Asthma is a heterogeneous disease with multiple clinical phenotypes and endotypes,1 each with inflammatory etiology, triggers, and increasingly diverse treatment options.2,3 It is increasingly accepted that a biomarker-based stratification is needed to match patients with targeted therapies for personalized treatment.4,5 In this regard it is advantageous to have data from the lung itself rather than a surrogate tissue.6 Sputum provides a non-invasive and economical sampling of inflammatory cells with which to interrogate the inflammatory state of the lung. Using flow cytometry we analyzed sputum cells from asthma and COPD patients and smokers to determine inflammatory cells and the expression levels of select biologic drug targets.