Pegylated Interferon Alfa-2b Versus Interferon Alfa Therapy in Childhood and Adolescent Essential Thrombocythemia

Inclusion Criteria: * \<20 years old * Male or Female * Diagnosis of essential thrombocythemia according to the 2016 WHO criteria. * Platelet count ≥ 450 × 109 / L for more than 6 months（If the patient has JAK2 V617F, CALR or MPL gene mutation, the history may be less than 6 months） * Platelet count ≥ 1000 × 109 / L or other therapeutic indications at screening. * The guardians has provided written informed consent prior to enrollment Exclusion Criteria: * Known to meet the criteria for primary myelofibrosis or polycythemia vera by 2016 WHO criteria * Presence of any life-threatening co-morbidity * Secondary thrombocytosis * Familial thrombocytosis * Resistance, or intolerance, or any contraindications to interferon * Interferon is used in the past 1 month before enrollment * Patients with previous or present thrombosis or active bleeding * WBC\<4× 109 / L * HGB\<110g/L * Poor control of thyroid dysfunction * Patients with a prior malignancy within the last 3 years * Patients with severe cardiac or pulmonary dysfunction * Severe renal damage (creatinine clearance \< 30 ml / min) * Severe liver dysfunction (ALT or AST \> 2.5×ULN) * Patients diagnosed as diabetes with poor control * Patients with hepatitis B virus, hepatitis C virus replication or HIV infection * Patients with a history of drug / alcohol abuse (within 2 years before the study) * Patients that have participated in other experimental researches within one month before enrollment * History of psychiatric disord…