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Shellfish allergy affects a substantial proportion of US adults, many of whom develop the disease during adulthood. Crustacean and mollusk allergies have different manifestations including differing symptomatology, geographic distribution, and are often not comorbid.

Background Shellfish allergy is a prevalent, long-lasting disorder usually persisting throughout life. Few options are available for treatment, and avoidance is the only therapy recommended. Objective We sought to identify relevant crustacean allergens for use as diagnostic and safe immunotherapeutic agents for subjects with shellfish allergy. Methods Thirty-eight patients were selected with immediate allergic reactions to shrimp and increased shrimp-specific serum IgE levels. One-dimensional and 2-dimensional electrophoresis of shrimp extracts were followed by IgE immunoblotting. Protein identification was done with matrix-assisted laser desorption/ionization–mass spectrometry and Edman sequencing. A cDNA library was generated from white pacific shrimp (Litopenaeus vannamei) and screened with primers designed on the basis of internal sequences obtained from 2-dimensional tryptic digests. Full-length cDNA clones were isolated from the library and sequenced. Recombinant protein was expressed and tested with sera from patients with shrimp allergy. Results Immunoblotting demonstrated IgE binding to a 20-kDa shrimp protein by 21 (55%) of 38 sera. Tryptic digestion of the protein followed by matrix-assisted laser desorption/ionization–mass spectrometric analysis and Edman sequencing identified it as a myosin light chain (MLC). Screening of the shrimp cDNA library resulted in isolation of a novel protein cDNA. Open reading frame translation provided the amino acid sequence of a new allergenic shrimp protein with high similarity to Bla g 8 (cockroach MLC). Recombinant protein was recognized by 17 patients, confirming the allergenicity of shrimp MLC. Conclusions We have identified and cloned a new major shrimp allergen, Lit v 3.0101, an MLC protein.

Background The National Electronic Injury Surveillance System (NEISS) captures a nationally representative probability sample from hospital emergency departments (EDs) in the United States. Objective Emergency department data from NEISS were analyzed to assess the magnitude and severity of adverse events attributable to food allergies. Methods Emergency department events describing food-related allergic symptomatology were identified from 34 participating EDs from August 1 to September 30, 2003. Results Extrapolation of NEISS event data predicts a total of 20,821 hospital ED visits, 2333 visits for anaphylaxis, and 520 hospitalizations caused by food allergy in the United States during the 2-month study period. The median age was 26 years; 24% of visits involved children ≤5 years old. Shellfish was the most frequently implicated food in persons ≥6 years old, whereas children ≤5 years old experienced more events from eggs, fruit, peanuts, and tree nuts. There were no reported deaths. Review of medical records found that only 19% of patients received epinephrine, and, using criteria established by a 2005 anaphylaxis symposium, 57% of likely anaphylactic events did not have an ED diagnosis of anaphylaxis. Conclusion Analysis of NEISS data may be a useful tool for assessing the magnitude and severity of food-allergic events. A criteria-based review of medical records suggests underdiagnosis of anaphylactic events in EDs.

Background Seafood allergy is potentially severe, but the prevalence of this group of food allergies in the US population has not been determined. Objective To estimate the prevalence of seafood (fish, shellfish) allergy in the United States. Methods We performed a nationwide, cross-sectional, random telephone survey by using a standardized questionnaire. Criteria were established in advance to define seafood allergy by report of convincing symptoms and physician evaluation. Results A total of 5529 households completed the survey (67.3% participation rate), representing a census of 14,948 individuals. Fish or shellfish allergy defined by established criteria was reported in 5.9% (95% CI, 5.3%-6.6%) of households and among individuals as follows: 2.3% (95% CI, 2%-2.5%) for any seafood allergy, 2% for shellfish, 0.4% for fish, and 0.2% for both types. Seafood allergy was more common in adults compared with children (2.8% vs 0.6%; P P Conclusions Physician-diagnosed and/or convincing seafood allergy is reported by 2.3% of the general population, or approximately 6.6 million Americans. Affected individuals typically report recurrent and sometimes severe reactions, indicating that seafood allergy represents a significant health concern.

