Beating the odds: factors implicated in the speed and availability of unrelated haematopoietic cell donor provision.

The demand for unrelated haematopoietic cell (HPC) donors has risen threefold over the last decade, and is likely to continue to rise over the next 10 years. The time taken from diagnosis to transplant is recognised to adversely affect patient outcome, and provision of unrelated donors (UDs) has been identified as a key source of delay. Obstacles to provision of UD include: delays in referral to a transplant centre, awaiting sibling typing, lack of matched donors (particularly for those from ethnic minorities and/or with rare HLA phenotypes), low- or intermediate-resolution donor HLA typing, donor attrition from the registries, donor ineligibility on grounds of health and difficulties encountered transporting HPC across international borders. There are now over 18 million volunteer donors in registries worldwide, and efficiency has improved, at least in part, because of a switch from paper to electronic searches. As a result, the average time from search request to transplant is estimated to be less than half of what it was two decades ago. Furthermore, registries have developed a number of strategies designed to minimise delays and, ultimately, improve patient outcomes. These include: optimisation of donor numbers and ethnic mix through focused and selective recruitment; high-resolution typing at donor recruitment; cord blood banking with aggressive recruitment in ethnic minorities; early identification of those unlikely to find a match so alternative transplant options may be pursued in a timely manner, through use of HLA-based predictive algorithms; reduction of donor attrition; centralised, registry-based, donor identification services; and provision of a back-up donor.