The Efficacy and Safety of HCQ Plus DEX in ANA Positive ITP

The goal of this clinical trial is to learn if hydroxychloroquine (HCQ) plus dexamethasone (DEX) works to treat primary immune thrombocytopenia with positive anti-nuclear antibodies in adults. It will also learn about the safety of HCQ plus DEX. The main questions it aims to answer are: Does HCQ plus DEX raise the response rate in participants, compared to DEX alone? Does HCQ plus DEX prolong the response duration in participants, compared to DEX alone? What medical problems do participants have when taking HCQ plus DEX? Researchers will compare HCQ plus DEX with DEX alone to see if HCQ plus DEX works better to treat primary immune thrombocytopenia with positive anti-nuclear antibodies. Participants will: Take DEX every day for consecutive 4 days ( if platelet count does not recover higher than 30×10\^9/L after 2 weeks, take DEX every day for another consecutive 4 days) with or without HCQ twice a day for 1 year , Visit the clinic once every 1 weeks for the first 4 weeks, and once every 2-4 weeks in the following 11 months for checkups and tests, Keep a diary of their symptoms.