Allogeneic stem cell transplantation without preconditioning in a child with therapy-related myelodysplastic syndrome: A case report.

Rationale: Infants with mixed-lineage leukemia (MLL)-rearranged leukemia are usually refractory to standard induction therapy and are not immediate candidates for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Chromosome 11q23 translocations, resulting in MLL rearrangement, have been well characterized in infant acute lymphoblastic leukemia (ALL). While t(4;11) ALL continues to have carry a bleak prognosis, patients with therapy-related myelodysplastic syndrome (t-MDS) have a shorter median overall survival than those compared with de novo MDS.

Patient Concerns: We describe a child with t-MDS who evolved from MLL-rearranged ALL and was successfully treated with HSCT without toxic preconditioning.

Diagnoses: MDS diagnosis was based on morphological characteristics of bone marrow dysplasia in patients with clinical manifestations evidence of hematopoiesis impairments by different combinations of anemia, leukopenia, neutropenia, and thrombocytopenia.

Interventions: Although the best donor for allo-HSCT is generally considered an human leukocyte antigen-matched sibling, only ~ 30% of patients have a suitable sibling. HSCT from an unrelated donor is a suitable option for patients with t-MDS who do not have matched sibling donors.

Outcomes: Allo-HSCT without recipient preconditioning could be a promising treatment option for t-MDS, especially for patients with recurrent or persistent infections.

Lessons: Cytogenetics, prognosis, and treatment of t-MDS are briefly discussed. Preconditioning before allo-HSCT seriously damages immune function. This work reviews our experience with a patient with t-MDS following ALL complicated by recurrent infections, and highlights our choice to omit preconditioning from allo-HSCT.