Peanut allergy: Emerging concepts and approaches for an apparent epidemic

Loss-of-function variants in the filaggrin gene are a significant risk factor for peanut allergy

BACKGROUND

IgE-mediated peanut allergy is a complex trait with strong heritability, but its genetic basis is currently unknown. Loss-of-function mutations within the filaggrin gene are associated with atopic dermatitis and other atopic diseases; therefore, filaggrin is a candidate gene in the etiology of peanut allergy.

OBJECTIVE

To investigate the association between filaggrin loss-of-function mutations and peanut allergy.

METHODS

Case-control study of 71 English, Dutch, and Irish oral food challenge-positive patients with peanut allergy and 1000 non peanut-sensitized English population controls. Replication was tested in 390 white Canadian patients with peanut allergy (defined by food challenge, or clinical history and skin prick test wheal to peanut ≥ 8 mm and/or peanut-specific IgE ≥ 15 kUL(-1)) and 891 white Canadian population controls. The most prevalent filaggrin loss-of-function mutations were assayed in each population: R501X and 2282del4 in the Europeans, and R501X, 2282del4, R2447X, and S3247X in the Canadians. The Fisher exact test and logistic regression were used to test for association; covariate analysis controlled for coexistent atopic dermatitis.

RESULTS

Filaggrin loss-of-function mutations showed a strong and significant association with peanut allergy in the food challenge-positive patients (P = 3.0 × 10(-6); odds ratio, 5.3; 95% CI, 2.8-10.2), and this association was replicated in the Canadian study (P = 5.4 × 10(-5); odds ratio, 1.9; 95% CI, 1.4-2.6). The association of filaggrin mutations with peanut allergy remains significant (P = .0008) after controlling for coexistent atopic dermatitis.

CONCLUSION

Filaggrin mutations represent a significant risk factor for IgE-mediated peanut allergy, indicating a role for epithelial barrier dysfunction in the pathogenesis of this disease.

Clinical practice: Allergen-specific immunotherapy in children: facts and FAQs

Allergen-specific immunotherapy (SIT) in its various application forms represents the main treatment approach of IgE-mediated allergic diseases in adults and children. Despite this clear recommendation, many particularities of products, patient characteristics, and product availability in different countries hamper the use of allergen-specific immunotherapy in particular in children. The frequently asked questions by parents, patients, and physicians are the backbone of this review. Thus, the potentials and limitations of allergen-specific immunotherapy in children and adolescents will be highlighted. IgE-mediated allergic diseases are affecting about 20% of the population. They manifest commonly early in life, and hence, the use of SIT should be considered also early in the course of the disease.

Enzymatic treatment of peanut kernels to reduce allergen levels

This study investigated the use of enzymatic treatment to reduce peanut allergens in peanut kernels as affected by processing conditions. Two major peanut allergens, Ara h 1 and Ara h 2, were used as indicators of process effectiveness. Enzymatic treatment effectively reduced Ara h 1 and Ara h 2 in roasted peanut kernels by up to 100% under optimal conditions. For instance, treatment of roasted peanut kernels with α-chymotrypsin and trypsin for 1-3h significantly increased the solubility of peanut protein while reducing Ara h 1 and Ara h 2 in peanut kernel extracts by 100% and 98%, respectively, based on ELISA readings. Ara h 1 and Ara h 2 levels in peanut protein extracts were inversely correlated with protein solubility in roasted peanut. Blanching of kernels enhanced the effectiveness of enzyme treatment in roasted peanuts but not in raw peanuts. The optimal concentration of enzyme was determined by response surface to be in the range of 0.1-0.2%. No consistent results were obtained for raw peanut kernels since Ara h 1 and Ara h 2 increased in peanut protein extracts under some treatment conditions and decreased in others.

Epidemiology of food allergy

Adverse reactions to foods can occur for a variety of reasons, but a food allergy is caused by a specific immune response. Challenges to determine the prevalence of food allergy include misclassification, biased participation, lack of simple diagnostic tests, rapid evolution of disease, large numbers of potential triggers, and varied clinical phenotypes. Nonetheless, it is clear that this is a common disorder, with studies suggesting a cumulative prevalence of 3% to 6%, representing a significant impact on quality of life and costs. The inclusion of mild reactions to fruits and vegetables could result in calculation of prevalence exceeding 10% in some regions. There are data from numerous studies to suggest an increase in prevalence, but methodologic concerns warrant caution. Prevalence varies by age, geographic location, and possibly race/ethnicity. Many childhood food allergies resolve. Population-based epidemiologic studies have generated numerous novel theories regarding risks, including modifiable factors such as components of the maternal and infant diet, obesity, and the timing of food introduction. Recent and ongoing studies provide insights on risk factors, prevalence, and natural course that may inform clinical trials to improve diagnosis, prevention, and treatment.

Vaccine approaches for food allergy

The prevalence of food allergy appears to be increasing. Hypersensitivity reactions to foods account for significant morbidity and mortality. The current standard of care for treatment of food allergies is limited to diligent dietary avoidance and prompt pharmacotherapy should an unexpected ingestion result in a reaction. Complex interactions between dietary antigens, the gastrointestinal flora, and the gut associated mucosal system drive host immune responses towards oral tolerance or hypersensitivity. Oral tolerance is achieved by regulatory T cell suppression of immune responses and by clonal anergy. Many novel therapies to treat food allergies are currently under investigation. Most utilize antigen-specific strategies in an attempt to induce oral tolerance. Oral immunotherapy (OIT) has been the focus of much attention. Early studies had established the safety and efficacy of OIT, but its ability to induce long-term tolerance versus a state of desensitization remains to be firmly established. Nevertheless, recent advances in our understanding of oral tolerance induction has increased optimism that disease-modifying therapies for food allergies will soon be the standard of care.

Illustrating risk: anaphylaxis through the eyes of the food-allergic child

The risk perception research is widely focused on children as targets of risk. To date, very few studies have consulted with the impacted group to assess the perceptions of risk associated with the exposures of interest. Much less research has investigated the experiences of children at risk for anaphylaxis, their concerns, and the psychosocial stresses associated with risk. The present study explores the perceptions and experiences of Ontario students with anaphylaxis, and their parents regarding school as a safe place in order to inform school policy around risk management and coping. A "child-centered" analytical framework incorporating illustrative techniques within interpretative analysis is outlined. Five prominent themes: (a) social and environmental barriers to safety, (b) coping strategies, (c) emotional burden of responsibility, (d) balance of responsibility (transitions), and (e) redefining "normal" are discussed. Results found that "child-centered" techniques empowered children in a process that is meaningful and relevant to their lives. A preliminary framework for understanding what risk means to children highlighted the differences in how they cope in the public sphere of school.

