The transfusions were laced with growth factors, natural body proteins that help regulate the number of blood cells in circulation. When given in high concentrations, growth factors can help neutrophils survive longer, boosting their numbers, Adkins said. Stem cells may be harvested from bone marrow, but the researchers opted for a second technique, called pheresis, where the cells are obtained from blood. These peripheral blood stem cells were collected from 30 healthy donors. The concept of giving peripheral blood stem cells as opposed to bone marrow in this donor scenario is relatively new, he added.
Platelets are sticky cells that help control bleeding.
They are another casualty of chemotherapy, leaving cancer patients at an increased risk of severe vascular bleeding, including some forms of stroke, Adkins said. Though the neutrophils were taken from healthy donors, the researchers also discovered that age plays a significant role in the quantity and quality of the donor harvest. Donors under the age of 50 yielded nearly twice as many neutrophils as their counterparts. The likelihood of getting a useful harvest from donors more that 50 years old was 18 percent, Adkins said. Future studies will treat donors with growth factors before the neutrophils are harvested, Adkins said.