Determinism of the Mechanism of Action of Specific Immunotherapy in Hymenoptera Venom Allergy

University Hospital, Rouen29 enrolled

Overview

Currently, most of the protocols used for desensitization to Hymenoptera venoms consist of a very rapid increase in doses of venom extracts administered during the SIT in a day without systemic reaction of the patient which is not yet explained. The hypothesis is that this good tolerance is due to a rapid decrease in the response of mast cells and basophils to the allergen.. The main objective is to study basophil activation in response to the allergen during the first day of desensitization, measured by basophil activation test. The initiation of desensitization follow a protocol of rapid growth rates. The basophil activation level in the course of desensitization will be analyzed by flow cytometry after in vitro stimulation by allergen. Changes in T cell polarization is also analyzed by flow cytometry. Evolution of the expression of different proteins in blood basophils will be studied by measuring their messenger RNAs

Study Type

INTERVENTIONAL

Allocation

Purpose

PREVENTION

Masking

NONE

Enrollment

Conditions

Hymenoptera Allergy

Interventions

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients over 18 years and below 75 years age * Patient who presented a generalized allergic reaction after an puncture of a hymenoptera * Patient with positive skin tests against the venom of a hymenoptera * Patient with positive specific IgE against the venom of a hymenoptera • to which an indication of accelerated desensitization was chosen in day hospitalization * Information and consent signed by the patient * Patient affiliated to french social security system * For women of childbearing age, taking an effective contraceptive. Exclusion Criteria: * Patients with the following diseases: Mastocytosis, systemic infection or hospitalization within 4 weeks before inclusion, chronic inflammatory disease, cancer, unbalanced asthma, immune deficiency * Patients on beta-blocker, following another specific immunotherapy, or ongoing immunosuppressive therapy. * Pregnant or lactating * People placed under judicial protection * Patient participating or having participated in another biomedical research within six months

Outcomes

Primary Outcomes

Evolution of basophil activation test value

Evolution of the basophil activation test (% of activated basophils) between the morning before the start of desensitization (Alyostall®) and before the last dose of the first day

Time frame: Day 1 - 3h30

Secondary Outcomes

Correlation between results of activation basophil test results and tolerance

Looking for a correlation between the results of activation basophil test (% of activated basophils) and tolerance on the one hand and on the other hand the effectiveness of clinically evaluated desensitization (Alyostall®)

Time frame: Day 1 - 5h30

Evolution of basophil surface markers

Evolution of activated basophil surface markers by cytometric flow (% of activated) between the start of desensitization and before the last injection of the fist day of desensitization (Alyostall®)