Bone marrow and blood stem cell donation is a life-saving medical procedure that replaces a patient’s unhealthy blood-forming cells with healthy ones from a donor. This treatment is often the only potential cure for individuals battling blood cancers like leukemia and lymphoma, various blood disorders, and immune system deficiencies. The process involves donating hematopoietic stem cells, which produce all other blood cells. Since only about 30% of patients find a suitable match within their own family, national and international registries are a beacon of hope for thousands of people each year.
Eligibility and Screening Requirements
The ability to donate is determined by a combination of age, overall health, and specific medical history to ensure safety for both the donor and the recipient. Most registries, such as the National Marrow Donor Program (NMDP), recruit individuals between the ages of 18 and 40, though they may keep donors on the registry up to age 60. This preference for younger donors is rooted in medical research showing that transplants from younger individuals often lead to better long-term success for the patient.
Potential donors must be in good health and not have chronic conditions that could complicate the donation or put them at risk. Several health issues automatically disqualify a person, including HIV/AIDS, Hepatitis B or C, and most cancers. Serious systemic autoimmune disorders, such as severe rheumatoid arthritis or lupus, along with chronic heart conditions or insulin-dependent diabetes, are also typically disqualifying.
Initial registration involves a self-screening process and a health questionnaire. If a potential donor is identified as a preliminary match, they undergo a thorough medical evaluation. This comprehensive screening includes a physical exam, blood and urine tests, and sometimes an EKG or chest X-ray to confirm the donor meets all stringent health requirements.
Joining the Registry and Finding a Match
The first step to becoming a donor is joining a registry by completing a registration form and submitting a tissue sample. This sample is most often collected via a simple cheek swab for genetic analysis. The registry then analyzes the sample to determine the donor’s Human Leukocyte Antigen (HLA) type, which is a set of proteins found on the surface of most cells in the body.
HLA markers are the primary factor in determining compatibility, as they help the immune system distinguish between the body’s own cells and foreign invaders. Unlike blood type matching, HLA matching is complex and highly specific, involving the comparison of multiple antigen markers, with a 10/10 or 12/12 match being the ideal scenario. The donor’s HLA type is then entered into a global database, where it can be compared to the typing of patients in need of a transplant.
If a patient’s HLA profile suggests a match, the donor is contacted for confirmatory typing. This involves a more detailed blood test to perform high-resolution HLA typing, which confirms the exact level of compatibility. Finding the closest possible match is essential to minimize the risk of the recipient’s body rejecting the transplant.
The Two Methods of Donation
There are two methods for collecting hematopoietic stem cells, and the patient’s specific disease or the physician’s preference determines which procedure is used. The most common method, accounting for approximately 80% of all donations, is Peripheral Blood Stem Cell (PBSC) donation. This non-surgical procedure collects stem cells directly from the bloodstream using a process called apheresis.
Before a PBSC donation, the donor receives daily injections of a medication called granulocyte colony-stimulating factor (G-CSF) for four to five days. This drug stimulates the bone marrow to produce a greater number of stem cells and encourages them to move out of the bone marrow and into the circulating blood. The apheresis procedure itself is similar to donating plasma; blood is drawn from one arm, passed through a machine that filters out the stem cells, and the remaining blood is returned to the donor through the other arm.
The second method is a surgical procedure called Marrow Harvest, which accounts for the remaining donations. This procedure is performed in an operating room under general or regional anesthesia, ensuring the donor feels no pain during the collection. The surgeon uses a sterile needle to withdraw liquid bone marrow directly from the posterior iliac crest, which is the back of the pelvic bone.
The procedure typically lasts one to two hours. The donor is placed face down, and multiple small aspirations are often performed from both sides of the pelvic bone to gather the required number of cells for the transplant. While the PBSC method is often preferred for its non-surgical nature, Marrow Harvest remains a necessary option for certain patients, particularly younger children.
Recovery and Donor Care
Recovery time varies significantly depending on the donation method, but both procedures have an excellent long-term safety record.
PBSC Recovery
For PBSC donation, the most common side effects occur while receiving the G-CSF injections before the procedure. Donors may experience flu-like symptoms, including headaches, bone pain, and muscle aches, which typically subside within a couple of days after the injections stop.
Most PBSC donors are able to return to their normal daily activities within a few days to a week after the apheresis procedure. Side effects immediately following the donation are usually mild and may include lightheadedness, fatigue, or bruising at the needle sites. The body naturally replaces the donated peripheral stem cells quickly, often within a few weeks.
Marrow Harvest Recovery
Recovery from a Marrow Harvest takes longer because it is a surgical procedure. Donors often report feeling soreness or stiffness in the lower back or hips, similar to a pulled muscle, which can last for several days or a few weeks. Fatigue is also a common symptom during the initial recovery period.
While some donors may be released the same day, an overnight stay in the hospital for observation is sometimes required. Full recovery, allowing a return to strenuous activity, is generally expected within one to three weeks. The medical team provides comprehensive post-donation care, ensuring the donor’s body replenishes the small amount of marrow removed within four to six weeks.