Management of food allergy in the school setting

Food allergy is estimated to affect approximately 1 in 25 school-aged children and is the most common trigger of anaphylaxis in this age group. School food-allergy management requires strategies to reduce the risk of ingestion of the allergen as well as procedures to recognize and treat allergic reactions and anaphylaxis. The role of the pediatrician or pediatric health care provider may include diagnosing and documenting a potentially life-threatening food allergy, prescribing self-injectable epinephrine, helping the child learn how to store and use the medication in a responsible manner, educating the parents of their responsibility to implement prevention strategies within and outside the home environment, and working with families, schools, and students in developing written plans to reduce the risk of anaphylaxis and to implement emergency treatment in the event of a reaction. This clinical report highlights the role of the pediatrician and pediatric health care provider in managing students with food allergies.

Peanut allergy: Clinical and immunologic differences among patients from 3 different geographic regions

BACKGROUND

Peanut allergy affects persons from various geographic regions where populations are exposed to different dietary habits and environmental pollens.

OBJECTIVE

We sought to describe the clinical and immunologic characteristics of patients with peanut allergy from 3 countries (Spain, the United States, and Sweden) using a molecular component diagnostic approach.

METHODS

Patients with peanut allergy from Madrid (Spain, n = 50), New York (United States, n = 30), Gothenburg, and Stockholm (both Sweden, n = 35) were enrolled. Clinical data were obtained either from a specific questionnaire or gathered from chart reviews. IgE antibodies to peanut extract and the peanut allergens rAra h 1, 2, 3, 8 and 9, as well as to cross-reactive birch (rBet v 1) and grass (rPhl p 1, 5, 7, and 12) pollen allergens, were analyzed.

RESULTS

American patients frequently had IgE antibodies to rAra h 1 to 3 (56.7% to 90.0%) and often presented with severe symptoms. Spanish patients recognized these 3 recombinant peanut allergens less frequently (16.0% to 42.0%), were more often sensitized to the lipid transfer protein rAra h 9 (60.0%), and typically had peanut allergy after becoming allergic to other plant-derived foods. Swedish patients detected rAra h 1 to 3 more frequently than Spanish patients (37.1% to 74.3%) and had the highest sensitization rate to the Bet v 1 homologue rAra h 8 (65.7%), as well as to rBet v 1 (82.9%). Spanish and Swedish patients became allergic to peanut at 2 years or later, whereas the American children became allergic around 1 year of age.

CONCLUSIONS

Peanut allergy has different clinical and immunologic patterns in different areas of the world. Allergen component diagnostics might help us to better understand this complex entity.

Skin prick testing does not reflect the presence of IgE against food allergens in adult eosinophilic esophagitis patients: a case study

Skin prick testing is widely used to predict the presence of allergen-specific IgE. In eosinophilic esophagitis patients, who frequently exhibit polysensitization and broad reactivity upon skin prick testing, this is commonly used to aid avoidance recommendations in the clinical management of their disease. We present here the predictive value of skin prick testing for the presence of allergen-specific IgE, in 12 patients, determined by immunoblot against the allergen extracts using individual-matched serum. Our results demonstrate a high degree of predictive value for aeroallergens but a poor predictive value for food allergens. This suggests that skin prick testing likely identifies IgE reactivity towards aeroallergens in adult eosinophilic esophagitis but this is not true for foods. Consequently, IgE immunoblotting might be required for determining food avoidance in these patients.

Maternal consumption of peanut during pregnancy is associated with peanut sensitization in atopic infants

BACKGROUND

Peanut allergy is typically severe, lifelong, and prevalent.

OBJECTIVE

To identify factors associated with peanut sensitization.

METHODS

We evaluated 503 infants 3 to 15 months of age (mean, 9.4 months) with likely milk or egg allergy but no previous diagnosis of peanut allergy. A total of 308 had experienced an immediate allergic reaction to cow's milk and/or egg, and 204 had moderate to severe atopic dermatitis and a positive allergy test to milk and/or egg. A peanut IgE level ≥5 kU(A)/L was considered likely indicative of peanut allergy.

RESULTS

A total of 140 (27.8%) infants had peanut IgE levels ≥5 kU(A)/L. Multivariate analysis including clinical, laboratory, and demographic variables showed frequent peanut consumption during pregnancy (odds ratio, 2.9; 95% CI, 1.7-4.9; P < .001), IgE levels to milk (P = .001) and egg (P < .001), male sex (P = .02), and nonwhite race (P = .02) to be the primary factors associated with peanut IgE ≥5 kUA/L. Frequency of peanut consumption during pregnancy and breast-feeding showed a dose-response association with peanut IgE ≥5 kU(A)/L, but only consumption during pregnancy was a significant predictor. Among 71 infants never breast-fed, frequent consumption of peanut during pregnancy was strongly associated with peanut IgE ≥5 kU(A)/L (odds ratio, 4.99, 95% CI, 1.69-14.74; P < .004).

CONCLUSION

In this cohort of infants with likely milk or egg allergy, maternal ingestion of peanut during pregnancy was strongly associated with a high level of peanut sensitization.

Peanut allergy

PURPOSE OF REVIEW

To highlight recent advances in management of peanut allergy.

RECENT FINDINGS

Peanut allergy presents during early childhood. The prevalence of peanut allergy in children in developed countries appears to be increasing. Several factors, such as peanut-specific or environmental, are hypothesized as contributing to increased prevalence. However, there is no consensus on this matter. Component-related diagnostic tests are being explored to characterize clinical sensitivity. Currently, the primary treatment includes avoidance of peanut and immediate treatment of anaphylaxis. Recent peanut oral immunotherapy (OIT) trials achieved successful desensitization to peanuts in study participants, which may benefit many patients. Newer prospective studies are exploring effects of early high-dose peanut protein introduction versus avoidance in high-risk infants and development of peanut tolerance [Learning Early About Peanut Allergy (LEAP) study]. Several other immunotherapeutic approaches are being investigated in animal models.

SUMMARY

There is no cure for peanut allergy. Peanut oral immunotherapy offers a potential treatment for desensitization.

IgE-mediated facilitated antigen presentation underlies higher immune responses in peanut allergy

BACKGROUND

Peanut allergy poses significant healthcare problems, because its prevalence is increasing in many countries, and it is rarely outgrown. To explore the immunological mechanisms that underlie peanut allergy and tolerance, we compared the peanut-specific responses of peanut-allergic (PA) and nonallergic (NA) individuals.

METHODS

We measured peanut-specific peripheral blood mononuclear cells (PBMC) proliferation using tritiated thymidine. The frequency of peanut-specific T cells amongst PBMC was determined by carboxyfluorescein succinimidyl ester labelling. The role of IgE-dependent facilitated antigen presentation (FAP) in modulating proliferation was investigated by depleting IgE from plasma with anti-IgE-coated beads and then assessing PBMC proliferation in the presence of IgE-depleted or nondepleted plasma.

