Collection of autologous peripheral blood stem cells in steady state

Cells normally present in the circulation are capable of providing sustaine d haematopoietic function in a manner similar to cells normally present in the bone marrow, when transplanted to an autologous or allogeneic recipient . The function of these circulating cells is not known, but they may serve as a reservoir of haematopoietic stem cells which can migrate via the blood stream to sites of need when called upon, thereby providing a protective r ole. In the past, these cells were collected from the blood during steady-s tate marrow function to serve as both autologous and allogeneic graft produ cts for transplantation. While this application has since been abandoned in favour of mobilized blood stem-cell transplantation, laboratory investigat ion of non-mobilized circulating stem cells will be needed if a full unders tanding of their purpose and function is to be learned.