Crustacean Allergy and Dust Mites Sensitization
This study evaluates the diagnostic efficacy of CAP System (capsulated hydrophilic carrier polymer) for recombinant tropomyosin from shrimp extract in discriminating between subjects allergic to shrimp with CAP positive subjects allergic to mites, crustaceans asymptomatic but with a positive CAP to shrimp, to identify those at greatest risk of food reactions.
|Study Design:||Observational Model: Case Control
Time Perspective: Prospective
|Official Title:||Crustacean Allergy and Sensitization to Dust Mites in Patients With Respiratory Allergy: Clinical Study and Analysis of Common and Peculiar Allergens|
- Evaluation of the ability of the CAP System for recombinant tropomyosin in identifying those most at risk of food reactions [ Time Frame: One day ] [ Designated as safety issue: No ]Will be carried out the assay of specific IgE to the extract of shrimp and other shellfish and dust mites by the CAP System.On the same blood sample will be also made for the CAP recombinant major allergens Der p1,Der p2 and tropomyosin recombinant mite Der p 10 and the recombinant shrimp tropomyosin Pen a 1.The test consists of a reaction between allergens covalently bound to a solid phase(ImmunoCAP) and the specific IgE in the serum.This reaction is highlighted by the use of anti-IgE conjugated with an enzyme and the subsequent addition of a reagent of development
- Determination of specific IgE reactivity profile of each individual patient by immunoblotting [ Time Frame: One day ] [ Designated as safety issue: No ]After separation by SDS-PAGE (Sodium Dodecyl Sulphate - PolyAcrylamide Gel Electrophoresis) proteins are transferred thanks to an electric field on a nitrocellulose membrane, which will subsequently be cut into strips. Each strip will be incubated with the serum of a patient; the binding of specific IgE to allergenic proteins will be detected by anti-human IgE antibodies radiolabeled with I125. Using autoradiographic films will be highlighted so the pattern corresponding to the specific IgE-binding allergenic profile recognized by each patient studied and related to both mite and shrimp.
- Oral provocation test in double-blind placebo-controlled [ Time Frame: Two days ] [ Designated as safety issue: No ]Patients with a doubtful allergic reaction to shrimp will be tested for oral provocation against placebo with shrimp cooked according to the method described in 1988 by Lherer
Biospecimen Retention: Samples Without DNA
Blood for in vitro investigations
|Study Start Date:||September 2010|
|Study Completion Date:||October 2012|
|Primary Completion Date:||November 2011 (Final data collection date for primary outcome measure)|
Patients with shellfish allergy
Patients with symptoms of allergy to shellfish (OAS-Oral allergy syndrome and/or systemic symptoms) and circulating IgE positive for the extract of shrimp (> 0.10 kU/L)
Patients with respiratory allergy
Patients with respiratory allergy and IgE positive to dust mites, asymptomatic for shrimp or other shellfish and circulating IgE positive for shrimp
Most epidemiological data related to allergy to shellfish come from the USA, where 2.5% of the adult population is subject to an allergy to shellfish, which is also the leading cause of anaphylaxis in adults in these areas. This allergy affects also the European adult population, so that the crustaceans were included in the European Directive 2003/89/EC on the labeling requirement to indicate any allergenic ingredients (listed in Annex 3 a) used in the production of a food and present, although in other form, in the finished product. The allergen mainly involved in allergic reactions to shellfish food is the tropomyosin protein of PM of about 34-36 kDa, isolated for the first time in the shrimp (Pen to 1), involved in the mechanisms of muscle activation and identified in the muscle fiber of many crustaceans (Pen i 1, Cha f 1, Cra c 1, Hom a 1, v 1 Lit, Pan s 1, Pen m 1) and molluscs (Hel as 1, d 1 Hal, Cra g 1, Oct 1 st, Tod p 1). The tropomyosins, identified in many other invertebrates, such as dust mites and cockroaches, seem to be cross-reactive with each other, suggesting the role of allergens inside of the Invertebrates. In those circumstances, the positivity of specific IgE for the crustaceans can thus be determined also by sensitization to tropomyosin even for simple cross-reactivity with tropomyosin of the mites, which represents a minor allergen Der known as p10.