Treatment of immune thrombocytopenia with hydroxychloroquine and dexamethasone

Inclusion Criteria:

1. Age is between 15-75 years old, and gender is unlimited.
2. Before randomization, the clinical diagnosis is primary immune thrombocytopenia. The platelet count is less than 30×10\^9 / L within 1 week before enrollment, or platelet count is less than 50×10\^9 / L with bleeding symptoms within 1 week before enrollment.
3. The antinuclear antibody is positive.
4. Other autoantibodies (mainly including dsDNA antibodies, SSA, SSB, RNP, β 2-GP, ACA, ANCA) are negative.
5. Prothrombin time does not exceed ± 3s of the normal value ranget, activated partial thrombin time is not outside normal range ± 10s; no history of coagulopathy except ITP.
6. Understand the study procedures and sign the written informed consent form.

Exclusion Criteria:

1. Secondary thrombocytopenia caused by myelodysplastic syndrome, immune diseases such as systemic lupus erythematosus, early aplastic anemia, atypical reanemia, antiphospholipid syndrome, thrombotic thrombocytopenic purpura and various other causes.
2. The participant has experienced any arterial or venous thrombosis (stroke, transient ischemic attack, myocardial infarction, deep vein thrombosis or pulmonary embolism), or clinical symptoms and medical history indicate thrombophilia.
3. Congestive heart disease, including New York Heart Association (NHYA) Grade III / IV, occurred within 3 months prior to screening, arrhythmia requiring medication or myocardial infarction, or arrhythmia known to increase the risk of thrombotic events (such as atrial fibrillation), or corrected QT interval (QTc) is longer than 450 ms, or QTc\> 480 ms in paricipants with bundle branch block.
4. With severe hemorrhage (intracranial hemorrhage) or coagulation dysfunction (INR and APTT\> 125% upper limit of normal).
5. With poorly controlled hypertension and diabetes mellitus.
6. With severe digestive tract diseases affecting drug absorption.
7. With serious mental illness patient.
8. With liver cirrhosis or portal hypertension.
9. With evidence of malignant tumor activity, or receiving anti-tumor treatment within 5 years prior to the screening.
10. Addicted to alcohol or drugs.
11. Having participated in other clinical trials within 3 months prior to screening.
12. Having received any immunomodulatory medication for other diseases 3 months before screening.
13. Having received any medication affecting platelet function ( Including but not limited to aspirin, aspirin-containing complexes, clopidogrel, salicylates, and / or non-steroidal anti-inflammatory drugs NSAIDs ) or anticoagulant therapy for over consecutive 3 days within 2 weeks before screening.
14. With Glucose-6-phosphate dehydrogenase deficiency.
15. With retinal or visual field changes caused by 4-aminoquinoline compounds.
16. Being allergic to 4-aminoquinoline compounds.
17. Having evidence of Human Immunodeficiency Virus (HIV)/ hepatitis C virus(HCV)/ hepatitis B virus(HBV) infection (HIV antibody or HCV antibody is positive, HBV surface antigen is positive, or HBV surface antigen is negative but HBV-DNA indicating viral replication.
18. With a history of vaccination within 8 weeks before enrollment or scheduled for vaccination during the trial period.
19. Moderate to severe anaemia (hemoglobin \<90g / L).
20. Glutamate transaminotransferase (ALT) or glutamate transaminase (AST) is higher than 1.5 times the upper limit of normal value (ULN), or total bilirubin or blood creatinine is higher than 1.2 times the ULN.
21. Participants being pregnant or lactating, or with potential fertility, reluctance to use effective contraception within the entire trial cycle and within 28 days after the end of the trial (or within 28 days after premature withdraw).