphylactic antibodies to either casein or β-lactoglobulin as tested by PCA.

There is some indirect evidence that results of the guinea-pig test are relevant to responses in infants with cows' milk protein intolerance.

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