Inclusion Criteria:  moderate-severe grass pollen allergic rhinoconjunctivitis positive skin prick test for grass pollen extract  Exclusion Criteria:  significant mugwort allergy previous AIT for grass pollen allergy uncontrolled non-allergic upper airways disease uncontrolled asthma planned depot steroid injections during season uncontrolled autoimmune diseases active malignancies uncontrolled other severe condition, including psychiatric diseases