aging process

Human stem cells aren't immune to the aging process, according to scientists. Researchers studied hematopoietic stem cells, which create the cells that comprise the blood and immune system. Understanding when and how these stem cells begin to falter as the years pass may explain why some diseases, such as acute myeloid leukemia, increase in prevalence with age, and also why elderly people tend to be more vulnerable to infections such as colds and the flu.