Incorporating the possibility of an unrelated donor hematopoietic cell transplant (bone marrow, PBSC, or cord blood transplant — BMT) into a patient's treatment plan from the beginning can improve the chances for a successful transplant. If BMT may be a treatment option for a patient who does not have a matched sibling donor, early consultation with a transplant center that performs unrelated donor transplants through the National Marrow Donor Program® (NMDP) is appropriate.
Referral timing and planning affect outcomes
Early referral to an NMDP-affiliated transplant center enables effective planning for a potential unrelated donor BMT by helping physicians to:
- Identify if and when transplant may be an appropriate treatment option for the patient
- Determine how challenging the search for an unrelated donor or cord blood unit may be and develop an effective search strategy
- Start a donor search on the Be The Match Registry® (operated by the NMDP) as a backup to enable a timely response in case other treatment fails or the patient relapses
- Avoid treatments that could increase a patient's transplant risks
Resources to assist with referral
Be The Match® Patient Services can also offer assistance with identifying and contacting a U.S. Transplant Center. Physicians can call (888) 999-6743 (toll-free in the United States) or (612) 362-3410 or e-mail firstname.lastname@example.org.
Resources for your patient
The Patients & Families section of this website provides resources to help your patient plan for an unrelated donor or cord blood transplant, including:
MatchView® is also available to patients, who can enter their HLA type to see the number of potential donors and cord blood units they may have on the Be The Match Registry. Patients are encouraged to bring their results to their physician as a resource to discuss transplant as a treatment option.
Note: MatchView is not an alternative to a donor search conducted by a physician. For more information, see MatchView Physician Information.
Other factors that affect unrelated donor/cord blood transplant outcomes
In general, the following patient and donor factors also lead to more favorable transplant outcomes:
- HLA matching — better donor-patient matching leads to better outcomes [1,2]
- Younger patients (though in recent years outcomes for older patients have improved)
- Cytomegalovirus (CMV) sero-negative patients
- Patients in better health — considerations include organ function, performance status, significant infections and other factors (For more details, see Evaluating Adult Patients Prior to Hematopoietic Cell Transplant)
- Younger donors (Donors 45 years of age or younger may yield better outcomes) 
- Higher cell dose of cord blood units [4,5]
Disease stage is the only patient characteristic that physicians can affect — by transplanting earlier in the course of the disease. In a 2007 study of 3,857 unrelated donor transplants, patients with intermediate-stage disease had a 38% greater risk of mortality than patients with early-stage disease and patients with advanced disease had approximately twice the mortality risk as patients with early-stage disease. 
When there is more than one potential donor or cord blood unit identified through a search of the Be The Match Registry, additional factors may be considered. Although NMDP outcome studies have shown that the following factors do not influence patient survival, some transplant centers also prefer [1,3]:
- Larger donors, because they can provide a larger volume of cells
- CMV sero-negative donors (to prevent CMV transmission when the patient is CMV sero-negative)
- Male donors, because they are associated less frequently with the occurrence of chronic GVHD
- Female donors who have never been pregnant (Female donors with multiple pregnancies are associated with higher risk of chronic GVHD.)
- ABO compatible donors
- Donors of the same race or ethnicity as the patient (They may be more likely to match at several HLA loci.)
- Hurley C, Baxter Lowe LA, Logan B, et al. National Marrow Donor Program HLA-matching guidelines for unrelated marrow transplants. Biol Blood Marrow Transplant. 2003; 9(10):610-615.
- Lee SJ, Klein J, Haagenson M, et al. High-resolution donor-recipient HLA matching contributes to the success of unrelated donor marrow transplantation. Blood. 2007; 110(13):4576-4583.
- Kollman C, Howe CWS, Anasetti C, et al. Donor characteristics as risk factors in recipients after transplantation of bone marrow from unrelated donors: the effect of donor age. Blood. 2001; 98(7):2043-2051.
- Eapen M, Rubinstein P, Zhang MJ, et al. Outcomes of transplantation of unrelated donor umbilical cord blood and bone marrow in children with acute leukaemia: a comparison study. Lancet. 2007; 369(9577):1947-1954.
- Laughlin MJ, Barker J, Bambach B, et al. Hematopoietic engraftment and survival in adult recipients of umbilical-cord blood from unrelated donors. N Engl J Med. 2001; 344(24):1815-1822.