Safety and Efficacy of Zanubrutinib in the Treatment of Antiphospholipid Syndrome With Secondary Thrombocytopenia

Inclusion Criteria: * Age 18 and above, male or female； * Diagnosis of antiphospholipid syndrome； * Failure to receive glucocorticoid treatment in the past (the curative effect cannot be maintained, or recurs, or cannot be tolerated); Can not choose other second-line treatment, such as rituximab, cyclosporine, cyclophosphamide, etc.; Or rituximab, cyclosporine and other treatments are ineffective, relapsed or intolerable; * Plt \< 30×10\^9/L； * Liver and kidney function, such as ALT, AST, BUN, SCR \< 1.5 × upper limit of normal value, passing physical examination; * ECOG physical state score ≤ 2 points； * Cardiac function of the New York Society of Cardiac Function ≤ 2； * Signed and dated written informed consent. Exclusion Criteria: * Uncontrollable primary diseases of important organs, such as malignant tumors, liver failure, heart failure, renal failure and other diseases； * HIV positive; * Accompanied by uncontrollable active infection, including hepatitis B, hepatitis C, cytomegalovirus, EB virus and syphilis positive; * Accompanied by extensive and severe bleeding, such as hemoptysis, upper gastrointestinal hemorrhage, intracranial hemorrhage, etc.; * At present, there are heart diseases, arrhythmias that need treatment or hypertension that researchers judge is poorly controlled; * Patients with thrombotic diseases such as new pulmonary embolism and unstable period of various arteriovenous thrombosis; * Those who have received allogeneic stem cell transplantation or organ transplantation in the past; * Patients with mental disorders who cannot normally obtain informed consent and conduct trials and follow-up; * Patients whose toxic symptoms caused by pre-trial treatment have not disappeared; * Other serious diseases that may limit the subject's participation in this test (such as diabetes; Severe cardiac insufficiency; Myocardial obstruction or unstable arrhythmia or unstable angina pectoris in recent 6 months; Gastric ulcer，etc.); * Patients with septicemia or other irregular severe bleeding; * Pregnant women, suspected pregnancies (positive pregnancy test for human chorionic gonadotropin in urine at screening) and lactating patients.