Detection of antibodies in serum of patients with idiopathic pulmonary fibrosis against isolated rat alveolar type II cells

The serum of 2 patients suffering from idiopathic pulmonary fibrosis (IPF) repeatedly demonstrated a positive antibody reaction against rat alveolar type II cells isolated by the use of a combination of elastase and trypsin for disaggregation and a Percoll density gradient for purification. Neither of the other 8 IPF patients examined nor any of the controls showed a positive reaction. Because the 2 patients with serum antibodies against alveolar type II cells did not show any antinuclear antibodies, it is concluded that the antibodies against the surface of rat alveolar type II cells found in the serum of IPF patients may be autoantibodies involved in the pathogenesis of IPF.