[Combined deficiency in neutrophil functions after bone marrow transplantation and the in vitro effect of granulocyte...

In order to investigate the mechanism of susceptibility to bacterial infection after bone marrow transplantation (BMT), we evaluated the neutrophil functions at 1, 3, 6, and 12 months after hematological reconstitution in a 29-year-old AML patient who received allogeneic bone marrow transplantation. Acute graft-versus-host disease (GVHD) was grade I, and chronic GVHD was not present. The patient exhibited complications of upper and lower respiratory infections several times after BMT, all of which subsided within a month. Chemotactic responses toward all three chemotactic factors, random mobility, phagocytosis, superoxide (O2-) release and bactericidal activity were severely impaired early after reconstitution. These neutrophil functions gradually improved with time after BMT, and all normalized at 12 months after reconstitution of transplanted bone marrow. Both O2- release and bactericidal activity of neutrophils were significantly enhanced at 6 and 12 months after marrow reconstitution following pretreatment of 50 ng/ml of granulocyte colony-stimulating factor (G-CSF) in vitro. These findings suggest that the combined disorders in neutrophil functions in early phase after BMT may play an important role in susceptibility to bacterial infections until one year after BMT. Administration of G-CSF, which potentiates the bactericidal activity of neutrophils, is recommended for preventing infectious complications and for treating prolonged and unmanageable infections after BMT.