Bone marrow donation provides healthy blood stem cells to treat patients suffering from blood cancers like leukemia, lymphoma, and other life-threatening blood disorders. These donated stem cells replace the patient’s diseased marrow, allowing them to rebuild a new, healthy immune system. For many patients who cannot find a match among family members, an unrelated volunteer donor represents their only hope. Understanding the specific requirements and the process involved is the first step in determining if you can be a match for someone in need.
Who Qualifies to Register
The first step toward becoming a donor involves meeting initial health and age requirements set by donor registries. Most registries accept new members between the ages of 18 and 55. Donors aged 18 to 44 are often preferred because their stem cells generally lead to better patient outcomes and influence transplant success.
Beyond age, a potential donor must be in good health and should not have a history of specific chronic or severe medical conditions. Disqualifying conditions include HIV, most forms of heart disease, severe asthma, autoimmune disorders such as lupus or rheumatoid arthritis, and certain blood clotting disorders. Registries also assess Body Mass Index (BMI), as being significantly underweight or overweight can present a safety risk during the donation procedure.
The Donor Registry and Matching Process
The process begins with registration, which involves a simple cheek swab to collect cells for Human Leukocyte Antigen (HLA) typing. HLA markers are proteins found on most cells in the body that the immune system uses to distinguish between “self” and foreign cells. A close match between the donor’s and patient’s HLA types is necessary to prevent the patient’s body from rejecting the transplanted cells, a complication known as graft-versus-host disease.
HLA typing identifies a person’s unique genetic markers, and doctors look for a match at 7 to 10 specific markers. Because HLA markers are inherited, full siblings have only about a 25% chance of being a perfect match, necessitating reliance on the worldwide volunteer registry. Once a potential match is identified, the donor receives a commitment confirmation call, followed by a thorough medical screening and blood tests to confirm health suitability and final HLA compatibility.
Understanding the Two Donation Methods
Once a match is confirmed, the patient’s doctor determines the most suitable method: Peripheral Blood Stem Cell (PBSC) donation or traditional bone marrow donation. PBSC donation is the most common method, accounting for about 90% of donations, and is a non-surgical, outpatient procedure. For five days leading up to the procedure, the donor receives injections of filgrastim, which stimulates the bone marrow to release blood-forming stem cells into the bloodstream.
The PBSC collection uses apheresis, similar to donating platelets, where blood is drawn from one arm, processed by a machine to separate stem cells, and returned through the other arm. This process takes four to eight hours and is completed in one or two sessions. In contrast, traditional bone marrow donation is a surgical procedure performed in a hospital under general or regional anesthesia. Doctors use specialized needles to withdraw liquid marrow directly from the back of the donor’s pelvic bone.
Donor Safety and Recovery
Both donation methods are considered safe, but they carry different risks and recovery timelines. For PBSC donation, the primary side effects relate to the filgrastim injections, which can cause temporary symptoms like bone or muscle pain, headaches, or flu-like symptoms. Most PBSC donors return to their normal activities within a week.
The risks associated with traditional marrow donation are primarily linked to the use of anesthesia and the surgical nature of the procedure. Common short-term side effects include bruising, fatigue, and pain at the collection site. While serious complications are rare (occurring in about 2.4% of donors), bone marrow donors take longer to recover, with a median time of about 2.3 weeks to return to full physical status. The body naturally replenishes the donated marrow within four to six weeks.