RESULTS

We found that peanut-specific PBMC proliferation is higher and peaks earlier in PA than in NA donors. We investigated the immunological mechanisms that could underlie these differences. We found that both PA and NA have memory responses to peanut, but the frequency of peanut-specific T cells is higher in PA than in NA. Facilitated antigen presentation could cause both the higher proliferation and precursor frequency in PA. Facilitated antigen presentation activity in vitro was confirmed by showing that IgE depletion decreases proliferation, while adding IgE back restores it.

CONCLUSION

Our results identify FAP as a mechanism that underlies higher responses to peanut in PA. In these individuals, high levels of peanut-specific IgE could furthermore maintain long-term allergic T-cell responses. We raise the question whether, in the future, therapies targeting IgE such as anti-IgE antibodies may be used to suppress these T-cell responses.

Peanut-allergic subjects and their peanut-tolerant siblings have large differences in peanut-specific IgG that are independent of HLA class II

We enrolled 53 peanut-allergic subjects and 64 peanut-tolerant full siblings, measured peanut-specific IgG and IgE, determined HLA class II at high resolution, and analyzed DRB1 alleles by supertypes. Peanut-specific IgG and IgE were elevated in the peanut-allergic subjects (p<0.0001) but did not stratify with HLA alleles, haplotypes, or supertypes. There were no significant differences in HLA class II between the peanut-allergic and peanut-tolerant siblings but there was an increased frequency of DRB1*0803 in both sets of siblings compared to unrelated controls (p(c)=4.5×10⁻⁹). Furthermore, we identified 14 sibling pairs in which the peanut-allergic and the peanut-tolerant siblings have identical HLA class II and again found an elevation of anti-peanut IgG in the peanut-allergic subjects (p<0.0001). In conclusion, although DRB1*0803 may identify a subset of families with increased risk of peanut allergy, differences in peanut-specific immunoglobulin production between peanut-allergic subjects and their peanut-tolerant siblings are independent of HLA class II.

A population-based questionnaire survey on the prevalence of peanut, tree nut, and shellfish allergy in 2 Asian populations

BACKGROUND

There has been a substantial increase in the prevalence of peanut and tree nut allergy in Western populations in the last 2 decades. However, there is an impression that peanut and tree nut allergy is relatively uncommon in Asia.

OBJECTIVE

To evaluate the prevalence of peanut, tree nut, and shellfish allergy in schoolchildren in 2 Asian countries (Singapore and Philippines).

METHODS

A structured written questionnaire was administered to local and expatriate Singapore (4-6 and 14-16 years old) and Philippine (14-16 years old) schoolchildren.

RESULTS

A total of 25,692 schoolchildren responded to the survey (response rate, 74.2%). Of these, 23,425 responses fell within the study protocol's 4 to 6 and 14 to 16 year age groups and were included in the analysis. The prevalence of convincing peanut and tree nut allergy were similar in both local Singapore (4-6 years, 0.64%, 0.28%; 14-16 years, 0.47%, 0.3%, respectively) and Philippine (14-16, 0.43%, 0.33%, respectively) schoolchildren, but was higher in the Singapore expatriates (4-6 years, 1.29%, 1.12%; 14-16 years, both 1.21%, respectively; 4-6 years, expatriates vs local Singaporeans: peanut, P = .019; tree nut, P = .0017; 14-16 years, P > .05). Conversely, shellfish allergy was more common in the local Singapore (4-6 years, 1.19%; 14-16 years, 5.23%) and Philippine (14-16 years, 5.12%) schoolchildren compared with expatriate children (4-6 years, 0.55%; 14-16 years, 0.96%; P < .001). When data were pooled, respondents born in Western countries were at higher risk of peanut (adjusted odds ratios [95% CIs]: 4-6 years, 3.47 [1.35-8.93]; 14-16 years, 5.56 [1.74-17.76]) and tree nut allergy (adjusted odds ratios [95% CIs]: 4-6 years, 10.40 [1.61-67.36]; 14-16 years, 3.53 [1.00-12.43]) compared with those born in Asia.

CONCLUSION

This study substantiates the notion that peanut and tree nut allergy is relatively low in Asian children, and instead shellfish allergy predominates. Environmental factors that are yet to be defined are likely to contribute to these differences.

Immunologic features of infants with milk or egg allergy enrolled in an observational study (Consortium of Food Allergy Research) of food allergy

BACKGROUND

Immune features of infants with food allergy have not been delineated.

OBJECTIVES

We sought to explore the basic mechanisms responsible for food allergy and identify biomarkers, such as skin prick test (SPT) responses, food-specific IgE levels, and mononuclear cell responses, in a cohort of infants with likely milk/egg allergy at increased risk of peanut allergy.

METHODS

Infants aged 3 to 15 months were enrolled with a positive SPT response to milk or egg and either a corresponding convincing clinical history of allergy to milk or egg or moderate-to-severe atopic dermatitis. Infants with known peanut allergy were excluded.

RESULTS

Overall, 512 infants (67% male) were studied, with 308 (60%) having a history of a clinical reaction. Skin test responses, detectable food-specific IgE, or both revealed sensitization as follows: milk, 78%; egg, 89%; and peanut, 69%. SPT responses and food-specific IgE levels were discrepant for peanut (15% for IgE > or = 0.35 kU(A)/L and negative SPT response vs 8% for positive SPT response and IgE <0.35 kU(A)/L, P = .001). Mononuclear cell allergen stimulation screening for CD25, cytokine-inducible SH2-containing protein (CISH), forkhead box protein 3 (FOXP3), GATA3, IL10, IL4, IFNG, and T-box transcription factor (TBET) expression by using casein, egg white, and peanut revealed that only allergen-induced IL4 expression was significantly increased in those with clinical allergy to milk (compared with nonallergic subjects) and in those sensitized to peanut, despite the absence of an increase in GATA3 mRNA expression.

CONCLUSIONS

Infants with likely milk/egg allergy are at considerably high risk of having increased peanut-specific IgE levels (potential allergy). Peanut-specific serum IgE levels were a more sensitive indicator of sensitization than SPT responses. Allergen-specific IL4 expression might be a marker of allergic risk. Absence of an increase in GATA3 mRNA expression suggests that allergen-specific IL-4 might not be of T-cell origin.

What do asthmatics have to fear from food and additive allergy?

International studies report marked increases in the prevalence of food allergy, along with increases in hospital admissions and emergency presentations for severe allergic reactions due to foods. The prevalence of self-reported food allergy is common, but generally exceeds that which can be verified from challenge studies, although nut allergies appear to be an important exception to this rule. Studies examining food allergy deaths suggest that those who die of food allergy usually have co-existent asthma. Adolescents and young adults are at most risk, and adrenaline auto-injectors are sub-optimally used. Food chemical sensitivity is very commonly reported but not usually verified by challenge testing. However, the exception to this is sulphite sensitivity, which can elicit reproducible reactions in some. The increasing prevalence of severe food allergies and awareness of its risk in those with asthma demands an especially rigorous approach to the diagnosis and management of co-existent food allergy and asthma, especially in young people who appear to be at most risk from death from severe food allergy.