Background: Cockroaches produce several proteins that induce IgE antibody responses. Although cockroaches are abundant in warm and humid areas, sensitization to cockroach allergens has not been investigated in Brazil. Objective: The aims of this study were to investigate the frequency of cockroach allergy among patients with asthma, rhinitis, or both in Brazil and to identify American cockroach allergens. Methods: Skin tests using cockroach extracts were performed on children and young adults with asthma, rhinitis, or both. A Periplaneta americana complementary (c)DNA library was screened by using IgE antibodies from Brazilian patients allergic to cockroaches. Reactivity of an mAb directed to Dermatophagoides pteronyssinus tropomyosin against cockroach tissue was examined by immunofluorescence. Results: Cockroach allergy was present in 55% and 79% of the patients, as determined by using skin prick tests alone or combined prick and intradermal tests, respectively. Five cDNA clones reacted with IgE antibody and contained the same sequence. A representative clone (1300 bp), pa12, coded for a protein that reacted with 50% of the sera from patients allergic to cockroaches on plaque immunoassay and showed a high degree of homology to tropomyosins, particularly those from invertebrates. P americana tropomyosin showed 80%, 81%, and 82% sequence identity to tropomyosins from D pteronyssinus, D farinae, and shrimp, respectively, which have been previously defined as important allergens. An mAb directed against D pteronyssinus tropomyosin, which also recognizes shrimp tropomyosin, showed binding to cockroach striated muscle. Conclusion: Our results support the recommendation that cockroach extracts should be routinely used for the evaluation of patients with asthma, rhinitis, or both in Brazil. The identification of P americana tropomyosin as an important allergen will make it possible to investigate cross-reactivity among cockroaches, mites, and food derived from invertebrates. (J Allergy Clin Immunol 1999;104:329-37.)

Background: Although cross-reactivity between mollusks and other crustaceans in shrimp-sensitive subjects has been reported, the mechanism of this allergenic cross-reactivity has not been studied in detail. Objective: To investigate this cross-reactivity in vitro, we have taken advantage of a complementary DNA that expresses tropomyosin, the immunodominant shrimp allergen. Methods: Serum IgE from nine patients with known anaphylaxis to shrimp and five normal volunteers were analyzed by immunoblotting against 13 distinct crustaceans and mollusks. As additional antigens, muscle preparations were isolated from grasshopper, cockroach, fruit fly, chicken, and mouse. Results: Sera from all patients, but not control subjects, reacted specifically with a 38 kd protein in all crustaceans and mollusks studied. In addition, 8 of 9 sera from patients, but from none of the normal control subjects, recognized proteins of various other molecular weights among the mollusk extracts studied. The 38 kd protein was identified as tropomyosin and was shown to share immunodominant epitopes among all species of crustaceans and mollusks tested by specific absorption studies. Moreover, sera from all nine subjects with shrimp allergy demonstrated IgE reactivities against grasshopper, cockroach, and fruit fly but not chicken or murine muscle. Conclusion: The allergic epitopes on tropomyosin are conserved among invertebrates including not only shellfish but also insects. This latter observation suggests that persons sensitive to shrimp should undergo further study for potential cross-reactive inhalant or ingested insect sensitivity. (J ALLERGY CLIN IMMUNOL 1996;98:954-61.)

Rationale Seafood is a major allergen in adults with food hypersensitivity in Japan. Recently seafood anaphylaxis is increasing in children. We measured serum specific IgE to salmon roe, Alaska Pollack roe, clam, oyster and scallop in children with seafood allergy to investigate sensitization to these allergens. Methods Forty-five patients, the average age 3.6 years, with seafood allergy are enrolled in the study. Those consist of 28 fish allergy, 26 shellfish allergy, 13 mollusks allergy and 5 fish roe allergy. Specific IgE antibodies to salmon roe, Alaska Pollack roe, clam, oyster and scallop were measured by UniCAP specific IgE kit. Results Forty-one patients with fish and/or shellfish allergy were divided into 3 groups; group1 (15 cases): fish only, group2 (13 cases): fish+shellfish, group3 (13 cases): shellfish only. Positive IgE to one or more mollusks were identified 85% in group 3, 56% in group 2 and 27% in group 1. One third of the 3 groups were positive IgE to one or both fish roe. Twelve patients had history of hypersensitivity to mollusks and 8 of these were positive IgE to all 3 mollusks tested. Three patients with anaphylaxis to salmon or Alaska Pollack roe had positive IgE (Score 3 ∼4) to both fish roes. Conclusions The results suggest that measurements of serum specific IgE to these seafood allergens are useful for diagnosis of fish roe and mollusks in patients with fish or shellfish allergy.

