Your physician has asked Canadian Blood Services' OneMatch Stem Cell and Marrow Network to conduct a search for a suitable stem cell donor on behalf of yourself or your loved one. This information will help you understand the role that OneMatch has in conducting a search and in coordinating the donation of volunteer stem cells. While you still may be coming to terms with the diagnosis, be assured that OneMatch staff are working hard to find a donor for you or your loved one.
About the OneMatch Stem Cell and Marrow Network
The OneMatch Stem Cell and Marrow Network is a Canadian Blood Services program dedicated to recruiting and finding healthy, committed volunteer donors for patients in need of stem cell transplants. OneMatch staff coordinates searches in Canada, and with other international registries, towards a single goal - helping patients get the stem cells they need.
Fewer than 25 percent of patients who need stem cell transplants find a compatible donor in their own family. The rest rely on those who have volunteered to donate stem cells to anyone in need. The decision to begin a search for an unrelated donor, as well as choosing a suitable donor, rests entirely with the transplant centre. Our mandate is to coordinate the search and subsequent donation of an unrelated volunteer donor. These volunteer donors must meet a variety of eligibility requirements and undergo a comprehensive health assessment to ensure that the donation process will be safe for them and anyone receiving their stem cells.
Because Canadian Blood Services' OneMatch program belongs to an international network of registries, we can search more than 23 million donors in more than 70 registries in other countries when we need to find a match. By making donor data available worldwide, international registries have significantly increased the odds of finding a matching donor for any patient anywhere in the world.
The OneMatch Stem Cell and Marrow Network operates according to international standards established by the World Marrow Donor Association (WMDA). The WMDA is the international organization that promotes the ethical, technical, medical and financial aspects of stem cell transplantation.
Searching for a Donor
The search begins when the transplant physician forwards a request to OneMatch. He or she is the only person who can request for the search to begin. Within 24 business hours of receiving the request, OneMatch forwards a report of all potential matches, both Canadian and International, to the transplant centre. The transplant team, using their clinical experience, will choose potential donors who may be a suitable match and request blood samples for additional testing. Every month, the search is repeated, so that new registrants may be checked. The search process continues until a donor is found and makes a stem cell donation or until the transplant centre cancels the search request.
The transplant physician is responsible for identifying any potential matches within the patients' family and arranging for testing. If there are questions with respect to a relative's potential to become a donor, these should be discussed with the physician or the transplant centre coordinator. OneMatch will not test any individual for a specific patient.
Stem cell matches are determined according to DNA markers called Human Leukocyte Antigens (HLA). When a person joins OneMatch, a buccal swab is collected and tested for six of these antigens known as HLA-A, HLA-B and HLA-DR. These antigens are inherited from both your mother and father, therefore a sibling represents the best potential match. However, most patients only have a 25 per cent chance of a sibling match. The rest rely on a donor from outside their family.
HLA antigens differ from person to person. Some antigens appear more frequently in certain populations and ethnic groups. When a donor and patient have matching antigens, the donor is considered a candidate. The transplant centre may use up to 12 HLA antigens to determine compatibility. If more than one donor is found to be an HLA match, the transplant physician may consider other factors such as the the donor's age, sex or blood type when determining who should be asked to donate.
What Happens When a Match is Found
Once the transplant centre identifies potential donors that require further testing, the donor needs to be contacted. This process can be lengthy and time consuming. If the potential donor is in another country, OneMatch contacts the appropriate international registry. The registry is responsible for contacting the donor, ensuring they are healthy, and collecting blood samples to ship to the patient's transplant centre. Depending on how long a potential donor has been on OneMatch, their typing results may not be as complete or detailed as today's standards. The transplant centre may request samples from a number of potential donors to find the best possible match. While the patient may be anxious to find a donor right away, it is important that the necessary testing is completed to ensure the best possible match.
A potential donor may be on the list for many years before being contacted and may have moved. They may be difficult to locate. In Canada, the Royal Canadian Mounted Police helps OneMatch staff locate potential donors who have moved. Once located, if the potential donor is still interested, he or she undergoes a health assessment with a Canadian Blood Services registered nurse. After the potential donor passes the health assessment, arrangements are made to collect blood samples. Some of the samples are sent to the transplant centre where tests determine the compatibility between the patient and the potential donor. The remaining samples are tested for infectious diseases. This whole process may take several weeks or even months.
How is a donor prepared for making a donation?
Once the transplant centre finds a suitable donor, they make a formal request to OneMatch and state the preferred method of stem cell collection - either from bone marrow or peripheral blood. OneMatch in turn contacts the appropriate international registry or, if the potential donor is in Canada, contacts the person directly. Every registry is responsible for ensuring the potential donor is healthy and that the stem cell donation will not endanger their health or the patient's.
A Canadian potential donor will go through a number of steps before making an actual donation. These include:
- A health assessment with a Canadian Blood Services registered nurse;
- A review of the donation method, including the associated risks involved in making either a bone marrow or peripheral blood stem cell donation;
- A physical exam and overview of the collection process by a physician;
- Sign an "Intent to Donate" document which states the person intends to donate stem cells.
- The transplant centre may choose to advise the patient that a suitable donor has been found only after all of these steps have been completed.
Need More Information?
As a patient, it’s important that you understand the transplant process. The best way to do this is to ask questions! Keep a list of questions handy whenever meeting with the doctor, the transplant physician or the Transplant Centre coordinator.
A stem cell transplant is a stressful process, both for the patient and his or her loved ones. Many transplant centres have counselling resources to help the patient get through this difficult time. It may be useful to know what services are available. Don't hesitate to use these services - they exist for the benefit of the patient and his or her loved ones.