Significance Of HLA Typing In Stem Cell Transplantation

A stem cell transplant is a medical treatment procedure where diseased or damaged cells in your own body or donor cells. A bone marrow transplant is also known as stem cell transplant or hematopoietic stem cell transplant¹.

Globally, approximately 90,000 stem cell transplants are carried out annually and the number is increasing each year². Stem Cell Transplants offer hope to patients who are in the advanced stage of the disease (Leukemia, Beta thalassemia etc).

Now, let us discuss the types of stem cell transplants and what they constitute.

The 2 Types Of Stem Cell Transplants:

• Autologous Stem Cell Transplant: The patients use their own stem cells.³
• Allogeneic Stem Cell Transplant: The patient uses stem cells from a donor. A donor can be a family member or not related to the recipient.³

The success of these transplants depends on various factors including the patient's overall health, disease stage, and availability of a compatible/matching donor. This is where the role of human leukocyte antigens (HLA) becomes critical.

The degree of HLA match between the donor and the recipient is an important factor in deciding the outcome of the transplantation.

Now, let us understand what HLA is and its role in detail.

Human Leukocyte Antigens

Human Leukocyte Antigens (HLA) are proteins that are expressed on almost all cells. They are primarily responsible for the immune response of the body and help in differentiating our own cells from foreign bodies⁴. Interestingly, each individual has a unique set of antigens which are inherited from the parents - half are from the mother and half from the father⁴. This means that children can be born with these possibilities:

• Siblings from the same parents have a 25% chance (1 in 4) of being a close HLA match.
• Extended family members are highly unlikely to be a close match.
• About 70% of patients who need a transplant do not have a matched family donor⁴.

HLA Typing - All About The “Perfect Match”

The “Perfect Match” is where a healthy donor’s HLA matches closely with the recipient's. This process is called HLA typing ¹.

HLA typing is used to match donors and recipients and is much more complex than blood typing. Principally, for stem cell matching, there are between 6 - 10 parameters that need to be matched, with each parameter having between 2000-4000 variants. Detailed testing is required for finding the best match.

Adult bone marrow requires 9-10 parameters to be matched. For umbilical cord blood, ideally an 8/8 is considered a perfect match. However, even a partial match of 6/8 is also an acceptable match for umbilical cord blood stem cell transplants, thereby making it 10-100x more easier to find a match ^{5, 6}.

A close HLA match between a donor and recipient is critical for a successful stem cell transplantation because of the following reasons⁷

1. Improves the chances of a successful stem cell transplantation
2. Promotes engraftment (growth & development of healthy blood cells)
3. Reduces the risk of complications including graft-versus-host disease (GVHD)

Now that you know how and why HLA typing is important, let’s take a look at the challenges that recipients of Indian ethnicity often face.

Challenges Of Finding A Match In India

Ethnicity and racial background is also an important factor when looking for the perfect match for stem cell transplantation. A few HLA markers are more common than the others or are found more often in certain ethnicities. Therefore, a person’s best chance of finding a good match is more likely to be with a donor of similar ethnic background⁴.

Finding a match in India can be challenging due to the following reasons:

• The chances of finding a matching donor in international registry is less than 10%⁸
• High donor dropout rate
• Cost of procuring a matching donor unit in an international registry can be as high as 30 lakhs⁸
• Public bank limitations
• Low inventory (repository contains approx. 6500 units only) due to lack of donors
• Lack of funds for the functioning of the registry

However, it is important to note that despite these hurdles, it’s not always a dead-end. In this seemingly grim scenario, we tell you how LifeCell community banking program can offer a ray of hope.

How LifeCell Community Banking Helps

Lifecell Community Banking works on the concept of sharing preserved stem cells exclusively amongst its community members. This means that LifeCell’s over 60,000 qualified & consented cord blood units are available for allogeneic stem cell transplantations. The sheer number of the available units combined with the fact that the majority of them are of Indian origin ensures the chance of finding a perfect matching unit for an Indian patient drastically shoots up to  >97%⁹. 

This makes LifeCell’s StemMatch*, a one-of-its-kind exclusive service to enrolled stem cell banking customers, India’s best matchmaker.

With this test, you can readily know the exact number of 6/8, 7/8 & 8/8 matching stem cell units available for your baby and family members in the LifeCell registry, the largest repository of Indian origin stem cells. All it takes is 3 simple steps!

1. Sign up
2. Sample collection: Cord blood for the child, peripheral blood for mother and saliva for the adults
3. Comprehensive results shared in 15 days

What’s more? Once you sign up for StemMatch, you get these additional benefits:

• Any member of the family can avail it.
• Reduced testing & matching time for expedited stem cell transplantation process.
• Affordable pricing for trusted customers @ INR 10,000  per person
• Annual updates based on new samples added in or retrieved from the registry with no additional cost

Sounds great, doesn’t it? But wait, there’s more. With LifeCell’s financial assistance of up to rupees 20 lakhs for every stem cell transplant treatment, the cost of the treatment also gets substantially reduced. Thus, making it a win-win situation for all. Now, that’s what we believe is a “Perfect match” - from all points of view!

To Summarize

We all wish to see our loved ones in the pink of health. In the unfortunate event that they are diagnosed with a serious condition, we can always look out for better treatment options like  stem cell transplantations. However, the initial time spent in finding the perfect matching donor for a stem cell transplant can play a key role in the outcome of the treatment. Therefore, it is always prudent to equip ourselves with a health assurance such as StemMatch. It can help reduce the critical search-time while providing access to a large repository of stored stem cells of Indian ethnicity - all of which can prove handy when a medical emergency arises. Afterall, nothing can be more precious than the good health of your family!