US prevalence of self-reported peanut, tree nut, and sesame allergy: 11-year follow-up

BACKGROUND

Allergy to peanuts and tree nuts (TNs) is the leading cause of fatal allergic reactions in the United States, and the prevalence appears to be increasing.

OBJECTIVES

We sought to determine the US prevalence of self-reported peanut, TN, and sesame allergy in 2008 and compare results with comparable surveys conducted in 1997 and 2002.

METHODS

A nationwide, cross-sectional, random telephone survey for peanut and TN allergy was conducted with a previously used questionnaire, with additional questions about sesame.

RESULTS

A total of 5,300 households (13,534 subjects) were surveyed (participation rate, 42% vs 52% in 2002 and 67% in 1997). Peanut allergy, TN allergy, or both was reported by 1.4% of subjects (95% CI, 1.2% to 1.6%) compared with 1.2% in 2002 and 1.4% in 1997. For adults, the prevalence was 1.3% (95% CI, 1.1% to 1.6%), which was not significantly different from prior surveys. However, the prevalence of peanut or TN allergy for children younger than 18 years was 2.1% (95% CI, 1.6% to 2.7%) compared with 1.2% in 2002 (P = .007) and 0.6% in 1997 (P < .001). The prevalence of peanut allergy in children in 2008 was 1.4% (95% CI, 1.0% to 1.9%) compared with 0.8% in 2002 (P = not significant) and 0.4% in 1997 (P < .0001). The prevalence of childhood TN allergy increased significantly across the survey waves (1.1% in 2008, 0.5% in 2002, and 0.2% in 1997). Sesame allergy was reported by 0.1% (95% CI, 0.0% to 0.2%).

CONCLUSIONS

Although caution is required in comparing surveys, peanut allergy, TN allergy, or both continue to be reported by more than 1% of the US population (eg, >3 million subjects) and appear to be increasingly reported among children over the past decade. Sesame allergy is reported much less commonly.

Therapeutic approaches for the treatment of food allergy

Food allergy is a life-changing and potentially life-threatening diagnosis, affecting approximately 6% of children and 4% of adults in the United States. A small number of foods account for the vast majority of food allergies, and the reactions after ingestion of a food to which a person is allergic are varied. At present, the standard of care for food-allergic patients is strict avoidance along with immediate access to self-injectable epinephrine and antihistamines. New treatment options are on the horizon. This review discusses the current research in the field of food allergy. Remarkable progress in the field of food allergy treatment demonstrates promise for disease-modifying therapies to be available clinically in the near future.

The EuroPrevall-INCO surveys on the prevalence of food allergies in children from China, India and Russia: the study methodology

BACKGROUND

Very little is known regarding the global variations in the prevalence of food allergies. The EuroPrevall-INCO project has been developed to evaluate the prevalence of food allergies in China, India and Russia using the standardized methodology of the EuroPrevall protocol used for studies in the European Union. The epidemiological surveys of the project were designed to estimate variations in the prevalence of food allergy and exposure to known or suspected risk factors for food allergy and to compare the data with different European countries.

METHODS

Random samples of primary schoolchildren were recruited from urban and rural regions of China, Russia and India for screening to ascertain possible adverse reactions to foods. Cases and controls were then selected to answer a detailed questionnaire designed to evaluate the possible risk factors of food allergies. Objective evidence of sensitisation including skin-prick test and serum specific IgE measurement was also collected.

RESULTS

More than 37 000 children from the three participating countries have been screened. The response rates for the screening phase ranged from 83% to 95%. More than 3000 cases and controls were studied in the second phase of the study. Further confirmation of food allergies by double blind food challenge was conducted.

CONCLUSIONS

This will be the first comparative study of the epidemiology of food allergies in China, India, and Russia using the same standardized methodology. The findings of these surveys will complement the data obtained from Europe and provide insights into the development of food allergy.

Allergy or tolerance in children sensitized to peanut: prevalence and differentiation using component-resolved diagnostics

BACKGROUND

Not all peanut-sensitized children develop allergic reactions on exposure.

OBJECTIVE

To establish by oral food challenge the proportion of children with clinical peanut allergy among those considered peanut-sensitized by using skin prick tests and/or IgE measurement, and to investigate whether component-resolved diagnostics using microarray could differentiate peanut allergy from tolerance.

METHODS

Within a population-based birth cohort, we ascertained peanut sensitization by skin tests and IgE measurement at age 8 years. Among sensitized children, we determined peanut allergy versus tolerance by oral food challenges. We used open challenge among children consuming peanuts (n = 45); others underwent double-blind placebo-controlled challenge (n = 34). We compared sensitization profiles between children with peanut allergy and peanut-tolerant children by using a microarray with 12 pure components (major peanut and potentially cross-reactive components, including grass allergens).

RESULTS

Of 933 children, 110 (11.8%) were peanut-sensitized. Nineteen were not challenged (17 no consent). Twelve with a convincing history of reactions on exposure, IgE > or =15 kUa/L and/or skin test > or =8mm were considered allergic without challenge. Of the remaining 79 children who underwent challenge, 7 had > or =2 objective signs and were designated as having peanut allergy. We estimated the prevalence of clinical peanut allergy among sensitized subjects as 22.4% (95% CI, 14.8% to 32.3%). By using component-resolved diagnostics, we detected marked differences in the pattern of component recognition between children with peanut allergy (n = 29; group enriched with 12 children with allergy) and peanut-tolerant children (n = 52). The peanut component Ara h 2 was the most important predictor of clinical allergy.

CONCLUSION

The majority of children considered peanut-sensitized on the basis of standard tests do not have peanut allergy. Component-resolved diagnostics may facilitate the diagnosis of peanut allergy.

Multiple T cell epitope peptides suppress allergic responses in an egg allergy mouse model by the elicitation of forkhead box transcription factor 3- and transforming growth factor-beta-associated mechanisms

BACKGROUND

Peptide-based immunotherapy (PIT) represents an attractive approach for targeted interventions in immunological disorders, but has not been widely explored in the context of food allergy.

OBJECTIVE

In this study, we built on the information obtained from the recent identification of three immunodominant T cell epitopes of hen ovalbumin (OVA), a major egg allergen, to assess the therapeutic potential of PIT for food allergy, using the BALB/c mouse model.

METHODS

Groups of mice were sensitized to OVA by repeated oral gavages, and subsequently administered with single or multiple synthetic peptides containing OVA T cell epitopes. Following the peptide administration period, all mice were orally challenged with high doses of OVA to elicit active anaphylaxis. Serum, spleen, and intestinal tissues were collected for the determination of immunoglobulin levels, cytokine secretions, and intestinal gene expression.

