Unrelated cord blood and mismatched unrelated volunteer donor transplants, two alternatives in patients who lack an HLA-identical donor

Abstract

The aim was to evaluate two transplant strategies for patients who lack HLA-identical donors, namely HLA-A, HLA-B or -DRb1 mismatched unrelated donor (MM URD) transplants (n ¼ 14) and umbilical cord blood transplants (UCB, n ¼ 27). Diagnosis, disease stage and age were similar in the two groups. Cell dose was lower in the UCB group (Po0.001). Median time to ANC of 40.5 Â 10 9 /l was 30 days in the UCB group and 17 days in the MM URD group (P ¼ 0.002). Engraftment of plt was delayed in the UCB group (P ¼ 0.03). The UCB patients required fewer erythrocyte transfusions (P ¼ 0.001). At 100 days, complete donor chimerism for CD3 was 63 and 44% in the UCB and MM URD groups, respectively. Acute GVHD of grades II-IV were 30% in the UCB group and 21% in the MM URD group. The corresponding figures for chronic GVHD were 9 and 20%, respectively. TRM was 30% in the UCB patients and 50% in the MM URD patients. Three-year survival was 66% in the UCB group and 14% in the MM URD group (P ¼ 0.006). Although the material is small and heterogeneous, engraftment was delayed, leukocyte chimerism was not significantly different and survival was superior using UCB rather than MM URD transplants.

Increased costs after allogeneic haematopoietic SCT are associated with major complications and re-transplantation

“…28 Cord blood transplants have a high incidence of graft failure and delayed engraftment, which may increase costs. [29][30][31] Despite this, the costs were not higher in this cohort of patients, which may be because of the fact that only 20 patients were included in this analysis. We mainly use cord blood transplants when an HLA-identical donor is not available, and because there was a better outcome than using mismatched unrelated donors.…”

“…We mainly use cord blood transplants when an HLA-identical donor is not available, and because there was a better outcome than using mismatched unrelated donors. 29 Non-myeloablative conditioning was associated with reduced costs (Figure 2a). The reason for this is that it can be done on an outpatient basis, with a short neutropenic period and few toxic side effects.…”

Defining umbilical cord blood stem cells

“…Furthermore, transplantation with HLA-mismatched cord blood samples shows a lower risk of graft-versus-host diseases (GvHD) in comparison with bone marrow transplantation. This is also attributed to the fact that the cells transplanted from umbilical cord blood are more naïve and have lower (HLA) protein expression than adults stem cells including bone marrow stem cells [59,[64][65][66]. In addition, umbilical cord blood transplantation was shown to be associated with a lower risk of infection transmission in comparison with bone marrow transplantation [67].…”

“…On the other hand, the low number of stem cells per cord blood unit represents a limitation that is associated with delayed engraftment of these cells into host targeted tissues [62,68]. However, this obstacle has been tackled with the possibility of combining multiple cord blood units in order to increase the final transplanted cell dose resulting in improved engraftment and survival of the transplanted cells [3,61,64,68]. Umbilical cord blood has added advantages over other sources of stem cells.…”

“…Due to the immature HLA status of umbilical cord blood cells, transplantation with cord blood shows better tolerance for HLA-mismatching in comparison with adults HSCs [63]. This unique feature of cord blood allows the safe use of unrelated and HLA-mismatched donor samples when HLA-identical donors are not available, thus providing the clinicians with alternative effective therapeutic options [3,64]. Furthermore, transplantation with HLA-mismatched cord blood samples shows a lower risk of graft-versus-host diseases (GvHD) in comparison with bone marrow transplantation.…”