Skin Testing With Recombinant Bet v 1 and Hypoallergenic Recombinant Bet v 1 Fragments
Condition: Atopic Dermatitis
MeSH terms: Dermatitis, Atopic; Dermatitis; Eczema
Study type: Observational

Summary: 
      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.
    

Detailed 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.
    

Intervention name(s): SPT and APT
Intervention type(s): Other
Intervention description(s): All patients will be tested by skin prick testing (SPT: Histamine, buffer, commercial birch pollen extract, rBet v 1 (20 and 40 μg/ml), rBet v 1 fragment 1 (20 and 40 μg/ml), rBet v 1 fragment 2 (20 and 40 μg/ml), equimolar rBet v 1 fragment mix (20 and 40 μg/ml) in duplets.
Atopy patch testing (APT: birch pollen extract, rBet v 1:160 μg/application, rBet v 1 fragment 1: 160 μg/application, rBet v 1 fragment 2: 160 μg/ml, equimolar mix of rBet v 1 fragments: 160 μg/application; negative control with vaseline alone.
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Different types of individuals will be recruited and divided in four groups. A total of 30
        allergic and non-allergic persons will be included in this study:

        patients with Birch pollen-related atopic dermatitis (AD), Birch pollen allergic patients
        without AD (group 2), allergic individuals without birch pollen allergy and non-allergic
        individuals.
      
Keywords: atopic dermatitis; bet v 1; bet v 1 fragments; allergy