Relationship between platelet counts at 1 month and recovery at 6 and 12 months after IVIG treatment. (A) Seventy-two patients were followed up at 6 months after the initial diagnosis of ITP and IVIG treatment. Among 15 patients with platelet <100×10³/µL at 1 month after IVIG treatment, 6 patients (40%) had persistent ITP at 6 months, while 8 of 57 patients (14%) with platelet ≥100×10³/µL at 1 month had persistent ITP at 6 months (P=0.003). (B) Forty patients were followed up at 12 months after the initial diagnosis and IVIG treatment. Among 14 patients with platelet <100×10³/µL at 1 month of IVIG treatment, 5 patients (35.7%) had chronic ITP at 12 months, while only 2 of 26 patients (7.7%) with platelet ≥100×10³/µL at 1 month had chronic ITP (P=0.039).