Inclusion Criteria:
1. Willingness to complete the informed consent process and to comply with study procedures and visit schedule;
2. Men and women aged 8-75;
3. Participants diagnosed with chronic (\>12 months duration) or refractory (a documented intolerance or insufficient response to the first and second line standard treatment of ITP) ITP;
4. The results of physical, instrumental, and laboratory examination of patients not suggest any disease which may cause thrombocytopenia other than ITP;
5. Platelet count \<30 x 109 / L;
6. If the patient is taking corticosteroids, the treatment regimen/dose should be stable (at least 2 weeks prior to screening);
7. The results of physical, instrumental, and laboratory examination of patients should be within the normal range or deviations should be regarded by the researcher as clinically insignificant;
8. Willingness to use effective and reliable methods of contraception throughout the entire study period;
Exclusion Criteria:
1. All subjects with diseases which may cause secondary immune thrombocytopenia
2. Patients with preventive splenectomy;
3. Hemostatic disorders other than chronic thrombocytopenia;
4. Subject treated with drugs that affect platelet function (including but not limited to aspirin, clopidogrel and/or NSAIDs) or anti-coagulants for \> 3 consecutive days within 2 weeks of the study start and until the end of the study;
5. History of platelet agglutination abnormality that prevents reliable measurement of platelet counts;
6. Concurrent malignant disease and/or history of cancer treatment with cytotoxic chemotherapy and/or radiotherapy;
7. Grade III-IV heart failure or myocardial infarction, cardiac angioplasty or stenting, unstable angina pectoris, or other clinically prominent heart disease within one year prior to enrollment;
8. History of thrombosis or presence of significant risk factors for thrombosis;
9. Persons with acute or exacerbation of chronic diseases of the gastrointestinal tract associated with the risk of bleeding, acute infectious diseases, pathologies of the respiratory system;
10. Any clinically significant hepatic impairment (increase of serum transaminase levels by more than 3 times the upper limit of normal);
11. Serum creatinine levels are more than two times higher than the upper limit of normal for a given age and sex;
12. Any other concomitant decompensated diseases or acute conditions, the presence of which, according to the researcher, may significantly affect the results of the study;
13. Human immunodeficiency virus (HIV) seropositivity, Hepatitis B surface antigen positive or hepatitis B core antibody positive and HBV-DNA positive, Patients with hepatitis C (HCV-RNA quantitative test results positive), Or the presence of other serious active viral or bacterial infections or uncontrolled systemic fungal infections;
14. Patients with severe history of allergy or allergic constitution;
15. Pregnancy and lactation;
16. History of mental illness and known alcohol/drug addiction;
17. Poor compliance due to physiological, family, social, geographical and other factors, unable to cooperate with the study protocol and follow-up plan;
18. Had undergone other clinical trials in the 4 weeks prior to participating in this trial;
