If you were keeping count: the millionth blood stem-cell transplant occurred in December 2012

Data compiled by the Worldwide Network for Blood and Marrow Transplantation (WNBMT) measures the landmark; some 70 diseases are now treated by the therapy

“Hematopoietic stem cell” (HSC) transplantation—the preferred term for what is commonly called bone marrow transplants—reached the one-millionth application late last year. The procedure has become standard for a variety of leukemias and lymphomas since its first use in the mid-1960s, and is now being used worldwide not only in cancer treatments but also sickle cell anemia and thalessemia, among other diseases, according to Dr. Dennis Confer, an officer of the WNBMT and chief medical officer of the US’ National Marrow Donor Program (Minneapolis). Along the way, the technology evolved from transplants from close relatives (allogenic) to self-infusion (autologous) and unrelated donors that can be matched genetically. HSCs are more commonly harvested from one’s blood through an apheresis procedure (blood fractionation) than from extraction from bone marrow; a growing application is harvesting from cord blood. Via all types of autologous or allogenic processes, roughly 60,000-70,000 procedures are being performed annually.

Cord blood or bone-marrow extraction usually results in a sample of 15-40 mL, stored in a vial or syringe, while apheresis-derived cells result in a 250-1,500-mL sample, contained in a transfusion bag similar to those used in blood donations. Confer says that HSCs are stored at refrigerated conditions, or at cryogenic temperatures for longer storage. Because of donor-matching procedures, samples are being shipped globally as a matter of routine—and usually in the insulated, gel-packed containers common for blood or biopharmaceutical shipping. Looking ahead, “There is only a little overlap between HSC usage and the evolving field of stem-cell research for things like regenerative medicine, but because of the substantial history of HSCs, I expect that there will be more collaboration in the future,” he says.