Stem cell donation (bone marrow and peripheral blood stem cell, or PBSC) provides a life-saving treatment for people battling diseases like leukemia, lymphoma, and other blood disorders. Donations replace a patient’s unhealthy blood-forming cells with healthy cells, allowing the body to regenerate a new, healthy blood and immune system. Success relies on finding a close match of human leukocyte antigens (HLA) between the donor and the patient. HLA markers are proteins on the surface of most cells that help the immune system recognize what belongs in the body; a mismatch can lead to serious complications like graft-versus-host disease. Because HLA types are inherited and highly diverse, finding a perfectly matched, unrelated donor is often difficult.
Eligibility Requirements for Donors
Donating stem cells requires meeting strict health and age criteria designed to protect both the donor and the patient. Potential donors must be in good health and free of medical conditions that could put them at risk during the donation process or negatively impact the recipient. Certain health histories, such as heart disease, autoimmune disorders (like lupus or rheumatoid arthritis), or specific types of cancer, prevent registration.
Age is a significant factor; most national registries seek individuals between 18 and 40, though many allow registration up to age 55 or 60. Younger donors are preferred because research indicates that stem cells from younger people provide patients with a higher chance of long-term transplant success. Some registries also enforce a Body Mass Index (BMI) limit, typically under 40, to ensure donor safety during the procedure.
Joining the National Registry
The journey to becoming a potential donor begins by joining a national registry, which involves a commitment to donate if called upon. The first step is completing an online registration form and a health questionnaire to screen for eligibility. The registry then sends a simple cheek swab kit to the potential donor.
This swab collects cells for DNA analysis to determine the individual’s unique HLA type, a process called HLA typing. Once the HLA profile is generated, it is added to the national database, where transplant centers worldwide can search it. The probability of being identified as a match is low, but registrants must be prepared to honor their commitment quickly. Maintaining current contact information is critical, as a delay in reaching a match could be devastating for a waiting patient.
Understanding the Two Donation Methods
There are two methods for collecting blood-forming stem cells: Peripheral Blood Stem Cell (PBSC) donation and surgical bone marrow donation. The patient’s physician determines which method is best based on the specific disease and treatment plan. PBSC donation is the more common method, accounting for approximately 80% of all donations.
For a PBSC donation, the donor receives daily injections of filgrastim for about five days before the procedure. This synthetic protein acts as a growth factor, signaling the bone marrow to release a higher number of stem cells into the bloodstream. The collection process, known as apheresis, is non-surgical and similar to donating plasma or platelets. Blood is removed from one arm, filtered through a machine that collects the stem cells, and then the remaining blood is returned through the other arm. This outpatient procedure typically takes four to eight hours and may occasionally require a second day of collection.
The less common method is surgical bone marrow donation, which involves extracting liquid marrow directly from the back of the pelvic bone (hip). This procedure requires general or regional anesthesia, ensuring no pain is felt during the collection. The surgeon inserts a sterile needle into the pelvic bone to withdraw the liquid marrow, usually collecting one to two pints. The procedure typically takes one to two hours, and most donors go home the same day or after an overnight stay.
Donor Recovery and Safety
Donor safety is important, and the procedures are generally well-tolerated, though side effects vary between the two methods. Donors undergoing the PBSC method often experience temporary bone or muscle aches, headaches, or fatigue due to the filgrastim injections. These flu-like symptoms are generally mild and disappear quickly once the medication is stopped. Most PBSC donors return to normal activities within one to seven days.
For surgical bone marrow donation, the most common after-effects include soreness, bruising, and discomfort at the lower back collection site. Donors may also feel fatigue for a few days, and there are small, standard risks associated with receiving anesthesia. While the median time to full recovery is about three weeks, most donors can return to work or school within one to seven days. Regardless of the method, the body naturally replenishes the donated blood-forming cells within a few weeks.