High prevalence of lupin allergy among patients with peanut allergy: Identification of γ-conglutin as major allergen.

BACKGROUND: Lupin is a protein-rich legume with a growing presence in the food market worldwide. With increased consumption, lupin allergy (LA) reports are also rising. Uncertainties exist on the cross-reactivity between peanut and lupin, the allergenic potential of different lupin species, and sensitization patterns among different populations. OBJECTIVE: To evaluate the molecular basis of LA and to determine lupin allergens from 3 different species that may be involved in peanut allergy (PA) cross-reactivity. METHODS: A total of 43 subjects with PA, those with LA, or controls without food allergy were evaluated with skin prick tests (SPTs) and specific IgEs (sIgEs). Lupin-sensitized subjects were offered a lupin oral food challenge (OFC). Immunoblots and enzyme-linked immunosorbent assays were performed on sera from lupin-sensitized subjects. RESULTS: In this study, 44% of the PA subjects were confirmed to have LA by OFC. Anaphylaxis was the most frequent manifestation after lupin consumption, with a minimal eliciting dosage of 1 g lupin flour. There was no difference in lupin sIgE or SPT wheal size between lupin-sensitized and confirmed LA subjects or in the severity of symptoms among confirmed LA subjects. Sera from lupin-sensitized subjects uniformly reacted to all 3 different lupin species. Immunoblotting and enzyme-linked immunosorbent assays revealed immunoglobulin E binding to α- and γ-conglutin in all analyzed sera, whereas α- and ß-conglutin recognition was variable. CONCLUSION: Our findings reveal a high prevalence of LA among PA subjects, emphasizing lupin must be labeled as an allergen in foods. Owing to high variability in lupin-sIgE and lupin-SPT results, LA diagnosis may require OFC. In our population, γ-conglutin is the major allergen of lupin.

Peanut allergy among Mexican adults with allergic respiratory diseases: prevalence and clinical manifestations.

BACKGROUND: Peanut allergy among adults with respiratory diseases has seldom been studied within Mexico. OBJECTIVE: To establish the prevalence of peanut allergy among adults that have been diagnosed with either asthma or allergic rhinitis; we will also be describing the symptoms that are associated with peanut allergy. METHODS: We carried out a cross-sectional study through which we analyzed the corresponding data of 257 patients with allergic respiratory diseases, asthma or allergic rhinitis, all participants were 16 years of age or older, and were recruited in a consecutive manner. Peanut allergy was established by testing positive to a peanut skin-prick test; we also conducted a standard interview with each patient. RESULTS: From our sample of 257 patients, 18 tested positive to peanut sensitization, (7.0%; 95% CI = 3.9% to 10.1%); among these 18 participants, 7 were considered to be allergic to peanuts (2.7%; 95% IC: 0.7% to 4.7%). Predominant symptoms were oral, primarily affecting the pharynx and the palate, followed by swelling of the lips. When it came to respiratory discomfort, sneezing and rhinorrhea stood out, and lastly there were cutaneous symptoms. We did not detect any systemic reactions to the peanut. CONCLUSION: In our study, peanut allergy among adults with allergic respiratory diseases is not an uncommon occurrence.

Antecedentes: La alergia al cacahuate en adultos con enfermedades respiratorias alérgicas pocas veces ha sido estudiada en México. Objetivo: Establecer la prevalencia de alergia al cacahuate en un grupo de adultos con asma o rinitis alérgica; también se describen los síntomas asociados con la alergia al cacahuate. Métodos: Se realizó estudio transversal en el que analizaron los datos correspondientes a 257 pacientes con enfermedades respiratorias alérgicas, asma o rinitis alérgica, con edad igual o mayor a 16 años; los pacientes fueron reclutados consecutivamente. La alergia al cacahuate se determinó por una prueba cutánea positiva al cacahuate y a través de una entrevista estandarizada. Se estimaron intervalos de confianza (IC) a 95 % para proporciones. Resultados: De los pacientes incluidos, 18 estuvieron sensibilizados al cacahuate (7.0 %, IC 95 % = 4.4-10.9), siete de ellos fueron considerados alérgicos al cacahuate, para una prevalencia de 2.7% (IC 95%: 1.2% - 5.6%). En los pacientes con alergia al cacahuate, los síntomas predominantes fueron los orales, principalmente el prurito en la faringe y en el paladar, seguidos de edema de los labios; entre las molestias respiratorias sobresalieron los estornudos y la rinorrea y, al final, los síntomas cutáneos. No se documentaron reacciones sistémicas al cacahuate. Conclusión: En nuestro estudio, la alergia al cacahuate en adultos con enfermedades respiratorias alérgicas no fue infrecuente.

Role of dendritic cells in peanut allergy.

