Senescent CGD neutrophils did not show apoptosis in vitro. Neutrophils from normal donors (A and C) and CGD patients (B and D) were cultured in medium for 24 hours. The cells were treated with hypotonic propidium iodide solution and the DNA content was analyzed by flow cytometry (A and B). Morphology of these same cultures is shown for comparison with May-Grünwald-Giemsa–stained preparations photographed at a magnification 1,000× (C and D).