Cross-reactivity and allergic rhinoconjunctivitis: Practical implications for immunotherapy with a timothy grass pollen tablet

Specific immunotherapy (SIT) is currently the only causal treatment of allergic respiratory diseases. Sublingual immunotherapy (SLIT) is widely utilized for allergic rhinitis to grass pollen. Its effectiveness is due to the presence in the oral mucosa of immune cells with a regulatory phenotype, which is why SLIT is particularly suitable for inducing an antigen-specific tolerance with greater safety. Among the plants, it has been demonstrated in recent years many structural homologies. The existence of this high cross-reactivity can explain why allergens of timothy administered to a patient allergic to various grasses protect against all allergens in this family. Thus, recently, there appeared a new form of SLIT based on a tablet of allergen extract of timothy grass (Grazax (R)) used in order to "change the course of rhinitis and allergic conjunctivitis triggered by pollen Grasses in adults and children (from 5 years) with clinical symptoms due to an allergy to grass pollen". The clinical development of this tablet has indeed demonstrated its effectiveness in reducing allergic symptoms and consumption of symptomatic treatments for patients. After 5 years of availability and more than 50,000 year-equivalent treatments, the systematic review of the safety profile of this tablet is very favorable with less than two serious incidents per 1000 treatments. While the prevalence of allergic rhinitis has doubled in 10 years and that it affects 18% of adults and 11 to 27% of children in France, how will be use this new form of desensitization? (C) 2012 Published by Elsevier Masson SAS.