Title: Notch4, uncovering an immunomodulator in allergic asthmaAuthors: Beatriz Moyaa, Manali Mukherjeeb and Parameswaran Nairba. Department of Allergy, Hospital Universitario 12 de Octubre, Madrid, Spainb. Division of Respirology, Department of Medicine, McMaster University, Hamilton & Firestone Institute for Respiratory Health, St Joseph’s Healthcare, Hamilton, ON, CanadaCorrespondence to : Beatriz Moya. Allergy Department. Hospital Universitario 12 de Octubre, Madrid, SpainEmail:[email protected] : Dr. Mukherjee is supported by investigator award from Canadian Institutes of Health Research and Canadian Allergy, Asthma, and Immunology Foundation. She has received honorarium from AZ, GSK and her university has received grants from Methapharm Speciality Pharmaceuticals. Dr. Nair is supported by the Frederick E. Hargreave Teva Innovation Chair in Airway Diseases. He has received honoraria from AZ, Sanofi, Teva, Merck, Novartis and Equillium and his university has received research grants from AZ, Teva, Sanofi, Novartis, BI and Methapharm. The authors recognize Dr. Anna Globinska for graphical abstract design and Dr. Rodrigo Jiménez-Saiz for critical review of the manuscript.Keywords: Allergic asthma; Airway inflammation; Th2 cell; Th17 cell; Treg cell; Notch4 receptorAbbreviations: Th, T helper; UFPs, pollutant ultrafine particles; AMs, alveolar macrophages; Treg cells, regulatory T cells; ILC2s, type 2 innate lymphoid cells; GDF15, cytokine growth and differentiation factor 15; IL, interleukin; IL-6R, interleukin-6 receptor; IL-4R, interleukin-4 receptorWord count: 918/1000