For patients with serious blood disorders, immune deficiencies, and certain cancers, a stem cell transplant can be a life-saving treatment. In Sweden, approximately every third patient in need of a stem cell transplant is unable to find a suitable donor 1, 7. Compatibility depends in part on highly specific genetic markers known as Human Leukocyte Antigens (HLA), which vary significantly between individuals. While HLA compatibility is only one of several factors considered by transplant physicians, it remains a fundamental part of donor matching and transplantation planning 2. Before a stem cell transplant can take place, physicians assess compatibility between donor and recipient through HLA matching. These genetic markers play a crucial role in how the immune system recognizes cells as either “self” or “foreign”. A closer HLA match is generally associated with lower risks of complications following transplantation 2. Although international donor registries contain millions of potential donors, not every patient can find a suitable match when treatment is needed. Research published in the New England Journal of Medicine demonstrated that the likelihood of finding a suitably matched unrelated donor varies considerably depending on genetic background and ancestry 3. In the study, patients of European ancestry had the highest probability of finding a well-matched donor, while several minority populations faced substantially lower matching rates. These findings highlight a fundamental challenge within transplantation medicine: donor registries are valuable, but they do not guarantee that every patient will find a compatible donor. Because HLA markers are inherited, close relatives are often the first individuals evaluated when a stem cell transplant is being considered. Children inherit half of their HLA markers from each parent, while full siblings have a significantly higher likelihood of sharing transplantation-relevant HLA characteristics than unrelated individuals 4. For this reason, family members are frequently assessed before physicians expand the search to international donor registries. Curious about your family’s compatibility? HLA typing can identify transplantation-relevant genetic markers and provide insight into compatibility between family members. Cord blood has several characteristics that have made it an important source of stem cells for transplantation. Unlike traditional donor sources, cord blood can be collected, tested, and cryopreserved in advance, making it immediately available when needed. Research has shown that cord blood transplantation can often be performed with less stringent HLA matching requirements than many traditional donor sources 5, 6. This flexibility may help expand treatment options for patients who are unable to find a fully matched donor through conventional donor searches. For patients diagnosed with aggressive conditions such as acute leukemia, time can be critical. Searching for a compatible donor may take weeks or months. Preserved cord blood, on the other hand, has already been collected, tested, and stored, allowing it to be retrieved and prepared for transplantation when needed 5. For some families, this immediate availability is one of the reasons they choose to preserve stem cells at birth. No future medical need can be predicted. However, preserving stem cells at birth ensures that a unique biological resource remains available rather than being discarded. While preservation does not guarantee future use, it may provide additional options if a future medical situation requires transplantation evaluation, donor matching, or compatibility assessment. Learn how HLA markers influence stem cell transplantation and explore your family’s compatibility profile through accredited laboratory testing.
Why matching matters
Every third patient does not find a suitable stem cell donor
Explore HLA Transplant Match
Why finding a donor can be difficult
Not everyone has the same chance of finding a match
Why family members are often considered first
Learn about stem cell transplantation
Why cord blood has become an important transplant source
When timing matters
Why some families choose stem cell preservation
Approximately every third patient in need of a stem cell transplant is unable to find a suitable donor 1, 7.
Understanding compatibility starts with understanding HLA
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