IL10 and Nasal congestion: Although in the present study no significant effect was observed on the primary outcome i.e. nasal congestion, treatment with L. paracasei NCC2461 positively modulated several secondary endpoints: it significantly improved a key subjective clinical feature of allergic rhinitis, nasal pruritus, significantly decreased the percentage of leukocytes in nasal fluid, enhanced allergen specific IL-10 secretion by PBMC and tended to decrease IL-5 in the nasal fluid, both biological effects supporting the improvement in nasal pruritus.