HcT

HCT stands for hematopoietic cell transplantation, a medical procedure in which hematopoietic stem cells capable of giving rise to all blood cell lineages are transplanted to a patient to reconstitute the bone marrow after damage from disease or treatment.

Sources of cells include autologous (the patient’s own cells), allogeneic (from a donor), including related or unrelated matched donors, haploidentical relatives, and umbilical cord blood. The choice of source depends on disease, availability, and risk considerations such as graft-versus-host disease.

Prior to transplantation, recipients undergo conditioning regimens that use high-dose chemotherapy, with or without radiation, to ablate or suppress the existing marrow and immune system, creating space for the donor cells and reducing disease burden. Following infusion, the graft must engraft and reconstitute the recipient’s blood and immune systems, a process monitored in the ensuing weeks to months.

Indications include hematologic malignancies such as leukemias, lymphomas, and multiple myeloma; myelodysplastic syndromes; aplastic anemia; and certain inherited metabolic or immune disorders.

Outcomes vary with disease, patient age, performance status, and donor type. Allogeneic transplants carry a risk of graft-versus-host disease and other immune complications, while autologous transplants avoid GVHD but may not remove all disease. Common post-transplant complications include infections, organ toxicity, relapse, infertility, and long-term endocrine or metabolic issues.

History notes: hematopoietic transplantation emerged in the mid-20th century and advanced with improvements in donor matching, graft sources, and supportive care, including cord blood transplantation as an alternative source.