Food allergy knowledge; attitudes; and beliefs in the United States
BACKGROUND: Members of the general public play a significant role in the well-being of food-allergic children; although little is known about the knowledge; attitudes; and beliefs of food allergy among the public. OBJECTIVE: To provide insight into food allergy knowledge and perceptions among the general US population. METHODS: A national sample of adults was recruited in February 2008 to complete the validated Web-based Chicago Food Allergy Research Survey for the General Public. Findings were analyzed to provide composite/itemized knowledge scores; describe attitudes and beliefs; and examine the effect of prior knowledge/familiarity with food allergy on knowledge; attitudes; and beliefs. RESULTS: A sample of 2;148 respondents was obtained. Participants answered 64.9% (range; 12.5%-100.0%) of knowledge-based items correctly. Strengths were identified in areas related to symptoms/severity and triggers/environmental risks of food allergy. Knowledge was poor concerning the distinction between food allergy and food intolerance; the absence of a cure; and current means to treat food allergy. Higher scores were significantly associated with self-report of prior knowledge/familiarity with food allergy; particularly among those with prior training in food allergy (median increase; 7.9%). Perceptions regarding food allergy were generally well distributed; although respondents tended to minimize the stigma associated with food allergy and to oppose specific food allergy policies in schools. CONCLUSIONS: Increased food allergy knowledge among the general public is needed. Improved public awareness of the challenges faced by food-allergic children may encourage adoption of standardized school policies to keep affected children safe. These efforts are critical for protecting young children with food allergy and avoiding life-threatening anaphylactic reactions.
Early consumption of peanuts in infancy is associated with a low prevalence of peanut allergy
BACKGROUND: Despite guidelines recommending avoidance of peanuts during infancy in the United Kingdom (UK); Australia; and; until recently; North America; peanut allergy (PA) continues to increase in these countries. OBJECTIVE: We sought to determine the prevalence of PA among Israeli and UK Jewish children and evaluate the relationship of PA to infant and maternal peanut consumption. METHODS: A clinically validated questionnaire determined the prevalence of PA among Jewish schoolchildren (5171 in the UK and 5615 in Israel). A second validated questionnaire assessed peanut consumption and weaning in Jewish infants (77 in the UK and 99 in Israel). RESULTS: The prevalence of PA in the UK was 1.85%; and the prevalence in Israel was 0.17% (P < .001). Despite accounting for atopy; the adjusted risk ratio for PA between countries was 9.8 (95% CI; 3.1-30.5) in primary school children. Peanut is introduced earlier and is eaten more frequently and in larger quantities in Israel than in the UK. The median monthly consumption of peanut in Israeli infants aged 8 to 14 months is 7.1 g of peanut protein; and it is 0 g in the UK (P < .001). The median number of times peanut is eaten per month was 8 in Israel and 0 in the UK (P < .0001). CONCLUSIONS: We demonstrate that Jewish children in the UK have a prevalence of PA that is 10-fold higher than that of Jewish children in Israel. This difference is not accounted for by differences in atopy; social class; genetic background; or peanut allergenicity. Israeli infants consume peanut in high quantities in the first year of life; whereas UK infants avoid peanuts. These findings raise the question of whether early introduction of peanut during infancy; rather than avoidance; will prevent the development of PA.
Advances in allergic skin disease; anaphylaxis; and hypersensitivity reactions to foods; drugs; and insects in 2008
This review highlights some of the research advances in anaphylaxis; and hypersensitivity reactions to foods; drugs; and insects and in allergic skin disease that were reported in the Journal in 2008. Key epidemiologic observations include a rise in anaphylaxis in a population-based study and lower rates of peanut allergy in Israel; where infants consume peanut early compared with the United Kingdom; where dietary introduction is generally delayed. Advances in food allergy diagnosis include IgE epitope mapping that discloses the likelihood and severity of allergy; studies correlating likelihood of clinical reactivity on the basis of food-specific IgE to sesame; peanut; milk; and tree nuts; and an observation that a low baseline angiotensin-converting enzyme level may be associated with having pharyngeal edema during a reaction. Molecular; immunologic; and genetic studies are discerning pathways that are key in development of food allergy; identifying new modalities to interrupt mast cell degranulation; and elucidating risks associated with penicillin allergy. Regarding treatment; clinical studies show a majority of children with milk and egg allergy tolerate these proteins in modest amounts when they are extensively heated in baked goods; and studies show promise for oral immunotherapy to treat milk allergy and sublingual immunotherapy for honey bee venom hypersensitivity. The importance of skin barrier dysfunction has continued to be highlighted in the pathophysiology of atopic dermatitis (AD). Research has also continued to identify immunologic defects that contribute to the propensity of patients with AD to develop viral and bacterial infection. New therapeutic approaches to AD; urticaria; and angioedema have been reported including use of probiotics; biologics; vitamin D; and skin barrier creams.
