Increased circulating levels of plasma ATP in cystic fibrosis patients

Recent studies have shown that the cystic fibrosis transmembrane conductanc e regulator (CFTR), an ATP-binding cassette (ABC) transporter whose mutatio ns are responsible for cystic fibrosis (CF), permeates ATP. However, little information is available concerning extracellular ATP concentrations in CF patients. Thus, the goal of this preliminary study was to determine the ci rculating levels of plasma ATP in CF patients. Circulating levels of plasma ATP were determined by the luciferin-luciferase assay in both CF patients and healthy volunteer control subjects. The two groups were compared using an analysis of variance. CF genotype and age, which ranged from 7 to 56 yea rs, were also used to compare data by single-blind analysis. With comparabl e sample numbers, CF patients had statistically higher levels of circulatin g ATP (34%, P < 0.01) when compared by analysis of covariance with the age of the subjects as the cofactor. The CF patients bearing the Delta F508 gen otype had a 54% (n = 33, P < 0.01) higher plasma ATP concentration compared to controls, while patients bearing other CF genotypes were similar to con trols (n = 10, P < 0.4). We conclude that CF patients have higher circulati ng levels of ATP when compared to controls. Increased levels of plasma ATP, which is an important autocrine/paracrine hormone in many cell types, may be associated with chronic manifestations of the disease.