Reduced phagocytosis of pathogenic bacteria by neutrophils from COPD patients

Acute exacerbations of COPD are the commonest cause of acute medical admissions in the UK, with ∼50% associated with bacterial infection. An acute bacterial insult is usually associated with increased recruitment and activation of neutrophils. COPD is characterized by airway neutrophilia; however, despite increased numbers of these cells, bacterial colonization persists. This study examined whether neutrophil phagocytosis was altered in COPD. Neutrophils were obtained from COPD, smoking and healthy subjects and phagocytosis of fluorescently-labelled polystyrene beads, Haemophilus influenzae (HI) or Streptococcus pneumoniae (SP) measured by flow cytometry. Neutrophils from all subjects ingested beads similarly showing that all cells were capable of phagocytosis. Neutrophils from all subjects phagocytosed SP with a maximum response at 5 min, however COPD neutrophils ingested significantly less SP (p