DNA CONCENTRATION AND LENGTH IN SPUTUM OF PATIENTS WITH CYSTIC-FIBROSIS DURING INHALATION WITH RECOMBINANT HUMAN DNASE

Background - The clinical benefit of the administration of aerosolised recombinant human DNase (rhDNase) on pulmonary function in patients w ith cystic fibrosis has already been demonstrated but the biochemical action of rhDNase on DNA in bronchial secretions in vivo has not yet b een investigated. Methods - Sputum was collected from 135 patients wit h cystic fibrosis before and during treatment with aerosolised rhDNase and examined to ascertain DNA concentration and length by colorimetri c assay and densitometry of gel separated DNA. Results - Treatment wit h rhDNase reduced the concentration and the size of extracellular DNA in the sputum. The median interquartile range of DNA length decreased from 0.5-2.6 kbp before treatment to 0.3-1.0 kbp during treatment. Con clusions - rhDNase was delivered to the secretions and was enzymatical ly active in vivo.