The short answer is yes, but only if the recipient is compatible with certain proteins in the donor’s stem cells called HLAs (Human Leukocyte Antigens). These HLAs are passed on genetically in equal amounts from the mother and father.
The likelihood of HLA compatibility diminishes the further away you get from the donor in the family tree.
So what is in HLA and how will you know if your child’s cord blood is HLA-compatible with other family members?
What Is HLA?
The HLA system is a group of genes that play a critical role in the immune system. Discovered in 1958, the HLA gene system has proteins on the surface of nearly all cells in the body that are programmed to recognize compatible proteins and attack foreign ones. HLAs are what cause the immune system to attack viruses and bacteria.
While the gold standard is a perfect match among siblings, not all stem cell transplants require a 100% match of all HLA markers. Determining a match depends to a large extent on the matching grade required by the transplant center [*].
Mismatched cells can cause GVHD, or graft-versus-host disease, a serious condition that is the leading cause of death following transplant surgery. Nearly 50% of all patients who develop GVHD will die as a result [*]. GVHD occurs when the healthy cells of the donor tissue attack the immunocompromised cells of the recipient.
HLA Typing – Cord Blood Compatibility Testing
Prior to a stem cell transplant, HLA typing is used to assess the recipient’s compatibility with the donor’s stem cells. There are many HLA markers or loci, and some are more important than others when it comes to transplants; It’s far more complicated than blood typing.
The major HLA antigens essential for immune responses are HLA-A, -B, -C, -DR, -DQ, and -DP, which are encoded by polymorphic genes in the human genome, with 1–1,543 alleles per locus [*].
The test itself has many levels of detail, ranging from low resolution to intermediate resolution, high resolution, and allele level resolution. The compatibility status of each patient/donor pair depends on the level of resolution of the HLA typing and which loci or markers are tested.
That said, collecting genetic material for HLA typing is simple. It typically involves swabbing the inside of your cheek or drawing a blood sample from your arm. Insurance may cover HLA typing, so check with your provider.
Cord Blood vs. Bone Marrow vs. Peripheral Blood for Transplants
Cord blood is one of three sources of blood-forming stem cells used in transplants. Bone marrow and peripheral blood (blood that circulates through the body) are the other two.
In general, cord blood transplants (even mismatched ones) carry a lesser risk of developing GVHD than bone marrow transplants. For instance, children who have transplants using cord blood matched from a sibling have a less than 10% chance of developing GVHD, much less than when using bone marrow from the same donor [*].
Peripheral-blood stem cells are easier to harvest and may demonstrate better engraftment than those of bone marrow, but also show higher rates of acute and chronic GVHD [*].
Cord blood stems cells allow for more leniency in HLA matching than that of bone marrow. Cord blood transplants often require 3 or 4 out of 6 HLA markers, whereas bone marrow transplants require 6 out of 6 [*].
Stem cells from cord blood rarely carry any infectious diseases and are half as likely to be rejected as adult stem cells. They can also be accessed more quickly than stem cells from an adult bone marrow donor who may have registered years ago.
Transplant Types: Allogeneic, Autologous, and Haploidentical
There are three types of transplants, based on where the stem cells come from and how well matched they are:
- Allogeneic transplants: Transplants that use stem cells from another individual, whether a sibling or an unrelated donor. Allogeneic transplants are required when the patient’s disease has a genetic basis, such as sickle cell disease, cystic fibrosis, immune deficiency syndromes, bone marrow failure, lymphoma, and genetic metabolism disorders. For genetic diseases, the donor’s own stem cells cannot be used because the genetic mutations that cause these disorders are present in the baby's cord blood.
- Autologous transplants: Transplants that use the patient’s own cord blood stem cells. They are typically used in people who need to undergo high doses of chemotherapy and radiation to cure their diseases and are often used to treat Hodgkin's lymphoma, Myeloma, Non-Hodgkin's lymphoma, and Plasma cell disorders. There is also promising data on the use of autologous infusions or transplants for Cerebral Palsy [*].
- Haploidentical transplants: Transplants in which the donor need only be a 50% match to the recipient. A healthy first-degree relative – a parent, sibling, or child – can often serve as a donor [*]. These transplants are increasingly common.
Can Cord Blood Be Used for Siblings?
