E. Donnall Thomas Biography (1920-)


E. Donnall Thomas has pioneered techniques for transplanting bone marrow, anoperation that has been utilized to treat patients with cancers of the blood,such as leukemia. For proving that such transplants could save the lives ofdying patients, Thomas was awarded the Nobel Prize in physiology of medicinein 1990 (he shared the award with Joseph E. Murray).

E. Donnall Thomas was born on March 15, 1920, in the small town of Mart, Texas. After graduating from a high school class of approximately fifteen students, Thomas entered the University of Texas at Austin in 1937. He received a B.A. in 1941 and continued on for a master's degree, which was awarded in 1943.

After completing his master's degree, Thomas started medical school at the University of Texas Medical Branch in Galveston. After six months, however, hetransferred to Harvard Medical School, where he received his M.D. in 1946. Hebecame an intern and then a resident at Peter Bent Brigham Hospital in Boston and began to specialize in blood diseases. Thomas interrupted his formal medical training to serve as a physician in the United States Army (1948-1950).He then returned to the Boston area and did research on leukemia treatmentsfor a year as a postdoctoral fellow at the Massachusetts Institute of Technology. In 1953 he worked as an instructor at Harvard Medical School.

Thomas moved to New York in 1955 to take the position of physician-in-chief at the Mary Imogene Bassett Hospital in Cooperstown. The next year he became,in addition, an associate clinical professor of medicine at the College of Physicians and Surgeons at Columbia University. During the next eight years Thomas had the opportunity to develop and research his ideas about bone marrow transplants, and he applied these concepts to treating cancers of the blood.

Leukemia is a type of cancer in which certain blood cells, known generally aswhite blood cells, are produced in abnormally large numbers by the bone marrow. In other kinds of cancer, the diseased cells pile up into a tumor, whichcan often be treated by simply cutting out the lump. Leukemic blood cells, however, circulate throughout the body, making them much more difficult to eliminate. Furthermore, the white blood cells that become abnormal in leukemia are an important part of the body's immune system. Even if they could be destroyed by a means such as radiation, without them the patient would be vulnerable to infections.

In the 1950s, researchers showed that inbred laboratory mice could be irradiated, thus destroying the production of white blood cells by their bone marrow, and then saved from infection by a transplant of bone marrow taken from healthy mice. Inspired by these experiments, Thomas began similar studies on dogs, but he faced two important obstacles. First, the recipient animal's immunesystem had to be prevented from attacking and destroying the transplanted bone marrow--such immune rejection has long been a problem for bone marrow as well as organ transplant surgery. And second, if the bone marrow transplant was successful and the donated marrow began to produce white blood cells, thesecells were likely to attack the recipient's other tissues, perceiving them as foreign. Both of these problems had been avoided in the earlier studies with inbred mice because the mice were genetically identical, and hence, have identical immune systems. People are not so similar genetically, with the exception of identical twins. All attempts to graft bone marrow between a donor and recipient who were not identical twins failed. In 1956, Thomas performed the first bone marrow transplant to a leukemia patient from an identical twin.Although the patient's immune system did not reject the transplant, the cancer recurred.

Many researchers gave up working on organ transplants because the problems ofimmune rejection seemed insurmountable, but Thomas persisted. In 1963 he moved to Seattle to become a professor at the University of Washington Medical School. There he put together a team of expert researchers and began experimenting with new drugs that could suppress the recipient's immune system and thus prevent rejection of the new tissue. In the meantime, new methods were being developed by other researchers to identify people whose immune systems weresimilar, in order to match organ donors and recipients. The new methods of tissue typing were based on molecules known as histocompatibility antigens. Thomas's team performed the first bone marrow transplant to a leukemia patientfrom a matched donor in March 1969. During the 1970s they developed and perfected a comprehensive procedure for treating leukemia patients: first the patients receive radiation, both to kill cancer cells and to weaken the immune system so that it does not reject the transplant; then their bone marrow is replaced with marrow from a compatible donor. The patients also are given drugsthat continue to suppress their immune systems. Many patients had been curedof leukemia using this technique by the late 1970s. Since then Thomas and hiscolleagues have improved their success rate from about 12-50%. In addition to leukemia and other cancers of the blood, bone marrow transplants are used to treat certain inherited blood disorders and to aid people whose bone marrowhas been destroyed by accidental exposure to radiation.

It was in 1990 that Thomas was awarded the Nobel Prize in physiology or medicine in 1990, a commendation he shared with Joseph E. Murray, another Americanphysician who has done important work in the area of transplants. The NobelPrize came as a surprise. Thomas told reporters that the award is more oftengiven to scientists who do basic research than to those that develop clinicaltreatments. As reported in Time magazine, both men were cited by theNobel committee for discoveries "crucial for those tens of thousands of severely ill patients who either can be cured or given a decent life when other treatment methods are without success."

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