Background: Eosinophils act as a secondary antigen-presenting cell (APC) to stimulate Th cell responses against antigens. IL-25 plays an important role on eosinophil activation in allergic asthma. The role of IL-25 on the classic APC functions of dendritic cells has been elucidated. However, whether IL-25 facilitates eosinophils for antigen presentation is unknown. Objective: To elucidate IL-25 on eosinophils antigen presenting function during allergic asthma and its related mechanism. Methods: Eosinophils from allergic asthma subjects were cultured with IL-25 and HDM to identify the co-stimulator molecules expression. Co-cultures of eosinophils and autologous naïve CD4+ T cells in the same culture system were to explore whether eosinophils had the capacity to promote Th cell differentiation in response to IL-25 engagement. In asthma mouse model, IL-25 -/- mice were exposed to HDM to investigate IL-25 functions on eosinophils during sensitization phase. The impact of IL-25 on the capacity for eosinophil taking up antigens and costimulatory molecules expression was evaluated. Mouse bone marrow derived eosinophils (BmEOS) were co-cultured with naïve CD4+T cells sorted from spleens under HDM and IL-25 stimulation to identify T cell differentiation. Results: IL-25 upregulated HLA-DR, PD-L1 and OX-40L expression on eosinophils from allergic asthma patients. IL-25 and HDM co-sensitized eosinophils promoted Th2 differentiation. In animal model, IL-25 -/- mice experienced restrained allergic pulmonary inflammation and reduced eosinophils chemotaxis during early sensitization phase. In vitro, IL-25 promoted antigen uptake by eosinophils. During BmEOS and naïve CD4+T cells co-culture, IL-25 accreted the proportion of CD4+Th2 cells, which was absent in CD4+T cells culture alone. Conclusion: Our data identify a novel role of IL-25 in enhancing eosinophils antigen presenting capacity to induce Th2 priming in the context of allergic inflammation.

Changes in sensitization rates in patients with asthma and/or rhinitis in China between 2008 and 2018: a national cross-sectional studyWanjun Wang1*, Jianhong Wang2*, Guihua Song3*, Hua Xie4*, Xiaoping Lin4*, Ruonan Chai4*, Rongfei Zhu5*, Yong He6*, Jun Tang7*, Junge Wang8*, Jinghua Yang9*, Lili Zhi10*, Lin Wu11*, Yan Jiang12*, Xiaoqin Zhou13*, Dongming Huang14*, Ning Wang15*, Rui Xu16*, Yuan Gao17*, Zhimin Chen18*, Jinling Liu18*, Xiaoli Han19*, Guolin Tan20*, Jinzhun Wu21*, Deyu Zhao22*, Jianjun Chen23*, Xiwei Zhang24*, Mengrong Li24*, Yuemei Sun25*, Yi Jiang26*, Weitian Zhang27*, Qianhui Qiu28*, Chuanhe Liu29*, Jie Yin30*, Guodong Hao31*, Huabin Li32*, Yongsheng Xu33*, Shaohua Chen34*, Hua Zhang35, Shi Chen36, Juan Meng37, Dan Zeng38, Wei Tang39, Chuangli Hao40, Jing Li1†, Nanshan Zhong1†, for the China Alliance of Research on Respiratory Allergic Disease*Contributed equally†Joint corresponding authors1 National Clinical Research Center for Respiratory Disease, State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University;2 The First People’s Hospital of Yibin, Sichuan;3 The First Affiliated Hospital of Henan University of Traditional Chinese Medicine;4 General Hospital of Northern Theater Command;5 Tongji Hospital, Tongji Medical College, Huazhong University of Science&Technology;6 The Affiliated Hospital of Medical School, Ningbo University;7 Foshan First people’s hospital;8 Beijing Hospital of Traditional Chinese Medicine;9 GuangDong Provincial Hospital of Chinese Medicine;10 The First Affiliated Hospital of Shandong First Medical University, Shandong Institute of Respiratory Diseases;11 Hangzhou Hospital of Traditional Chinese;12 The Affiliated Hospital of Qingdao University;13 Hubei Province Maternal and Child Health Hospital;14 Boai Hospital of Zhongshan City;15 Xi’an Children’s Hospital;16 The First Affiliated Hospital of Sun-Yat University;17 The First Affiliated Hospital of Zhengzhou University;18 Children’s Hospital of Zhejiang University School of Medicine, National Clinical Research Center for Child Health;19 Hebei General Hospital;20 Third Xiangya Hospital of Central South University;21 The Women and Children’s Hospital affiliated to Xiamen University;22 Children’s Hospital of Nanjing Medical University;23 Union hospital of Tongji medical college;24 The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University;25 Yu Huang Ding Hospital;26 The First Hospital of Shanxi Medical University;27 Shanghai Jiao Tong University Affiliated Sixth People’s Hospital;28 Zhujiang Hospital of Southern Medical University;29 Children’s Hospital Capital Institute of Pediatrics;30 Chengdu First People’s Hospital;31 Tangshan Gongren Hospital;32 ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, Fudan University;33 Children’s Hospital of Tianjin University;34 Guangdong Provincial People’s Hospital;35 The First Affiliated Hospital of Xinjiang Medical University;36 Hainan provincial people’s Hospital;37 West China Hospital of Sichuan University;38 Chongqing General Hospital, University of Chinese Academy of Sciences;39 Ruijin Hospital of Shanghai Jiaotong University;40 Children’s Hospital of Soochow University.