RESUMO
Pulmonary fibrosis is an interstitial lung disease caused by different pathogenic factors. It has the characteristics of high morbidity and poor prognosis, which seriously affects the quality of life of patients. However, its pathogenesis has not yet been fully elucidated. Surfactant protein(SP)-A and SP-D are lipoprotein complexes distributed at the air-liquid interface of alveoli, synthesized and secreted by alveolar type Ⅱ epithelial cells and bronchiolar cells. They are important parts of the innate immune system, which participate in the host defense process through a variety of regulatory methods, and play an important role in regulating cell apoptosis and lung inflammation, promoting the process of epithelial repair and maintaining the stability of alveolar structure. The disorder and mutation of SP-A and SP-D may be the influencing factors of the pathogenesis of pulmonary fibrosis. Serum SP-A and SP-D levels are differentially expressed in patients with pulmonary fibrosis and normal healthy individuals, and are related to the severity of pulmonary fibrosis. They are considered to be a class of biomarkers that sensitively reflect lung epithelial cell damage and can be used in the diagnosis, treatment and prognostic evaluation of pulmonary fibrosis.