IL4 and inflammation: We speculate that other pathways may be more dominant in the development of eosinophilic inflammation in the nasal polyposis in these subgroups (IL4/IL13 dominant type-2 inflammation) or that the dose of mepolizumab may be insufficient to reduce eosinophilic inflammation at the tissue level (the mepolizumab dose used in the two, abovementioned studies on CRSwNP was 750 mg; the dose used in the present study was 100 mg).