Effect of Bacterial Lysate on Nasal Carriage of Staphylococcus Aureus

Inclusion Criteria: * Children of both genders aged 5 to 17 years. * Children with grass pollen-induced allergic rhinitis recognized and treated according to current ARIA (Allergic Rhinitis and its Impact on Asthma) recommendations. * Positive skin prick test to grass pollen allergens or positive specific IgE (defined as ≥ class 2, ≥ 0,70 kU/l) against timothy grass pollen allergens. * Presentation of clinical symptoms of the allergic rhinitis (rhinorrhea, nasal congestion, nasal itching, sneezing) in at least two recent grass pollen seasons in Poland before inclusion in the study. * Proper use of polyvalent mechanical bacterial lysate sublingual tablets. * Written informed consent obtained from parents/guardians before any study related procedures are performed. Exclusion Criteria: * Patient received mechanical or any other polyvalent bacterial lysate immunostimulation within the previous 12 months before randomisation visit. * Patient received oral/subcutaneous allergen-immunotherapy within the previous 3 years before the start of the study. * Vaccination performed within 3 months before the beginning of the study. * Deficiencies in cellular and humoral immunity. * Treatment with antibiotics within the last 1 month before the start of the study. * Treatment with systemic corticosteroids within the last 6 months before the start of the study. * Pregnant or breastfeeding woman. * Other chronic conditions of the nose or nasal sinuses.