E. Donnall Thomas advances bone-marrow transplantation

Historical milestone — this page describes an event dated 1990. It is not current breaking news.

The obstacle everyone accepted

For most of the twentieth century, moving living tissue from one person to another was thought to be impossible in principle.

The Nobel Assembly's own account traces the belief. Alexis Carrel, who won the prize in 1912, concluded there was a "biological force" preventing successful transplantation between individuals. As late as the end of the 1940s, Peter Medawar, himself a Nobel laureate, said that force would "forever" block transplantation from one person to another.

Some researchers refused to accept that. Through the 1950s and 1960s they worked out what the force actually was: specific molecules on the cell surface, called transplantation antigens, known in humans as HLA antigens, for human leukocyte antigens. A recipient's immune system reads the HLA on donated tissue as foreign and attacks it.

The problem that runs backwards

Bone marrow is a special case, and it is the one E. Donnall Thomas solved.

An organ transplant risks the recipient rejecting the graft. A marrow transplant carries that risk plus a second one running the other way, because marrow contains immune cells of its own. Those donor cells can read the recipient's whole body as foreign and attack it.

That is the graft-versus-host reaction, and the illness it causes is graft-versus-host disease. It can kill.

Thomas found that the cytotoxic drug methotrexate could damp it down. He also showed something that had to be demonstrated before any of this could work: bone marrow cells infused into a vein, like a blood transfusion, would travel to the marrow, settle there, and start producing new blood cells.

In 1990 the Nobel Assembly at the Karolinska Institute awarded the Nobel Prize in Physiology or Medicine jointly to Joseph E. Murray and E. Donnall Thomas for discoveries concerning organ and cell transplantation in the treatment of human disease.

How the procedure works

Unlike an organ transplant, a marrow transplant involves no surgery on the recipient.

The Nobel account describes the sequence. Marrow cells are drawn from the donor, most often from the iliac crest, the ridge of the pelvis. The recipient's own marrow and immune cells are first destroyed with total body irradiation or cytotoxic drugs. The donor cells are then infused into a vein. Stem cells travel to the marrow, repopulate it, and give rise to both blood cells and immune cells. Immunosuppressive treatment continues for some months to hold down the graft-versus-host reaction, and it can usually be withdrawn once the donor cells become tolerant.

That is the same procedure, in outline, that is used today.

What it treats now

NCI describes the modern versions. An autologous transplant uses the person's own stem cells, collected before intensive treatment and given back afterwards. An allogeneic transplant uses cells from someone else, related or unrelated, matched closely enough that the recipient's immune system accepts them. A syngeneic transplant uses cells from an identical twin.

Each has a trade-off. Autologous cells match perfectly, but carry a small risk that cancer cells travel back with them. Allogeneic cells avoid that but bring the graft-versus-host risk.

NCI lists the main uses as cancers affecting blood cells: leukemia, lymphoma, multiple myeloma and myelodysplastic syndromes. Transplants are also used for neuroblastoma, Ewing sarcoma and some brain tumors. Our page on stem cell transplant covers what the process asks of a patient.

NCI is clear that graft-versus-host disease remains a serious problem after allogeneic transplant. Donor white cells can attack the skin, liver, intestines and other organs. Acute graft-versus-host disease appears within the first three months; chronic disease appears after that. It is treated with steroids or other drugs that suppress the immune system.

A leukemia example

The American Cancer Society projects 9,650 new US chronic myeloid leukemia diagnoses and 1,170 deaths in 2026, and SEER republishes that projection. SEER's own measurement of five-year relative survival, for cases diagnosed in 2016 to 2022, is 71.1%.

That figure looks the way it does partly because targeted drugs have replaced transplant as first-line treatment for that particular leukemia. Transplant remains the option when drugs stop working or were never suitable. It is a group statistic over past years and does not predict any individual's course. Our page on leukemia explains the main types.

When to get checked

Blood cancers often begin quietly, and a full blood count is the test that finds most of them. These are worth an appointment when they persist beyond two to three weeks:

• Fatigue that does not lift with rest
• Drenching night sweats
• Fever with no infection to explain it
• Unexplained weight loss
• Bruising easily, or bleeding gums and frequent nosebleeds
• Repeated infections
• Painless swollen lymph nodes in the neck, armpit or groin
• Bone or joint pain, or fullness under the ribs on the left

What this does not mean

• Thomas's work made transplantation possible. It did not make it safe. Graft-versus-host disease is still a major cause of illness and death after allogeneic transplant.
• Transplant is not a treatment for most cancers. It is concentrated in blood and marrow cancers and a few solid tumors in specific situations.
• Finding a donor match depends on HLA type, and matching is harder for people from under-represented ancestries in donor registries.
• The Nobel account describes the state of the field in 1990. Conditioning regimens, matching, cord blood transplants and supportive care have all changed since.
• Nothing here indicates whether a transplant is right for any individual. That depends on disease, age, fitness and donor availability.

Sources

• NobelPrize.org, The Nobel Prize in Physiology or Medicine 1990 — press release — https://www.nobelprize.org/prizes/medicine/1990/press-release/
• NobelPrize.org, E. Donnall Thomas — Facts — https://www.nobelprize.org/prizes/medicine/1990/thomas/facts/
• NCI, Stem Cell and Bone Marrow Transplants for Cancer — https://www.cancer.gov/about-cancer/treatment/types/stem-cell-transplant
• SEER Cancer Stat Facts, Chronic Myeloid Leukemia — https://seer.cancer.gov/statfacts/html/cmyl.html

How this article was prepared

An AI-assisted editorial system helped prepare this page. No named medical reviewer has reviewed it unless one is listed.

The National Cancer Information Foundation publishes Cancer Explained. This page is for learning. It is not medical advice and does not suggest a test or treatment.

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