Skin Testing With Recombinant Bet v 1 and Hypoallergenic Recombinant Bet v 1 Fragments

Stefan Woehrl

Status: Completed

Conditions: Atopic Dermatitis

Treatments: Other: SPT and APT

Study type: Observational

Funder types: Other

Identifiers

NCT02098551

147/2009

Details and patient eligibility

About

Aim of this study is to use the major allergen 1 of birch-tree pollen (Bet v 1, Betula verrucosa, synonymous Betula pendula), to investigate the contribution of immunoglobulin E (IgE)- versus non-IgE-mediated mechanisms to chronic skin inflammation in atopic dermatitis patients.

Full description

In this study non-IgE-reactive recombinant Bet v 1 (rBet v 1) fragments (F1: aa 1-74; F2: aa 75-160) and the fully IgE-reactive recombinant Bet v 1 (aa 1-160)will be used for skin prick testing and atopy patch testing in birch pollen allergic patients with birch pollen induced exacerbation of atopic dermatitis. For control purposes birch pollen allergic patients without birch pollen-induced atopic eczema, persons with allergies other than to birch and non-allergic people will be tested.

The individuals will be subjected to in vivo skin prick and atopy patch testing with rBet v 1, rBet v 1 fragment 1, rBet v 1 fragment 2 and an equimolar mix of the rBet v 1 fragments. In parallel, the IgE reactivity, and in vitro T cell proliferation, and cytokine production will be studied. Those analyses should help to determine the relevance of IgE mediated mechanisms to chronic skin inflammation and T cell proliferation in AD patients.

A staining for the surface markers chemokine receptor (CCR4)+ and cutaneous lymphocyte antigen (CLA)+ which reportedly are enriched in inflamed skin will further allow to investigate whether patients with high numbers of T lymphocytes expressing CCR4 and CLA tend to exhibit stronger skin inflammation. Moreover, allergen-specific antibody and T cell responses will be analyzed 6-8 weeks after the epicutaneous allergen application.

Enrollment: 30 patients

Sex: All

Ages: 18 to 75 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

1. Age between 18 and 75 years
2. They will be available to complete the study

Exclusion criteria

1. Severe general maladies
2. Severe skin inflammation in the test area
3. Risk of non-controllable general reaction
4. Pregnancy and breast-feeding
5. Autoimmune diseases, immune-defects including immuno-suppression, immune-complex-induced immunopathies
6. Contra-indication for adrenaline
7. Patients under long-term treatment with systemic corticosteroids immunosuppressive drugs, tranquilizers or psychoactive drugs
8. Positive IgE reaction on hypoallergenic Bet v 1 derivatives
9. The subject is currently participating in another clinical study in which the subject is or will be exposed to an investigational or a non-investigational drug.
10. The subject is at risk of non-compliance with the study procedures/restrictions

Trial design

30 participants in 1 patient group

Four (4)

Description:

Group 1: Birch pollen-related atopic dermatitis (AD) (n=15) Group 2: Birch pollen allergic patients without AD (n=5) Group 3: Allergic individuals without birch pollen allergy (n=5) Group 4: Non-allergic individuals (n=5) Patients will be tested by SPT and APT: SPT: Histamine, buffer, commercial birch pollen extract, rBet v 1, rBet v 1 fragment 1, rBet v 1 fragment 2, and equimolar rBet v 1 fragment mix (20 and 40 μg/ml) in duplets. APT: birch pollen extract, rBet v 1, rBet v 1 fragment 1, rBet v 1 fragment 2, equimolar mix of rBet v 1 fragments (160 μg/application); negative control with vaseline

Treatment:

Other: SPT and APT