Inclusion Criteria:  All groups  Male or female 18 to 50 years of age Willingness to comply with the study protocol and written informed consent Subjects must have a standard health care insurance Subjects must be available during the study period to complete all treatments and assessments  Allergic Rhinitis  Moderate to severe allergic rhinitis to grass pollen for at least two seasons according to medical history Skin prick test positive to grass pollen extract Blood ImmunoCAP sensitisation to grass pollen (>0.35 kU/L grass pollen extract specific IgE or higher as determined by UniCAP-FEIA) No history of Asthma  Allergic Asthma  Clinical history of asthma Spirometry reversibility or PC20 methacholine/histamine <8mg Skin prick test positive to grass extract Blood ImmunoCAP sensitisation to grass pollen (>0.35 kU/L grass pollen extract specific IgE or higher as determined by UniCAP-FEIA)  Non-Allergics  No history of Asthma No history of allergy Negative skin prick test to a common skin prick test panel including grass pollen No ImmunoCAP sensitisation to to grass pollen (<0.35 kU/L grass pollen extract specific IgE or higher as determined by UniCAP-FEIA)  Exclusion Criteria:  Older than 50 or younger than 18 years Active smoker History of anaphylaxis Any severe chronic, malignant or general disease Treatment with systemic or topical (intranasal, inhaled, external) corticosteroids within the previous 2 months before the start of the study Treatment with antihistamines 3 days prior to the screening visit of the study Treatment with other immunosuppressant drugs within the previous 6 months prior to the start of the study Arterial hypertension or use of anti-hypertensive therapy, including beta-blockers Contra-indications to skin prick testing such as: skin inflammation in the test area, urticaria facticia Pregnant, lactating or sexually active women with childbearing potential who are not using a medically accepted birth control method A mental condition rendering the subject unable to understand the nature, scope and possible consequences of the study, and/or evidence of an uncooperative attitude Participation in another clinical trial within one month prior to the study; however participation during the previous month solely in the form of blood donation and/or without other interventions will be accepted Known alcohol or drug addiction or abuse Risk of non-compliance with the study procedure Previous immunotherapy with grass pollen Nasal polyps, history of chronic sinusitis or substantial deviation of the nasal septum