In this study, participants will receive either intranasal anti-IgE-antibodies (n=5) or intranasal allergen (n=5) or intranasal placebo (n=5). Blood samples will be obtained before nasal administration of study drugs and 3, 5 and 8 weeks thereafter. In the serum samples, specific and total IgE levels will be assessed.

The intranasal challenge study will be performed over 8 weeks outside of the birch pollen season (November to January) as a randomized, double blind and placebo-controlled study. During a screening visit, 15 individuals will be recruited according to eligibility criteria. They will be randomized into 3 groups (i.n. administration of anti-IgE antibodies, Bet v 1 or placebo). Intranasal administration will take place on three consecutive days and serum samples will be taken 3, 5, and 8 weeks (+/- 4 days) after the treatment for analysis of total and specific IgE levels

Inclusion Criteria:

birch pollen allergy

Exclusion Criteria:

history of anaphylaxis autoimmune diseases treatment with corticosteroids, antihistamines, immunosuppressant drugs, beta-blockers significant medical conditions pregnancy or lactation