Much ado about Biologicals: Highlights of the Master Class on Biologicals, Prague, 2018

To the Editor, Novel insights into the interactions between our genome, exposome, and innate and adaptive immunity underlying asthma and allergic disease prompted the development of targeted treatments including biologicals and small molecules (Figure 1). These novel agents may revolutionize the treatment of asthma and related conditions, but simultaneously impose challenges on physicians and researchers. These topics were addressed in the Master Class on “Personalized treatments of chronic inflammatory upper and lower airways disease: biologicals, immunomodulators and other targeted therapeutics,” organized by the sections Asthma, ENT, and Immunology of the European Academy of Allergy and Clinical Immunology (EAACI). Interactions exist between environmental factors, including air pollutants, allergens, viruses, and the microbiome, and our immune system. Mucosal surfaces provide barrier and interface functions, while the epithelium itself can be subject to functional adaptation based on microenvironmental cytokine profiles. Dendritic cells (DCs) migrating between epithelium and lymph nodes present antigens to T cells and thus elicit systemic immune responses or tolerance to antigen. Likewise, innate lymphoid cells 2 (ILC2) contribute to type 2 (T2) responses by rapid production of IL‐5 or IL‐13 and, similar to DCs and T cells, also respond to epithelial alarmins (TSLP, IL‐25, IL‐ 33). Adaptive responses enable individual immunological memory and advanced target repertoires using T cells and B cells, including