Can Spouses Donate a Kidney to Each Other Even Without a Blood Relationship? A Physician Explains: After Years Together, the Body May Already Be Familiar with Each Other’s Antigens

When a loved one faces the ordeal of dialysis, can a husband or wife without a blood relationship really become an organ donor? Research suggests that the key to a successful transplant lies not in genetic relatedness, but in immunological compatibility. Through years of close companionship and shared life experiences, spouses may even develop a remarkable degree of immune tolerance toward one another, transforming the cold science of transplantation into one of the most moving expressions of lifelong devotion.

June 4, 2026
By Po-Chang Lee, MD
Edited by Bi-Jun Liao

One day in clinic, a patient with end-stage kidney disease was referred to me for a consultation about kidney transplantation. His wife sat quietly beside him, but her eyes revealed both anxiety and determination.

As we discussed treatment options, I explained frankly:

“If possible, kidney transplantation remains the best treatment. In most cases, it offers a better quality of life and higher survival rate than long-term dialysis.”

The husband smiled bitterly and replied:

“But I’ve heard that waiting for a deceased donor kidney in Taiwan is extremely difficult…”

Before he could finish, his wife spoke without hesitation:

“If I can, I would like to donate one of my kidneys to him.”

The Key to Transplant Success Is Not Blood Relationship, but Immune Matching

For a moment, the consultation room fell silent.

As a transplant surgeon, I have heard these words many times, yet they still move me every time. This is not merely a romantic promise—it is a person’s willingness to give a part of their own body to sustain another person’s life.

Marriage is often described as “staying together through life,” but for some couples, true companionship means facing life’s greatest storms side by side when illness strikes.

Many people assume that living-donor kidney transplantation requires a blood relationship—such as a parent donating to a child or siblings donating to one another. Since spouses are not genetically related, many believe they are less suitable donors.

In reality, what determines transplant suitability is immunological evaluation, not blood relationship itself.

According to Article 983 of Taiwan’s Civil Code, direct blood relatives, direct relatives by marriage, and collateral blood relatives within six degrees of kinship are prohibited from marrying. Although spouses have no biological relationship, transplant compatibility depends on immune testing rather than genetics.

Before a kidney transplant can proceed, the medical team conducts comprehensive evaluations, including:

• Blood type compatibility
• Human Leukocyte Antigen (HLA) matching
• Most importantly, the crossmatch test, which detects whether the recipient has antibodies that would immediately attack the donor kidney

Because spouses typically have significantly different HLA profiles, a successful transplant depends largely on whether the crossmatch result is negative. If the recipient does not possess antibodies that would attack the donated kidney, transplantation can often be performed successfully.

Long-Term Companionship May Teach the Body to Recognize a Spouse’s Antigens

Perhaps surprisingly, international studies have shown that when spousal transplants are performed with a negative crossmatch, long-term outcomes are often better than many people expect—sometimes approaching those seen in highly favorable immunological matches.

Many years ago, while at the National Cheng Kung University College of Medicine, I conducted research on crossmatch testing and mixed lymphocyte culture reactions between spouses. Our experiments demonstrated that adding serum from the prospective recipient could suppress mixed lymphocyte culture responses.

This research was published in Transplantation, one of the leading journals in the field, and served as the principal work supporting my promotion to Associate Professor.

At the time, many international colleagues were intrigued:

If spouses are unrelated by blood, why do some spousal transplants achieve such favorable outcomes? Why did recipient serum suppress immune responses in our experiments?

My friend, Professor Huan-Yao Li, an immunology expert, proposed a fascinating and deeply human hypothesis.

Over years of living together, spouses are continually exposed to one another’s antigens through intimate daily interactions. Exposure to seminal fluid during sexual activity, and even immune-related substances found in saliva during kissing, may gradually train the immune system to develop a degree of immune tolerance toward the partner.

In other words, during years of sharing life together, the body may quietly learn how to accept the other person’s tissues and organs.

Of course, this remains an immunological observation and hypothesis. Whether transplantation is feasible must always be determined through rigorous scientific testing—not by the depth of affection alone.

Transplantation Is More Than Surgery—It Is a Commitment to Keep Living Together

This perspective reminds us of an important truth:

Medicine is never just about numbers and laboratory results. Human relationships can leave biological traces within our bodies.

Looking back on my career as a transplant surgeon, I have always felt that kidney transplantation is more than an organ transplant procedure—it is the restoration of human connection.

Sometimes it reflects the protection of parents for their children. Sometimes it represents the support between siblings. But transplantation between spouses is especially moving because the greatest challenge in marriage is not saying, “I love you.”

Rather, it is being willing to continue living together when illness arrives, and working together to protect the family you have built.

One of the most profound lessons from my medical career is this:

The greatest satisfaction for a transplant surgeon is not completing the operation itself, but seeing patients return to their families, careers, and lives.

At the same time, I must be honest: not every married couple is suitable for living kidney donation. Some individuals are unable to donate because of their own health conditions; others are not immunologically compatible. Some patients ultimately must continue waiting for an organ from a deceased donor.

This is why I continue to advocate for a more mature culture of organ donation in Taiwan. More people need to understand that deceased organ donation is an extraordinary act of generosity—one that allows another family to begin again at the end of someone else’s life journey.

Original Source: Common Health Magazine