A case of allergy to cow's milk hydrolysate

Evaluation of an extensively hydrolysed casein formula (Damira 2000) in children with allergy to cow's milk proteins

OBJECTIVE

To assess the allergenic capacity of a new extensively hydrolysed casein formula (Damira 2000) in vivo in children with allergy to cow's milk, and to conduct an immunochemical evaluation of the product.

PATIENTS AND METHODS

The study comprised 67 children (1 month-7 years) with allergy to cow's milk proteins (ACMP). Skin testing was made with whole milk, milk formula for infants, the study hydrolysate and the milk fractions (alpha-lactoalbumin, beta-lactoglobulin and casein). Specific IgE against these allergens, and oral provocation test were also performed. Immunochemical evaluation of the product was carried out with gel filtration chromatography, 4-15% acrylamide gradient gel electrophoresis, specific IgE quantification versus the casein hydrolysate and a study of its allergenic potency.

RESULTS

The hydrolysate was tolerated by 66 of the 67 patients (98.5%) with ACMP. Biochemical analysis of the product confirmed the absence of traces of whole milk proteins. Specific IgE against the hydrolysate proved negative in all cases, and it was unable to inhibit FEIA even at concentrations 10 times greater than those used in the whole milk inhibition control. Likewise, no immunoblotting inhibition was recorded.

CONCLUSIONS

The new extensively hydrolysed casein product is safe and well tolerated by most children with ACMP. However, as with other extensive hydrolysates, some highly sensitised patients may present clinical manifestations. Controlled tolerance testing is therefore advised, under specialised medical supervision.

Temporary allergy to Neocate: possible association with immunisation

A 5-month-old baby exhibited an allergic reaction to Nutramigen 1 day after his third set of immunisations. The following day he had a similar reaction to Neocate, which was being used as an alternative to Nutramigen. One month later Neocate was slowly reintroduced back into the diet with no ill effects.

The efficacy of amino acid-based formulas in relieving the symptoms of cow's milk allergy: a systematic review

The aim of this systematic review was to evaluate the efficacy of amino acid-based formulas (AAF) in patients with cow's milk allergy (CMA). Studies were identified using electronic databases and bibliography searches. Subjects eligible for inclusion were patients of any age with CMA or symptoms suggestive of it. Comparisons of interest were AAF vs. extensively hydrolysed formula (eHF), AAF vs. soy-based formula (SF) and AAF vs. cow's milk or cow's milk-based formula. Outcomes of interest were gastrointestinal (GI), dermatological, respiratory and behavioural symptoms as well as growth. A total of 20 studies [three head-to-head randomized controlled trials (RCTs), three cross-over challenge RCTs, seven clinical trials (CTs) and seven case reports (CRs)] were included in the review. In infants with confirmed or suspected CMA, the use of an AAF was shown to be safe and efficacious. Findings from RCT comparisons of AAF with eHF showed that both formulas are equally efficacious at relieving the symptoms of CMA in confirmed or suspected cases. However, infants in specific subgroups (e.g. non-IgE mediated food-induced gastro-enterocolitis-proctitis syndromes with failure to thrive, severe atopic eczema, or with symptoms during exclusive breastfeeding) were more likely overall to benefit from AAF, as intolerance to eHF may occur. In such cases, symptoms persisting despite eHF feeding usually remit on AAF, and catch-up growth may be seen. Meta-analysis of the findings was not possible due to lack of homogenous reporting of outcomes in the original trials. This systematic review shows clinical benefit from use of AAF in both symptoms and growth in infants and children with CMA who fail to tolerate eHF. Further studies are required to determine the relative medical or economic value of initial treatment with AAF in infants at high risk of eHF intolerance.

A consensus protocol for the determination of the threshold doses for allergenic foods: how much is too much?

BACKGROUND

While the ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies, little information is known regarding these threshold doses for specific allergenic foods. While low-dose challenge trials have been conducted on an appreciable number of allergic individuals, a variety of different clinical protocols were used making the estimation of the threshold dose very difficult.

OBJECTIVE

A roundtable conference was convened to develop a consensus clinical protocol for low-dose challenge trials for the estimation of threshold doses for specific allergenic foods.

METHODS

In May 2002, 20 clinical allergists and other interested parties were invited to participate in a roundtable conference to develop consensus of the key elements of a clinical protocol for low-dose challenge trials.

RESULTS

A consensus protocol was developed. Patients with convincing histories of food allergies and supporting diagnostic evidence including past challenge trials or high CAP-RAST scores can be enrolled in low-dose challenge trials. Care must be taken with younger patients to assure that they have not outgrown their food allergy. An approach was developed for the medication status of patients entering such trials. Challenge materials must be standardized, for example, partially defatted peanut flour composed of equal amounts of the three major varieties of peanuts (Florunner, Virginia, Spanish). Challenge materials must be appropriately blinded with sensory evaluation used to confirm the adequacy of blinding. A double-blind, placebo-controlled design should be used for low-dose challenge trials. Low-dose challenge trials would begin at doses of 10 microg of the allergenic food and would continue with doses of 100 microg and 1 mg followed by specific higher doses up to 100 mg depending upon the expert judgement of the physician; even higher doses might be applied to assure that the patient is indeed reactive to the particular food. A 30-min time interval would be used between doses, and reactive doses would be expressed as both discrete and cumulative doses. The goal of each challenge would be to develop objective symptoms; trials should not be discontinued on the basis of subjective symptoms only. Statistically, a minimum of 29 patients would be enrolled in low-dose challenge trials for each allergenic food because 0 reactors out of 29 patients at a particular dose allow the conclusion that there is 95% certainty that 90% of allergic individuals will not react to that dose.

