Respiratory epithelial ion transport in patients with disseminated bronchiectasis

The nosological limits between disseminated bronchiectasis and cystic fibrosis (CF) remain unclear. In patients with isolated congenital bilateral absence of the vas deferens, a forme fruste of the CF disease, a normal baseline nasal transepithelial potential difference (PD) but an impaired response to pharmacological interventions have been reported. The purpose of the present study was to explore ion transport in respiratory epithelium from patients with disseminated bronchiectasis. The PD under both baseline and pharmacological interventions was investigated in 13 healthy subjects, six patients with genetically proven CF and 15 patients with disseminated bronchiectasis as confirmed by computed tomography scan. Baseline PD was similar in the control and bronchiectasis groups but, as expected, was significantly more negative in the CF group. Patients with bronchiectasis responded to pharmacological tests (sequential perfusion with amiloride, chloride-free solution, isoprenaline and uridine triphosphate (UTP) similarly to healthy subjects. In contrast, CF patients exhibited an increased response to amiloride and an impaired response to chloride-free solution and isoprenaline. The data show that patients with disseminated bronchiectasis exhibit normal electrophysiological properties in their nasal epithelium. Nasal transepithelial potential difference including pharmacological tests may appear a valuable diagnostic procedure for cystic fibrosis with disseminated bronchiectasis.