The fibrotic lung diseases represent 15 to 20 percent of the non-infectious disorders of the lung. Idiopathic pulmonary fibrosis, one of the 10 general groups of fibrotic lung disorders, is a chronic and devastating illness resulting in death within an average of 4 to 5 years from the onset of symptoms. Although 5 to 10 percent of these patients respond to corticosteroids, there is no known treatment for the remainder.