[Long-term remission achieved with allogeneic hematopoietic stem cell transplantation at first complete remission in a pediatric patient with TCF7::SPI1 fusion-positive T-cell acute lymphoblastic leukemia].

Abstract

T-cell acute lymphocytic leukemia (T-ALL) with SPI1 fusion, a leukemia subtype first identified in Japan, has a very poor prognosis. A 7-year-old boy was admitted to our hospital with fever, cervical lymphadenopathy, eyelid edema, and purpura. White blood cell count was markedly increased (551,000/µl). Flow cytometric analysis revealed cyCD3, CD1a, CD8, and HLA-DR positive T-ALL, and fusion gene screening identified TCF7::SPI1 fusion. The patient was treated according to the JPLSG ALL-T11 protocol. He responded poorly to prednisolone, but favorably to L-asparaginase. After completion of early intensification therapy, molecular remission was confirmed. However, due to the patient's poor response to prednisolone, and the presence of the SPI1 fusion gene, hematopoietic stem cell transplantation from an HLA-matched unrelated donor was performed in first remission. So far, the patient has been in remission for 36 months from the time of onset. Hematopoietic stem cell transplantation in first remission may be effective treatment for patients with T-ALL and SPI1 fusion.