When was the first human stem cell transplant performed?

Human stem cell transplantation has its roots in the 1950s, when bone marrow transplants were first shown to work in people. In 1956, E. Donnall Thomas and colleagues reported successful transplant experiments that laid the groundwork for the field. At the time, scientists did not yet fully understand stem cells as we do now. Later discoveries showed that the transplanted marrow contained blood-forming stem cells, revolutionizing treatment for blood cancers and immune disorders.