Increased nitric oxide production by neutrophils in bronchial asthma.

This study was designed to assess the production of nitric oxide (NO) by neutrophils in bronchial asthma. Thirty asthmatic patients (ten each of mild, moderate and severe asthma) and ten healthy controls were included in the study. Neutrophils from peripheral venous blood were stimulated with latex, and production of nitrite (an NO metabolise) and L-citrulline (a co-product of NO) was studied. It was postulated that peripheral blood neutrophils, being in a primed or activated state in asthma, would reflect the changes occurring in bronchial tree neutrophils. Nitrite and L-citrulline production by neutrophils was significantly higher in asthmatics (p < 0.001) and increased with disease severity. A strong negative correlation was observed between peak expiratory flow and both nitrite (r = -0.87, p < 0.001) and L-citrulline (r = -0.88, p < 0.001) production. It is concluded that nitric oxide production by neutrophils is increased in bronchial asthma and can possibly contribute to airway narrowing and disease severity.