Providing a detailed understanding of cellular and gene changes that happen in the human lung with COPD, a new study has for the first time developed a blueprint of a COPD-affected lung. The study, led by Maor Sauler, assistant professor of medicine, and John McDonough, an instructor at the Yale School of Medicine, used single-cell RNA sequencing to measure gene activity within each individual cell of a tissue sample and used it to compare the lung tissue of patients with and without COPD. The researchers also said in their report, published in Nature Communications, that they focused on a subtype of alveolar epithelial cells, a cell population that lines the inside surface of the alveoli. The report highlighted that the genes known to be associated with predisposition to COPD were mostly expressed in structural cells of the lung and not infiltrating immune cells.