The match that matters most
Every person carries a unique set of markers on their cells — half from one parent, half from the other. Those tiny "this is us" signals are called HLA.
Your baby's biological fingerprint
Your baby's cells carry a little bit of both of you — three markers from you, three markers from your partner. Together they make a one-of-a-kind pattern that tells the immune system, "this is us."
These markers are called HLA (Human Leukocyte Antigen). HLA are tiny proteins on the surface of most cells that help the immune system tell "this is me" from "this is not me." Think of them as your baby's cellular name tag.
If your child ever needs a cord blood transplant, doctors compare these six markers between your child and a donor unit to see how easily their body will recognize those cells as helpers, not strangers. The closer the match, the more gently those cells can do their work.
Why cord blood has an advantage: Bone marrow transplants need a near-perfect match. Cord blood can work with just 4 out of 6 markers matching, because the younger stem cells are gentler on the recipient's body. That means more potential donors, more chances to find a match, and more options for your family.
Most families will never need to think about HLA again. But if you ever do, understanding these tiny markers can make a complicated decision feel a little less mysterious.
Your baby's HLA type
A one-of-a-kind combination of all six
What "4/6" or "6/6" actually means
When doctors evaluate a cord blood unit, they compare 6 HLA markers between donor and recipient. More matches generally mean better outcomes.
Cord blood is more forgiving. Unlike bone marrow, cord blood transplants can succeed with 4/6 matches. The younger, more adaptable immune cells in cord blood are less likely to attack the recipient's body, giving families more options when a perfect match isn't available.
Matching determines outcomes
Engraftment success
A better HLA match increases the likelihood that transplanted stem cells will take hold and begin producing healthy blood cells.
Reduced complications
Closer matches lower the risk of graft-versus-host disease, where donor immune cells attack the recipient's tissues.
Faster recovery
Well-matched transplants tend to engraft more quickly, shortening the window when the immune system is most vulnerable.
Family advantage
Siblings have a 25% chance of being a perfect HLA match, and each parent is always a 50% (3/6) match. Banking cord blood gives each new child a potential match for the whole family.
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