Single-cell RNA sequencing of surgical CRS samples [58] and epithelial cell cultures [59] identified high TSLP expression levels in basal cells, and sequencing of basal cells obtained from patients with CRSwNP found higher TSLP expression than in cells of those with CRSsNP and greater numbers of TSLP+ basal cells [46]. Here, TSLP is linked to chronic rhinosinusitis without nasal polyps.