Successful oral tolerance induction in severe peanut allergy
Background: Peanut allergy is common; potentially severe and rarely resolves causing impaired quality of life. No disease-modifying treatment exists and there is therefore a need to develop a therapeutic intervention. Aims of the study: The aim of this study was to investigate whether peanut oral immunotherapy (OIT) can induce clinical tolerance to peanut protein. Methods: Four peanut-allergic children underwent OIT. Preintervention oral challenges were performed to confirm clinical allergy and define the amount of protein required to cause a reaction (dose thresholds). OIT was then administered as daily doses of peanut flour increasing from 5 to 800 mg of protein with 2-weekly dose increases. After 6 further weeks of treatment; the oral challenge was repeated to define change in dose threshold and subjects continued daily treatment. Results: Preintervention challenges confirmed peanut allergy and revealed dose thresholds of 5-50 mg (1/40-1/4 of a whole peanut); one subject had anaphylaxis during challenge and required adrenaline injection. All subjects tolerated immunotherapy updosing to 800 mg protein and i.m. adrenaline was not required. Each subject tolerated at least 10 whole peanuts (approximately 2.38 g protein) in postintervention challenges; an increase in dose threshold of at least 48-; 49-; 55- and 478-fold for the four subjects. Conclusions: We demonstrated a substantial increase in dose threshold after OIT in all subjects; including the subject with proven anaphylaxis. OIT was well tolerated and conferred protection against at least 10 peanuts; more than is likely to be encountered during accidental ingestion.
Clinical Features of Four Cases with Cashew Nut Allergy and Cross-Reactivity between Cashew Nut and Pistachio
Background: Few cases of cashew nut (CN) allergy have been reported in Japan. We evaluated the clinical features of 4 cases with CN allergy and investigated the allergens involved. Methods: In order to investigate the cross-reactivity between CN and pistachios; we performed ImmunoCAP inhibition tests using sera of 4 cases with positive histories of CN allergy and positive results of specific IgE measurement (ImmunoCAP) and skin prick tests. Furthermore; we analyzed the molecular weights of allergens of CN and pistachios by IgE-immunoblotting. Results: Of the 4 cases (male:female = 1:3); there were 3 cases (patient #2-4) and 1 case (patient #1) of anaphylaxis and oral allergy syndrome; respectively. The initial symptom was an oropharyngeal symptom in 3 of the 4 cases; of which 2 cases developed anaphylaxis within 10 minutes after eating only a few pieces of CN. All 4 cases reacted positively to the skin prick test with CN; although 1 case of anaphylaxis tested negatively for CN by ImmunoCAP. Additionally; in 2 cases; IgE-binding to CN and pistachio were inhibited with both pistachios and CN; indicating cross-reactivity between CN and pistachios. IgE-immunoblotting of CN using sera from the 4 cases revealed 2 bands at molecular weights of approximately 33 kd and 42 kd; whereas that of pistachios showed a single band at 36 kd. However; IgE in all 4 sera did not bind to rAna o 2. Conclusions: In CN allergy; a small amount of CN could induce a severe anaphylactic reaction. Moreover; in cases of suspected CN allergy; reactions to not only CN but also pistachio; which could be cross-reactive to CN; should be examined.
Effects of processing on immunoreactivity of cashew nut (Anacardium occidentale L.) seed flour proteins
Cashew nut seeds were subjected to processing including autoclaving (121 degrees C for 5; 10; 20; and 30 min); blanching (100 degrees C for 1; 4; 7; and 10 min); microwave heating (1 and 2 min each at 500 and 1000 W); dry roasting (140 degrees C for 20 and 30 min; 170 degrees C for 15 and 20 min; and 200 degrees C for 10 and 15 min); gamma-irradiation (1; 5; 10; and 25 kGy); and pH (1; 3; 5; 7; 9; 11; and 13). Proteins from unprocessed and processed cashew nut seeds were probed for stability using anti-Ana o 2 rabbit polyclonal antibodies and mouse monoclonal antibodies directed against Ana o 1; Ana o 2; and Ana o 3 as detection agents. Results indicate that Ana o 1; Ana o 2; and Ana o 3 are stable regardless of the processing method to which the nut seeds are subjected.
