A bone marrow transplant, also known as a hematopoietic stem cell (HSC) transplant, is a life-saving treatment for individuals battling blood diseases and cancers, such as leukemia, lymphoma, and sickle cell disease. This procedure involves infusing healthy blood-forming stem cells into a patient to replace their own diseased or damaged marrow. Since approximately 70% of patients lack a familial match, they rely on unrelated volunteer donors found through national or global registries. Compatibility is determined by inherited genetic markers called Human Leukocyte Antigens (HLA). Because HLA markers are inherited, a patient’s best chance of finding a match is with someone who shares a similar ethnic background, creating a continuous need for a diverse pool of registered donors.
Eligibility and Joining the Registry
The initial step to becoming a donor involves joining a registry, such as Be The Match, by confirming basic eligibility criteria. Prospective donors must generally be between the ages of 18 and 55, though registries prioritize those aged 18 to 35 because younger cells offer patients the best chance for successful outcomes. Donors must also be in good health, without a history of conditions like HIV, autoimmune disorders, specific cancers, or severe heart, lung, or kidney diseases. Once requirements are met, a person requests a cheek swab kit for initial registration.
The kit contains swabs used to collect cells from the cheek, which are analyzed for the donor’s HLA type. This initial analysis, called low-resolution HLA typing, identifies genetic markers on the surface of the white blood cells. The donor’s information and HLA profile are then added to the global search database, making them available as a potential match worldwide. Registering is a non-binding commitment, and a person remains on the registry until they reach the maximum age, typically 61, or request removal.
The Confirmation Process for a Potential Match
If a preliminary match is identified, the registry contacts the donor to begin the confirmation process, which involves deeper genetic testing. The donor provides a blood sample for high-resolution HLA typing, a detailed analysis confirming the highest degree of compatibility with the patient. This blood test also screens for infectious diseases and confirms the donor is healthy enough to proceed with donation, typically taking a few weeks.
If the high-resolution typing confirms the donor is the best match, they enter the “work-up” phase. This stage involves a comprehensive physical examination, a detailed health questionnaire, and educational counseling sessions. Medical professionals ensure the donor fully understands the procedural steps, potential risks, and the commitment required for the donation. The registry covers all associated costs, including travel and medical expenses, to make the experience accessible.
Procedures for Donation Explained
There are two primary methods for collecting the cells, and the patient’s physician determines which method is best based on the patient’s disease and needs. The most common method, used in about 90% of cases, is Peripheral Blood Stem Cell (PBSC) donation, a non-surgical outpatient procedure. The second method, Bone Marrow Harvest, is a surgical procedure performed under anesthesia.
Peripheral Blood Stem Cell (PBSC) Donation
PBSC donation requires the donor to receive daily injections of filgrastim for four to five days before collection. Filgrastim is a colony-stimulating factor that stimulates the bone marrow to produce and release stem cells into the bloodstream. Common side effects from the injections include mild headaches, bone or muscle aches, and flu-like symptoms, which typically disappear shortly after the donation is complete.
The collection is a procedure called apheresis, similar to donating plasma, which usually takes four to six hours. Blood is drawn from one arm and passed through a machine that filters out the stem cells before the rest is returned to the body through the other arm. Minor side effects during the process, such as tingling around the mouth or mild muscle cramps, are due to the anticoagulant used in the machine. Occasionally, a donor may need a second collection session the following day to gather the required number of cells.
Bone Marrow Harvest
Bone Marrow Harvest is a surgical procedure performed in a hospital operating room under general anesthesia, typically lasting one to two hours. The doctor uses special, hollow needles to aspirate liquid marrow directly from the back of the donor’s pelvic bone (iliac crest).
Approximately one to two pints of liquid marrow, representing about 10% of the donor’s total marrow cells, are collected. The bone marrow naturally replenishes itself completely within a few weeks. Most donors are able to leave the hospital the same day, though some may require an overnight stay for observation.
Recovery and Post-Donation Care
Recovery time varies depending on the donation method, but most donors return to their normal routines quickly. Following a PBSC donation, many donors feel recovered within two to three days and can resume work or school the day after the procedure. Any lingering side effects from the filgrastim injections, such as bone pain or fatigue, typically resolve completely within a few days.
For donors who undergo a Bone Marrow Harvest, the recovery period is slightly longer due to the surgical nature of the procedure. Common short-term side effects include soreness, tenderness, and bruising at the collection site, managed with over-the-counter pain medication. Most marrow donors return to work or school within two to seven days, with full recovery typically reached within a few weeks. The registry provides follow-up care and medical checks to monitor recovery in the weeks and months following the donation.