Single Cell Transcriptional Archetypes of Airway Inflammation in Cystic Fibrosis

Cystic fibrosis (CF) is a life-shortening multisystem hereditary disease caused by abnormal chloride transport. CF lung disease is driven by innate immune dysfunction that perpetuates inflammation. The airways provide a window into CF pathogenesis, as immune cells display exaggerated inflammatory responses and impaired phagocytic function, contributing to tissue injury. In order to define the transcriptional profile of this airway immune dysfunction, we performed the first single-cell transcriptome characterization of CF sputum. We show that the airway immune cell repertoire shifted from alveolar macrophages in HC to a predominance of recruited monocytes and neutrophils in CF. Recruited lung mononuclear phagocytes were abundant in CF, separated into three archetypes: activated monocytes, monocyte-derived macrophages, and heat-shock activated monocytes. Neutrophils were most prevalent in CF, with a dominant immature proinflammatory archetype. While CF monocytes exhibited proinflammatory features, both monocytes and neutrophils showed transcriptional evidence of abnormal phagocytic and cell-survival programs. Our findings offer an opportunity to understand subject-specific immune dysfunction and its contribution to divergent clinical courses in CF. As we progress towards personalized applications of therapeutic and genomic developments, we hope this inflammation profiling approach will enable further discoveries that change the natural history of CF lung disease.