Bacterial biofilms are associated with inflammatory cells infiltration and the innate immunity in chronic rhinosinusitis with or without nasal polyps.

To investigate the role of bacterial biofilms in the pathogenesis of chronic rhinosinusitis, we applied scanning electron microscopy to detect bacterial biofilms, immunohistochemical and hemotoxylin-eosin staining to identify the types of inflammatory cells infiltration, and real-time PCR array analysis to evaluate the innate immune responses to bacteria biofilms. Biofilms were found in 14 of 19 (73.7%) of CRSwNP (chronic rhinosisusitis with nasal polyps), 11 of 15 (73.3%) of CRSsNP (chronic rhinosisusitis without nasal polyps), and none of biofilms were found in 13 normal controls. T helper lymphocytes, cytotoxic T lymphocytes, and neutrophils were the most frequently observed immune cells. The inflammatory cells did not reveal any significant differences in CRSwNP between with biofilms and without biofilms. CRSsNP with biofilms had significantly more neutrophils than CRSsNP without biofilms, and it was inclined to Th1 inflammatory response. Fifty and fifty-one genes were upregulated respectively in CRSwNP and CRSsNP with biofilms. Twenty genes were upregulated separately when comparing biofilms-positive CRSwNP with biofilms-positive CRSsNP. CRSwNP and CRSsNP with biofilms had different types of inflammatory cells infiltration and characteristic changes of the innate immunity. Further research about the direct role of bacterial biofilms in the pathogenesis of CRS will provide a new target for CRS.