When a fully matched sibling or a suitable donor from a bone marrow registry cannot be found, haploidentical transplants from relatives and cord blood become crucial alternative options. Haploidentical transplants from relatives, in particular, have emerged as a significant and increasingly adopted treatment modality worldwide over the past decade. These donors typically share 50% to 80% of HLA genes with the patient. While a sibling has a 50% chance of being haploidentical, all children, parents, and siblings are inherently haploidentical to the patient.
The process of finding a matched unrelated donor from a registry, confirming high-resolution HLA compatibility, and collecting stem cells can span two to three months. For patients with relapsed blood cancers, such delays can be critical. Conversely, obtaining stem cells from haploidentical relatives is often much quicker due to their immediate accessibility.
Furthermore, in instances of disease relapse after an allogeneic transplant, donor lymphocyte infusions (DLI) from the same donor can be an effective salvage therapy; however, this option is unavailable when cord blood is the source. While re-collecting cells from an unrelated donor can be time-consuming, haploidentical transplants offer the advantage of easily obtaining additional cells from the same healthy donor if needed. Significantly, studies in acute leukemia patients, including those from China, have demonstrated comparable treatment outcomes between haploidentical transplants and fully matched unrelated donor transplants.