Component resolved diagnostics demonstrates that most peanut allergic individuals could potentially introduce tree nuts to their diet.
BACKGROUND: Nut allergy varies from pollen cross-allergy, to primary severe allergy with life-threatening symptoms. The screening of IgE antibodies to a wide spectrum of allergens, including species-specific and cross-reactive allergens, is made possible via microarray analysis. OBJECTIVE: We sought to study the association of variable IgE sensitization profiles to clinical response in peanut-challenged children and adolescents in a birch-endemic region. In addition, we studied the avoidance of tree nuts and species-specific sensitizations. METHODS: We studied 102 peanut-sensitized patients who underwent a double-blind placebo-controlled challenge to peanut. We analyzed ISAC ImmunoCAP microarray to 112 allergens, singleplex ImmunoCAPs for hazelnut Cor a 14 and cashew Ana o 3, and performed skin prick tests to peanut, tree nuts and sesame seed. We surveyed avoidance diets with a questionnaire. RESULTS: Sensitization to PR-10 proteins was frequent (Bet v 1 90%), but equally high in the challenge negatives and positives. IgE to Ara h 2 and Ara h 6 discriminated peanut allergic (n=69) and tolerant (n=33) the best. Avoidance of tree nuts was common (52 to 96%), but only 6 to 44% presented species-specific sensitizations to tree nuts, so a great number could potentially introduce these species into their diet. CONCLUSIONS AND CLINICAL RELEVANCE: PR-10-sensitizations were frequent and strong regardless of peanut allergy status. Component resolved diagnostics can be employed to demonstrate to patients that sensitization to seed storage proteins of tree nuts is uncommon. Several tree nuts could potentially be reintroduced to the diet.
Thermal processing effects on the IgE-reactivity of cashew and pistachio.
Thermal processing can modify the structure and function of food proteins and may alter their allergenicity. This work aimed to elucidate the influence of moist thermal treatments on the IgE-reactivity of cashew and pistachio. IgE-western blot and IgE-ELISA were complemented by Skin Prick Testing (SPT) and mediator release assay to determine the IgE cross-linking capability of treated and untreated samples. Moist thermal processing diminished the IgE-binding properties of both nuts, especially after heat/pressure treatment. The wheal size in SPT was importantly reduced after application of thermally-treated samples. For cashew, heat/pressure treated-samples still retain some capacity to cross-link IgE and degranulate basophils, however, this capacity was diminished when compared with untreated cashew. For pistachio, the degranulation of basophils after challenge with the harshest heat/pressure treatment was highly decreased. Boiling produced more variable results, however this treatment applied to both nuts for 60 min, led to an important decrease of basophil degranulation.
Prevalence and longitudinal trends of food allergy during childhood and adolescence: results of the Isle of Wight Birth Cohort study
BACKGROUND: The prevalence and time trends of food allergy change during childhood depending on the age of the child and the type of food. OBJECTIVE: To study prevalence and longitudinal trends in food allergy from birth to 18 years in an unselected birth cohort in the Isle of Wight. METHOD: Information on food allergy was collected at ages 1, 2, 4, 10 and 18 years from the Isle of Wight Birth Cohort (n = 1456). Skin prick testing (SPT) was performed at the age of 1 and 2 years in symptomatic children. At 4, 10 and 18 years of age, participants were tested to a panel of food and aero-allergens. Food allergy was diagnosed based on the criteria: symptoms suggestive of a typical IgE mediated reaction and reaction <4 hours following exposure to a known food allergen. McNemar's test was used to determine significance of changes in prevalence over time. RESULTS: The prevalence of food allergy remained relatively constant in early childhood (5.3%, 4.4% and 5.0% at 1, 2 and 4 years respectively), with significant decline at 10 years (2.3%, p<0.001 versus 4 years) followed by significant rise at 18 years (4%, p=0.02 versus 10 years). Cow's milk (1.6-3.5%) and egg (1.1-1.4%) were the most common allergens in the first 10 years with peanut (1%) and tree-nuts (0.5%) becoming more prevalent beyond 10 years. Fruit and wheat allergy were less common at 10 years, and shellfish and kiwi emerged during adolescence. The prevalence of food allergy plus positive SPT were 1.3%, 0.8%, 0.8%, 0.9% and 2.2% at 1, 2, 4, 10 and 18 years respectively. CONCLUSION: Food allergy is highly prevalent in infancy with partial resolution during late childhood. However, a number of children acquire new food allergy during adolescence resulting in a relatively higher prevalence at 18 years.
With tree nut sensitization, take the current when it serves, or lose our ventures.
Tree nut allergy affects approximately 1.4-2.3%, depending on the study methodology, patient age, and region in which the study was conducted. Tree nut allergy can be severe, and tends to persist throughout life. Tree nut is not a singular allergen like the other allergens-we use the term "tree nut" to refer to these items, but in essence it can refer to one nut, eight nuts, or per the US Food and Drug Agency classification, on the order of 19 items. Older, more conservative practice is to treat one nut as "all nuts", and instruct avoidance of all tree nuts where there is a clinical allergy proven to just one. This is often supported by high rates of co-sensitization, which is high among tree nuts because of structural similarity, and fueled concerns of cross-contamination, proper identification, or labeling confusion.