Silvia Sánchez-García

Greater epitope recognition of shrimp allergens by children than by adults suggests that shrimp sensitization decreases with age

BACKGROUND Shellfish allergy is a long-lasting disorder typically affecting adults. Despite its high prevalence, there is limited information about allergenic shrimp proteins and the epitopes implicated in such allergic reactions. OBJECTIVE We sought to identify the IgE-binding epitopes of the 4 shrimp allergens and to characterize epitope recognition profiles of children and adults with shrimp allergy. METHODS Fifty-three subjects, 34 children and 19 adults, were selected with immediate allergic reactions to shrimp, increased shrimp-specific serum IgE levels, and positive immunoblot binding to shrimp. Study subjects and 7 nonatopic control subjects were tested by means of peptide microarray for IgE binding with synthetic overlapping peptides spanning the sequences of Litopenaeus vannamei shrimp tropomyosin, arginine kinase (AK), myosin light chain (MLC), and sarcoplasmic calcium-binding protein (SCP). The Wilcoxon test was used to determine significant differences in z scores between patients and control subjects. RESULTS The median shrimp IgE level was 4-fold higher in children than in adults (47 vs 12.5 kU(A)/L). The frequency of allergen recognition was higher in children (tropomyosin, 81% [94% for children and 61% for adults]; MLC, 57% [70% for children and 31% for adults]; AK, 51% [67% for children and 21% for adults]; and SCP, 45% [59% for children and 21% for adults]), whereas control subjects showed negligible binding. Seven IgE-binding regions were identified in tropomyosin by means of peptide microarray, confirming previously identified shrimp epitopes. In addition, 3 new epitopes were identified in tropomyosin (epitopes 1, 3, and 5b-c), 5 epitopes were identified in MLC, 3 epitopes were identified in SCP, and 7 epitopes were identified in AK. Interestingly, frequency of individual epitope recognition, as well as intensity of IgE binding, was significantly greater in children than in adults for all 4 proteins. CONCLUSIONS Children with shrimp allergy have greater shrimp-specific IgE antibody levels and show more intense binding to shrimp peptides and greater epitope diversity than adults.

Tropomyosin IgE-positive results are a good predictor of shrimp allergy.

To cite this article: Gámez C, Sánchez‐García S, Ibáñez MD, López R, Aguado E, López E, Sastre B, Sastre J, del Pozo V. Tropomyosin IgE‐positive results are a good predictor of shrimp allergy. Allergy 2011; 66: 1375–1383.

New shrimp IgE‐binding proteins involved in mite‐seafood cross‐reactivity

SCOPE Shrimp is a seafood consumed worldwide and the main cause of severe allergenic reactions to crustaceans. Seafood allergy has been related to mite sensitization, mainly mediated by tropomyosin, but other proteins could be involved. The aim of the study was to identify new shrimp allergens implicated in mite-seafood cross-reactivity (CR) in two different climate populations: dry and humid climates. METHODS AND RESULTS Shrimp and mite IgE-binding profiles of patients from continental dry and humid climates were analyzed by immunoblotting, and the most frequently recognized Solenocera melantho shrimp proteins were identified by MS as α-actinin, β-actin, fructose biphosphate aldolase, arginine kinase, sarcoplasmic calcium-binding protein, and ubiquitin. Using inhibition immunoblot assays, we demonstrate that tropomyosin and ubiquitin were responsible for mite-seafood CR from both climates; but also α-actinin and arginine kinase are implicated in dry- and humid-climate populations, respectively. Reciprocal inhibition assays demonstrated that mites are the primary sensitizer in humid-climate, as shrimp is in continental dry-climate population. CONCLUSION Several new shrimp allergens have been identified and should be considered in the diagnosis and treatment of shrimp allergy and mite-seafood CR. Differences in mite-seafood CR were founded to be based on the climate.

Early sustained unresponsiveness after short‐course egg oral immunotherapy: a randomized controlled study in egg‐allergic children

No studies have evaluated the potential of egg oral immunotherapy (egg‐OIT) to induce sustained unresponsiveness after discontinuing therapy following short‐term treatments.

Molecular Diagnosis of Shrimp Allergy: Efficiency of Several Allergens to Predict Clinical Reactivity