INTRODUCTION: The prevalence of peanut allergy (PA) has increased, affecting approximately 1.1% of children in Western countries. PA causes life-threatening anaphylaxis and frequently persists for life. There are no standardized curative therapies for PA, and avoidance of peanuts remains the main therapeutic option. A better understanding of the pathogenesis of PA is essential to identify new treatment strategies. Intestinal dendritic cells (DCs) are essential in the induction and maintenance of food tolerance because they present dietary allergens to T cells, thereby directing subsequent immune responses. Areas covered: In this review, we discuss the factors related to the acquisition of oral tolerance to peanut proteins. We focus on intestinal DC-related aspects, including the latest advances in the biology of intestinal DC subtypes, effect of tolerance-inducing factors on DCs, effect of dietary components on oral tolerance, and role of DCs in peanut sensitization. Expert commentary: Given the increasing prevalence of PA, difficulty of avoiding peanut products, and the potentially serious accidental reactions, the development of novel therapies for PA is needed. The ability of DCs to trigger tolerance or immunity makes them an interesting target for new treatment strategies against PA.

Peanut Allergy: An Epidemiologic Analysis of a Large Database.

OBJECTIVE: To confirm new observations on peanut allergy and answer current concerns that families and healthcare providers have about peanut allergy. STUDY DESIGN: Children who presented with a story of peanut allergy or peanut sensitization were asked to participate in a registry, which allowed an analysis focused on questions that a food allergy support group had about children with peanut allergy or sensitization. RESULTS: A total of 1070 children were entered into the registry over 5 years. Two-thirds had a reaction to peanut. Children with peanut allergy were predominantly male (63%), white (78%), and with private health insurance (80%). Most reactions involved the skin (55%) and anaphylaxis occurred in 35%. The median age of a reaction was 1 year old. Atopic dermatitis was noted in 60% and asthma in 41%. Additional food allergy was noted in 58%. When second exposures occurred 28% had a more severe reaction. Skin test size did not differentiate the type of a reaction and children with anaphylaxis had slightly higher specific IgE levels. Severe reactions with inadvertent exposure in children who were peanut sensitized was rare (<1%). CONCLUSIONS: The strategies for peanut allergy prevention and treatment have evolved. The data obtained in this large registry can answer many questions that families and healthcare providers have during this transition.

Prevalence and factors associated to peanut allergy in Mexican school children.

BACKGROUND: In our country, the prevalence and the factors associated to peanut allergy are unknown, a health problem that has been emerging worldwide. OBJECTIVE: To establish the prevalence and the factors that are associated to peanut allergy amongst school children. METHODS: This is a population-based cross-sectional study. We included 756 children aged 6-7 years. The children's parents were questioned about their peanut intake habits. A structured questionnaire was applied, it included questions regarding peanut intake; family and personal history of asthma; rhinitis; and atopic dermatitis. Allergic reactions to peanuts were registered as: probable, convincing and systematic. The statistical analyses included logistical regression models to look for associated factors. RESULTS: Males were 356/756 (47.1%). Peanut allergy prevalence: probable reaction: 14/756 (1.8%), convincing reaction: 8/756 (1.1%) and systemic reaction: 3/756 (0.4%). Through multivariate analysis, the presence of symptoms of allergic rhinitis (OR=4.2 95% CI 1.3-13.2) and atopic dermatitis (OR=5.2; 95% CI 1.4-19.5) during the previous year, showed significant association to probable peanut reaction. The former year, the presence of atopic dermatitis was the only variable that was substantially associated to a convincing reaction (OR=7.5; 95% CI 1.4-38.4) and to a systematic reaction (OR=45.1; 95% CI 4.0-510.0), respectively. CONCLUSIONS: The reported prevalence of peanut allergy was consistent with that found in previous studies; symptoms of allergic rhinitis and atopic dermatitis were identified as associated factors to peanut allergy.

Peanut allergy in Mexican children: what is the effect of age at first consumption?

Studies suggest that children who start solid foods early are at risk for developing food allergies. Herein, we evaluated the effects of the introduction of peanuts to the diets of children on emerging peanut allergies. Children with allergic rhinitis and asthma were enrolled in the present study and evaluated in four stages. In the first stage, a clinical history was completed for all participants. In the second stage, skin tests were conducted to detect the sensitization to peanuts. In the third stage, the parents were interviewed about the peanut-eating habits of their children. In the fourth stage, children with a convincing history of allergy or a positive peanut skin test result were subjected to an open oral food challenge (OOFC). Three hundred children in four groups were included, 58.2% of the subjects were male, and the mean age was 7.3±3.9 years. The median age of first exposure to peanuts in patients with peanut allergies was greater than that in children without peanut allergies (2 years versus 1 year; p=0.009). The multivariate analysis, including only those children subjected to the OOFC, revealed that the consumption of peanuts after the age of ≥2 years is a risk factor for developing a peanut allergy (odds ratio=8.0, 95% confidence interval 1.3-50.0, p=0.026). The results of the present study showed that the late introduction of peanuts to children increases the risk of developing a peanut allergy.