TGFB1 and chronic rhinosinusitis with nasal polyps: Activin A, follistatin and TGF-β1 were all spontaneously released by the samples, although the relative ratios released by tissue fragments from CRSsNP and CRSwNP samples were significantly different, with a higher follistatin/activin A-ratio and a follistatin/TGFß1-ratio (with less overall TGF-β1) in CRSwNP than in CRSsNP.