MicroRNA profiles in nasal mucosa of patients with allergic and nonallergic rhinitis and asthma

Background Rhinitis and asthma commonly coexist and are often regarded as “unified airways disease.” Evidence exists that microRNAs are important in controlling inflammatory processes, but little is known about their role in airway inflammation. The present study evaluated the inflammatory profiles of patients with allergic rhinitis (AR), with and without concomitant asthma, and of patients with nonallergic rhinitis (NAR). Methods We analyzed inflammatory cells, cytokines, and microRNAs from nasal biopsies and measured nasal nitric oxide (nNO) levels in 159 young adult subjects subdivided into 4 groups: (1) AR; (2) AR+asthma; (3) NAR; and (4) controls. Results We observed the upregulation of T‐helper 2 (Th2) cytokines and the trend of elevation of nNO levels in AR patients compared to controls. Subjects with current AR symptoms had increased levels of miR‐155, miR‐205, and miR‐498, but reduced levels of let‐7e. In addition, patients with positive skin prick test (SPT) reactions exhibited increased miR‐155 and miR‐205 expression and a decreased level of let‐7e, compared to subjects with negative SPT findings. Concomitant asthma had little effect on the inflammatory profile of AR. No significant changes in inflammatory markers were found in NAR patients compared to healthy controls. Conclusion Our results suggest that microRNAs miR‐155, miR‐205, miR‐498, and let‐7e may be important in the allergic inflammation present in nasal mucosa. Regarding NAR, our findings support the view that mechanisms other than inflammation are pivotal.