Likelihood of Finding a Match for Patients
About 70% of patients in need of hematopoietic cell transplantation (HCT) do not have a human leukocyte antigen (HLA) fully matched family donor and need a transplant using an unrelated donor or cord blood unit (CBU) on an unrelated donor registry such as the Be The Match Registry®.
Because of the continuing growth and increasing ethnic diversity of the Be The Match Registry, an overwhelming percentage of patients who need an unrelated donor transplant will have a suitably matched, available donor or a CBU with an adequate cell dose on the Be The Match Registry. A 2014 study found that depending on a searching patient's ethnic background, this match likelihood is between 91-99%. [1]
Likelihood of Finding a Match
The 2014 study used population-based genetic models for 21 ethnic groups, and Figures 1-5 below show the likelihood of a match for searching patients in these 21 groups. A suitably matched adult donor is defined as one matched with the patient at ≥7/8 HLA loci (HLA-A, -B, -C, and -DRB1). Due to the less stringent HLA matching requirements of cord blood, a suitably matched CBU is defined as one matched with the patient at ≥4/6 HLA loci (HLA-A, -B, and -DRB1)
Figure 1. Likelihood of Finding a Matching Available Adult Donor, by Ethnic Background
Figure 2. Likelihood of Finding a Matching CBU with Adequate Cell Dose, Patients ≥20 Years, by Ethnic Background
Figure 3. Likelihood of Finding a Matching CBU with Adequate Cell Dose, Patients <20 Years, by Ethnic Background
Figure 4. Likelihood of Finding a Matching Available Adult Donor or CBU with Adequate Cell Dose, Patients <20 Years, by Ethnic Background
Figure 5. Likelihood of Finding a Matching Available Adult Donor or CBU with Adequate Cell Dose, Patients ≥20 Years, by Ethnic Background
Growth of the Be The Match Registry
A patient's likelihood of finding a potential unrelated donor or CBU has increased with the continuing growth and increasing ethnic diversity of the Be The Match Registry, which includes nearly 12.5 million potential adult donors (marrow or peripheral blood stem cells) and more than 209,000 CBUs. And through our international connections, NMDP/Be The Match searches more than 24.5 million potential donors and more than 622,000 CBUs.
Figure 6. Growth of the Donor Registry
Figure 7. Growth of the Cord Blood Registry
Reference
- Gragert L, Eapen M, Williams E, et al. HLA match likelihoods for hematopoietic stem-cell grafts in the U.S. registry. N Engl J Med. 2014; 371(4): 339-348. Access