Historical Perspective and Current Focus

Abstract

In the beginning days of blood banking, surgeons would call imperiously for “fresh whole blood” recognizing its superior restorative properties over banked blood. Since then technological advances have made it possible to break down the therapeutic elements of fresh blood into their constituent platelets, red cells, plasma, and clotting factors, and through apheresis, blood bankers can even provide granulocytes, lymphocytes, progenitors, and stem cells. The component therapy concept is so widely accepted that we cease to think it as being unusual. Curiously, and in contrast, transplant physicians have been slower to apply a component therapy approach to their practice. Even today the majority of hematopoietic cell transplantation (HCT), whether from the bone marrow, peripheral blood, or cord blood, is as unmanipulated as the “fresh whole blood” beloved of our surgeons of the past. Nevertheless, the attractions of a component therapy approach to HCT are many including but not limited to (1) T-cell depletion by selection of CD34⁺ cells, which can reduce GvHD, and (2) infused donor lymphocytes which can improve engraftment and treat leukemic relapse. Careful studies in the 1990s determined the doses of CD34⁺ cells and lymphocytes in the graft that led to the best outcomes, and donor lymphocyte infusion doses were calibrated to achieve graft-versus-leukemia effects with minimal graft-versus-host disease (see Chap. 6).