Sublingual immunotherapy with natural grass pollen extracts: an appraisal of the evidence

Danilo Di Bona, Maria Stefania, Leto-Barone, Simona La Piana and Gabriele Di Lorenzo

Many clinical studies have demonstrated that sublingual immunotherapy is effective against allergic symptoms, but caution must be exercised with these conclusions because of the wide variation among different studies in, for example, allergen dose used, type of treatment, patient selection and type of outcome measures. In order to overcome the inconsistency between the results of different studies and to assess the magnitude of the treatment effect, we performed a systematic review of double-blind, placebo-controlled, randomized clinical trials of grass pollen-specific immunotherapy for the treatment of seasonal allergic rhinoconjunctivitis in adults and children. Our conclusions were that sublingual immunotherapy (SLIT) with grass allergens improves rhinosinusitis symptoms and that it reduces the need for medications compared with placebo in adults. Further studies are needed to define the role of SLIT with grass allergens in children.