Allergenicity of Cows' Milk Formula Hydrolysates 1. In Vitro Evaluation by Fast Inhibition

Cows' milk allergy is a significant clinical problem in infants. Treatment until recently has used soy, which is allergenic, and a casein hydrolysate (CH), which is costly and relatively nonpalatable. Since the CH and the newer whey hydrolysates (WH) are capable of causing anaphylaxis, we have evaluated the allergenicity, by IgE binding capacity, of several CH and WH using the in vitro fluoroallergosorbent test (FAST) inhibition assay comparing them to nonfat dried milk (NFDM) and Similac. Using sera from patients with cows' milk anaphylaxis and high IgE activity to whole milk (CM), casein (C), beta-lactoglobulin (BLG), and alpha-lactalbumin (ALA), we evaluated the CH Nutramigen and Alimentum and the WH Good Start (GS), Ultra, and Alfaré. Using a cumulative score of percentage fast inhibition (FI), the rank order of allergenicity was NFDM > Similac > GS > Ultra > Nutramigen > Alfaré > Alimentum. In general, all hydrolysates bound significantly (p < 0.05) less IgE than NFDM and Similac, whereas Good Start bound significantly more (p < 0.05) than the other hydrolysates, and Alimentum appeared to bind the least IgE antibody. However, all hydrolysates were capable of binding IgE specific to CM, C, BLG, and ALA. It is concluded that although the newer CH and WH hold promise with reduced allergenicity, they must be used with great caution, since they may be capable of causing anaphylaxis in the highly milk-allergic infant. It is recommended that tests for allergenicity, such as FI, become part of the food industry's protocol in developing new infant formulas with reduced allergenicity, which deserve further evaluation.