Therefore, the main objective of this study is to determine the levels of IL5RA gene expression in peripheral blood in a population of patients with nasal polyposis versus a control group and to analyze the differences in expression among different clinical phenotypes, and the possibility of considering IL5RA a suitable biomarker for nasal polyposis, with regards to a more precise approach to the treatment of CRSwNP. The gene discussed is IL5RA; the disease is Nasal polyposis.