Research highlights from the 2018 European Respiratory Society International Congress: airway disease. - Schleich, F; Bikov, A; Mathioudakis, AG; McDonnell, M; Andersson, C; Bonini, M; Uller, L; Idzko, M; Singh, D; Lopez-Campos, JL; Bossios, A; Adcock, IM; et al. (ERJ Open Research, 2019)