Asthma is a heterogeneous disease with multiple phenotypes. There are no tissue or
bronchoalveolar lavage biomarkers that are “specific” for asthma. Markers associated with
eosinophilic, neutrophilic, and paucigranulocytic asthma are discussed here, and those for
remodeling. Efforts are to compare tissue and lavage biomarkers with less invasive
measures, such as sputum, serum, or exhaled breath, to improve the treatment and
management of asthma.