Granulocyte transfusion: revisited

Neutrophils are the immune system's main cellular defense against bacterial and fungal infections. Transfusion of granulocytes has been considered a therapeutic modality for severe bacterial and fungal infections in patients with prolonged neutropenia and with functional neutrophil disorders. Good theoretic and experimental evidence demonstrating granulocyte transfusion efficacy exists in preventing and treating severe infection. However, clinical evidence has been more difficult to interpret, with efficacy equivocal in many studies and further trials hindered by limitations in collecting adequate doses of leukocytes from healthy steroid-mobilized donors. The development and use of granulocyte colony-stimulating factor to stimulate normal donors has generated renewed interest in granulocyte transfusions. In clinical studies, granulocyte colony-stimulating factor has markedly enhanced the yield of leukocytes collected from normal donors, which may improve clinical outcomes in patients with severe infections and neutropenia who receive granulocyte transfusions. Preliminary clinical evidence, when correct granulocyte dose per patient body weight is optimized, suggests efficacy. However, well-designed randomized clinical trials are necessary to definitively establish granulocyte transfusions as a viable therapeutic modality in the treatment of severe bacterial and fungal infections in patients with functional neutrophil disorders or neutropenia.