Study of the Etiology and Immunological Pathogenesis in Acute Exacerbation of Idiopathic Pulmonary Fibrosis (AE-IPF)

Idiopathic pulmonary fibrosis (IPF) is a highly heterogeneous and lethal pathological process with limited therapeutic options, which is the most common and severe of the idiopathic interstitial pneumonias (IIPs). During the past 20 years, the incidence of IPF increased significantly. Most of IPF patients show a median survival time of 2-3 years after diagnosis. Five-year survival rate is 30%-50%. It's difficult to diagnose in the early stage of IPF. Once the patients go to hospital, it's already in the late stage. Now there is no effective therapy except lung transplant for IPF in clinical application. Acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) is a fatal condition with high mortality (over 80%). Its etiology and pathogenesis remain unknown. There is a lack of effective treatment for it. Based on the investigators' long-term clinical observation, most cases of AE-IPF initially got "common cold" and had coryza, more cough, nasal obstruction，rhinorrhea, sore throat, some patients had fever, headache, and etc. Some of these patients' condition developed very rapidly and then became very severe similar to the situation of acute respiratory distress syndrome (ARDS). Why these AE-IPF patients were so hypersensitive to "cold"? What were the immunologic and pathological mechanisms of their lung lesions after patients exposed to "common cold"? How to effectively offer interventional treatment for AE-IPF? All the above questions are yet to be explained clearly. In the investigators' previous retrospective study, the investigators found that there were some obviously imbalanced immune responses in IPF patients, including increased cluster of differentiation 4 (CD4) T cell population, immunoglobulin and complements. The investigators also found highly expressed inflammatory cytokines (IL-17, MIG and IL-9) and high detection rates of pathogens in AE-IPF patients, especially serum immunoglobulin M (IgM) antibody of some respiratory virus. These findings provi