Granulocyte mobilization, collection and transfusion - where do we stand?

SUMMARY Bacterial and fungal infections are the main cause of morbidity and mortality in neutropenic patients. The transfusion of granulocytes to restore host defenses in severely neutropenic patients has been studied for a long time. However, inadequate dosage of granulocytes and inconsistent efficacy has limited the usage of these transfusions in the past. Recently, the use of mobilizing agents such as granulocyte colony-stimulating factor has renewed interest in these treatment modalities. Some studies have shown a benefit in neutropenic patients transfused with high doses of granulocyte concentrates. A number of tests of granulocyte function can be performed in vitro to assess the quality of granulocyte concentrates, which may be useful to optimize granulocyte collection and storage. Such studies that have examined granulocyte function in concentrates focused on the assessment of viability, chemotaxis, phagocytosis and oxidative burst and showed that granulocyte colony-stimulating factor-mobilized granulocytes can be stored prior to transfusion. Evidence-based benefit of granulocyte transfusion is still lacking and randomized controlled studies are necessary to prove the efficacy of granulocyte transfusion in the era of improved antibacterial and antifungal agents.