Human leukocyte antigen (HLA) matching is done when doctors are trying to find bone marrow or cord blood matches for a patient that needs one or both of these things. HLA matching is not as simple as knowing a person needs cord blood or bone marrow and finding someone who is willing to donate, it’s a very delicate process to ensure that there will not be any ill effects from the transplantation of either material into the patient in need. 

HLA antigens are found on most cells in your body and your system uses these proteins or markers to recognize which cells belong in your body and which do not. If your donors HLA antigens are different from yours, your body will respond accordingly and attack those cells. A close HLA match needs to be found to decrease the chance that your immune cells will attack your donor’s cells or that your donor’s immune cells will attack your body after the transplant.

How is a match found?

Human leukocyte antigens are said to be a match if the donor and the patient’s tissues are found to be immunologically compatible with one another. There are three general groups of HLA, and doctors can do blood tests to see which of the groups that you fall into and then try to find someone in the same group that matches closely to your personal HLA.

Can’t my family donate?

Your family can be tested to see if they are an HLA match to you, but just because you are related doesn’t guarantee that you will be a match. A well-matched donor is important, and HLA is inherited, so your best chance of finding a close donor is with your family, preferably a brother or sister. If you have the same parents, your siblings have a 25% chance of having a close HLA match. Other family members probably will not be a match for you, though it’s worth testing parents and children. Approximately 70% of people who need a transplant do not have a match within their family, though it’s always worth checking.

Does HLA matching need to be done?

HLA matching needs to be done to improve your chances of a successful transplant, otherwise your body will attack the cells or the cells will attack your body. This attacking often turns into GVHD or graft-versus-host-disease which is a disease of varying degrees where your body is attacked or attacks the cells put into your body.

If you do not have a match in your family, your doctor will typically search a registry for an unrelated donor or cord blood unit. There are currently more than 5.5 million volunteer donors and more than 40,000 cord blood units listed in the registry, meaning your doctor will likely find a match for you so your transplant can be done and you can get on with your life.

 
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