T U E S D A Y 911 Role Of Disulfide Bridges In The Proteolytic Susceptibility And Allergenicity Of Ara H 6, A Major Allergen From Peanut B. Guillon, S. Hazebrouck, K. Adel-Patient, E. Paty, P. Scheinmann, J. M. Wal, H. Bernard; INRA, Gif sur Yvette, FRANCE, Hopital Necker Enfants Malades, Paris, FRANCE. RATIONALE: Five disulfide (S-S) bridges stabilize the structure of Ara h 6. We investigated the impact of each S-S bridge on Ara h 6 susceptibility to pepsin and trypsin digestion and on its immunoreactivity. METHODS: Progressive deletion of the S-S bridges by substituting alanine for cysteine was performed on a recombinant Ara h 6. Proteolysis by pepsin and trypsin were followed using SDS-PAGE and the peptides produced during digestion were identified by mass spectrometry. Immunoreactivity of the recombinant proteins and their proteolytic fragments was assessed by IgE binding studies using sera from 5 peanut-allergic patients sensitized to Ara h 6. The capacity to induce the degranulation of humanized ratmast cells passively sensitized with human specific IgE was also evaluated. RESULTS: The recombinant Ara h 6 and the mutant lacking the C-terminal (C84-C124) S-S bridge exhibited identical structure to and the same immunoreactivity as the natural counterpart. The loss of an additional S-S bridge slightly decreased the protein immunoreactivity. However, the susceptibility to proteolysis was highly dependant on the S-S bridge deleted. Complete degradation of Ara h 6 by pepsin and trypsin occurred when the central S-S bridges (C26-C58 or C59-C107) were mutated, thus leading to a total loss of allergenicity after digestion. Immunoreactivity of Ara h 6 was conserved only when a heterodimeric structure, characteristic of the 2S albumin, was preserved after digestion. CONCLUSIONS: The central S-S bridges stabilize the protease-resistant coreofArah 6 andhave amajor role on its structure andbiological properties. 912 The Use of Epinephrine for the Treatment of Initial Allergic Reactions to Peanut M. Ben-Shoshan, L. Soller, R. Alizadehfar, J. Fragapane, L. Joseph, Y. St. Pierre, L. Harada, M. Allen, A. Clarke; McGill University Montreal Children Hospital, Montreal, QC, CANADA, Division of Pediatric Allergy and Clinical Immunology, Department of Pediatrics, McGill University Health Center, Montreal, Quebec, Canada, Montreal, QC, CANADA, Division of Clinical Epidemiology, Department of Medicine, McGill University Health Center, Montreal, QC, CANADA, Departments of Epidemiology and Biostatistics, McGill University, Montreal, QC, CANADA, Anaphylaxis Canada, Toronto, ON, CANADA, Allergy/Asthma Information Association, Toronto, ON, CANADA, Division of Allergy and Clinical Immunology, Department of Medicine, McGill University Health Center, Montreal, QC, CANADA. RATIONALE: To assess the use of epinephrine to treat initial allergic reactions to peanut in health care facilities (HCF). METHODS: Parents of children with an allergist-confirmed peanut allergy recruited from the Montreal Children’s Hospital and from PanCanadian food allergy advocacy associations were queried on the management of the initial allergic reactions. RESULTS: Six hundred twenty-nine individuals reported an initial allergic reaction to peanut. Median age of initial reaction was 1.6 years (IQR, 1.1, 2.6) and 46.1% (95% CI, 42.2, 50.1) were brought to HCFs. Epinephrine was administered to 23.1% (95% CI, 18.4, 28.4) of those brought to HCFs. Among those with moderate/severe reactions, 55.2% (95% CI, 50.5, 59.7) were brought to HCFs, and 24.9% (95% CI, 19.7, 30.7) of these received epinephrine. Epinephrine auto-injector (EAI) was prescribed in 58.0% (95% CI, 51.5, 64.3) of cases brought to HCF. Factors associated with epinephrine treatment in a HCF were the presence of a severe reaction [OR 3.26 (95% CI, 1.72, 6.15)] and a family history of atopy [OR 2.25 (95% CI, 1.20, 4.20)]. Factors associated with EAI prescription were use of epinephrine for the initial reaction: [OR 5.23 (95% CI, 2.39, 11.45)]; living in Quebec: [OR 2.55 (95%CI, 1.43, 4.56)] and calendar year of initial reaction [OR 1.09 95% CI 1.02, 1.16)]. CONCLUSIONS: Our results reveal underuse of epinephrine and low rates of EAI prescriptions in HCFs. Guidelines prompting epinephrine use and prescription to all individuals presenting with a likely allergic reaction to peanut are required. 913 Food Avoidance Following Physician Diagnosis Of Food Allergy: Results From A Canadian Study L. Soller, J. Fragapane, M. Ben-Shoshan, D. Harrington, R. Alizadehfar, L. Joseph, Y. St-Pierre, S. Godefroy, S. J. Elliott, A. E. Clarke; McGill University, Montreal, QC, CANADA, McMaster University, Hamilton, ON, CANADA, Health Canada, Ottawa, ON, CANADA, Waterloo University, Waterloo, ON, CANADA. RATIONALE: To identify predictors associated with avoidance of known allergens. METHODS: Individuals reporting physician-diagnosed allergy to peanut, tree-nut, fish, shellfish and/or sesame in a nationwide telephone survey conducted in 2008/9 were asked about avoidance of the food since diagnosis. Multivariate logistic regression performed to identify predictors (education, allergen, characteristics of most severe reaction) associated with avoidance. RESULTS:Of 10,596 households surveyed, 3666 responded, representing 9667 individuals, (35%) of which 208 (2.15% [95% CI, 1.86, 2.44]) reported at least one physician-diagnosed allergy to the above-mentioned foods. 202 of 208 (97%) provided sufficient information to be included in the analysis. Of these, individuals with an allergy to peanut/tree-nut/sesame were less likely to avoid compared to those with fish/shellfish (Odds Ratio (OR) 0.062 [95% CI, 0.025, 0.15]). Individuals who received epinephrine during their most severe reaction were more likely to avoid than those who did not (OR 4.51 [95% CI, 1.70, 12.0]). CONCLUSIONS: We hypothesize that those with fish/shellfish allergy are more able to avoid their known allergen as it is easily identifiable whereas many foods are labeled as containing trace amounts of peanut/ tree-nut/sesame and hence are more difficult to avoid. Those who received epinephrine presumably are better able to appreciate the potential severity of a subsequent reaction and hence were more diligent about avoidance. Given the unpredictability of allergic reactions to peanut/tree-nut/sesame, all allergic individuals, even thosewith a previousmild reaction, should receive education regarding importance of food avoidance. Additionally, food labels should be clearer so that allergic individuals can easily avoid foods containing peanut/tree-nut/sesame.

