Why blood group mismatch is no longer a barrier in kidney transplants

Once considered impossible, blood group mismatch no longer means kidney transplants cannot happen, as new immune therapies and kidney swap programmes improve outcomes

For years, a blood group mismatch between a kidney donor and recipient meant transplantation was not possible. Today, with advances in immunology, better drugs, and organised kidney swap programmes, blood group mismatch is no longer an automatic barrier.

 

“What was once considered too risky is now increasingly manageable, offering new hope to patients who were earlier left with no options,” says Dr Amit Goel, Director & Unit Head – Urology, Kidney Transplant, Uro-Oncology & Robotic Surgery, Max Super Speciality Hospital, Gurugram. 

Why blood group mismatch was once a complete deal-breaker 

Blood group mismatch in kidney transplantation happens when the recipient’s immune system recognises the donor kidney as a threat almost instantly.

 

 

“Blood type mismatch occurs when a recipient’s natural antibodies attack the donor’s blood group antigens, rapidly triggering hyperacute rejection and graft loss,” explains Dr Goel.

 

For years, this immune response was simply uncontrollable. The rejection could happen within minutes or hours. That is why ABO-incompatible transplants were considered too risky to attempt, no matter how willing the donor was. 

What changed in kidney transplantation science 

According to Dr Goel, medicine stopped trying to “defeat” incompatibility and started learning how to manage it.

 

“By developing new immunological methods, antibody depletion techniques, and improved immunosuppression regimens, transplant outcomes have changed dramatically,” says Dr Goel. “We are not eliminating the incompatibility; we are finding better strategies to control the immune response.”

 

In simple terms, doctors now reduce harmful antibodies before transplant and tightly regulate immune activity afterwards. Combined with closer monitoring, this has made incompatible transplants far safer than they once were.  

How desensitisation therapy works before transplant 

Before transplant, the patient’s existing antibodies are physically removed using procedures like plasmapheresis or immunoadsorption. Medications such as rituximab help reduce future antibody production.

 

“Strong immunosuppressants are then used after transplantation to temporarily suppress the immune response,” explains Dr Goel. “This gives the new kidney time to adapt and settle in.”

 

However, there are risks.

 

“With desensitisation, there is an increased short-term risk of infections, bleeding, and sometimes rejection,” says Dr Goel. Patients may remain immunocompromised for a prolonged period.

 

But with close follow-up, most patients eventually return to near-normal immune function. Long-term infection risk remains slightly higher, but manageable, reassures Dr Goel.  

How kidney swap programmes reduce risk and cost 

According to Dr Goel, not every patient needs desensitisation.

 

In kidney paired exchange programmes, incompatible donor–recipient pairs are matched with other pairs so everyone receives a compatible kidney.

 

“Donors and recipients are matched using registries and advanced computer algorithms,” explains Dr Goel. “The outcomes are similar to direct compatible living-donor transplants and do not require aggressive desensitisation.”

 

This approach is safer, cheaper, and increasingly preferred where systems allow it. 

Do ABO-incompatible kidney transplants last as long? 

According to Dr Goel, “The long-term outcomes of ABO-incompatible transplants are now equal to those of compatible transplants under current protocols.”

 

Yes, the early rejection risk is slightly higher, but in experienced transplant centres, long-term graft and patient survival are increasingly comparable.  

Who may still not be suitable for incompatible transplants 

Patients with extremely high antibody levels, uncontrolled infections, multiple serious illnesses, or poor medication adherence may still be excluded.

 

“Some immunologically high-risk patients continue to face unacceptably high rejection risk,” Dr Goel notes.

 

“ABO-incompatible transplants also cost more. Antibody removal, specialised drugs, and intensive monitoring add up. In resource-constrained settings like India, these costs can limit access,” says Dr Goel. That is why paired exchange programmes and government-supported transplant initiatives are essential.

 

Dr Goel stresses that the idea that incompatible transplants always fail is outdated. “Mismatch is no longer insurmountable. It requires additional treatment, higher costs, and shared responsibility,” he says.