(A) Lysosomal membrane permeabilization (LMP) and (B) cell death (apoptosis, necrosis and total cell death) in cultures of oxidatively stressed human lung macrophages that were retrieved from healthy subjects (n = 7), lung transplant recipients without azithromycin (n = 5) and with azithromycin treatment (AZM; 250 mg three times per week) (n = 3). LMP was assessed by cytosolic/nuclear green fluorescence due to acridine orange leakage into the cytosol (arbitrary units; A.U.) in non-oxidatively stressed lung macrophages (open symbols) and oxidatively stressed lung macrophages immediately after a 1-h oxidant exposure (filled symbols). Cell death, which appeared 10 h after the end of oxidant challenge, was assessed by typical morphology using a phase contrast microscope and by the fraction of apoptotic DNA (both methods gave similar results for apoptosis). In the non-oxidatively stressed cultures, cell death was < 3%. For details, see the Methods section. Values are the means ± 1 SD. Significant differences are indicated as follows: * p < 0.05 and ** p < 0.01, # p < 0.05 and ## p < 0.01 (vs. healthy subjects), § p < 0.05 and §§ p < 0.01 (vs. transplant recipients without AZM).