Immunosuppressant Combined With Pirfenidone in CTD-ILD

Inclusion Criteria: * Patients who meet the following inclusion criteria will be eligible to participate in the study: 1. Aged 18-80 years; 2. In accordance with the diagnostic criteria of connective tissue disease-related pulmonary interstitial disease (CTD-ILD);The diagnosis of CTD is in line with the international classification standard of rheumatism (including inflammatory myopathy, systemic sclerosis, rheumatoid arthritis, sjogren's syndrome, systemic lupus erythematosus, mixed connective tissue disease, undifferentiated connective tissue disease); 3. Subjects are willing to participate and use medication and follow-up time according to the treatment plan, and sign the informed consent; Exclusion Criteria: * Patients who meet any of the following criteria will be excluded from the study: 1. Subjects have non-diffuse connective tissue disease or other arthritis other than RA, such as ANCA-relateed vasculitis, psoriatic arthritis, etc; 2. Patients who have ILD with clear etiology, such as HIV, GVHD ； 3. Combined viscera function significantly abnormal patient: 1. Liver: AST, ALT \>1.3ULN; Bilirubin \>1.5 ULN; or previous diagnosis of viral hepatitis; 2. Kidney: Creatinine clearance \<30 mL/min; 3. Lung: Airway obstruction (pre-bronchodilator FEV1/FVC \<0.7); pleural effusion accounts for more than 20% of pleural effusion ;severe pulmonary infection or other clinically significant pulmonary abnormalities; 4. Cardiovascular: Myocardial infarction or unstable angina within six months; 5. Gastrointestinal tract: With active peptic ulcer or bleeding; 6. Blood system: Severe anemia, decreased white blood cells and platelets 7. Nervous system: Patients with mental disorders; cerebral thrombosis events within the past 1 year; 4. Combined with poor prognosis of diseases, such as cancer, genetic diseases and so on; 5. Women during pregnancy or lactation or childbearing age cannot ensure effective contraception; 6. According to the researchers, exhibited evidence of alcohol or drug abuse; 7. Any other major medical events beyond control;