RESULTS

Significantly lower anaphylactic scores were exhibited by mice that received multiple epitope-containing peptides, accompanied by lower serum histamine and OVA-specific IgE levels, compared with placebo-treated mice. Mechanistically, the quantification of cytokine secretions in splenocyte cultures revealed a T helper type 1-biased response (IFN-gamma) in all peptide-treated mice to the detriment of a T helper type 2-response (IL-4). Interestingly, a similar cytokine expression profile was determined in intestinal tissues, accompanied by a pronounced mRNA expression of regulatory molecules TGF-beta and forkhead box transcription factor 3 (FOXP3). These data suggest the activation of local repressive mechanisms mediated by subsets of regulatory T cells.

CONCLUSION

We demonstrated the therapeutic potential of PIT in a mouse model of food allergy model and provided evidence that mechanistic pathways entailing regulatory molecules TGF-beta and FOXP3, stand as promising trails for the further understanding of peptide-based strategies for food allergy.

Food allergy

Adverse immune responses to foods affect approximately 5% of young children and 3% to 4% of adults in westernized countries and appear to have increased in prevalence. Food-induced allergic reactions are responsible for a variety of symptoms and disorders involving the skin and gastrointestinal and respiratory tracts and can be attributed to IgE-mediated and non-IgE-mediated (cellular) mechanisms. Genetic disposition and environmental factors might abrogate oral tolerance, leading to food allergy. Disease outcomes are influenced by the characteristics of the immune response and of the triggering allergen. Diagnosis is complicated by the observation that detection of food-specific IgE (sensitization) does not necessarily indicate clinical allergy. Therefore diagnosis requires a careful medical history, laboratory studies, and, in many cases, an oral food challenge to confirm a diagnosis. Novel diagnostic methods, including ones that focus on immune responses to specific food proteins or epitopes of specific proteins, are under study. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and to initiate therapy (eg, with injected epinephrine for anaphylaxis) in case of an unintended ingestion. Improved therapeutic strategies under study include oral and sublingual immunotherapy, Chinese herbal medicine, anti-IgE antibodies, and modified vaccines.

Food allergy among children in the United States

OBJECTIVES

The goals were to estimate the prevalence of food allergy and to describe trends in food allergy prevalence and health care use among US children.

METHODS

A cross-sectional survey of data on food allergy among children <18 years of age, as reported in the 1997-2007 National Health Interview Survey, 2005-2006 National Health and Nutrition Examination Survey, 1993-2006 National Hospital Ambulatory Medical Care Survey and National Ambulatory Medical Care Survey, and 1998-2006 National Hospital Discharge Survey, was performed. Reported food allergies, serum immunoglobulin E antibody levels for specific foods, ambulatory care visits, and hospitalizations were assessed.

RESULTS

In 2007, 3.9% of US children <18 years of age had reported food allergy. The prevalence of reported food allergy increased 18% (z = 3.4; P < .01) from 1997 through 2007. In 2005-2006, serum immunoglobulin E antibodies to peanut were detectable for an estimated 9% of US children. Ambulatory care visits tripled between 1993 and 2006 (P < .01). From 2003 through 2006, an estimated average of 317000 food allergy-related, ambulatory care visits per year (95% confidence interval: 195000-438000 visits per year) to emergency and outpatient departments and physician's offices were reported. Hospitalizations with any recorded diagnoses related to food allergy also increased between 1998-2000 and 2004-2006, from an average of 2600 discharges per year to 9500 discharges per year (z = 3.4; P < .01), possibly because of increased use of food allergy V codes.

CONCLUSION

Several national health surveys indicate that food allergy prevalence and/or awareness has increased among US children in recent years.

Maternal peanut exposure during pregnancy and lactation reduces peanut allergy risk in offspring

BACKGROUND

Maternal allergy is believed to be a risk factor for peanut allergy (PNA) in children. However, there is no direct evidence of maternal transmission of PNA susceptibility, and it is unknown whether maternal peanut exposure affects the development of PNA in offspring.

OBJECTIVE

To investigate the influence of maternal PNA on offspring reactions to the first peanut exposure, and whether maternal low-dose peanut exposure during pregnancy and lactation influences these reactions and peanut sensitization in a murine model.

METHODS

Five-week-old offspring of PNA C3H/HeJ mothers (PNA-Ms) were challenged intragastrically with peanut (first exposure), and reactions were determined. In a subset of the experiment, PNA-Ms were fed a low dose of peanut (PNA-M/PN) or not fed peanut (PNA-M/none) during pregnancy and lactation. Their 5-week-old offspring were challenged intragastrically with peanut, and reactions were determined. In another subset of the experiment, offspring of PNA-M/PN or PNA-M/none were sensitized with peanut intragastrically for 6 weeks, and serum peanut-specific antibodies were determined.

RESULTS

PNA-M offspring exhibited anaphylactic reactions at first exposure to peanut that were associated with peanut-specific IgG(1) levels and prevented by a platelet activation factor antagonist. In a subset experiment, PNA-M/PN offspring showed significantly reduced first-exposure peanut reactions, increased IgG(2a), and reduced mitogen-stimulated splenocyte cytokine production compared with PNA-M/none offspring. In an additional experiment, PNA-M/PN offspring showed reduction of peanut-specific IgE to active peanut sensitization.

CONCLUSION

We show for the first time maternal transmission of susceptibility to first-exposure peanut reactions and active peanut sensitization. Low-dose peanut exposure during pregnancy and lactation reduced this risk.

Allergic status of schoolchildren with food allergy to eggs, milk or wheat in infancy

Although children allergic to eggs, milk or wheat in infancy tend to become tolerant by school age, the allergic status of these children at school age has not been well evaluated. To investigate the allergic status of schoolchildren who avoided eggs, milk or wheat because of an immediate-type allergic reaction at <1-yr-old (food avoiders in infancy), we conducted a large-scale questionnaire-based survey of schoolchildren. A questionnaire on allergic diseases was distributed to the parents of 14,669 schoolchildren aged 7 to 15 yr in 30 schools in Kyoto, Japan. Of these, 13,215 responded (response rate, 90.1%). The rate of 7-yr-old children who were food avoiders in infancy was 5.4%. This rate decreased as the current age of the children increased, down to 3% in 15-yr-old children, indicating that food allergy in infancy tended to become more prevalent over the past 8 yr. Although more than 80% became tolerant to these foods by school age, the prevalence of bronchial asthma, atopic dermatitis, allergic rhinitis and allergic conjunctivitis were significantly higher in this group. Moreover, avoidance of other foods (buckwheat, shellfish, fruits and others) at school age was seen at much higher frequencies than in non-food avoiders in infancy (adjusted odds ratio, 7.7; confidence interval, 5.9-10.2). This risk did not differ significantly between those who did and did not develop tolerance to eggs, milk and wheat by 3 yr old. In conclusion, food avoiders in infancy appear to have a higher risk of not only other allergic diseases ('atopic march') but also allergy to other foods ('food allergen march') at school age, indicating the need for continuous attention to food allergy.

