PTGDR2 and sinusitis: Meanwhile, this study also observed that CRTH2- ILC2 from peripheral blood and nasal polyps of patients with chronic sinusitis has low expression of GATA3 mRNA and high expression of TBX21 mRNA and RORC mRNA, and can secrete IFN-γ in response to type 1 stimulation, which indicated that the occurrence of chronic sinusitis promoted ILC2s to acquire the character of producing IFN-γ ILC1.