Respiratory epithelial ion transport in patients with disseminated bronchiectasis

The nosological limits between disseminated bronchiectasis and cystic fibro sis (CF) remain unclear. In patients with isolated congenital bilateral abs ence of the vas deferens, a forme fruste of the CF disease, a normal baseli ne nasal transepithelial potential difference (PD) but an impaired response to pharmacological interventions have been reported. The purpose of the pr esent study,vas to explore ion transport in respiratory epithelium from pat ients with disseminated bronchiectasis. The PD under both baseline and pharmacological interventions was investigat ed in 13 healthy subjects, six patients with genetically proven CF and 15 p atients with disseminated bronchiectasis as confirmed by computed tomograph y scan. Baseline PD was similar in the control and bronchiectasis groups but, as ex pected, was significantly more negative in the CF group. Patients,vith bron chiectasis responded to pharmacological tests (sequential perfusion with am iloride, chloride-free solution, isoprenaline and uridine triphosphate (UTP ) similarly to healthy subjects. In contrast, CF patients exhibited an incr eased response to amiloride and an impaired response to chloride-free solut ion and isoprenaline. The data show that patients with disseminated bronchiectasis exhibit normal electrophysiological properties in their nasal epithelium. Nasal transepit helial potential difference including pharmacological tests may appear a va luable diagnostic procedure for cystic fibrosis with disseminated bronchiec tasis.