Eleven million donors in Bone Marrow Donors Worldwide! Time for reassessment?

Abstract

On 16 November 2005, we celebrated the milestone when 10 million donors had been registered in Bone Marrow Donors Worldwide (BMDW). Since then another million donors have been added in little more than a year. It seems an appropriate time for reassessment and to ask whether we are on the right track or not. We will do so by discussing the strength, weaknesses, opportunities and threats of the unrelated stem cell donor operation.

What are a patient's current chances of finding a matched unrelated donor? Twenty years’ central search experience in a small country

“…In the Dutch study, it was also found that a significant percentage of patients become medically unfit for transplantation in spite of the presence of a matching donor. 8,20 An analysis of search times (Table 2) showed that patients who had a donor but were not transplanted had a significantly longer search time than patients who were given a transplant. The multivariate analyses (Table 4) showed that not proceeding to transplant is associated most significantly with two factors; namely being non-European and having a long time period between diagnosis and search start.…”

“…Sophisticated worldwide computer networks are available for the provision of MUDs from all around the world. About 15 million international HSCT donors are registered 8 in a network of interconnected national hubs (National Haematopoietic Stem Cell Donor Registries), where the data of the national donors is stored electronically. Two large computer networks-BMDW (Bone Marrow Donors Worldwide) and EMDIS (European Marrow Donor Information System)-connect the national hubs.…”

The graft-versus-leukemia effect using matched unrelated donors is not superior to HLA-identical siblings for hematopoietic stem cell transplantation

“…Duration of CR1 (for patients beyond CR1) Ͻ .001 Ͻ 6 mo 186 (35) 77 (27) 6-12 mo 92 (17) 75 (27) Ͼ 12 mo 157 (29) 98 (35) Missing 104 (19) 32 (11) Median (range), mo 8.0 (0.1-151.1) 9.6 (0.6-145.2) .008…”

“…by guest www.bloodjournal.org From a patient who lacks a family donor will be able to identify a suitable URD for transplantation. 19 With better matching due to genomic tissue typing and improved immunosuppression, outcomes using URD have approached those using HLA-identical sibling donors. [20][21][22] HLA-matched unrelated individuals are not identical by descent and have more genetic disparity compared with HLAgenotypical identical siblings for HLA-DPB1 that has been associated with a decreased risk of relapse, and for minor histocompatibility antigens (mHags), which may function as leukemia-associated specific antigens.…”

HLA-mismatched unrelated donors are a viable alternate graft source for allogeneic transplantation following alemtuzumab-based reduced-intensity conditioning

“…However, the likelihood of identifying a "fully matched" UD (MUD) has decreased as a result of using these more stringent criteria. Consequently, despite considerable expansion of international stem cell registries, 7 only approximately two-thirds of Caucasian patients will find a 10/10 HLA allele-matched donor. For other ethnic groups, the probability is often much lower.…”