Clinical Study on Autologous Platelet-rich Plasma (PRP) Treatment for Refractory Benign Airway Stenosis

Inclusion Criteria: 1. Subjects with aged between 18 to 75 2. Subjects diagnosed with refractory benign airway stenosis and meet the following conditions: a. Received two or more (including two) interventional treatments such as laser, high-frequency electrosurgical unit, argon plasma coagulation (APC), cryotherapy, balloon dilation, and metal stent placement. b. Restenosis within 1 month after more than 2 times interventional treatments suffering from repeated granulation hyperplasia of wound 3. Subjects tolerant to bronchoscope； 4. Subjects signed informed consent Exclusion Criteria: 1. Subjects with airway disease:congenital benign central airway stenosis, recurrent polychondritis, etc; 2. Subjects with the following pulmonary diseases: asthma, active pulmonary tuberculosis, pulmonary embolism, pneumothorax, pulmonary hypertension, etc; 3. Subjects with malignant tumors or have a history of malignant tumors; 4. Subjects with uncontrolled systemic infection; 5. Subjects requiring anti-clotting drugs; 6. Subjects with myocardial infarction, unstable angina, liver cirrhosis, acute glomerulonephritis, etc; 7. Subjects with syphilis, HIV,HBV,HCV antibody positive; 8. Subjects with Coagulation disorders such as hemophilia, giant platelet syndrome, thromboasthenia, etc; 9. Subjects with severe renal damage, serum creatinine is more than 1.5 times the upper limit of the normal value; 10. Subjects with liver disease or liver damage: ALT,AST, total bilirubin \> 2 times the upper limit of the normal value; 11. Subjects with a history of psychosis or suicide or epilepsy or other central nervous system diseases; 12. Subjects with severe arrhythmias(e.g. ventricular tachycardia, frequent supraventricular tachycardia, atrial fibrillation, atrial flutter, etc.) or degree II above abnormal conduction; 13. Subjects allergic to thrombin; 14. Subjects accepted by any other clinical study within the first three months of the study; 15. Subjects with poor compliance; 16. Any other conditions might increase the risk of the patient or interfere with the clinical study.