House Dust Mite Nonspecifically Induces Fluid Secretion from Nasal Glands

Abstract

Objective: Investigate the effects of the house dust mite (HDM) on fluid secretion in submucosal glands in nasal tissue and to compare its effects in control and diseased groups. In addition, we looked to see if PAR2 was involved in the HDM-induced fluid response. Method: Inferior nasal turbinate tissue was harvested from 26 patients with either allergic rhinitis (with HDM-specific IgE) and/or chronic rhinosinusitis, and eight controls. We used a microscope attached to a camera to quantify mucus bubbles secreted from individual submucosal glands in response to HDM extract and PAR2-AP (activating peptide). Results: HDM stimulated fluid secretion, and the diseased group showed a higher secretion rate than did the controls. Interestingly, there was no significant difference between the three diseased groups, and CRS patients without HDM-specific IgE were also stimulated by HDM. The nonspecific response induced by HDM was hypothesized to be through PAR2. The expression of PAR2 was predominant on the basolateral side of gland acini. HDM-induced secretion rates positively correlated with PAR2-AP-induced secretion rates. Carbachol responses and gland density were not different among the three groups. Conclusion: These findings suggest that HDM induces an IgE-independent nonspecific response from nasal submucosal glands, generating fluid secretion in allergic or infective nasal tissue, and PAR2 is at least partially involved in this process.