ABSTRACT
The neutrophil (polymorphonuclear leukocyte, PMNL) represents the initial and most important line of host defense against bacterial and opportunistic fungal infections. Neutropenia is the leading factor limiting the use of chemotherapy for the treatment of neoplastic diseases and a major cause of morbidity and mortality following hematopoietic stem cell transplantation (HSCT).1-5 Although clinical use of colony-stimulating factors, namely granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF), has significantly reduced the duration and severity of neutropenia in many circumstances, some patients are still at risk for prolonged and severe neutropenia, which renders them vulnerable to life-threatening bacterial and fungal infections.6-21
Both G-CSF and GM-CSF require that a patient have a sufficient supply of competent hematopoeitic stem cells in order to effectively ameliorate neutropenia. Even when this supply is sufficient, a lag period of several days occurs before the neutrophil response is observed. After dose-intensive chemotherapy for cancer or conditioning for HSCT, neutropenia may persist for 2 weeks or longer. In this setting, severe bacterial and opportunistic fungal infections remain a major clinical problem, despite optimal conventional antimicrobial therapy.1,3-5,19,22-24 Granulocyte (neutrophil) transfusion therapy has been considered a logical therapeutic intervention in patients who develop serious, lifethreatening infections during periods of prolonged neutropenia. However, despite decades of sporadic use, the clinical utility of granulocyte transfusion therapy remains controversial.2,4,25-28
In 1934, Strumia29 injected a ‘leukocyte cream’ intramuscularly into neutropenic patients with the hope that endogenous neutrophil production would be stimulated. The first study reporting transfusion of normal leukocytes followed in 1953, when lethally irradiated dogs received isogeneic leukocytes.30
