Blood Neutrophils are Reprogrammed in Bronchiectasis.

Introduction Excessive neutrophilic airways inflammation is the central feature of bronchiectasis, but little is known about neutrophils in bronchiectasis. The aim of this study was to assess blood neutrophil phenotype in bronchiectasis patients both whilst stable and during exacerbations. Methods In the clinically-stable arm of this study were 8-healthy volunteers, 8-mild and 8-severe bronchiectasis. In addition, 6-severe bronchiectasis patients were compared with 6-community-acquired pneumonia patients at the start and end of an exacerbation. We assessed neutrophils for spontaneous apoptosis, cell surface marker expression, degranulation, reactive oxygen species generation, phagocytosis and killing of Pseudomonas aeruginosa (PAO1). In addition, blood neutrophil function was compared to airway neutrophil function in bronchiectasis. Results In stable bronchiectasis, compared to healthy volunteers, blood neutrophils had: significantly prolonged viability; delayed apoptosis; increased CD62L shedding; upregu...