Kidney Transplant and Blood Type

Introduction

Kidney transplant remains the best treatment available to save the lives of patients with end-stage renal disease (ESRD) or chronic kidney disease. Dialysis can keep people alive for a while, and kidney transplant makes them healthier and keeps them younger for longer. Isn’t it the blood type that really matters for kidney donation?That’s one of them. But another key factor in a successful transplantation is blood type compatibility – A, B, AB or O – between the donor and the recipient.

Knowledge about the role of blood type in non-directed kidney transplant outcomes, can help clinicians and harmed individuals that live in the complicated sphere of organ transplantation. In the first of this two-part series, we explain the science behind blood-type compatibility donors and transplant recipients, and consider recent progress in overcoming these disparities.

What Is Blood Type and Why Does It Matter in Kidney Transplantation?

Understanding of the role of blood type in non-directed kidney transplant, and transplant results, can assist both physicians and injured parties who coexist in the complex world of organ transplantation.

In the ABO system, there are four main blood types:

• Type A: Has A antigens and anti-B antibodies
• Type B: Has B antigens and anti-A antibodies
• Type AB: Has both A and B antigens but no anti-A or anti-B antibodies
• Type O: Has no A or B antigens, but has both anti-A and anti-B antibodies

Kidney donor and recipient are conventionally matched in ABO blood group compatibility to reduce the risk of an immune response leading to transplant rejection.

ABO Compatibility Chart for Kidney Transplant

Recipient’s Blood Type	Compatible Donor Blood Types
Type O	O only
Type A	A or O
Type B	B or O
Type AB	AB, A, B, or O (universal recipient)

Blood type is based on whether or not you have specific antigens (proteins) on the surface of your red blood cells. The most important antigen systems in kidney transplantation are:

Kidney donor and recipient are conventionally matched in ABO blood group compatibility to reduce the risk of an immune response leading to transplant rejection.

How ABO Incompatibility Leads to Rejection

If someone gets a kidney from a donor with a different blood type, the recipient’s body would ‘see’ the kidney the same way it would look at a harmful bacteria or virus, (i.e. as a foreign invader and treat it as such). This response is known as hyperacute rejection and can develop as soon as several minutes up to hours after the transplant.

Rejection within the first forty eight hours (hyperacute rejection) is irreparable and leads to the failure of the transplant. As a result, ABO compatibility has traditionally served as a primary consideration in the choice of kidney donor.

Exceptions: What If You Don’t Have a Compatible Donor?

Some patients wait years to find a match. Luckily, medical science has had developed several solutions for patients in need who lack an ABO-compatible living donor:

Paired Kidney Exchange (Kidney Swap)

With a paired exchange, two or more incompatible donors and recipients can “exchange” donors. For example:

Couple 1: Donor A (blood group A) and Recipient A (blood group B)

Couple 2: Donor B (blood type B) and Recipient B (blood type A).

Because Donor A is compatible with Recipient B, and Donor B is compatible with Recipient A, a swap may ensue to the satisfaction of both patients.

These are paired and chain exchanges, which can include multiple donor-recipient pairs, and are typically facilitated through local national and international registries.

2. ABO-Incompatible Transplantation (ABOi)

Due to desensitization therapies, it is currently possible to offer some patients kidneys from ABOi donors. These procedures typically involve:

• Plasmapheresis: (to remove antibodies)
• Immunosuppressive therapy: (to prevent new antibodies from forming)
• Rituximab or IVIG: to suppress B cells (which produce antibodies)

After years of poor renal transplant survival, patients receiving an incompatible kidney (an ABOi transplant) are now doing much better, although these transplants are still more complicated and riskier than those with compatible recipients, with the added problem of antibody-mediated rejection.

Other Important Factors Beyond Blood Type

1. HLA Matching

Human leukocyte antigen (HLA) matching is another key compatibility factor. These proteins are found on the surface of cells and help the immune system distinguish between self and non-self.

There are six key HLA markers (HLA-A, HLA-B, and HLA-DR being the most critical). The better the match between donor and recipient, the lower the risk of rejection.

2. Crossmatch Test

Even if the donor and recipient are ABO compatible, a crossmatch test is necessary. This test determines whether the recipient has pre-formed antibodies against the donor’s HLA antigens. A positive crossmatch indicates high risk of rejection.

The latest studies Exploring the Link Between Blood Type and Waiting Time Before Transplant

The type of blood you have influences how long you will wait for a transplant. For instance:

• Recipients who receive type O blood are often those who wait the longest, due to the fact that only type O donors can donate to them.

