Is Allergen-Specific Immunotherapy (AIT) Helpful in Treating CRSwNP?

Abstract

Chronic rhinosinusitis is a set of conditions involving inflammation, but its precise pathogenesis is, at present, unknown. CRS exhibits phenotypical heterogeneity, which is divided into two types: with nasal polyps (CRSwNP) and without (CRSsNP) nasal polyps. CRSwNP has been closely associated with allergic rhinitis (AR) due to the co-occurrence of the two and because both involve inflammation. The relationship between AR and CRSwNP remains subject to considerable debate, with the data gathered so far not pointing clearly in one direction. CRSwNP is being seen as a disorder wherein inflammation plays a key role and both the innate and adaptive immune systems are involved. Reports currently emerging have sought to explain the apparent paradox of cases where a patient has no systemic allergic response, yet does benefit from anti-IgE treatment, as representing a localized IgE-mediated allergic response. According to what is currently known and recommended by guidelines, allergy assessment in cases of CRSwNP is discretionary. It is uncertain whether AIT is beneficial in CRSwNP, given the absence of good-quality RCTs. The lack of supportive evidence, and the heterogeneous nature of the disease and of data currently available, means that it is not possible to make a recommendation to use immunotherapy in CRSwNP. However, in subjects with CRSwNP plus AR uncontrolled by pharmacotherapy, AIT should be considered.