CONCLUSION

A consensus protocol was developed. Using this protocol, it will be possible to estimate threshold doses for allergenic foods, the lowest amount that elicits mild, objective symptoms in highly sensitive individuals.

Digestion stability as a criterion for protein allergenicity assessment

Assessing the allergenic potential of transgenic proteins introduced into genetically engineered food remains a critical part of the overall safety assessment of these foods. Stability to digestion has been proposed as one of the steps in the decision tree approach to assess the allergenic potential of transgenic proteins. The validity of digestion stability as a criterion for protein allergenicity assessment, however, has encountered some criticism in recent years. This chapter gives an overview of the rationale behind the use of digestion stability as a criterion for protein allergenicity assessment and reviews the available data that may or may not support its use. The application of in vitro digestion assays for the assessment of allergenic potential of novel proteins and the factors that affect the assay results are also discussed. There is a need to establish standardized assay conditions so that direct comparison of results from different laboratories can be made. Consensus also needs to be reached on relating the measured digestibility to the allergenic potential of proteins.

Determination of allergenicity to three cow's milk hydrolysates and an amino acid-derived formula in children with cow's milk allergy

BACKGROUND

Products based on hydrolysed cow milk proteins or amino acid mixtures are recommended in children with cow's milk hypersensitivity. However, some children who are allergic to cow's milk and who clinically react to substitute milk formulas have been observed.

OBJECTIVE

To determine the tolerance and allergenicity of protein hydrolysate or amino acid-derived formulas in children with IgE-mediated cow's milk allergy.

METHODS

Twenty children with positive cow's milk challenges, positive skin prick tests and/or serum-specific IgE antibodies to cow's milk were selected. Oral challenges, skin prick tests and serum-specific IgE antibodies to extensively hydrolysed whey formula, partially hydrolysed whey formula, extensively hydrolysed casein formula and amino acid-derived formula were performed.

RESULTS

Five out of 17 (5/17) children reacted to partially hydrolysed whey formula, (3/16) to extensively hydrolysed whey formula, (2/10) to amino acid-derived formula, (1/16) to extensively hydrolysed casein formula. Only extensively hydrolysed casein formula was tolerated by at least 90% (with 95% confidence intervals) of children. Hydrolysates provoked early and delayed clinical reactions, amino acid mixtures only delayed reactions. Partially hydrolysed whey formula elicited a significantly higher number of positive skin prick test reactions than other formulas. Two children had specific IgE antibodies to extensively hydrolysed whey formula, one to partially hydrolysed whey formula, one to extensively hydrolysed casein formula and none to amino acid-derived formula.

CONCLUSION

In this study, none of the cow's milk substitutes has been found to be non-allergenic. Our results suggest that in children with IgE-mediated cow's milk allergy, the first ingestions of extensively hydrolysed cow's milk protein formulas require strict medical supervision because of immediate reactions. This is not the case for amino acid-derived formula. Moreover, our data suggest that treatment of children allergic to cow's milk with cow's milk substitutes should be monitored for several days to document tolerance.

[Protein hydrolysates: hypoallergenic milks and extensively hydrolyzed formulas. Immuno-allergic basis for their use in prevention and treatment of milk allergy]

Allergy to milk has an estimated incidence of 2.5%. Hypoallergenic milks are partial hydrolysates of proteins with lactose. Extensive hydrolysates of casein are mainly small peptides and do not include lactose in their formula. A primary allergenicity as well as a cross-sensitivity are shown for all partial hydrolysates. Even extensive hydrolysates have a weak potential of cross-allergy. The prevention of cow's milk allergy in infants at peculiar risk, born from atopic parents, is based on breast-feeding and/or partial or extensive hydrolysates. There is no conclusive evidence for the usefulness of eviction of dairy products during pregnancy or during the period of breast-feeding. The treatment needs exclusively extensive casein hydrolysates ensuring a 90% protection with 95% confidence intervals. Predictive prick tests in certain cases may help the choice of another hydrolysate. Severe cases with failure to thrive or multiple food intolerance require an amino-acid based formula (Neocate). A rational diversification of the diet is advised in order to prevent the onset of a multiple food intolerance syndrome which could avert from the recovery of cow milk allergy.

Effects of gamma radiation on the allergenic and antigenic properties of milk proteins

This study was carried out to evaluate the application of food irradiation technology as a method for reducing milk allergies. Bovine alpha-casein (ACA) and beta-lactoglobulin (BLG) were used as milk proteins. Using milk-hypersensitive patients' immunoglobulin E (IgE) and rabbit IgGs individually produced to ACA and BLG, the changes of allergenicity and antigenicity of irradiated proteins were observed by competitive indirect enzyme-linked immunosorbent assay. Allergenicity and antigenicity of the irradiated proteins were changed with different slopes of the inhibition curves. The disappearance of the band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and increase of the turbidity showed that solubility of the proteins decreased by radiation, and this decrease might be caused by agglomeration of the proteins. These results indicated that epitopes on milk allergens were structurally altered by gamma irradiation.