Freshly isolated granulocytes from patients with BTHS display normal morphology and mitochondrial structures. Granulocytes from patients with BTHS were tested for internal signs of apoptosis in a freshly purified preparation (A,C) and upon overnight culture (B,D). (A-B) Neutrophil morphology by light microscopy. (C-D) Mitochondrial staining with MitoTracker GreenFM assessed by confocal laser scanning microscopy. All bars are 5 μm. Results shown are representative of 10 experiments performed on different occasions with cells from 6 patients in total. For comparison with normal neutrophils, see Maianski et al.¹¹