Faith Huang

Effect of heat treatment on milk and egg proteins allergenicity

Heating destroys many conformational epitopes and reduces allergenicity of some foods. IgE‐epitope binding has been shown to be different among patients who outgrew their cows milk or hens egg allergy and those who did not. A significant proportion of milk‐ or egg‐allergic children are tolerant to these foods in their baked forms. We sought to explore the effects of heating on milk and egg proteins and to evaluate for differences in immunolabeling among children with regard to reactivity to heated milk or egg.

Extensively heated milk and egg as oral immunotherapy.

Purpose of reviewThe introduction of extensively heated milk and egg protein into the diet has been explored in recent years. Recent findingsStudies have suggested that a large subset of children who react to unheated milk or egg can tolerate extensively heated forms of these foods. Immunologic changes induced by a diet containing baked milk and egg are similar to changes that have been observed during oral immunotherapy trials. The baked milk and egg diet appears to accelerate the development of regular milk and egg tolerance when compared with strict avoidance. SummaryAn oral challenge to extensively heated milk and egg into milk and egg allergic childrens diets should be considered when appropriate. Oral food challenges are the most reliable means of establishing a diagnosis and should be undertaken under physician supervision.

IgE-Mediated Cow’s Milk Allergy in Children

The age at which the majority of children outgrow cow’s milk allergy now appears to be later than previously reported. Recent studies have attempted to elucidate factors that may help prevent cow’s milk allergy, assess markers of persistence, and evaluate the usefulness of new diagnostic methods. Strict avoidance of cow’s milk has been the mainstay of treatment. However, given the potential nutritional, social, and immunologic ramifications of cow’s milk elimination from a child’s diet, there has been a focus on reevaluating this therapeutic approach.

Early Consumption of Peanuts in Infancy Is Associated With a Low Prevalence of Peanut Allergy

Du Toit G, Katz Y, Sasieni P, et al. J Allergy Clin Immunol . 2008;122(5):984–991 PURPOSE OF THE STUDY. To determine the prevalence of peanut allergy (PA) among Israeli and United Kingdom Jewish children and to evaluate the relationship of PA to peanut consumption by infants and mothers. STUDY POPULATION. The study included Jewish children between the ages of 4 and 19 years who attended targeted primary and high schools. Eligible Jewish schools in greater London, United Kingdom, and Israeli schools in the Mehoz Merkaz region of Tel Aviv were selected because they were thought to represent comparable residential environments. The mothers of Jewish infants 4 to 24 months of age in general practitioner clinics in the United Kingdom and Tipat Halav clinics in Israel were also surveyed about the timing of ingestion of peanut. METHODS. Two validated questionnaires were used. The Food Allergy Questionnaire was completed by high school pupils …

Cord Blood Allergen-Specific IgE Is Associated With Reduced IFN-γ Production by Cord Blood Cells: The Protection Against Allergy–Study in Rural Environments (PASTURE) Study

Pfefferle PI, Sel S, Ege MJ, et al; PASTURE Study Group. J Allergy Clin Immunol . 2008;122(4):711–716 PURPOSE OF THE STUDY. To investigate the relationship between allergen-specific cord blood (CB) immunoglobulin E (IgE) levels, parental allergen sensitization, CB cytokine production, and environmental influences. STUDY POPULATION. This study included families recruited for the multicenter Protection Against Allergy–Study in Rural Environments (PASTURE) study, an ongoing longitudinal birth cohort study designed to evaluate risk factors and preventative factors for atopic disease. Pregnant women in their third trimester were recruited for participation from Finland, Germany, France, Switzerland, and Austria. METHODS. CB samples were collected from umbilical cord veins, and parental blood …

