“Leukemia” is a dreaded thing to be told after bringing your child to the doctor because she has become inexplicably tired with a cold that just won’t go away. In the U.S., every year, more than 5000 families hear this cancer name. Thanks to many years of research and clinical investigation, though the treatments are harsh with long-term debilitating side effects, overall survival from leukemia in children and young adults is now about 90%. This high rate of survival is quite an achievement, reflecting the shared efforts of nurses, doctors, counselors, communities, families, and patients. But that remaining lost 10% represents more than 500 real families, each year, destined to face the death of their child. Though medical science and technology may have given the best care available, many of these deaths are not preventable within the present state of knowledge. However, there may be a significant subset of these children for whom a new technology for counting blood stem cells could make a difference.
Many children with leukemia will eventually require a blood stem cell transplant to be cured of their cancer. This need is especially true for a type of leukemia called acute myelogenous leukemia (AML). Essentially all of the nearly 1150 children who present each year in the U.S. with AML will undergo a transplant of either bone marrow or umbilical cord blood, which contain blood stem cells that are crucial for their survival after treatments designed to kill all leukemia cells. These treatments also kill their own blood stem cells that are required for life.
It is in the case of cord blood transplants that counting blood stem cells could ease a lot of anguish and save more children from leukemia. In 2013, there were a reported 931 cord blood transplants performed in the U.S, including 317 for AML, with most being used to treat children. About 10-20% of these transplants failed, resulting in the deaths of 30-60 children with AML. They failed because of insufficient blood stem cells. Cord blood samples have fewer blood stem cells than bone marrow, which has much scarcer donors but a lower failure rate (1-5%). Unfortunately, previously, there has been no way to predict which transplants would fail due to insufficient blood stem cells, because there was no means to count the number of blood stem cells before the transplant.
So today, throughout the country, and the world for that matter, each year hundreds of very sick children wait with their families for more than two months with dread and deep anguish to find out if their cord blood transplant grafted successfully. The simple action of counting the number of blood stem cells in cord blood samples before using them would avoid deaths from inadequate transplants. Not only would this intervention save the lives of 30-60 children, it would eliminate a major source of distress for hundreds of children, their families, and their medical teams.
The current estimate of cord blood samples in the world is 700,000! However, only about 10% may be considered useful, because their total cell count (“TNC”) is below the number currently thought to indicate adequate blood stem cells, which are present in very low amounts. However, the number of blood stem cells present has no established predictive relationship to TNC. Clearly, TNC is in error 10-20% of the time for there being sufficient blood stem cells. All things being equal, it may have a similar error for indicating insufficient blood stem cells. In any case, with a new blood stem cell counting technology available, the clear mandate is to use it to count blood stem cells directly in any cord blood sample that might be used to save a child, or an adult, with leukemia. The same mandate applies to other sources of blood stem cells for transplant treatments. Though transplants with bone marrow or circulating blood that contains blood stem cells have much lower failure rates caused by insufficient blood stem cells, their greater number of transplant treatments (20,000 per year in the U.S.; 68,000 worldwide) result in a number of annual deaths comparable to the number estimated for cord blood transplants.