Myeloablation

Myeloablation is a clinical state or procedure characterized by the severe and permanent depletion of the bone marrow's hematopoietic stem and progenitor cells. It is not a molecular target but rather a pharmacological or radiological outcome intended as a conditioning regimen prior to hematopoietic stem cell transplantation (HSCT) to eliminate malignant cells or dysfunctional immune systems (1, 2). The process serves three primary goals: to eradicate underlying disease (such as leukemia), to suppress the recipient's immune system to prevent graft rejection, and to create physical space in the marrow niche for donor stem cell engraftment (2, 4). Historically, myeloablation is achieved through high-dose non-specific chemotherapy, such as busulfan or cyclophosphamide, or total body irradiation (TBI), which are associated with significant systemic toxicities (4). Modern therapeutic developments are moving toward "targeted myeloablation," which utilizes monoclonal antibodies or radioimmunoconjugates against specific hematopoietic markers like CD45 or CD117 (c-Kit) to achieve the same marrow-clearing effect with reduced off-target damage to non-hematopoietic tissues (3). Without the subsequent infusion of healthy stem cells (rescue), a myeloablative state is fatal due to the body's inability to produce essential blood components (2). Citations: (1) National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: Myeloablation. (2) StatPearls. Hematopoietic Stem Cell Transplantation (HSCT) Conditioning. (3) Majeti R, et al. (2022). Targeted conditioning for hematopoietic stem cell transplantation. (4) Gyurkocza B, Sandmaier BM. (2014). Conditioning regimens for hematopoietic cell transplantation. Blood.

Other names

Bone marrow ablationMarrow-ablative conditioningHematopoietic ablationAblative therapyTotal marrow ablation

Induction of severe or complete destruction of hematopoietic stem cells and progenitor cells in the bone marrow through high-dose alkylating agents, antimetabolites, total body irradiation, or targeted monoclonal antibodies.