Allergy to an Amino-Acid Formula in Infants: Residual Soy Allergens in Soybean Oil are Incriminated

Abstract

RATIONALE: Treatment of allergy to cow milk (CM) proteins comprises avoidance and replacement of CM with various infant formulas. However, clinical manifestations have been associated with CM protein hydrolysates (CMPH). In this situation, in the frame of multiple food allergies (MFA), substitution of CMPH with an amino-acid-based formula (AAF) is recommended.METHODS: Seven infants allergic to AAF have been referred for a MFA. In all cases, the breast-feeding was stopped; CMPH and/or soy protein and pork collagen hydrolysates were replaced by Neocate® (SHS International), an AAF containing a soy lipid emulsion. As there was no clinical improvement, prick-tests (PT) and atopy patch-test (APT) to soy or Neocate® were carried out.RESULTS: PIPs were positive in 2/7 patients. APTs to soy and APTs to Neocate® were positive respectively for 5/5 and 3/5 infants. In one case, an oral challenge with the soy lipid emulsion was performed and was positive. Neocate® was replaced by Neocate Advance®, a soy-free AAF and the symptoms improved within 2-4 weeks in all children.Proteins of the Neocate emulsion were extracted. The amount was measured and their molecular mass estimated by SDS-PAGE. A western blot was conducted using the serum of a soy allergic patient . The western blot showed 2 bands (56-66 kDa).CONCLUSIONS: AAFs have represented a great advance. However, the risk of allergy to traces of vegetable proteins in certain oils has been confirmed yet again. Food industries must be made aware of the need to detect allergen traces in foods for infants at high risk of atopy. RATIONALE: Treatment of allergy to cow milk (CM) proteins comprises avoidance and replacement of CM with various infant formulas. However, clinical manifestations have been associated with CM protein hydrolysates (CMPH). In this situation, in the frame of multiple food allergies (MFA), substitution of CMPH with an amino-acid-based formula (AAF) is recommended. METHODS: Seven infants allergic to AAF have been referred for a MFA. In all cases, the breast-feeding was stopped; CMPH and/or soy protein and pork collagen hydrolysates were replaced by Neocate® (SHS International), an AAF containing a soy lipid emulsion. As there was no clinical improvement, prick-tests (PT) and atopy patch-test (APT) to soy or Neocate® were carried out. RESULTS: PIPs were positive in 2/7 patients. APTs to soy and APTs to Neocate® were positive respectively for 5/5 and 3/5 infants. In one case, an oral challenge with the soy lipid emulsion was performed and was positive. Neocate® was replaced by Neocate Advance®, a soy-free AAF and the symptoms improved within 2-4 weeks in all children. Proteins of the Neocate emulsion were extracted. The amount was measured and their molecular mass estimated by SDS-PAGE. A western blot was conducted using the serum of a soy allergic patient . The western blot showed 2 bands (56-66 kDa). CONCLUSIONS: AAFs have represented a great advance. However, the risk of allergy to traces of vegetable proteins in certain oils has been confirmed yet again. Food industries must be made aware of the need to detect allergen traces in foods for infants at high risk of atopy.