We see this question a lot. It’s a great question. It’s the same question our Executive Director, Glenn Cogan, asked UT Southwestern to answer during his living donor journey. For the record he never got an answer or even a broad approximation on his approval odds from UT Southwestern.
Determined to find the answers he was seeking, Glenn didn’t just ask UT Southwestern nurses, doctors, and surgeons; he turned the internet inside out looking for stats and other related data. During the process, he concluded there must be some unwritten understanding among medical professionals, transplant centers, and kidney nonprofits because none were willing to answer this question or post any firm numbers, for example – “Living donors with a blood type match have a 50%, 30%, 80% or 10% chance of approval.” We used arbitrary numbers here, but you get the idea.
While searching for answers, Glenn was told by a reliable source at UT Southwestern that medical professionals, doctors, surgeons, hospitals, transplant centers, kidney disease, and kidney donor nonprofits generally are not willing to answer this question with a firm number, or even with an approximation because they don't want to say or post anything that might give false hope to a recipient, donor, or their families. Considering the odds being tossed around loosely are dealing with real-life-and-death outcomes an incorrect prediction would be devastating for a recipient or donor.
We will not be answering this question with the usual vague or neutral canned precautionary medical response you probably got from your living donor advocate, hospital, or transplant center. We will answer this question to the best of our ability based on our personal experience as living donors and living organ recipients, and we will support this answer with verified, peer-reviewed medical information and other accepted medical stats.
The first thing we can tell you definitively is that sharing a similar blood type (RH factor) with a recipient puts you high on the list of potential living donor candidates. Since we repeatedly hit roadblocks getting the answers we sought, and since our thorough internet search for reliable information didn’t yield any firm answers to help us narrow down the odds to estimate reliable approval percentages, we will use notes, timelines, and the personal experience of our Directors who’ve been through this process,
1) BLOOD TYPING
Blood Typing is an exact black and white science. You are either a good match if these markers match, or you are not a good match if they do not match. Living donor transplants are still performed between mismatched donors/recipients but this is a topic for another post. Here is everything you need to know about Blood and HLA Typing:
1 a) DONOR: BLOOD TYPING
- Blood type A living donors can donate to recipients with blood types A and AB.
- Blood type B living donors can donate to recipients with blood types B and AB.
- Blood type AB living donors can donate to recipients with blood type AB only.
- Blood type O living donors (universal donors) can donate to recipients with blood types A, B, AB and O.
1 b) RECIPIENT: BLOOD TYPING
- Blood type O recipients can receive an organ from blood type O donors only.
- Blood type A recipients can receive an organ from blood types A and O.
- Blood type B recipients can receive an organ from blood types B and O.
- Blood type AB recipients (universal recipient) can receive an organ from blood types A, B, AB and O.
2) HLA TYPING: HUMAN LEUKOCYTE ANTIGEN
After blood typing, the next most critical match/mismatch typing in the approval process is HLA Tissue Typing. HLA Antigens are genetic markers on the membrane of human cells that allow our body to differentiate between self and non-self-cells. Our body protects itself against disease and foreign cells by recognizing and attacking anything that it does not recognize, or that it believes does not belong, i.e. bacteria, viruses, a newly conceived fetus...
100’s of different HLA Antigens have been identified on human cells but just six of those have been isolated and determined to play a vital genetic role in the success rate of organ transplant surgeries. These antigens are: A, B, and DR antigens. Each parent contributes a full set, and each of those is identified by numbers. Here’s an example of what a donor or recipient’s HLA Typing might look like:
Crossmatching is the final deciding factor in the living donor approval process. This test is done just before the parties' transplant surgery and it can derail a person’s plan to donate an organ to a specified recipient. Crossmatching determines whether the donor or recipient has antibodies that might attack the donor's antigens. UT Southwestern explained this process to us, and we were surprised to hear how it’s done. In crossmatching, the lab takes a vile of the donor’s blood and a vile of the recipient’s blood then combines them both into a single lab dish.
If either the donor or recipient has developed antibodies that would attack the other’s antigens, as it was explained to us by UT Southwestern, the (2) blood samples in the lab dish will go to war. Apparently, lab technicians watch this happen with their naked eyes. When this happens, even if your Blood and HLA Typing were a great match, the presence of these antibodies in the blood samples in the lab dish indicates the donated organ would be attacked and rejected by the recipient if it was transplanted into this person’s body. It is vital to know if you have antibodies against a potential donor because if you are incompatible with that donor you would not be able to safely receive a transplant from him/her.
How does one body develop antibodies against another body?
A living donor or recipient can make antibodies against another person’s HLA. For example, when a male and female couple conceived a child together, the female body develops antibodies to fight off the foreign cells in the body (a baby) that’s living inside her. The female body attacks a developing fetus just as it would a virus, bacteria, or infection which is why women experience morning sickness. These antibodies that are programmed to fight against the HLA of the father are the same antibodies that would attack and kill a kidney donated by the father.
The more children a couple has together, the more antibodies the female develops against the father’s HLA. This is why husbands and wives are often excluded from donating an organ to save their mates life. Over time, the mother has built up a defense against the father’s cells. If the father were approved to donate his organ to the mother, her body would already be ready and have more than enough antibodies on standby to fight anything with his HLA markers. In this case, it would be his donated kidney, and her body would attack it and try to kill it (reject it) because that is what it has been trained to do over the years of having children. Fortunately, medical technology has come a long way, and the lab results will show your doctors whether you have antibodies that would reject a transplant.
- Other ways living donors and recipients develop antibodies against each other are through blood transfusions, pregnancy, infections, and viral illness. None of these guarantees that you might have antibodies against the HLA of your living donor but having strong antibodies against a donor’s HLA exponentially increases the risk of rejection, so a healthy, willing donor would be excluded as a living donor for that reason.