Microarray gene analysis of Toll-like receptor signaling elements in chronic rhinosinusitis with nasal polyps.

OBJECTIVE: To identify the regulatory mechanisms of Toll-like receptor (TLR)-associated genes in chronic rhinosinusitis (CRS) with nasal polyps (NP) using gene microarray analyses.

METHODS: We pooled: (1) NP biopsy specimens from 10 nonatopic CRS patients and (2) healthy mucosal tissue from 10 additional nonatopic healthy patients (controls). These pooled samples were evaluated by gene microarrays that included 125 genes for TLRs and associated signaling elements. To validate gene product expressions, 20 NP and 15 normal nasal turbinate tissues were evaluated for TLR-9 expression by immunohistochemical staining and Western blots using samples from gland cells, epithelial cells, and mononuclear cells cytologically identified by HE staining.

RESULTS: In pooled NP samples compared to pooled controls, 4 genes were upregulated (≥ 2-fold higher expression) and 19 were downregulated (≤ 0.5-fold lower expression). TLR-9 was an upregulated gene in NP tissue. Compared to control tissue, there were significantly higher percentages of TLR-9 positively stained NP gland cells, epithelial cells, and mononuclear cells (p < 0.001). On Western blots, while both normal and NP tissues expressed TLR-9 protein, the expression was significantly more pronounced for NP tissue (p < 0.001).

CONCLUSIONS: Inflammation associated with CRS may be due to dysregulated innate immune elements, particularly TLR-9 and its associated signal transduction elements, which may impact upon prolonged activation of adaptive immune responses in the sinonasal mucosa.