• Type AB recipients usually have the shortest wait because any blood type can be accepted by them.

• Finding a suitably matched donor for type O patients is already tough, especially in areas with low organ donation rates.

The Role of Living Donors and Compatibility Challenges

The Benefits of Living Donor Transplants:

• Shorter wait time
• Better long-term outcomes
• It can be planned surgery

Yet, among related or unrelated willing donors, the ABO blood group system is frequently a barrier. The following would be appropriate options in these situations:

• Desensitization protocols
• Paired kidney exchange

Non-directed (universal) altruistic donors and donation with adult-to-adult living-related DDLT (LD), hereafter “LD donation” or “LD”

Advances in Overcoming ABO Barriers

The capacity to transplant kidneys across ABO barriers has been considerably improved by medical research. Innovations include:

Immunoadsorption

Advanced version of plasmapheresis which can more efficiently deplete the recipient of anti-ABO antibodies.

Rituximab and B-cell Depletion Therapy

B cells are less targeted before transplant because they are CD20-positive, the target of rituximab, which decreases antibody production. It is frequently applied in ABOi strategies.

Improved Post-Transplant Monitoring

A close DSA and protocol biopsies in a follow up of ABO-I renal transplants have helped to decrease post transplant rejections.

Kidney Transplant in Children and Blood Type Matching

In infants and especially in newborns under 1 year of age, the immune system is not mature, and the anti-A or anti-B antibodies may be absent or low. In pediatric patients, therefore, ABOi transplantation seems to be possible without the same degree of risk observed in adults.

This has provided more opportunities for prompt transplantation in children as well as for greater survival.

Case Studies: Real-Life Scenarios

Case 1: Recipient Type O and Donor Type A

Sarah, who is 35, and has type O blood, was not a match for her sister (who is type A). After looking into paired exchange, the transplant center discovered another family in nearly the same situation. The two patients received life-saving kidney transplants in a 2-way kidney swap.

Case 2: ABO-Incompatible Transplant

In Iran, a 42-year-old man named Ali received a kidney from his wife, whose blood type was B (his was A). He received plasmapheresis and rituximab therapy prior to transplantation. His renal function remains stable after 3 years which shows the pain.

Ethical and Cultural Considerations

Donor-to-recipient incompatibility with respect to blood type and kidney transplantation also pose ethical and cultural issues:

• Family members as living donors may cause psychological or financial stress.

• Attitudes about bodily integrity and blood in the culture may influence willingness to contribute.

• Legislation across the globe differs with respect to non-closely related and paid donation, and Iran uniquely allows for remuneration of live donors under a coordinated system.

• To piece together this complicated puzzle of medical, administrative, and ethical issues regarding kidney transplantation, even understanding the compatibility of blood types is critical.

Frequently Asked Questions (FAQs)

1. Can a person with blood type O receive a kidney from type A, B, or AB?

No. Blood type O individuals can only receive kidneys from type O donors due to the presence of anti-A and anti-B antibodies.

2. Is ABO-incompatible kidney transplant safe?

While more complex, ABOi transplants have become safer due to desensitization protocols. Success rates have improved, especially in experienced centers.

3. How long does desensitization take before an ABOi transplant?

It varies but usually takes 2–4 weeks before transplantation. Some patients may need additional sessions depending on antibody levels.

4. Can blood type change after kidney transplant?

No. A person’s blood type does not change after transplant, as blood type is determined by the bone marrow, not the kidney.

5. Why is blood type O considered a universal donor?

Because type O blood lacks both A and B antigens, it’s less likely to trigger an immune response in recipients of other blood types.

Conclusion

The ABO blood type incompatibility is the basis for compatibility and in fact, determines the donor choice, and determines when to go for transplant, and what is to be expected after transplant. Although ABO incompatibility was once a solid firewall, today s medicine can find ways around it through paired exchange and desensitization.

If you are a patient waiting for a kidney, or you’re considering becoming a donor, or if you’re a doctor or nurse who deals with these patients and donors, it’s important to know how kidney donations and blood type relate to each other. As technology continues to progress and worldwide organ sharing programs continue to expand, the expectation is that blood type will increasingly become less of a barrier and more of a hurdle to work around when pursuing kidney transplantation.

Resources:

https://www.kidney.org/kidney-topics/incompatible-blood-types-and-paired-exchange-programs

https://health.ucdavis.edu/transplant/livingkidneydonation/matching-and-compatibility.html