Bone marrow donation is a medical procedure that offers a life-saving treatment for patients facing serious conditions affecting their blood and immune systems. These often include aggressive blood cancers like leukemia and lymphoma, aplastic anemia, and various inherited immune deficiency disorders. For many, a transplant of healthy blood-forming cells is their best, and sometimes only, chance for a cure. Donors play a crucial role in providing these cells, directly impacting a patient’s recovery and quality of life.
Understanding the Match: HLA Typing
A successful bone marrow transplant requires precise biological compatibility between the donor and patient, primarily determined by Human Leukocyte Antigens (HLA). These proteins are found on the surface of most cells, which the immune system uses to distinguish between its own cells and foreign invaders. A close HLA match is crucial to prevent the patient’s immune system from rejecting donated cells and to reduce the risk of complications such as graft-versus-host disease (GVHD), where donor cells attack the patient’s body.
HLA genes are inherited from both parents, with offspring receiving one set from each. Siblings have a 25% chance of being a perfect match and a 50% chance of being a partial match. The HLA system is highly diverse, with numerous variations across different populations, meaning a patient is more likely to find a suitable match from someone of a similar ethnic background. Laboratories typically examine 10 to 12 specific HLA markers to assess compatibility.
How to Register and Get Tested
Individuals interested in determining if they could be a bone marrow match can join a national bone marrow registry. The process typically begins online by requesting a registration kit, which is then mailed to your home. Alternatively, some registries host in-person drives where you can register on-site.
Initial testing is straightforward and generally involves a cheek swab. The kit usually contains multiple cotton swabs that are rubbed firmly against the inside of your cheek to collect cells. These swabs are sealed and returned to the registry in a prepaid envelope. Collected cells are analyzed to determine your unique HLA tissue type, and this information is entered anonymously into the global donor database.
What Happens if You’re a Potential Match
If your HLA type is identified as a potential match for a patient, the registry will contact you to confirm your continued interest and availability. This initial contact is followed by more thorough confirmatory testing, often involving a blood sample, to ensure match accuracy. A comprehensive medical evaluation and counseling sessions are also part of this stage to assess your general health and discuss the donation process in detail.
There are two primary methods for donating blood-forming cells: Peripheral Blood Stem Cell (PBSC) donation and bone marrow harvest. PBSC donation is the more common method, accounting for approximately 90% of donations. This non-surgical procedure involves receiving daily injections of a medication called filgrastim for several days before the donation to increase the number of blood stem cells circulating in your bloodstream. On the day of donation, blood is drawn from one arm, passed through a machine that separates the stem cells, and the remaining blood is returned to the other arm. This process, called apheresis, typically takes 4 to 8 hours.
Bone marrow harvest is a surgical procedure performed under general anesthesia, ensuring you feel no pain during the collection. A medical professional uses a sterile needle to withdraw liquid bone marrow from the back of your pelvic bone. This procedure typically lasts between one to two hours, and donors usually remain in the hospital for a few hours or overnight for observation. The choice between PBSC and bone marrow harvest depends on the patient’s specific medical needs and the transplant center’s recommendation.
Eligibility and Addressing Common Concerns
To become a bone marrow donor, individuals generally need to be in good overall health and meet specific age criteria. Most registries prefer donors between the ages of 18 and 40, as research indicates that cells from younger donors often lead to more successful transplant outcomes for patients. While some registries accept donors up to age 60 or 61, the emphasis remains on younger donors. Certain chronic health conditions or recent medical treatments may exclude an individual from donating.
Concerns about pain and recovery are common among potential donors. During the bone marrow harvest procedure, donors are under anesthesia, so they do not experience pain. Afterward, some donors report soreness, aching, or bruising in the lower back or hip area, which can feel similar to a muscle strain.
For PBSC donation, side effects from the filgrastim injections can include flu-like symptoms such as headaches, bone aches, and fatigue. These side effects are usually temporary and can be managed with over-the-counter pain medication. Most donors recover relatively quickly, often returning to their routine activities within a few days to a few weeks, with full recovery for bone marrow donation typically taking around 20 days and for PBSC donation about one week.