Aberrant free radical activity in cystic fibrosis.

It has been suggested that the molar ratio of octadeca 9,11 dienoic acid to linoleic acid in biological material provides an index of activity along the non-peroxide pathway of a free radical attack on polyunsaturated fatty acids. In 17 adults with cystic fibrosis the 'molar ratio' in nasal epithelial cells--a recognised target of the disease--exceeded that in 20 controls (median 2.09%, range 1.70-3.01% versus 1.56, 0.92-2.23%, p = 0.0002). The difference was also apparent, although less stark, upon analysis of serum in a further 22 CF patients (2.48%, 1.60-5.24%) and 25 controls (1.96%, 0.81-3.90%, p = 0.0348). There was no correlation between the 'molar ratio' and blood white cell count or erythrocyte sedimentation rate, severity of lung or liver disease, indicating that the raised values are a primary feature, rather than reflecting disease severity. Aberrant free radical activity may underlie cellular dysfunction in cystic fibrosis.