Patients
Children aged at 18 years or younger characterized by isolated thrombocytopenia (platelet count less than 100×109/L) who visited our center from January 2013 to January 2022 were included. Those who had confirmed secondary causes of thrombocytopenia at diagnosis, who had no record of ANA at the initial evaluation for ITP, whose course of thrombocytopenia was ≤ 12 months, or who were lost to follow-up after the baseline visit were excluded.