Natural killer cell activity in specific and non-specific bronchial challenge.

In specific bronchial challenge with birth, mugwort, or timothy pollen, five asthmatics showed a significant increase in peripheral blood natural killer (NK) activity in conjunction with bronchoconstriction. In non-specific bronchial challenge with histamine, four patients showed a significant initial decrease of NK activity followed by a later augmentation of reactivity. The later boost of NK activity was detectable also a trend in specific bronchial challenge. No significant changes of NK activity were observed during control days when no bronchial challenges were performed. The results indicate that pulmonary hypersensitivity reactions are associated with augmentation of NK activity.