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.

Rationale To determine the prevalence of self-reported allergy to fish and shellfish in the US. Methods Nationwide, cross-sectional, random sample telephone survey using a standardized questionnaire and predetermined criteria to indicate seafood allergy. Results A total of 5,529 households completed the interview (participation rate 67%, census of 14,948 persons). Applying criteria for "report of convincing symptom histories" (e.g., typical allergic symptoms, timing with exposure, treatments) and/or physician-diagnosed allergy, the overall prevalence of seafood allergy was the following: fish (e.g., fin fish) 0.4%, shellfish (including crustaceae, mollusks, bivalves) 2.0%, both fish and shellfish, 0.2% (any seafood allergy-2.3% [95% CI, 2.0-2.5]). Allergy to some type of seafood was reported for 0.6% of children under age 18 years and 2.8% of adults. Report of a physician diagnosis was given by 50% with fish and 35% with shellfish allergy; in 28% of fish and 21% of shellfish allergy, the physician diagnosis included allergy tests (positive). Multiple reactions were reported by 53% for fish and 57% for shellfish allergy. Medical care was sought by 55% with fish (26% overall received epinephrine) and 40% with shellfish (15% received epinephrine) reactions. The most common offending foods were salmon, tuna and halibut among fish, and shrimp, crab and lobster among shellfish/bivalves/mollusks. Conclusions Self reported, physician diagnosed and/or convincing allergy to seafood is reported by 2.3% of the general population, or an estimated 6.5 million Americans.

IgE-antibody reactivity to oysters and crustacea of sera from six oyster-sensitive, seven oyster- and crustacea-sensitive, and 12 crustacea-sensitive subjects was investigated. All six subjects with a history of only oyster sensitivity had minimal RAST reactivity (ratios 2 to 5) to extracts of raw or boiled oysters. Three of the seven oyster- and crustacea-sensitive subjects and six of the 12 crustacea-sensitive, oyster-tolerant or unexposed subjects had elevated RAST ratios to oyster (14 to 41). Generally, elevated oyster RAST correlated with skin prick test reactivity to oyster but not with total serum IgE levels. The oyster RAST values of the 19 crustacea-sensitive subjects (with or without oyster sensitivity) correlated with crustacea RAST reactivity (crab RAST, most significant; shrimp RAST, least significant). Rabbit antisera to crustacea extracts detected precipitating antigens present in extracts of raw or boiled oysters. Significant inhibition of the oyster RAST was obtained with oyster or crustacea extracts. These studies suggest that in the diagnosis of oyster sensitivity the RAST may not be useful and that oyster and crustacea contain common antigenic structures.