Abstract
In the 1950s and 1960s, many bone marrow transplantations were attempted in terminally ill patients with leukemia or aplastic anemia without success, except in a few patients who had identical-twin donors. The modern era of marrow transplantation began at the end of the 1960s with the development of knowledge about the HLA system and the development of tissue typing. In the 1970s, many patients began to survive the toxic effects of the early preparative regimens and acute graft-versus-host disease. Survival with a successful graft for more than 100 days made it possible to study relapse and chronic graft-versus-host disease. These . . .