The purpose of this study is to determine whether exhaled breath temperature, a surrogate marker of airway inflammation, rises during the pollen season in sensitized subjects with allergic rhinoconjucnctivitis with or without mild asthma. Sublingual Immunotherapy with respective allergens suppresses the seasonal increase of EBT. During the second year (2013) of the trial all patients will be treated with 5 grass allergen extract: carry over differences between the active and placebo arms from the previous year (2012) will be looked for.

Patients with grass pollen allergy are most typical and best responding to sublingual immunotherapy. Their selection will be done in accordance with the criteria listed in Chapter 9 of the World Allergy Organization Position Paper on specific immunotherapy 2009 and in compliance with the rules for good clinical practice.

Proposed primary variable: the difference between the changes of exhaled breath temperature before and in the pollen season of subjects treated with grass-pollen sublingual immunotherapy and the untreated control patients.

Suggested secondary variables: changes over time of exhaled breath temperature in the two groups, difference in symptoms scores, methacholine responsiveness, rescue medication usage.

Statistical analysis: On the basis of the available data about the variability of exhaled breath changes and its changes upon flare up of airway inflammation or after anti-inflammatory treatment we have calculated a sample size of 20 subjects in each group to be sufficient to prove differences in the primary variable with a significance level <0.05. However, as this is "first time ever" type of pilot study on sublingual immunotherapy and exhaled breath temperature in grass-pollen patients, this estimate is relative. By all means this study will identify trends to be used for sample size calculations in future studies. During the second year of the study when all patients will be on active treatment with 5 grass allergen extract, carry over effects from the first year of treatment with 5 grass allergen extract or placebo on exhaled breath temperature will be explored.

Inclusion Criteria:

• 60 randomized patients from either sex
• age range 5-55 years
• included patients should have a proven grass pollen sensitization

Exclusion Criteria:

• age under or above the stated
• lack of any other concomitant allergen sensitivities that may blur the clinical course of the natural exacerbation due to pollen