High-dimensional mass cytometry analysis of immune cells in emphysematous lung tissue

The lung niche provides important signals for proper functioning and interactions between epithelial and immune cells, and is suggested to be altered in emphysema in chronic obstructive pulmonary disease (COPD). Here, we determined whether high-dimensional mass cytometry (cytometry by time-of-flight; CyTOF) analysis is feasible to identify immune cell populations in the lung and can be used to delineate immune functions in human ‘healthy’ and diseased lungs. Therefore, we performed a first CyTOF analysis to compare immune cells derived from non-emphysematous and severe emphysematous lung tissue. We isolated single cells from fresh non-emphysematous lungs (n=5), emphysematous lungs (n=15) and paired blood samples and stored them at -80°C. We applied a CyTOF panel comprising 39 antibodies to obtain a global overview of the immune cell composition in the lung. Finally, we analyzed data with Hierarchical Stochastic Neighbor Embedding (HSNE) and dual t-SNE to identify tissue-specific cell clusters. CyTOF analysis revealed distinct immune cell populations in human lung tissue, which clustered differently from blood-derived cells. Importantly, tissue myeloid cells from emphysematous lungs clustered differently from cells derived from non-emphysematous controls. We showed that CyTOF analysis of lung tissue is feasible, and reveals distinct features of myeloid populations in emphysematous tissue. We are now further expanding the panel to detect lung-specific markers. Furthermore, we will apply imaging mass cytometry to allow the simultaneous detection of up to 40 markers with spatial information in a single lung tissue section, allowing examination of altered cellular interactions in emphysema.