Demonstration of neutrophil dysfunction in the serum of patients with cystic fibrosis.

The neutrophil function of 12 patients with cystic fibrosis was evaluated via the new Immunobead/NBT dye reduction test. While the neutrophils appeared to be hyperfunctional when studied in the standard assay using fetal calf serum, we demonstrated a significant neutrophil dysfunction when studied in their own respective serum. The dysfunction involved both the phagocytic and intracellular killing ability of the cells, which we postulate is due to an inhibitory factor present in the patient's serum. The inhibitory factor did not appear to be related to the level of circulating immune complexes.