History and current status of hematopoietic cell transplantation

The field of hematopoietic cell transplantation (HCT) has morphed tremendously over the past 60 years since the first few cases of bone marrow transplant were reported by the pioneers of HCT including Nobel Laureate E.D. Thomas. In the late 1960s and 1970s the field expanded to treat various nonmalignant and then malignant disorders and was subsequently used in the early stages of disease. Allografts not only replaced defective marrow and immunity but also yielded an immunologic antineoplastic impact to prevent relapse, the graft versus leukemia (GVL) effect. By the mid 1980s applicability expanded further with the availability of unrelated donors, partially matched donors, and umbilical cord blood; as a result of which a suitable donor can now be identified for almost all patients. Consequently, the numbers of HCTs continued to increase and crossed a million in 2012. More than 8000 allogeneic HCTs are now performed annually in the United States and almost double that in Europe and the rest of the world. Similarly, the numbers of autologous HCTs are also rising with more transplants being performed in older patients, even those aged over 70 years. As a result, more than 9000 annual autologous HCTs were performed in the United States and almost 21,000 in Europe in 2014-15. With further advances in supportive care, antibiotics, prevention, and management of graft-versus-host disease (GVHD), increasing knowledge of human leukocyte antigen matching and refinements in conditioning regimens, transplant outcomes are improving with lower transplant-related mortality and prolonged survival. The field has grown tremendously and can now cure more patients than ever before. New refinements in the immunology of HCT to understand GVHD and GVL will yield even better outcomes in the future.