(Ivanhoe Newswire) -- A type of stem cell responsible for all blood and immune system cells reproduces much more slowly than expected.

Using this subpopulation of hematopoietic stem cells may help treatment of leukemia and other marrow-based diseases by improving the outcome of stem cell transplants, also referred to as bone marrow transplants.

The entire population of hematopoietic stem cells (HSCs) in bone marrow are believed to reproduce at a rate of about 7 percent per day, with each cell dividing every two weeks; however, previous studies appear to have missed that some cells divide much less frequently. Massachusetts General Hospital (MGH) researchers found while 80 percent of HSCs reproduce at the expected rate, the rest do so much more slowly, only dividing every 100 days or even longer.

"Hematopoietic stem cell transplantation saves many lives every day and is the most established therapeutic application of stem cells, but ironically we know very little about the cells that have made this clinical success possible," Hanno Hock, M.D., Ph.D., lead researcher and an assistant professor at MGH's Center for Regenerative Medicine in Boston, was quoted as saying. "If we can improve our understanding of the biology of these cells, we should be able to offer our patients more therapeutic options."

SOURCE: Nature Biotechnology, published online December 5, 2008