Partially matched transplants with allogeneic CD34⁺ blood cells

Allogeneic CD34⁺ selected cell transplantation from a partially matched donor is feasible for the treatment of hematopoietic malignancies. Severe graft-versus-host disease (GvHD) can be prevented by this approach, and a lengthy search for an unrelated donor can be avoided. However, long-term engraftment is still a challenge, and may require intensified conditioning regimens with severe toxicities to sustain engraftment. Furthermore, unacceptable effects such as relapse and life-threatening viral infections might be more frequent after such transplants compared with non-T-cell-depleted transplants from an HLA-identical donor. Strict indications should be considered for this treatment based on a risk/benefit assessment for very high-risk patients. The early application of periodic donor leukocyte infusion (DLI) may be useful for preventing both late graft rejection and serious viral infections.