Surfactant protein-A in lung lavage fluid obtained from patients with idiopathic pulmonary fibrosis

Alterations in surface-active material may contribute to the pathogenesis of idiopathic pulmonary fibrosis both by increasing the elastic recoil due to surface forces and by promoting alveolar collapse. This study intends to evaluate the surfactant protein-A levels in bronchoalveolar lavage in patients of idiopathic pulmonary fibrosis.

Ten patients of idiopathic pulmonary fibrosis (IPF) of either sex were taken up for estimation of surfactant protein-A (SP-A) levels in bronchoalveolar lavage. The final diagnosis of IPF was based on histopathology and high resolution CT. Ten controls were taken out of which five patients were histopathologically proven cases of sarcoidosis and five patients with normal chest X-ray and CT scan. History, physical examination and routine investigations were done to rule out any concomitant illness.

Age range of patients varied from 37-65 years (mean +/- SD of 50.65 +/- 9.05) and controls 30-62 years (42.50 +/- 9.95). Fiberoptic bronchoscopy and bronchoalveolar lavage was carried out and fluid aspirated was studied for surfactant protein-A. The level of surfactant protein-A recovered was lower in patients with idiopathic pulmonary fibrosis in comparison to control group p < 0.01 (1.86 +/- 1.26 and 5.76 +/- 2.0 microg/ml respectively). The levels of surfactant protein-A also revealed that the level decreased with derangement of pulmonary function.

The study thus showed that the level of surfactant protein A is reduced in patients with idiopathic pulmonary fibrosis. It is likely that they have a significant role in pathogenesis of idiopathic pulmonary fibrosis and its progression. Surfactant-A may have important therapeutic implications. Further studies are required for a definite answer.