Food allergy: recent advances in pathophysiology and treatment

Food allergies, defined as an adverse immune response to food proteins, affect as many as 6% of young children and 3%-4% of adults in westernized countries, and their prevalence appears to be rising. In addition to well-recognized acute allergic reactions and anaphylaxis triggered by IgE antibody-mediated immune responses to food proteins, there is an increasing recognition of cell-mediated disorders such as eosinophilic gastroenteropathies and food protein-induced enterocolitis syndrome. We are gaining an increasing understanding of the pathophysiology of food allergic disorders and are beginning to comprehend how these result from a failure to establish or maintain normal oral tolerance. Many food allergens have been characterized at a molecular level, and this knowledge, combined with an increasing appreciation of the nature of humoral and cellular immune responses resulting in allergy or tolerance, is leading to novel therapeutic approaches. Currently, management of food allergies consists of educating the patient to avoid ingesting the responsible allergen and initiating therapy if ingestion occurs. However, numerous strategies for definitive treatment are being studied, including sublingual/oral immunotherapy, injection of anti-IgE antibodies, cytokine/anticytokine therapies, Chinese herbal therapies, and novel immunotherapies utilizing engineered proteins and strategic immunomodulators.

Characteristics of food-allergic patients placing them at risk for a fatal anaphylactic episode

Food allergy is a growing public health and food safety concern. Twelve million Americans-4% of the population-suffer from the disease, and the prevalence is increasing. There is no cure for food allergy; strict avoidance is the only way to prevent a reaction. Food allergy is a major cause of anaphylaxis, a severe, potentially life-threatening allergic reaction that results in an estimated 30,000 emergency department visits and 100 to 150 deaths annually. Factors that place food-allergic patients at greater risk for a fatal anaphylactic episode include asthma; being a teen or young adult; peanut, tree nut, and seafood allergy; not carrying epinephrine; restaurant food; spending time in schools and child care settings; and lack of information from health care providers. Better education of patients and their families about managing their food allergy and high-risk situations can help to prevent future fatalities.

The non-specific lipid transfer protein, Ara h 9, is an important allergen in peanut

BACKGROUND

Plant food allergy in the Mediterranean area is mainly caused by non-specific lipid transfer proteins (nsLTP). The aim of this study was to characterize peanut nsLTP in comparison with peach nsLTP, Pru p 3, and assess its importance in peanut allergy.

METHODS

Peanut-allergic patients from Spain (n=32) were included on the basis of a positive case history and either a positive skin prick test or specific IgE to peanut. For comparison, sera of 41 peanut-allergic subjects from outside the Mediterranean area were used. Natural Ara h 9 and two isoforms of recombinant Ara h 9, expressed in Pichia pastoris, were purified using a two-step chromatographic procedure. Allergen characterization was carried out by N-terminal sequencing, circular dichroism (CD) spectroscopy, immunoblotting, IgE inhibition tests and basophil histamine release assays.

RESULTS

Compared with natural peanut nsLTP, the recombinant proteins could be purified in high amounts from yeast supernatant (> or =45 mg/L). The identity of the proteins was verified by N-terminal amino acid sequencing and with rabbit nsLTP-specific antibodies. CD spectroscopy revealed similar secondary structures for all preparations and Pru p 3. The Ara h 9 isoforms showed 62-68% amino acid sequence identity with Pru p 3. IgE antibody reactivity to rAra h 9 was present in 29/32 Spanish and 6/41 non-Mediterranean subjects. Recombinant Ara h 9 showed strong cross-reactivity to nPru p 3 and similar IgE-binding capacity as nAra h 9. The two Ara h 9 isoforms displayed similar IgE reactivity. In peanut-allergic patients with concomitant peach allergy, Ara h 9 showed a weaker allergenic potency than Pru p 3 in histamine release assays.

CONCLUSIONS

Ara h 9 is a major allergen in peanut-allergic patients from the Mediterranean area. Ara h 9 is capable of inducing histamine release from basophils, but to a lesser extent than Pru p 3.

Food allergy and food allergy attitudes among college students

BACKGROUND

Little information is known about food allergy among college students.

OBJECTIVE

We sought to assess food allergy trends and behavioral attitudes on a large university campus.

METHODS

An online survey was distributed by e-mail to local university undergraduate students. Symptom severity was determined based on previously published criteria for anaphylaxis.

RESULTS

A total of 513 individuals responded, with 57% reporting an allergic reaction to food. Of this group, 36.2% reported symptoms consistent with anaphylaxis, and these reactions frequently occurred while enrolled. Allergy to milk (P = .032), tree nut (P < .0001), shellfish (P < .0001), and peanut (P < .0001) was significantly associated with having symptoms of anaphylaxis. Some form of emergency medication was reportedly maintained in 47.7%, including self-injectable epinephrine (SIE; 21%), although only 6.6% reported always carrying this device. Medication maintenance was significantly lower among students who had not had a reaction while enrolled (P < .0001). Only 39.7% reported always avoiding foods to which they were allergic. Within the group that reported intentionally consuming known allergens, there were significantly lower numbers of individuals who reported carrying SIE (P < .0001) and significantly higher numbers of individuals with a history of a reaction that had not resulted in symptoms of anaphylaxis (P = .026).

CONCLUSION

Potentially life-threatening anaphylactic reactions to foods are occurring on college campuses. Only 39.7% of students with food allergy avoided a self-identified food allergen, and more than three fourths did not maintain SIE. Such behaviors might place these students at increased risk for adverse events.

Fatal anaphylaxis to foods: epidemiology, recognition, and prevention

The inability to accurately predict the severity of future allergic reactions to foods in a given individual coupled with the real--although usually remote--risk of a fatal anaphylactic reaction complicates care and remains a constant source of concern to food-allergic patients, their family members, and health care providers. Current epidemiologic evidence suggests that the incidence of food-induced anaphylaxis is increasing, although confidently approximating the incidence of fatal allergic reactions to foods remains difficult. This article briefly reviews the epidemiology of fatal anaphylactic reactions to foods, discusses factors that may aid in identifying individuals at higher risk, emphasizes important aspects of patient education and prevention, and touches on the psychological impact of having a family member with food allergy.

