Oral Immunotherapy for Hazelnut Allergy: A Single-Center Retrospective Study on 100 Patients.

BACKGROUND: Oral immunotherapy (OIT) protects patients with IgE-mediated food allergies from food-induced allergic reactions due to accidental exposure and may improve their quality of life. This approach has never been evaluated for hazelnut, a major cause of food allergy in Europe. OBJECTIVE: To determine the proportion of hazelnut-desensitized patients after 6 months of OIT and to identify predictors of successful desensitization. METHODS: In a retrospective single-center study, we included patients younger than 18 years who underwent at least 6 months of hazelnut OIT for IgE-mediated allergy, defined by history of hypersensitivity reaction after hazelnut ingestion, positive hazelnut skin prick test result or specific IgE, and positive double-blind, placebo-controlled food challenge. Patients able to tolerate 1635 mg of hazelnut protein (∼8 hazelnuts) were considered to be hazelnut desensitized. We determined the proportion of desensitized patients after 6 months of OIT, searched for associations between baseline variables and successful desensitization, and estimated the frequency and severity of OIT-related adverse reactions. RESULTS: One hundred patients were included (64% males; median age, 5 years). History of severe reactions was noted in 7% of cases. At 6 months, the proportion of desensitized patients was 34% (95% CI, 25-44). The median eliciting dose (defined as the amount of hazelnut protein provoking a hypersensitivity reaction during the double-blind, placebo-controlled food challenge) increased from 106 mg (interquartile range, 51-249) at baseline to 523 mg (interquartile range, 190-1635) after 6 months of OIT (P < .0001). With longer therapy, the proportion of desensitized patients increased. Using multivariate analysis, successful desensitization was associated with older age (odds ratio [OR], 1.5; 95% CI, 1.2-2.2), smaller hazelnut skin prick test wheal diameter (OR, 0.61; 95% CI, 0.4-0.8), lower hazelnut specific IgE level (OR, 0.86; 95% CI, 0.72-0.98), and absence of cashew allergy (OR, 0.42; 95% CI, 0.12-0.64). Adverse reactions occurred in 30% of patients; none were severe. CONCLUSIONS: In a cohort of 100 patients aged 3 to 9 years, our results show for the first time that hazelnut OIT is associated with hazelnut desensitization and may be safe in most patients undergoing this therapy.

Phenotypical characterization of peanut allergic children with differences in cross-allergy to tree nuts and other legumes.

BACKGROUND: Peanut allergy in children is often associated with allergies to tree nuts and/or legumes. The aim of this study was to analyze in cluster a cohort of children allergic to peanuts and assessed for cross-reactivity to nuts and legumes and to identify different phenotypes. METHODS: We included retrospectively 317 children with peanut allergy evaluated at the Allergy Unit of the Saint Vincent Hospital of Lille in the last 12 years. A complete workup for peanut allergy and nuts and legumes was carried out for each patient. A hierarchical agglomerative clustering method was used to search for clusters of individuals in the evaluated cohort. RESULTS: Cross-allergy to TN and/or other legumes was identified in 137 patients (43.2%), atopic dermatitis being a major risk factor (adjusted OR = 16 [95% CI: 7.4-37]; p < 0.001). Three phenotypes emerged from cluster analysis. Cluster 1 (72 patients) is characterized by high level of rAra h 2, low threshold reactive doses for peanut and high proportion of asthma; Cluster 2 (93 patients) is characterized by high threshold reactive doses for peanut and the lowest proportion of cross-allergy to TN and/or legumes; Cluster 3 (152 patients) has a high risk of cross-allergy to TN and/or legumes and most patients suffer from eczema. CONCLUSIONS: The three phenotypes highlighted by this study could be useful to identify children with high risk of cross-allergic reaction to TNs and legumes early after PA diagnosis.