Background Allergic rhinitis (AR) is a non-infectious chronic inflammatory disease of the nasal mucosa, which is mainly mediated by IgE after the body is exposed to allergens. It has been shown that transplantation of human mesenchymal stem cells (MSCs) into AR animal models can improve the AR behavioral phenotype. Furthermore, there are recent studies that states exosomes are the main mediators of MSC therapy. However, the effect of exosomes on AR has not been investigated. Methods In the established AR mouse model, different concentrations of MSC-derived exosomes (MSCs-Exo) were applied via intranasal delivery. The AR symptom scores, the eosinophils in the nasal mucosal section, the inflammation infiltration in the spleen section, and IgE, ovalbumin-specific IgE (OVA-sIgE), histamine, IgG1, IgG2a and other Th1/Th2 related inflammatory factors were evaluated by Hematoxylin–eosin staining, Elisa, real-time PCR. Results We found that intranasal administration of MSCs-Exo could not only reduce the behavior of nasal scratching and sneezing in mice, but also cause a decline in related immune indicators via the MAPK pathway, including the spleen index, tissue staining, and the expression of inflammation-related cytokines. Moreover, we found that the optimal concentration of MSCs-Exo was 4×10 8/mL. Conclusion The significant beneficial effects of exosomes may be exploited to develop a new, non-invasive treatment strategy for AR.

CircRNA expression profile and circRNA-miRNA-mRNA crosstalk in allergic rhinitisTo the Editor,Allergic rhinitis (AR) is a chronic multi-factorial inflammatory disease, with a prevalence on the rise in China1. CircRNAs, a newly discovered family of endogenous non-coding RNAs, function in various biological processes2. For instance, circRNAs are involved in neuronal activities, tumor development, and innate immune responses, inflammatory diseases3-4. However, the roles of circRNAs in AR remain unclear. In this study, using high-throughput sequencing (HTS), we explored the circRNA, miRNA, and mRNA expression profiles in nasal mucosa from AR patients, and constructed a differentially expressed (DE) circRNA-DEmiRNA-DEmRNA network to illustrate the molecular mechanism in AR.This study was approved by the Ethics Committee of the First Affiliated Hospital of Nanjing Medical University and each patient provided written informed consent. Patients and methods are detailed as online data.