Increased IL-1α expression in chronic rhinosinusitis with nasal polyps

Purpose To examine whether and how interleukin (IL)-1 alpha is involved in chronic rhinosinusitis with nasal polyps (CRSwNP). Methods Nasal polyp (NP) and control tissues were collected from CRSwNP patients and control subjects. The expression of IL-1 alpha and other proinflammatory cytokines (IL-1 beta, IL-8 and IL-13, etc.), as well as neutrophil and eosinophil accumulation, were examined in sinonasal tissues using immunohistochemical (IHC), immunofluorescent (IF) staining, qPCR, and Luminex, respectively. Moreover, the regulation of IL-1 alpha expression and its effects on other proinflammatory cytokines were evaluated in cultured nasal epithelial cells (NECs). Results The mRNA and protein levels of IL-1 alpha were significantly higher in NP tissues compared to that in control tissues. IL-1 alpha in polyp tissues was mainly located in epithelial cells and neutrophils. Polyps IL-1 alpha level was significantly associated with IL-8, IL-1 beta, IL-6, IL-4 and IL-13 production, as well as tissue neutrophil infiltration. Moreover, poly (I:C), lipopolysaccharides, Flagellin, R848 and cytokines (IL-4, IL-5, and IL-13) significantly increased the expression of IL-1 alpha in cultured NECs in vitro, and recombinant IL-1 alpha significantly promoted production of IL-8 and CXCL1 in cultured NECs. Conclusions These findings provided the evidence that IL-1 alpha were significantly increased in NP tissues, which may contribute to tissue neutrophilia in CRSwNP patients in China.