Immunological background for treatments with biologicals in CRSwNP

Abstract
Background: Chronic rhinosinusitis (CRS) is a heterogeneous and multifactorial inflammatory disease of the nasal and paranasal mucosa. To date, no internationally standardized uniform classification has been developed for this disease. Usually, a phenotype classification according to CRS with (CRSwNP) and without (CRSsNP) polyposis is performed. However, through a variety of studies, it has been shown that even within these phenotypes, different endotypes of CRS exist, each with a different underlying inflammatory pathophysiology. In this mini-review, we aim to outline the essential immunological processes in CRSwNP and to highlight the modern therapeutic options with biologics derived from this disease. Methods: Current knowledge on the immunological and molecular processes of CRS, especially CRSwNP, was compiled by means of a structured literature review. Medline, PubMed, national/international trial and guideline registries as well as the Cochrane Library were all searched. Results: Based on the current literature, the different immunological processes involved in CRS and nasal polyps were elaborated. Current studies on the therapy of eosinophilic diseases such as asthma and polyposis are presented and their results discussed. Conclusion: Understanding the immunological basis of CRSwNP may help to develop new personalized therapeutic approaches using biologics. Currently, 2 biologics (dupilumab, omalizumab) have been approved for the therapy of CRSwNP (polyposis nasi) in Europe.