Fig. 9

Efferocytosis inhibition and neutrophil elastase activity in PCD sputum. A Healthy donor-derived M2 macrophages were exposed for 3 h to sputum from patients with primary ciliary dyskinesia (PCD) with (n = 9) or without (n = 9) positive bacterial sputum culture. Subsequently, apoptotic neutrophils from a healthy donor were added, and the percentage of efferocytosing macrophages was determined. B A dilution series of native human neutrophil elastase (NE) was created, and the elastinolytic activity was measured to create a standard curve. Elastinolytic activity is displayed in relative fluorescence units (RFU) per min. C Elastinolytic activity was measured in the sputum of patients with PCD with (n = 18) or without (n = 18) positive bacterial sputum culture, and patients with non-PCD, non-CF bronchiectasis with positive bacterial sputum culture (BE, n = 5). D The NE immunoreactivity was measured in the sputum of patients with PCD by ELISA, and correlated to the elastinolytic activity in corresponding sputum samples, p = 0.3124. E The elastinolytic activity in sputum of PCD patents with positive bacterial sputum culture was measured and correlated to the forced expiratory volume in one second (FEV₁% pred) as measured on the day that the sputum was collected, p = 0.0422. F The elastinolytic activity in sputum of PCD patients without positive bacterial sputum culture was measured and correlated to FEV₁% pred, p = 0.6830. G The elastinolytic activity in sputum of PCD patients with (black circles, n = 9) or without (open circles, n = 9) positive bacterial sputum culture was measured and correlated to the inhibitory effect of sputum on efferocytosis by healthy donor-derived M2 macrophages, p = 0.5505. The inhibitory effect is displayed as % inhibition relative to a control condition without sputum