Case Report: Hematopoietic stem cell transplantation for refractory chronic immune thrombocytopenia in a child.

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by immune-mediated platelet destruction and impaired platelet production. While pediatric ITP is often self-limited or responsive to first-line therapies, such as corticosteroids and intravenous immunoglobulin (IVIG), a small subset develop refractory chronic disease. Hematopoietic stem cell transplantation (HSCT) has been explored as a potential immune-reconstituting rescue intervention for highly selected patients with multiple treatment failures, prolonged severe thrombocytopenia, and persistent bleeding risk. Here, we report a case of a 6-year-old child with refractory chronic ITP who had severe thrombocytopenia and recurrent life-threatening bleeding despite 11 first-line, second-line, and salvage treatment regimens and ultimately underwent 10/10 HLA-matched unrelated donor allogeneic HSCT (allo-HSCT). After transplantation, the patient experienced delayed platelet recovery, acute graft-versus-host disease (aGvHD), viral reactivation and transient transplant-associated thrombotic microangiopathy (TA-TMA). After repeated treatment adjustments guided by close real-time clinical monitoring, he eventually achieved stable trilineage engraftment and has remained in complete remission (platelet count ≥100×109/L) without major bleeding events for more than 11 months. We also review the available literature on HSCT for refractory ITP. This case highlights the therapeutic challenges of pediatric refractory chronic ITP, adds detailed longitudinal clinical evidence to the limited literature on HSCT in this setting, and supports consideration of allo-HSCT as a potential salvage option in exceptionally selected patients.