The National Bone Marrow Registry, operated by the organization known as NMDP (formerly Be The Match and the National Marrow Donor Program), functions as a centralized, worldwide database of volunteer blood stem cell donors and umbilical cord blood units. Its mission is to connect patients suffering from life-threatening blood cancers and disorders with an unrelated donor who can provide life-saving hematopoietic stem cells. The registry allows doctors to search for a compatible donor for patients who lack a suitable match within their own family, which occurs for approximately 70% of those needing a transplant.
The Purpose of the Registry and Conditions Treated
A transplant of healthy blood-forming cells is necessary when a patient’s own bone marrow is diseased or damaged and cannot produce healthy blood cells. These procedures, properly called hematopoietic cell transplants, replace the patient’s malfunctioning system with healthy donor cells. The new cells migrate to the bone marrow and begin to generate new, healthy red blood cells, white blood cells, and platelets.
Transplants are a standard treatment for over 70 different diseases, primarily blood cancers like leukemia and lymphoma. They are also used for conditions including aplastic anemia, certain inherited immune system disorders, and some metabolic disorders. Success hinges on a close match of Human Leukocyte Antigens (HLA), which are proteins the immune system uses to distinguish “self” from “non-self.” A mismatched transplant can result in Graft-versus-Host Disease (GVHD), where donor cells attack the recipient’s body.
The Process of Registering as a Potential Donor
Joining the registry begins with a simple, non-invasive process to determine a potential donor’s unique HLA type. Eligible individuals, generally aged 18 to 35, start by completing an online health questionnaire and requesting a free cheek swab kit. This age preference is based on research showing that cells from younger donors lead to better long-term outcomes for patients.
Once the kit is received, the potential donor swabs the inside of their cheeks to collect cells for DNA analysis and mails the kit back. A laboratory analyzes these cells to determine the individual’s high-resolution HLA typing, which is then added to the secure, searchable database. This initial testing does not require a blood draw or immediate commitment, only a willingness to proceed if a match is found.
The commitment to remain available and keep contact information current is important once a person is listed on the registry. While many registrants may never be called, some are needed quickly, and their availability is vital to a patient’s survival. If a match is identified, the donor is contacted for further blood tests and a physical exam to confirm they are the best possible match and that the donation is safe for both parties.
Distinguishing Between Donation Procedures
When a donor is selected, the medical team determines the collection method: either Peripheral Blood Stem Cell (PBSC) donation or traditional bone marrow donation. While the common misconception is that all donations involve a painful surgical procedure, PBSC donation is used in approximately 80% of cases. This non-surgical process is similar to donating plasma or platelets and is completed in an outpatient setting.
The PBSC procedure requires the donor to receive daily injections of the drug filgrastim for about five days leading up to the collection. Filgrastim stimulates the bone marrow to release a high number of blood-forming stem cells into the bloodstream. The actual collection uses apheresis, where the donor’s blood is drawn from one arm, passed through a machine to separate the stem cells, and the remaining blood is returned through the other arm. The typical recovery time for a PBSC donor is about one week.
The second, less frequent method is traditional Bone Marrow donation, accounting for about 20% of donations. This surgical procedure is performed in a hospital under general or regional anesthesia to ensure the donor feels no pain. Doctors use specialized needles to withdraw liquid marrow from the back of the pelvic bone, not the spinal cord.
The amount of marrow collected is typically less than 5% of the donor’s total marrow, which the body naturally replaces within four to six weeks. Donors usually experience some soreness or stiffness at the collection site, with a median time for full recovery being about three weeks. Both procedures are considered safe and are chosen based on which cell collection offers the patient the best chance for a successful transplant.
The Critical Need for Donor Diversity
The need for a diverse donor pool is rooted in the genetics of the Human Leukocyte Antigens (HLA). Since HLA markers are inherited, a patient’s best probability of finding a compatible match is from someone who shares a similar ethnic or ancestral background. Because certain HLA types are more common within specific ethnic groups, the probability of a match is significantly higher between individuals of the same heritage.
Patients from underrepresented racial and ethnic groups face a disproportionate challenge in finding a match due to a lack of diversity in the registry. For example, a patient of European descent has a much higher chance of finding a fully matched, unrelated donor compared to a patient of African or multi-racial descent. Expanding the diversity of the national bone marrow registry is necessary to ensure all patients have an equitable chance at a life-saving transplant.