TSLP and TSLPR mRNA increased in NP tissue from CRSwNP versus UT from CRSsNP and controls.Full-length protein decreased in NP tissue from CRSwNP versus CRSsNP and controls. Cleaved TSLP had greater biological activity than full-length TSLP. The gene discussed is TSLP; the disease is chronic rhinosinusitis without nasal polyps.