Sensitization to Human Milk

Schulmeister U, Swoboda I, Quirce S, et al. Clin Exp Allergy. 2008;38(1):60–68 PURPOSE OF THE STUDY. To analyze the specificity and possible biological relevance of immunoglobulin E (IgE) reactivity to human milk antigens in milk-allergic patients. STUDY POPULATION. Milk-allergic children and adults from different European countries with a positive case history, positive skin-prick reactions, and specific IgE to cows milk extract were selected. METHODS. The specificity of IgE reactivity to cows milk and human milk antigens was analyzed with sera from milk-allergic children and adults by immunoblotting. IgE cross-reactivity between milk antigens was studied by immunoblot inhibition experiments. To demonstrate that IgE reactivity to human milk antigens is not caused by alloreactivity or transmission of foreign antigens, genetically unrelated mothers’ milk samples were analyzed before and after intake of dietary milk products. Skin-prick tests were performed with cows, sheeps, mares, and human milk samples. RESULTS. IgE antibodies to human milk were found in >80% of the tested milk-allergic patients (n = 17). Cross-reactive IgE-reactive human antigens such as α-lactalbumin and non–cross-reactive human milk antigens were identified. Immunoblots showed IgE reactivity to antigens of the same molecular weights in each of the 4 milk samples from unrelated mothers. An immediate-type skin reaction could be elicited with human milk samples in 2 tested patients with IgE reactivity to human milk. CONCLUSIONS. IgE reactivity to human milk in milk-allergic patients may be caused by cross-sensitization and genuine sensitization, causing allergic symptoms. Sensitization to human milk is common in milk-allergic patients and may require diagnostic testing and clinical monitoring. REVIEWER COMMENTS. This is one of the first studies to have addressed the nature and biological relevance of IgE reactivity to human milk. The study demonstrated that sensitization to human milk is common in milk-allergic patients, but additional research is necessary, because it is unclear if patients with positive skin reactions suffered from clinically significant reactions to human milk. One may consider searching for the presence of IgE antibodies to human milk in children who have signs of allergy after breastfeeding. However, the benefits of breastfeeding, including its protective effect against early atopic diseases, must also be considered before advising dietary changes.

Drug Allergy Claims in Children: From Self-reporting to Confirmed Diagnosis

Rebelo Gomes E, Fonseca J, Araujo L, Demoly P. Clin Exp Allergy. 2008;38(1):191–198 PURPOSE OF THE STUDY. To assess the prevalence of self-reported adverse drug reactions and drug allergy in a pediatric population and confirm the diagnosis in children with suspected drug allergy. STUDY POPULATION. Patients (n = 1426) responded to an initial cross-sectional survey. A total of 60 of 67 patients with reported drug allergy were evaluated at an allergy clinic. METHODS. The first phase included a cross-sectional survey that assessed the life occurrence of adverse drug reactions and self-reported drug allergy in the outpatient clinic of a pediatric hospital. The second phase involved a diagnostic workup in children with parent-reported drug allergy, including detailed clinical history and in vitro and in vivo investigations. Specific immunoglobulin E (IgE) level determination for β-lactams, prick and intradermal skin testing for β-lactams, local anesthetics and sulfonamides, and patch tests (if a delayed reaction was reported) were performed. If all other investigations were inconclusive and a provocation test was not contraindicated, this test was performed. RESULTS. The prevalence of self-reported adverse drug reactions and drug allergy were 10.2% and 6.0%, respectively. The frequency of a medical diagnosis of drug allergy was 3.9%. The majority of the suspected allergic reactions were nonimmediate cutaneous events attributed to β-lactam antibiotics in younger children. Of 60 patients evaluated in the allergy clinic, 39 patients had a plausible clinical history, and additional investigation including a skin test, IgE-level measurement, and possible provocation tests were conducted. Drug allergy was diagnosed in 3 children on the basis of positive responses in skin (n = 1) and oral provocation (n = 2) tests. CONCLUSIONS. Although adverse drug reactions and suspected drug allergy are frequently reported in children, after a complete evaluation, only a few of these reactions can be attributed to immediate and nonimmediate drug allergy. Overall, 94% of the patients could tolerate the initially suspected drug. REVIEWER COMMENTS. This study underscores a serious problem: patients who experience or perceive a drug reaction are often classified as being truly allergic when this may not be the case. Such overdiagnosis and misdiagnosis may result in suboptimal medication choices. These results show that only 6% of the patients with initially suspected drug allergy were truly allergic. This study demonstrates the importance of a complete and detailed history, with consideration of additional testing including skin-prick tests, specific IgE-level determination, and provocation tests. It should be noted that for nonimmediate drug allergy, an oral provocation test may require prolonged treatment to observe for symptoms. Such provocation tests would not be undertaken for severe previous reactions (eg, toxic epidermal necrolysis).