Abstract

Several reports have been published on autoimmune hematologic complications, including immune thrombocytopenia (ITP), after cord blood transplantation (CBT). However, there have been no reports of late-onset ITP following CBT. A 51-year-old male with chronic myelomonocytic leukemia received unrelated CBT in 2012. During regular follow-up visits every 3-6 months, his complete blood count remained normal until March 2024. In September 2024, 12 years after the CBT, the patient suddenly developed severe thrombocytopenia. Following a diagnosis of ITP, the patient was treated with intravenous immunoglobulins and prednisone. With follow-up period of 5 months after the onset of ITP, the patient is still alive with a platelet count of 126 × 10⁹/L. This case suggests that late-onset ITP after CBT occurred suddenly and may be life-threatening. Long-term follow-ups and regular clinic visits may reduce the risk of delays in diagnosis and treatment.