PERIPHERAL-BLOOD STEM-CELL TRANSPLANTATION

High dose chemo/radiotherapy requiring autologous haemopoietic stem ce ll support is increasingly used in a variety of malignant disorders. M obilised peripheral blood stem cells (PBSC) have largely replaced the use of autologous bone marrow due to more rapid haemopoietic reconstit ution with less resource use including blood and platelet transfusion requirements. PBSC graft adequacy is monitored by CD34+ cell and granu locyte-monocyte-colony-forming-cell measurements, and thresholds for r apid engraftment have been determined. Studies are in progress to dete rmine the optimal mobilisation regimens that will permit the achieveme nt of the necessary progenitor thresholds with only one or two apheres es. This will facilitate the use of multiple cycles of high dose thera py and possibly the use of PBSC collected by venesection rather than a pheresis. PBSC are also increasingly used in the allogeneic setting wh ere specific mobilisation protocols not using cytotoxic drugs are empl oyed. These technical advances will aid the execution of large trials to determine the efficacy of high dose therapy.