Effect of mesenchymal stem cell therapy in animal models of allergic rhinitis: A systematic review and meta-analysis

Background: Allergic rhinitis (AR) is a worldwide problem that affects people of all ages, impairing patients' physical and mental health and causing great social expenditure. Animal studies have suggested the potential efficacy of mesenchymal stem cell (MSC) therapy in treating AR. Our meta-analysis was performed to evaluate the effect of MSC therapy in animal models of AR by pooling animal studies.Methods: The search was executed in PubMed, Embase, Web of Science, OVID, and the Cochrane Library for relevant studies up to February 2023. The applicable data were extracted from the eligible studies, and the risk of bias was assessed for each study. The meta-analysis was conducted using Review Manager (version 5.4.1) and Stata (version 15.1).Results: A total of 12 studies were included in the final analysis. Compared to the model control group, the MSC therapy group presented lower frequency of sneezing [(Standardized mean difference (SMD) -1.87, 95% CI -2.30 to -1.43)], nasal scratching (SMD -1.41, 95% CI -1.83 to -0.99), and overall nasal symptoms (SMD -1.88, 95% CI -3.22 to -0.54). There were also remarkable reductions after transplantation with MSCs in the levels of total immunoglobulin E (IgE) (SMD -1.25, 95% CI -1.72 to -0.79), allergen-specific IgE (SMD -1.79, 95% CI -2.25 to -1.32), and allergen-specific immunoglobulin G1 (SMD -1.29, 95% CI -2.03) in serum, as well as the count of eosinophils (EOS) in nasal mucosa (SMD -3.48, 95% CI -4.48 to -2.49). In terms of cytokines, MSC therapy significantly decreased both protein and mRNA levels of T helper cell 2 (Th2)-related cytokines, including interleukin (IL)-4, IL-5, IL-10, and IL-13.Conclusion: MSC therapy has the potential to be an effective clinical treatment for AR patients by attenuating Th2 immune responses, reducing secretion of IgE and nasal infiltration of EOS, and consequently alleviating nasal symptoms.