Hyaluronan and type III procollagen peptide concentrations in bronchoalveolar lavage fluid in idiopathic pulmonary fibrosis

Abstract

The connective components hyaluronan (hyaluronic acid) and type III procollagen peptide were measured in bronchoalveolar lavage fluid in 22 patients with idiopathic pulmonary fibrosis and 21 healthy control subjects. The patients with idiopathic pulmonary fibrosis had higher concentrations of hyaluronan (median 46 μg/l) and type III procollagen peptide (median 0.45 μg/l) than the healthy controls (9 and < 0.2 μg/l; p < 0.001). The patients had normal serum concentrations of hyaluronan and of the procollagen peptide, and albumin concentrations in lavage fluid similar to those of the controls subjects. Neutrophil and lymphocyte counts in lavage fluid were increased on average 10 and two fold respectively in the patients with idiopathic pulmonary fibrosis and both correlated with the amount of hyaluronan recovered (p < 0.05). An inverse correlation was seen between the transfer factor for carbon monoxide and hyaluronan concentrations in lavage fluid in patients (p < 0.05). Deterioration in lung function and radiographic progression were seen over six months in 12 of the patients. These patients had higher lavage fluid concentrations of hyaluronan and type III procollagen peptide than the patients whose disease was stable (p < 0.01). Increased synthesis of hyaluronan and type III procollagen peptide in lung parenchyma may reflect activation or proliferation (or both) of pulmunary fibroblasts in idiopathic pulmonary fibrosis and seems to be linked to the severity and activity of lung disease.