NADPH oxidase expression and activity in neutrophils from SCN patients. (A) Cell lysates of neutrophils purified from 2 patients (P1 and P3) and 2 healthy subjects (C1 and C3) were subjected to Western blot analysis with anti-gp91phox–, p47phox-, p67phox-, p40phox-, or p22phox-specific antibodies. The gp91phox appears as a broad smear because it is highly glycosylated. β-Actin was used to compare protein levels. (B) Neutrophils (2 × 10⁵) from patients 1 (P1) and 3 (P3) and from a healthy subject (CTR) were stimulated with 100 nM fMLP or 20 ng/mL PMA for 60 minutes. When required, cells were preincubated with 50 ng/mL G-CSF or GM-CSF for 30 minutes before fMLP addition. O₂⁻ release was measured by cytochrome c reduction. Results shown are expressed as the mean value + SD of 3 independent experiments. (C) Neutrophils from patient 2 (P2) and a healthy subject (CTR) were incubated with opsonized C albicans blastospores or E coli for 90 minutes. Neutrophils were then lysed, diluted, and plated on Sabouroud or LB agar Petri dishes. The CFUs were counted after an overnight incubation, and the percentage of killing was evaluated as in “Patients, materials, and methods.” Results shown are expressed as the mean value ± SD of 2 experiments. Statistical analysis demonstrates that antimicrobial activities of neutrophils against C albicans and E coli are reduced in SCN patient compared with a healthy subject (P < .05).