BACKGROUND The diagnosis of shellfish allergy remains a challenge for clinicians. Several shellfish allergens have been characterized and their IgE epitopes identified. However, the clinical relevance of this sensitization is still not clear. OBJECTIVE The objective of this study was to identify allergens and epitopes associated with clinical reactivity to shrimp. METHODS Shrimp-sensitized subjects were recruited and grouped based on the history of shrimp-allergic reactions and challenge outcome. IgE reactivity to recombinant crustacean allergens, and IgE and IgG4 reactivity to peptides were determined. Subjects sensitized to dust mites and/or cockroach without shrimp sensitization or reported allergic reactions, as well as nonatopic individuals, were used as controls. RESULTS A total of 86 subjects were recruited with a skin prick test to shrimp; 74 reported shrimp-allergic reactions, 58 were allergic (38 positive double-blind placebo-controlled food challenge and 20 recent anaphylaxis), and 16 were tolerant. All subjects without a history of reactions had negative challenges. The individuals with a positive challenge more frequently recognized tropomyosin and sarcoplasmic calcium-binding proteins than those found tolerant by the challenge. Especially a sarcoplasmic-calcium-binding-protein positive test is very likely to result in a positive challenge, though the frequency of recognition is low. Subjects with dust mite and/or cockroach allergy not sensitized to shrimp recognized arginine kinase and hemocyanin. Several epitopes of these allergens may be important in predicting clinical reactivity. CONCLUSION Tropomyosin and sarcoplasmic-calcium-binding-protein sensitization is associated with clinical reactivity to shrimp. Myosin light chain testing may help in the diagnosis of clinical reactivity. Arginine kinase and hemocyanin appear to be cross-reacting allergens between shrimp and arthropods. Detection of IgE to these allergens and some of their epitopes may be better diagnostic tools in the routine workup of shrimp allergy.

Dehydrated egg white: An allergen source for improving efficacy and safety in the diagnosis and treatment for egg allergy

Raw and cooked eggs are used as allergens in oral food challenge (OFC). Raw egg is the best option, as it keeps proteins intact and retains their allergenicity, albeit microbiologically safe manipulation is difficult. Therefore, the use of dehydrated egg white (DEW) could improve the efficacy and safety profile of OFC. The aim of the study was to compare the allergenicity of DEW, a product that undergoes a double heat treatment (pasteurization and drying), with that of raw egg white (REW) and determine the efficacy of DEW in the diagnosis of egg allergy.

Allergy to goat’s and sheep’s milk in a population of cow’s milk–allergic children treated with oral immunotherapy*

To cite this article: Rodríguez del Río P, Sánchez‐García S, Escudero C, Pastor‐Vargas C, Sánchez Hernández JJ, Pérez‐Rangel I, Ibáñez MD. Allergy to goat’s and sheep’s milk in a population of cow’s milk–allergic children treated with oral immunotherapy. Pediatr Allergy Immunol 2012: 23: 128–132.

Medical and economic impact of misdiagnosis of drug hypersensitivity in hospitalized patients.

From the Division of Allergy-Immunology, Children’s Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Ill; the Department of Pediatrics, National Jewish Health, and the Department of Pediatrics, University of Colorado, Denver, Colo; and the Elliott and Roslyn Jaffe Food Allergy Institute, Mount Sinai School of Medicine, New York, NY. E-mail: j-pongracic@ northwestern.edu. Disclosure of potential conflict of interest: J. A. Pongracic is the chair of the Adverse Reactions to Foods committee for the American Academy of Allergy, Asthma & Immunology. S. A. Bock is employed by Boulder Valley Asthma and Allergy Clinic, is research affiliate faculty for National Jewish Health, and is on the medical advisory board for the Food Allergy and Anaphylaxis Network. S. H. Sicherer is a consultant for the Food Allergy Initiative; receives research support from the National Institute of Allergy and Infectious Diseases/National Institutes of Health and the Food Allergy Initiative; is a member of the American Academy of Allergy, Asthma & Immunology; is a section chair for the American Academy of Pediatrics; and is an advisor for the Food Allergy and Anaphylaxis Network.

Food Allergy in childhood: phenotypes, prevention and treatment.

The prevalence of food allergy in childhood increased in the last decades, especially in Westernized countries where this phenomenon has been indicated as a second wave of the allergic epidemic. In parallel, scientific interest also increased with the effort to explain the reasons of this sudden rise and to identify potential protective and risk factors. A great attention has been focused on early exposures to allergenic foods, as well as on other nutritional factors or supplements that may influence the immune system in a positive direction. Both interventions on maternal diet before birth or during breastfeeding and then directly on infant nutrition have been investigated. Furthermore, the natural history of food allergy also seems to be changing over time; IgE‐mediated cows milk allergy and egg allergy seem to be more frequently a persistent rather than a transient disease in childhood, as described in the last years. Food avoidance and the emergency drugs in case of an adverse event, such as epinephrine self‐injector, are currently the first‐line treatment in patients with food allergies, with a resulting impairment in the quality of life and social behaviour. During the last decade, oral immunotherapy emerged as an optional treatment with remarkable results, offering a novel perspective in the treatment for and management of food allergy.

Biomarkers in inflammometry pediatric asthma: utility in daily clinical practice

ABSTRACT Asthma is a common disease in both high and lower income countries that starts early and persists often for life. A correct and accurate diagnosis, treatment and follow-up during childhood are essential for a better understanding of adult asthma and avoiding over- or under-treatment. Th2 inflammation in children with asthma symptoms is usually assessed by measuring with serum total IgE, blood eosinophilia and FeNO levels that may help to predict asthma, particularly in those infants and young children in whom lung function tests are difficult to perform. FeNO measurement, compared to intra-individual levels, may be useful also for ascertaining treatment adherence. Nevertheless, an isolated measurement may be insufficient and only the combination of these markers improves the diagnosis, phenotyping and follow-up of an asthmatic child.