健康なドナーからの白血球採取の改善

Bacterial and fungal infections in neutropenic patients or in patients with inherited disorders of neutrophil function continue to cause substantial morbidity and mortality. In particular, fungal infections are an increasingly important cause of death in patients receiving aggressive chemotherapy, in patients undergoing hematopoietic stem cell transplantation (HSCT), in patients with chronic granulomatous disease, and in patients with bone marrow failure syndromes such as severe aplastic anemia. The strongest predictor of progression and death from invasive mold infection in the cancer/ HSCT setting is the duration of neutropenia. Any modality which increases the granulocyte count during periods of profound neutropenia and severe infection is thus likely to be of clinical benefit. In the 1970-80 s, collection of granulocyte concentrates by apheresis of healthy donors stimulated with corticosteroids alone yielded products with an insufficient number of granulocytes to substantially raise the circulating counts in neutropenic patients. Transfusion of such components was variably associated with clinical benefit. More recently, the ability to give donors recombinant human granulocyte colony-stimulating factor (G-CSF) in combination with corticosteroids (dexamethasone) dramatically increases the circulating neutrophil count prior to apheresis and results in the collection of granulocyte concentrates containing 2 to 6 times as many cells as those collected using steroids alone. Transfusion of granulocyte concentrates collected after G-CSF and dexamethasone stimulation of the donor typically increases the recipient s granulocyte count by 1,000 cells/uL, and the increase in counts is generally sustained for 24 to 48 hours. Transfusion of daily or every other day granulocytes derived by apheresis of G-CSF and dexamethasone-stimulated donors has been associated in observational and retrospective studies with clearance of life-threatening infections in neutropenic patients, but a single small randomized prospective study did not demonstrate improved survival in neutropenic infected patients who received granulocytes. Granulocyte components are not recognized as a licensed blood component by the Food and Drug Administration (FDA), and neither G-CSF nor dexamethasone is approved by the FDA for use in allogeneic granulocytapheresis donors. Studies at the NIH Department of Transfusion Medicine (DTM) have defined the optimal timing and dose of these drugs in granulocyte donors, and these components have been used for clinical care since 1996. Short term adverse effects of G-CSF and dexamethasone, including bone pain, myalgia, headache, insomnia and fatigue, are well known and possible long-term effects, including cataracts from serial steroid administration, have been described. The purpose of the current protocol is to determine the operational feasibility of managing a volunteer community donor granulocytapheresis program and to provide informed consent for the administration of filgrastim and dexamethasone to volunteer donors donating granulocytes by apheresis. Donor accrual and retention, immediate short term adverse effects of G-CSF and dexamethasone, and any long-term effects, will be assessed in healthy subjects who will be permitted to donate granulocytes a maximum of 12 times per year. Reasonable efforts will be made to equitably distribute opportunities for granulocyte donation so that the maximal number of annual donations is not met by any one donor.Participants will be selected based on general blood donor eligibility criteria, adequacy of antecubital venous access, and interest in the program. Most subjects will already have experience as plateletpheresis donors. The toxicity of granulocyte transfusions and the survival and discharge rates of the transfusion recipients will be monitored, but the protocol is not designed to evaluate the efficacy of granulocyte transfusions.