Since surfactant protein D (SP-D) is a surfactant protein and is mainly produced by type II alveolar epithelial cells and club cells which are present in the bronchial and alveolar epithelium [8,10], it can be used for clinical diagnosis and evaluation of the progress of the diseases of interstitial pneumonia and pulmonary fibrosis, which induce epithelial injury in the lung [11,12,13]. This evidence concerns the gene SFTPD and pulmonary fibrosis.