Neutropenia and its related opportunistic infections have always been a concern. The addition of chemotherapy to the cancer treatment options 40 years ago brought up morbidity and mortality related to marrow hypoplasia. These problems are as worrisome today as they were in the past.1–3 Paradoxically, improvement in the area of antibiotic therapies, as well as increased use of hematopoietic growth factors, can be considered major culprits. Specifically, more potent antibiotics and growth factors combined provided wider margins for the use of higher doses of chemotherapy, with some regimens approaching marrow transplantation ablative potency. While the supportive use of growth factors and improved antibiotics have advanced cancer treatment, they have not, even in combination, provided enough support to counterbalance deeper peaks of neutropenia and prolonged nadirs caused by the more aggressive chemotherapy strategies. As a consequence, fewer cycles of chemotherapy induce longer periods of marrow aplasia with consequently longer recovery periods. One procedure employed to overcome this problem is to provide adequate amounts of allogeneic functional granulocytes to granulocytopenic patients