ABO Incompatible Kidney Transplantation: Potential Game Changer
The number of patients with end stage kidney disease has and is increasing drastically every year. These are patients who are looking at complete renal failure where all other treatment modalities have been exhausted and a kidney transplant is the only option left. The process of renal transplant comes with its own inherent legal and clinical landmines. The social aspects of having a willing donor and then the biologic requirements of cross matching. Finding a suitable donor being the biggest hurdle which most patients cannot cross.
Around the world, the ability of these eligible patients who have end-stage kidney failure to receive that life-saving kidney transplantation is solely limited by a shortage of organ donors. It is roughly estimated that in India alone, almost 220,000 people are in need of kidney replacement therapy every year, which unfortunately remains hugely mismatched with the current number of 8000-9000 kidney transplants being performed across in roughly 250 centres all over the country. Most of these transplants are from living donors. In some families, matching living donors are available and volunteer to help, but even then, some of them are unable to donate because of blood group incompatibility, this is called ABO incompatibility -ABOi. This was until a decade seen to be an absolute dead end for kidney transplant potential.
The number of patients who needed a kidney transplant and those who finally managed to get one, had long been mismatched because of this incompatibility because even the best kidney transplant doctors / surgeons could not overcome this biologic hitch. In recent years, clinical research and trials at the highest level have broken this barrier and opened the floodgates for those thousands of patients who were suffering because of a lack of a compatible donor.
So far, it had not possible to perform a kidney transplant until and unless both the donor and kidney recipient had compatible blood types. About a third of all donors and recipients had to be refused because of this ABO blood type incompatibility.
Let us understand this ABO incompatibility.
Humans have four different blood types; A, B, AB and O.
People who have a certain blood type may form antibodies that will make their immune system react against one or more of the other blood types.
Being exposed to another blood type can cause a severe reaction. This is important to remember especially when someone needs any new tissue to be introduced into the body, like blood (transfusion) or an organ (kidney transplant)
The blood types of the donor and the recipient must be compatible in order to avoid an ABO incompatibility reaction.
For example, recipients who have, say type A blood will react against the tissue donated by a person of type B blood whereas those with type B blood will react against type AB, etc. Similarly, people who have type O blood will react against type A, type B, or type AB blood whereas recipients with type AB blood will not react against type A, type B, type AB, or O blood types.
Type O blood is called a universal donor because it does not cause any immune response when it is given to people with type A, type B, or type AB blood and this is why type O blood cells can be donated to people of all blood types. Unfortunately, people with type O can only receive type O blood.
Kidneys and ABO blood type compatibility
Following the above biologic law
- AB patients can receive a kidney from any blood type. They are the universal recipients.
- A patient can receive a kidney from an O or A blood type.
- B patients can receive kidneys from those with an O or B blood type.
- O patients can get a kidney only from someone with O blood type.
When a living donor has one blood type, and the patient has another incompatible blood type, that donor had so far been typically unsuited for that patient. Not anymore.
Thanks to the diligent research and testing by the scientific community, transplant teams have now broken this barrier and opened a whole new field for renal patients.
What is the process of ABO kidney incompatible transplantation?
In order to prevent immediate organ rejection following an ABO incompatible transplantation, we perform a blood test. This test tells us about the strength of the recipient’s resistance to the donor’s blood group by measuring the levels of antibodies.
The patient will then undergo a two-step process to remove the blood group antibodies:
First, the existing blood group antibodies (against the donor’s blood group) are removed from the bloodstream using a process known as plasmapheresis, which is similar to dialysis. Generally, the number of sessions of plasma exchange for the recipient depend on the level of the antibodies one has. If at all the level of antibodies is high, we use special filters which remove specific antibodies very efficiently from recipient’s blood
- Immune modulation and suppression:
The use of intravenous immunoglobulin (IVIG) - a blood product that contains the antibodies of thousands of people and along with other medications to turn off the formation of antibodies.
Fortunately, depending on the case, our transplant team comprising of skilled Nephrologists and transplant surgeons at our hospital in Dwarka can and has converted incompatible blood group donors into successful transplants.
Cases of ABO incompatible transplants in our centre at Dwarka are usually treated in about 3 weeks and when their antibodies are at an acceptable level, the transplant can be performed.
The antibody levels are monitored regularly after the transplant has been performed and the rest of the treatment regimen continues on the same footing as for a blood group compatible transplant
ABO incompatible transplant procedures are a ray of hope for a lot of patients and we hope to light more lives and help bring hope to many more against this clinical condition.
Dr. Vikram Kalra,
Nephrology, Urology & Kidney Transplant