Eosinophilic Chronic Rhinosinusitis with Nasal Polyps and the JESREC Study

Chronic rhinosinusitis with nasal polyps (CRSwNPs) is a heterogeneous disease. Eosinophilic CRSwNPs (ECRS) is a subgroup of CRSwNPs, associated with severe eosinophilic infiltration and is intractable. Its symptoms include loss of smell, nasal obstruction, and viscous nasal discharge. Asthma and nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD) are the major comorbidities of ECRS. ECRS can be easily diagnosed using the clinical scores of the Japanese Epidemiological Survey of Refractory Eosinophilic Chronic Rhinosinusitis (JESREC) study. We subdivided CRSwNPs into non-ECRS and mild, moderate, and severe ECRS based on the algorithm of the JESREC study. This classification was significantly correlated with the prognosis after endoscopic sinus surgery (ESS). Remarkably, this algorithm may provide useful information to clinicians about the refractoriness of CRS before ESS. The cause of ECRS is uncertain, although type 2 inflammation is dominant for eosinophilic infiltration through various pathways. The gene expression of the nasal polyps was analyzed using a next-generation sequencer. We identified some of the factors involved in ECRS, including periostin, which can be used as a biomarker. The coagulation system is activated, and the fibrinolysis system is suppressed, leading to the deposition of fibrinous networks in the nasal polyps. Therefore, a fibrin-degrading agent could be utilized for ECRS treatment.