Peanut and Tree Nut Desensitization

The investigators are proposing to initiate a study assessing a common desensitization protocol for peanut/tree nut allergy. This study would enable the investigators to better determine the potential benefit of desensitization in individuals with peanut/tree nut allergy.

More specifically, the investigators will address the following research objectives:

Objectives A. To develop a protocols for peanut/tree nut desensitization with high (300mg) and low (30mg maintenance dose).

B. To determine the rate of desensitization to peanut/tree nut. C. To characterize predictors of successful desensitization. D. To characterize molecular mechanisms involved in the process of desensitization

These objectives will be evaluated through a randomized controlled trial

Inclusion criteria

Patients between 2 and 40 years of age who satisfy all the following criteria will be included:

• A history suggestive of immediate allergy to peanut/tree nut . A convincing clinical history of an IgE mediated reaction to a specific food will be defined as a minimum of 2 mild signs/symptoms or 1 moderate or 1 severe sign/symptom that was likely IgE mediated and occurred within 120 minutes after ingestion or contact (or inhalation in the case of fish and shellfish). Reactions will be considered mild if they involve pruritus, urticaria, flushing, or rhinoconjunctivitis; moderate if they involve angioedema, throat tightness, gastrointestinal complaints, or breathing difficulties (other than wheeze); and severe if they involve wheeze, cyanosis, or circulatory collapse.(54-57)
• The presence of at least one of the following confirmatory tests:

• Positive SPT to peanut/tree nut or its proteins (weal diameter 3 mm larger than that of the normal saline control). The allergens used will be commercial extracts of peanut/tree nut (Omega Labs, Toronto, Ontario).
• Detection of serum specific IgE (>0.35 kU/L) to peanut/tree nut or any of its proteins, measured by fluorescence enzyme immunoassay (Phadia, CAP System, Uppsala, Sweden).
• Positive oral challenge test to peanut/tree nut. Oral challenges will be performed with raw peanut/tree nut according to the recommendations of the position paper of the European Academy of Allergology and Clinical Immunology (58).
• Informed consent form signed by the parents or legal guardian

Exclusion criteria

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• Patients who are unstable from a respiratory point of view ..
• Patients who present with intercurrent disease at the time of starting desensitization.
• Non-IgE-mediated or non-immunological adverse reactions to nuts.
• Malignant or immunopathological diseases and/or severe primary or secondary immune deficiencies.
• Patients receiving immunosuppressor therapy
• Patients receiving β-blockers (including topical formulations).
• Associated diseases contraindicating the use of epinephrine: cardiovascular disease or severe hypertension.
• Patients diagnosed with eosinophilic gastrointestinal disorder .