Yes, siblings have the best chance of being a perfect match. In fact, the first cord blood stem cell transplant occurred between two matched siblings in 1988, for the successful treatment of Fanconi Anemia.
Two full siblings have a 25% chance of being a perfect match, a 50% chance of being a half match, and a 25% chance of not matching at all.
That means with one sibling, there is a 75% chance overall of a potential match.
Is Cord Blood Banking for a Second Child Necessary?
The more siblings with banked cord blood, the more chance you have of finding a match for transplants or other therapies for which sibling stem cells are an option or in fact required.
The probability of finding an HLA-identical sibling donor depends on the number of siblings: While the likelihood of a perfect match is 25% for patients with one sibling, it goes up to 44% for those with two siblings, 58% for those with three, 68% for those with four, and up to 90% for patients with eight siblings [*].
Can Cord Blood Be Used for Parents?
Yes, a parent can use their child’s cord blood for treatment as long as there is a sufficient HLA match. Because each parent contributes 50% of the HLA markers, each parent is unlikely to exceed a 50% match. But there is the possibility of a haploidentical transplant when there is a 50% match.
Can Cord Blood Be Used for Grandparents?
Yes, a grandparent can use their grandchild’s cord blood for treatment as long as there is a sufficient HLA match. A recent story noted the use of such cells for treatment of stroke in the grandfather.
Diseases Treated With Cord Blood Stem Cell Transplants
Cord blood plays a major role in the treatment of over 80 diseases and conditions, with hundreds of clinical trials underway to identify more life-saving opportunities using cord blood stem cells [*].
Cord blood and cord tissue banking offers families access to potentially life-saving stem cells that can be used to treat your child or a compatible family member.
Doctors and researchers have been harnessing the incredible power of cord blood stem cells since 1988, following the first successful cord blood transplant between HLA-matched siblings for the treatment of Fanconi Anemia. In the years since, more than 40,000 cord blood transplants have been performed worldwide.
Neurodegenerative diseases such as Alzheimer’s, musculoskeletal diseases such as osteoarthritis, congenital cardiovascular diseases, and blood cell diseases such as leukemia are among the health conditions that have benefited from stem cell therapy advancements [*].
There is also promising data on the use of autologous cord blood infusions for children with cerebral palsy, with nine clinical trials underway testing efficacy in more than 2,500 patients.
Scientists believe future cord blood stem cell transplants may include treatment for ALS, muscular dystrophy, diabetes, and arthritis, among other diseases. In the rapidly advancing field of regenerative medicine, cord blood treatments are being studied for nerve, heart, bone, and metabolic diseases.
Why Bank Cord Blood Privately?
The short answer is, to be ready to act quickly in the face of a life-threatening disease.
In a family with a child already afflicted with a disease in which stem cell transplantation might become indicated or in families where both parents are known to carry the risk of a potentially lethal disease that could be treated with a stem cell transplant — even if they have not yet had an affected child — private cord blood banking is recommended.
If the family’s ethnic or ancestral background is mixed, it is even more important to bank privately, as ethnic groups are under-represented in cord blood donor registries. It’s also worth noting that not all public banks accept cord blood donations, and none accept tissue donations, again hamstringing the public option.
Parents who are unsure of their medical background due to being adopted or having conceived their child with a sperm or egg donor also may choose to bank cord blood privately.
Lastly, a family history of cancer or other diseases may not be known, but families who save their baby's cord blood privately understand that these conditions can occur without precedent and without warning.
The Bottom Line
Cord blood and tissue collected from your baby may prove life-saving for siblings and other family members, now and in the future. There are more than 80 diseases treated now with cord blood stem cells and hundreds more applications are in clinical trials.
With more lenient compatibility, viability, availability, and lower risk of GVHD than other sources, cord blood is the best source for family members who have an urgent, life-threatening genetic disorder, need a transplant quickly, or have an uncommon tissue type because of their racial or ethnic heritage. And the more children you bank for, the better the probability of finding a match in your own family.
These are but a few of the many compelling reasons parents bank all their children’s cord blood and/or tissue with MiracleCord.
Banking with MiracleCord gives parents peace of mind in the event that their child or another family member needs to find a compatible cord blood or tissue donor quickly. MiracleCord’s service, technology, and value have earned us “Best Cord Blood Banking Company in the U.S.” from Global Health & Pharma in 2021 and again in 2022. Discover why.