Blood Biomarker Spots At-Risk Pulmonary Fibrosis Patients

α-defensin levels found higher in patients with exacerbations versus stable disease

THURSDAY, July 16 (HealthDay News) -- A newly discovered blood biomarker could help clinicians identify patients with idiopathic pulmonary fibrosis (IPF) who are at risk for acute exacerbations, according to a study in the July 15 issue of the American Journal of Respiratory and Critical Care Medicine.

Kazuhisa Konishi, M.D., of the University of Pittsburgh School of Medicine, and colleagues extracted ribonucleic acid from 23 patients with stable IPF, eight patients with acute exacerbations (IPF-AEx), and 15 patients with normal lungs. The investigators analyzed gene activity profiles for the three groups to determine the signature gene expression for IPF-AEx compared to stable disease.

Though gene expression in IPF and IPF-AEx were similar for the genes that distinguished diseased lungs from normal lungs, the investigators identified 579 genes that were expressed differently in patients with stable disease and those with acute exacerbations. In particular, the investigators discerned high activity in the CCNA2 gene, as well as high plasma levels of a protein called α-defensin, in patients undergoing an exacerbation, making it a possible biomarker in a blood test to identify patients at risk for sudden lung function deterioration.

"Our results indicate that IPF-AEx is characterized by enhanced epithelial injury and proliferation, as reflected by increases in CCNA2 and α-defensins and apoptosis of epithelium. The concomitant increase in α-defensins in the peripheral blood and lungs may suggest their use as biomarkers for this disorder," the authors conclude.

Three of the investigators are involved in a patent application for the use of peripheral blood proteins as disease biomarkers, and another has received study grants from pharmaceutical companies.

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