CLINICAL OUTCOME OF PERIPHERAL-BLOOD STEM-CELL SUPPORT

Two clinical results of peripheral blood stem cell support are commonl y considered: (1) the effect on hematopoietic recovery and (2) the eff ect on the underlying malignancy. The dynamics of hematopoietic recove ry after autologous bone marrow transplantation and after autologous p eripheral blood stem cell transplantation in a clinical setting are si milar if no exogenous cytokines are administered and the peripheral st em cells are collected while their numbers are not deliberately increa sed (mobilised). If mobilized peripheral stem cells are transplanted, hematopoietic recovery is accelerated. In some circumstances, patients who receive peripheral stem cell transplantation may experience an im proved progression-free survival after high-dose therapy when compared with similar patients who receive autologous bone marrow transplantat ion. Explanations for such a survival advantage might include (1) a lo wer likelihood of occult tumor cells capable of restoring disease in p eripheral stem cell autograft products than in bone marrow harvests, ( 2) a greater number of cytotoxic effector cells capable of destroying occult tumor cells in the peripheral stem cell collections than in bon e marrow harvests, and (3) a different and advantageous pattern of imm unologic recovery following autologous peripheral stem cell transplant compared to autologous bone marrow transplant.