Tree nut and peanut consumption in relation to chronic and metabolic diseases including allergy
The New and Emerging Research session highlighted the emerging understanding of both the positive and negative effects of nuts consumption on health. The limited nature of both experimental and epidemiological evidence for positive relationship(s) between nut intake and health were noted. Study inconsistency and limitations; particularly survey methodology; were explored. Recent results from epidemiologic studies indicating a potential negative association between nut and seed intake and cancer risk were reviewed. The ability of walnuts to reduce endothelin suggests an interesting biochemical mechanism of nut action that may affect other endothelin-associated diseases; which should be further explored. The effects of nuts and their constituents on a nuclear receptor screen (PPARalpha; beta/delta; gamma; LXRalpha; beta; RXRalpha; beta; gamma; PXR; and FXR) have been explored. Nut allergenicity and approaches necessary to minimize this effect were also described. In contrast to the positive effects; nut allergies present tree nut-allergic consumers with health challenges. The Food Allergy and Anaphylaxis Network stressed the importance of ensuring that consumers with food allergies have legible; accurate food labels. The Food Allergen Labeling and Consumer Protection Act has engendered precautionary; worst-case allergen scenario labeling statements with unknown benefits to consumer health. Issues of cross-contamination due to shared equipment and shared facilities highlighted the need to rely on allergen control programs that use ELISA technology and have increased understanding of nut allergens. Ultimately; to maximize the positive benefits of nuts; the consumer must be provided with all the information required to make an informed choice.
Tree Nut and Peanut Consumption in Relation to Chronic and Metabolic Diseases Including Allergy
The New and Emerging Research session highlighted the emerging understanding of both the positive and negative effects of nuts consumption on health. The limited nature of both experimental and epidemiological evidence for positive relationship(s) between nut intake and health were noted. Study inconsistency and limitations; particularly survey methodology; were explored. Recent results from epidemiologic studies indicating a potential negative association between nut and seed intake and cancer risk were reviewed. The ability of walnuts to reduce endothelin suggests an interesting biochemical mechanism of nut action that may affect other endothelin-associated diseases; which should be further explored. The effects of nuts and their constituents on a nuclear receptor screen (PPAR{alpha}; Ã/{delta}; {gamma}; LXR{alpha}; Ã; RXR{alpha}; Ã; {gamma}; PXR; and FXR) have been explored. Nut allergenicity and approaches necessary to minimize this effect were also described. In contrast to the positive effects; nut allergies present tree nut-allergic consumers with health challenges. The Food Allergy and Anaphylaxis Network stressed the importance of ensuring that consumers with food allergies have legible; accurate food labels. The Food Allergen Labeling and Consumer Protection Act has engendered precautionary; worst-case allergen scenario labeling statements with unknown benefits to consumer health. Issues of cross-contamination due to shared equipment and shared facilities highlighted the need to rely on allergen control programs that use ELISA technology and have increased understanding of nut allergens. Ultimately; to maximize the positive benefits of nuts; the consumer must be provided with all the information required to make an informed choice.
In vivo and T Cell Cross-Reactivity between Walnut; Cashew and Peanut
Background: Examination of IgE cross-reactivity among nuts has been limited to in vitro experiments. Cross-reactivity studies of nuts at the T cell level are difficult to interpret because of the inability to determine which cellular responses are from a true sensitization and which are due to cross-reactivity. Using a mouse model in which the sensitizing nuts are controlled may provide novel methods to investigate in vivo and T cell cross-reactivity. Methods: C3H/HeJ mice were sensitized by intraperitoneal injection of cashew alone (monosensitized mice); or cashew plus walnut; utilizing alum as an adjuvant. Both groups underwent challenges to cashew; walnut and peanut; with subsequent monitoring of anaphylactic reactions. Anaphylactic antibodies were quantified by ELISA; and protein allergens were identified by Western blotting. Cellular responses were studied via splenocyte proliferation assay and measurement of secreted cytokines. Results: The monosensitized mice reacted to cashew and walnut during challenges; with significantly weaker reactions induced on challenge with peanut. Cross-reactive IgE to walnut and peanut were detected by ELISA; and the cross-reactive allergens were identified as vicilin proteins. In cellular assays; splenocytes from the monosensitized mice proliferated and produced IL-4 and IL-5 in response to cashew; walnut and peanut. The cashew- plus walnut-sensitized mice experienced stronger clinical reactions to walnut; recognized additional walnut allergens and secreted significantly more IL-4 and IL-5 in walnut-stimulated splenocyte assays compared to the monosensitized mice. Conclusions: Cross-reactivity in vivo was found between cashew and walnut; while cross-reactivity among cashew; walnut and peanut was demonstrated at the T cell level.