Oral immunotherapy for food allergy

Food allergy is an increasingly prevalent disorder with potentially life-threatening complications that requires life-altering changes in dietary habits and psychosocial interactions. The standard of care presently includes strict dietary elimination of the implicated allergen and ready access to injectable epinephrine; however, no active, definitive therapeutic options exist for food-allergic patients. Although the detailed immunologic mechanisms underlying the development of food allergy are still being fully defined, food allergy appears to be the direct result of a breakdown in oral tolerance. Thus, current therapeutic approaches to food allergy are focused on modulating the immunologic response to food proteins to promote induction of oral tolerance. In this review, we examine gastrointestinal mucosal immunity and the mechanisms of oral tolerance, as well as the breakdown in oral tolerance that promotes food allergy, and we also explore novel therapeutic interventions for treatment of food allergy.

The diagnosis of IgE-mediated food allergy in childhood

IgE-mediated food allergy is a common condition in childhood and a recognized public health concern. An accurate diagnosis of food allergy facilitates the avoidance of the allergen - and cross-reactive allergens - and allows for safe dietary expansion. The diagnosis of food allergy relies on a combination of rigorous history, physical examination, allergy tests [skin prick tests (SPT) and/or serum-specific IgE] and oral food challenges. Diagnostic cut-off values for SPT and specific IgE results have improved the diagnosis of food allergy and thereby reduced the need to perform oral food challenges. This clinical case series seeks to highlight a contemporary approach to the diagnosis of food allergy in children strategies.

Safety of a peanut oral immunotherapy protocol in children with peanut allergy

BACKGROUND

Oral immunotherapy (OIT) offers a promising therapeutic option for peanut allergy. Given that during OIT an allergic patient ingests an allergen that could potentially cause a serious reaction, the safety of OIT is of particular concern.

OBJECTIVE

The purpose of this study was to examine safety during the initial escalation day, buildup phase, and home dosing phase in subjects enrolled in a peanut OIT study.

METHODS

Skin, upper respiratory tract, chest, and abdominal symptoms were recorded with initial escalation day and buildup phase dosings. Subjects also maintained daily diaries detailing symptoms after each home dosing. A statistical analysis of these data was performed.

RESULTS

Twenty of 28 patients completed all phases of the study. During the initial escalation day, upper respiratory tract (79%) and abdominal (68%) symptoms were the most likely symptoms experienced. The risk of mild wheezing during the initial escalation day was 18%. The probability of having any symptoms after a buildup phase dose was 46%, with a risk of 29% for upper respiratory tract symptoms and 24% for skin symptoms. The risk of reaction with any home dose was 3.5%. Upper respiratory tract (1.2%) and skin (1.1%) symptoms were the most likely after home doses. Treatment was given with 0.7% of home doses. Two subjects received epinephrine after 1 home dose each.

CONCLUSIONS

Subjects were more likely to have significant allergic symptoms during the initial escalation day when they were in a closely monitored setting than during other phases of the study. Allergic reactions with home doses were rare.

Prevalence of immunoglobulin E-mediated food allergy in 6-9-year-old urban schoolchildren in the eastern Black Sea region of Turkey

BACKGROUND

The prevalence of adverse reactions to food in childhood in Turkey is not known.

OBJECTIVE

We aimed to investigate the prevalence and characteristics of IgE-mediated food allergies (FAs) in 6-9-year-old urban schoolchildren.

METHODS

This cross-sectional study recruited 3500 of the randomly selected 6-9-year-old urban schoolchildren from the eastern Black Sea region of Turkey during 2006. Following a self-administered questionnaire completed by the parents and the child, consenting children were invited for skin prick tests (SPTs) and oral food challenges. Children with suspected IgE-mediated FA were skin prick tested with a predefined panel of food allergens (milk, hen's egg, soy, wheat, peanut, fish, and hazelnut), aeroallergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, dog, Alternaria, grass pollen mix, weed pollen mix, and tree pollen mix), and food allergens reported in the questionnaire. All children with a positive SPT to any food were invited for a double-blind, placebo-controlled food challenge (DBPCFC). The prevalence of IgE-mediated FA was established using DBPCFCs.

RESULTS

The response rate to the questionnaire was 78.2% (2739/3500). The estimated prevalence of parental-reported IgE-mediated FA was 5.7% (156/2739) [95% confidence interval (CI), 4.83-6.57%]. The rate of sensitization to the food allergens was 33.1% (48/145) in the parental-reported group. The confirmed prevalence of IgE-mediated FA by means of DBPCFC in 6-9-year-old urban schoolchildren living in the eastern Black Sea region of Turkey was 0.80% (22/2739) (95% CI, 0.47-1.13%). The most common allergenic foods were beef (31.8%), cow's milk (18.1%), cocoa (18.1%), hen's egg (13.6%), and kiwi (13.6%).

CONCLUSIONS

The rate of reported IgE-mediated FA was significantly higher than clinically confirmed FA by means of DBPCFC (odds ratio, 7.46; 95% CI, 4.67-12.01; P<0.0001). The order of allergenic foods was different and somewhat unique to the eastern Black Sea region of Turkey when compared with western countries.

Safety assessment of biotechnology products for potential risk of food allergy: implications of new research

Food allergy is a potential risk associated with use of transgenic proteins in crops. Currently, safety assessment involves consideration of the source of the introduced protein, in silico amino acid sequence homology comparisons to known allergens, physicochemical properties, protein abundance in the crop, and, when appropriate, specific immunoglobulin E binding studies. Recently conducted research presented at an International Life Sciences Institute/Health and Environmental Sciences Institute-hosted workshop adds to the scientific foundation for safety assessment of transgenic proteins in five areas: structure/activity, serum screening, animal models, quantitative proteomics, and basic mechanisms. A web-based tool is now available that integrates a database of allergenic proteins with a variety of computational tools which could be used to improve our ability to predict allergenicity based on structural analysis. A comprehensive strategy and model protocols have been developed for conducting meaningful serum screening, an extremely challenging process. Several animal models using oral sensitization with adjuvant and one dermal sensitization model have been developed and appear to distinguish allergenic from non-allergenic food extracts. Data presented using a mouse model suggest that pepsin resistance is indicative of allergenicity. Certain questions remain to be addressed before considering animal model validation. Gel-free mass spectrometry is a viable alternative to more labor-intensive approaches to quantitative proteomics. Proteomic data presented on four nontransgenic varieties of soy suggested that if known allergen expression in genetically modified crops falls within the range of natural variability among commercial varieties, there appears to be no need to test further. Finally, basic research continues to elucidate the etiology of food allergy.

Isolation, purification, crystallization and preliminary crystallographic studies of chitinase from tamarind (Tamarindus indica) seeds

A protein with chitinase activity has been isolated and purified from tamarind (Tamarindus indica) seeds. N-terminal amino-acid sequence analysis of this protein confirmed it to be an approximately 34 kDa endochitinase which belongs to the acidic class III chitinase family. The protein was crystallized by the vapour-diffusion method using PEG 4000. The crystals belonged to the tetragonal space group P4(1), with two molecules per asymmetric unit. Diffraction data were collected to a resolution of 2.6 A.

