++
KEY CONCEPTS
Cord blood is a valuable alternative donor source for stem cell transplant, offering a number of advantages: ease of collection, availability for urgent need, less stringent human leukocyte antigen (HLA)-matching requirement, and lower risk of graft-versus-host disease.
Data are evolving about the difference in outcomes of stem cell transplant using different graft sources, but more recent data suggest that there is no survival advantage of a matched unrelated graft over cord blood.
To overcome the limitation of low cell doses in single cord blood units, double cord blood transplant has been adopted for many patients.
High-intensity myeloablative regimens are used in young and fit patients, whereas reduced-intensity regimens are used in older or unfit patients.
Infections are the leading cause of early nonrelapse mortality after cord blood transplant, and graft-versus-host disease is the leading cause of late mortality.
Novel strategies to improve cord blood transplant outcomes include improving cell collection, homing and engraftment, ex vivo expansion, and in vivo enhancement.
++
The number of allogeneic stem cell transplants (SCTs) performed in the United States has steadily increased, from more than 8000 per year in 2013 to 8839 in 2017 and an estimated 9028 transplants in 2018.1 Donor identification has always been a challenge, and only 25% to 30% of patients who need allogeneic SCT have a matched-sibling donor available.2 The National Marrow Donor Program (NMDP) and its cooperative international registries have more than 19 million volunteer donors, but the majority of them are White; other ethnicities are underrepresented in these large registries, which poses a significant challenge in finding donors for them.3 Mismatched related (often haploidentical), cord blood (CB), or mismatched unrelated donors (MMUD) with either peripheral blood (PB) or bone marrow (BM) graft sources are potential options for patients in need of SCT but who lack a matched related (MRD) or unrelated donor (MUD).
++
Cord blood is a valuable alternative donor source for allogeneic SCT, offering many logistic advantages; CB units are easy to collect with little or no risk to the mother or newborn. CB units can be obtained rapidly for 80% to 95% of the patients 20 years or older across all races, and in almost 100% of younger patients.4 This is particularly advantageous in cases where urgent transplant is needed. Owing to the rapid procurement of CB units, patients can receive CB transplantation (CBT) in 2 to 4 weeks from the initiation of search compared with 3 to 6 months for unrelated donor sources.5 Further, CBT is associated with a low risk of infection transmission, requires less stringent human leukocyte antigen (HLA) matching criteria, and has a relatively lower risk of graft-versus-host disease (GVHD) with preserved graft-versus-malignancy effects.6,7 However, it has been historically associated with a greater risk of graft rejection, delayed engraftment, and delayed immune reconstitution, leading to a heightened risk of infection or nonrelapse mortality (NRM).8–11 Many of the ...