Stem cells, specifically blood stem cells, are immature cells that can develop into any cell present in the bloodstream. Without stem cells, the body cannot make the blood cells needed for the immune system to function.

Red blood cells carry oxygen through out the body.

White blood cells fight infections.

Platelets help control bleeding.

Blood stem cells are not embryonic stem cells. They come from bone marrow, circulating (peripheral) blood or umbilical cord blood. When patients need a stem cell transplant, it means that their bone marrow (stem cell factory) has failed due to an illness. Patients who undergo chemotherapy or radiation treatment may also need a transplant of healthy stem cells to help heal and re-boost their immune system.