This trial is performed for the immunological and histological evaluation of specific immunotherapy with an aluminium hydroxide-adsorbed recombinant hypoallergenic derivative of the major birch pollen allergen, rBet v1-FV

Type I allergy is an immune-disorder which stems from the formation of IgE antibodies against proteins and glycoproteins from plants, insects, animals and fungi, most of which are normally considered harmless. The cross-linking of specific IgE antibodies on effector cells by allergens activates an immunological cascade leading to the symptoms of Type I allergy including rhinitis, conjunctivitis, asthma, and anaphylactic shock. Allergic Rhinitis is the most common chronic atopic disease and is associated with considerable cost and co-morbidity. Seasonal allergic rhinitis (SAR), triggered by pollen from trees, grasses and weeds, is characterized by sneezing, nasal congestion, nasal itching, rhinorrhea, and pruritic, watery, red eyes.

Recombinant preparations offer various advantages over those based on natural allergen extracts. Recombinant proteins can be produced in highly purified forms of pharmaceutical quality; proteins are molecularly defined thus ensuring product consistency and minimising problems related to allergen extract standardisation; preparations only include those proteins that are considered relevant for specific immunotherapy; the risk of contamination with other allergenic material is excluded; the whole production process can be designed to exclude any risk factors for the introduction of infectious agents; the relative dosages of individual components of a final preparation can be optimised to favour better clinical efficacy. Allergy vaccination (AV) mediates the immune response to allergen exposure by altering the TH2 response in favour of a TH1 T-cell response, increasing IgG production and decreasing the production of inflammatory cytokines. rBet v1-FV is an AV designed to enhance beneficial immune responses. The investigational product has demonstrated efficacy and good tolerability in one previous pivotal Phase III and two previous Phase II studies.

Inclusion Criteria:

• Positive SPT
• Positive EAST
• Positive specific provocation test

Exclusion Criteria:

• Serious chronic diseases
• Other perennial allergies