TLR4 and TLR9 Expression in Different Phenotypes of Rhinitis

Abstract

Background. Toll-like receptors (TLRs) represent a family of evolutionarily conserved proteins, that represent a fundamental link between innate and adaptive immune responses. Aim. The purpose of this study was to investigate the expression of TLR4 and TLR9 in the normal nasal mucosa and in the mucosa of subjects with different phenotypes of rhinitis. Methodology. A confocal analysis of TLR4 and TLR9 (co)expression was carried out on biopsies from the inferior turbinate obtained from 4 patients affected by persistent allergic rhinitis, 8 patients with chronic rhino-sinusitis, and 6 patients with vasomotor rhinitis The results were compared with those of specimens obtained from 4 subjects undergoing nasal surgery, but with signs of nasal inflammation. Results. TLR4 and TLR9 were expressed in the healthy nasal mucosa; TLR4 and TLR9 expression was significantly decreased in allergic rhinitis. TLR4 was over expressed in the epithelium of chronic rhino-sinusitis. Both TLRs were co-expressed in the sub-epithelial infiltrate of chronic and vasomotor rhinitis, even though this expression was higher in the former compared with the latter. Conclusions. This study indicates that TLR4 and TLR9 show a different pattern of expression in different phenotypes of rhinitis, possibly related to the type and severity of the disease.

Role of Toll‐like receptor 9 signaling on activation of nasal polyp–derived fibroblasts and its association with nasal polypogenesis

“…For instance, Tengroth et al . found from CRSwNP patients that TLR9 expression was decreased in turbinate epithelial cells, and Lauriello et al . found that TLR9 expression was decreased in nasal mucosal tissue taken from CRSwNP patients.…”

Release of Type 2 Cytokines by Epithelial Cells of Nasal Polyps

“…Wang et al [27] reported that nasal polyp epithelial cells mainly express TLR3, which is engaged by poly(I:C) [28], while expression of TLR4 was very low. On the other hand, mRNA expression of TLR4 has been reported to be significantly increased in chronic rhinosinusitis tissues compared with that in nasal polyps [29] and TLR4 was overexpressed in the epithelium of chronic rhinosinusitis, evaluated by confocal analysis [30]. CRSsNP is a heterogeneous disease and the frequency of type 2 inflammation has been reported to be even higher than type 1 inflammation in Western world.…”

Association between Vasomotor Rhinitis and Irritable Bowel Syndrome

“…TLR activation triggers a cascade of reactions, which lead to increased expression of proinflammatory genes. 30 Lauriello et al 25 pointed out that, in VMR, both TLR4 and TLR9 seemed to be significantly downregulated. 8–31 Results of biopsy study 26 indicate that the expression of the TLR family is altered in IBS.…”