Patient population
The Ethics Committee of the Charité University Hospital approved this study (EA2/009/07). All investigations were conducted according to the principles expressed in the Declaration of Helsinki. The patients diagnosed with CRS according to the EPOS 2012 criteria (16) were recruited to participate in the study. All subjects gave their written informed consent. Control subjects were recruited from patients undergoing inferior turbinate surgery but free of CRS symptoms, as per EPOS 2012 (16). Steroids (oral/ nasal) were not taken four weeks before surgery. Leukotriene inhibitors were not used two weeks before surgery. Patients were considered allergic according to clinical allergy symptoms (positive skin prick test results or elevated specific IgE-levels to aeroallergens plus present allergy symptoms). Subjects were registered as having asthma upon clinical diagnosis by a pulmonologist. N-ERD diagnosis was made based on the history of reactions to NSAIDs. Of 151 patients from the Berlin cohort, 91 nasal biopsies were obtained from 66 CRS patients and 25 control subjects. The CRS group consisted of 66 patients (mean age 42.3 years [min 25, max 65] 26 females, 40 males). The control group consisted of 25 individuals (mean age 31.4 years [min 18; max 60]; 12 females; 13 males).
In detail, in the CRS group were included 26 CRSwNP patients (mean age 47.2 years [min 28, max 65] 11 females, 15 males ) and 40 patients with CRSsNP (mean age 39.8 years [min 25, max 54]; 15 females, 25 males).