Objective of the study is to show, on an exploratory basis, that treatment with SUBLIVAC Birch is also effective compared to treatment with Staloral Birch by means of reduction in allergic symptoms during nasal provocation in subjects suffering from IgE mediated allergic complaints triggered by birch pollen.

Inclusion Criteria:

• Subjects with allergic rhinoconjunctivitis with or without mild asthma (FEV1 ≥ 70%) due to birch pollen for at least 2 years.
• Use of anti-allergy symptomatic medication in the last birch pollen season (in case of a season with low pollen counts, in one of the two previous years).
• No seasonal allergic complaints induced by birch, grasses or mugwort pollen for at least 4 weeks in the absence of rescue medication during at least the last 2 weeks before the baseline.
• A positive SPT (diameter ≥3 mm) for birch pollen and a positive specific serum anti birch IgE-test (>1 U/ml).
• A positive TNPT with a birch allergen extract containing a concentration of 10, 100 or 1000 AU/ml at the baseline visit.
• Age 18 years and older.
• Subjects shall give a written informed consent.

Exclusion Criteria:

• A positive SPT (diameter ≥ 3mm) for hazel or alder and the maintenance dose will not be reached before 8 October 2009.
• A positive SPT (diameter ≥ 3mm) for pets and symptoms related to concomitant sensitization to pets while having these animals at home.
• A positive SPT (diameter ≥ 3mm) for house dust mite or moulds and clinically relevant symptoms related to concomitant sensitization to house dust mite or moulds, based on the investigator's research (TNPT for example).
• Allergy to any of the excipients of SUBLIVAC Birch or Staloral Birch.
• Chronic asthma or emphysema, particularly with an FEV1 < 70 % of predicted value or use of inhalation corticosteroids outside grass and tree pollen season for more than two episodes and/or longer than fourteen days.
• Specific findings for nose and mouth at screening or rhinoscopy before TNPT.
• Serious immuno-pathological diseases or malignancies (including auto-immune diseases, tuberculosis, HIV).
• Inflammation or infection of the target organ (nose, eyes and lungs).
• Severe atopic dermatitis requiring systemic immuno-suppressive medication.
• Allergen specific immunotherapy treatment for a period longer than 3 months within the last 5 years.
• History of life threatening anaphylactic events, including anaphylactic food allergy, insect venom anaphylaxis, exercise or drug induced anaphylaxis.
• A positive pregnancy test, lactation or inadequate contraceptive measures. (adequate measures: oral contraceptives, IUD, condom use and having no sexual relationship with a man)
• Alcohol- or drug abuse.
• Lack of co-operation or severe psychological disorders.
• Completed or ongoing long-term treatment with tranquilizer or psycho active drugs.
• Low compliance or inability to understand instructions/study documents
• Completed or ongoing treatment with anti-IgE-antibody
• Patients being in any relationship or dependence with the sponsor or investigator