|Blood cells like these are all generated from blood-forming stem cells in the bone marrow|
The stem cell field passed a milestone recently, according to the Worldwide Network for Blood and Marrow Transplantation: There have now been more than 1 million blood stem cell transplants worldwide.
This milestone came not long after the death of E. Donnall Thomas, who performed that first transplant in 1957 (we blogged about that here). These so-called bone marrow transplants are the original stem cell transplant. Doctors eliminate the bone marrow in people with leukemia or lymphoma, destroying the cancer. That bone marrow contains the blood-forming stem cells that create all the blood and immune cells in the body. Then doctors transplant a donor’s bone marrow to recreate a person’s blood and immune system.
“One million transplants is a milestone that may surprise many people, because blood stem cell transplants were viewed as a rare procedure until the last decade or so,” said Dietger Niederwieser, M.D., president of the WBMT and professor of medicine in the division of hematology and medical oncology at the University Hospital of Leipzig, Germany. “But important discoveries—and the vital cooperation of many scientists and physicians around the world—have dramatically improved outcomes for patients who undergo stem cell transplantation.”
Several CIRM-funded projects build on traditional bone marrow transplants. In these, the scientists are harvesting the patient’s own blood-forming stem cells and modifying those cells to resist disease before transplanting them back into the patient.
In the case of sickle cell disease, scientists at UCLA are fixing the genetic defect that causes the disease. Those repaired blood-forming stem cells then create a new, healthy blood system.
Two groups are using similar approaches to treat HIV infection. Teams at UCLA and City of Hope are altering the patient’s blood-forming stem cells to make them resistant to HIV infection. Those stem cells then generate a new immune system that HIV can’t infect.