Blood Group O Recipients With Non-O Donors: Why Is ABO-Incompatible Transplantation the First Choice?
ABO-incompatible (ABOi) transplantation is often considered the first choice for blood group O recipients with non-O donors because it addresses the severe systemic disadvantage these patients face in traditional organ allocation and exchange programs. For these candidates, the biological barrier of blood group incompatibility is frequently a smaller risk than remaining on dialysis.
The primary reasons for this clinical preference include:
- Disadvantage in Standard Allocation
Blood group O recipients are uniquely disadvantaged because they can only receive kidneys from blood group O donors. While group O donors are “universal donors” whose organs can be given to any recipient, group O recipients have the most restricted donor pool.
Because group O deceased-donor kidneys are sometimes allocated to non-O recipients (to prioritize highly sensitized patients), group O candidates often wait significantly longer for a transplant.
In the UK, for example, group O candidates wait twice as long as A candidates and four times longer than AB candidates.
- Low Success in Kidney Exchange Programs
Kidney paired exchange (KPE) programs are often the first alternative for incompatible pairs, but blood group O recipients have the lowest chance of success.
Because they can only be matched with an O donor—and O donors are in high demand for other hard-to-match pairs—many group O recipients fail to find a match even after multiple rounds of exchange.
As a result, ABOi transplantation becomes a faster and more viable way to utilize a willing living donor.
- Superior Survival Compared to the Alternatives
While ABOi transplantation carries more procedural risk than a compatible transplant, it offers a clear survival advantage over remaining on the deceased-donor waitlist.
The cumulative risk of dying while on dialysis is often higher than the risk associated with the ABOi procedure itself, especially in regions where the wait for a deceased donor can exceed ten years.
Studies show:
- Patient survival after an ABOi living-donor transplant is superior to receiving an ABO-compatible deceased-donor transplant.
- Although mortality risk is slightly higher in the first 30 days due to intensive desensitization,
ABOi recipients have significantly lower mortality beyond 180 days compared to those who remain on the waitlist.