Efficacy and mechanisms of action of traditional Chinese medicines for treating asthma and allergy

BACKGROUND

Although corticosteroids and beta(2)-agonists are effective in managing asthma symptoms, a curative therapy for asthma is lacking. Traditional Chinese medicine (TCM), used in Asia for centuries, is beginning to play a role in Western health care as a complementary and alternative medicine modality. There is increasing scientific evidence supporting the use of TCM for asthma treatment.

OBJECTIVE

This review article discusses promising TCM interventions for asthma and explores their possible mechanisms of action.

METHODS

We first reviewed 5 clinical studies of antiasthma TCM herbal remedies published between 2005 and 2007. We then summarized possible mechanisms underlying their effects on the basis of data in the original articles, published abstracts, and available databases. Possible mechanisms include anti-inflammation, inhibition of airway smooth muscle contraction, and immunomodulation. Research on TCM herbal therapy for food allergy is rare, and we therefore focused on the effect and mechanism of action of food allergy herbal formula-2 on a murine model of peanut allergy and preliminary clinical study results.

CONCLUSION

Evidence from clinical studies supports beneficial effects of TCM herbal therapy on asthma. A number of mechanisms may be responsible for efficacy of these agents. Strong preclinical study data suggest the potential efficacy of food allergy herbal formula-2 for food allergy.

Increasing anaphylaxis hospitalizations in the first 2 decades of life: New York State, 1990 -2006

BACKGROUND

Although an increase in the occurrence of anaphylaxis has been reported in several parts of the world, this phenomenon has not been described in the United States.

OBJECTIVE

To characterize anaphylaxis hospitalizations in New York State in patients younger than 20 years.

METHODS

Using a statewide administrative database, hospital admissions of patients with an allergic disease (anaphylaxis, angioedema, urticaria, and allergy unspecified) as the primary diagnosis were analyzed from 1990 through 2006 in New York State. Admission rates were calculated for the allergic disease groups, as were hospitalization characteristics. Statistical modeling and group comparisons were performed with the use of negative binomial distribution analysis.

RESULTS

For patients younger than 20 years, the anaphylaxis hospitalization rate increased by more than 4-fold during the study period and by 2002 exceeded the combined hospitalization rates for urticaria, angioedema, and unspecified allergy. After the widespread adoption of food anaphylaxis codes in 1994, food anaphylaxis predominated hospitalizations for anaphylaxis. Peanut was the most common food allergen in food anaphylaxis admissions. The anaphylaxis hospitalization rate for males was significantly greater than that of females (risk ratio, 1.45; 95% confidence interval, 1.26-1.66). Blacks were not disproportionately hospitalized for anaphylaxis. An overall bimodal age distribution showed peaks in the very young and in teens.

CONCLUSION

These data demonstrate that in a populous Northeastern state in the United States, anaphylaxis requiring hospitalization is increasing in the age group younger than 20 years.

The etiology and incidence of anaphylaxis in Rochester, Minnesota: a report from the Rochester Epidemiology Project

BACKGROUND

Reported incidences of anaphylaxis range from 3.2 to 20 per 100,000 population. The incidence and trend over time has meaningful public health implications but has not been well characterized because of a lack of a standard definition and deficiencies in reporting of events.

OBJECTIVE

We sought to determine the incidence and cause of anaphylaxis over a 10-year period.

METHODS

We performed a population-based incidence study that was conducted in Rochester, Minnesota, from 1990 through 2000. Anaphylaxis episodes were identified on the basis of symptoms and signs of mast cell and basophil mediator release plus mucocutaneous, gastrointestinal tract, respiratory tract, or cardiovascular system involvement.

RESULTS

Two hundred eleven cases of anaphylaxis were identified (55.9% in female subjects). The mean age was 29.3 years (SD, 18.2 years; range, 0.8-78.2 years). The overall age- and sex-adjusted incidence rate was 49.8 (95% CI, 45.0-54.5) per 100,000 person-years. Age-specific rates were highest for ages 0 to 19 years (70 per 100,000 person-years). Ingested foods accounted for 33.2% (70 cases), insect stings accounted for 18.5% (39 cases), medication accounted for 13.7% (29 cases), radiologic contrast agent accounted for 0.5% (1 case), "other" causes accounted for 9% (19 cases), and "unknown" causes accounted for 25.1% (53 cases). The "other" group included cats, latex, cleaning agents, environmental allergens, and exercise. There was an increase in the annual incidence rate during the study period from 46.9 per 100,000 persons in 1990 to 58.9 per 100,000 persons in 2000 (P = .03).

CONCLUSION

The overall incidence rate is 49.8 per 100,000 person-years, which is higher than previously reported. The annual incidence rate is also increasing. Food and insect stings continue to be major inciting agents for anaphylaxis.

Towards a cure for food allergy

Over the past two decades, food allergies have become both more prevalent and long lasting. This burgeoning problem has not been met with any therapeutic options to date, and patients must attempt to avoid known allergenic foods and treat any allergic reactions with 'as-needed' medications. There are a number of promising emerging therapeutic modalities for food allergy, including allergen-specific and allergen non-specific immunotherapeutic approaches. Although the allergen-specific approaches have some distinct differences, they all attempt to induce tolerance by exposing the patient to an allergen via the mucosal route (oral tolerance induction). Allergen non-specific approaches include biologics to suppress free total IgE levels (e.g. anti-IgE antibody) or to induce more general immune suppression (Chinese herbal medication).

Development of a food allergy education resource for primary care physicians

BACKGROUND

Food allergy is estimated to affect 3-4% of adults in the US, but there are limited educational resources for primary care physicians. The goal of this study was to develop and pilot a food allergy educational resource based upon a needs survey of non-allergist healthcare providers.

METHODS

A survey was undertaken to identify educational needs and preferences for providers, with a focus on physicians caring for adults and teenagers, including emergency medicine providers. The results of the survey were used to develop a teaching program that was subsequently piloted on primary care and emergency medicine physicians. Knowledge base tests and satisfaction surveys were administered to determine the effectiveness of the educational program.

RESULTS

Eighty-two physicians (response rate, 65%) completed the needs assessment survey. Areas of deficiency and educational needs identified included: identification of potentially life-threatening food allergies, food allergy diagnosis, and education of patients about treatment (food avoidance and epinephrine use). Small group, on-site training was the most requested mode of education. A slide set and narrative were developed to address the identified needs. Twenty-six separately enrolled participants were administered the teaching set. Pre-post knowledge base scores increased from a mean of 38% correct to 64% correct (p < 0.001). Ability to correctly demonstrate the use of epinephrine self injectors increased significantly. Nearly all participants (>95%) indicated that the teaching module increased their comfort with recognition and management of food allergy.

CONCLUSION

Our pilot food allergy program, developed based upon needs assessments, showed strong participant satisfaction and educational value.