AlloSCT

Allogeneic hematopoietic stem cell transplantation (alloSCT) is a medical procedure in which hematopoietic stem cells are collected from a donor and infused into a patient after preparative therapy. The transplanted cells repopulate the recipient’s bone marrow to restore blood cell production. A donor immune system can also recognize residual malignant cells and exert a graft-versus-tumor effect, which can contribute to disease control but may cause graft-versus-host disease (GVHD).

Donor sources include matched related donors (often siblings), matched unrelated donors, haploidentical related donors, and umbilical cord blood. The degree of HLA matching and donor characteristics influence engraftment, GVHD risk, and overall outcomes.

Preparative regimens are described as myeloablative or reduced-intensity conditioning (RIC). After transplantation, engraftment occurs as donor cells take hold in the recipient’s marrow. Immunosuppressive therapy is used to prevent GVHD, with regimens that vary by center and donor type; some haploidentical transplants employ post-transplant cyclophosphamide for GVHD prevention.

Indications for alloSCT include various hematologic malignancies such as acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndromes, chronic myeloid leukemia, lymphomas, and selected cases of multiple myeloma or aplastic anemia, particularly when disease risk or relapse potential warrants a curative approach.

Complications can include acute and chronic GVHD, infections due to immunosuppression, organ toxicity, graft failure, and disease relapse. Long-term care involves infection prevention, GVHD management, monitoring for relapse, and surveillance for secondary complications.

AlloSCT has advanced with better donor matching and supportive care, offering potential durable remissions for some patients while carrying substantial risk that requires careful patient selection and follow-up.