Phagocytic and Oxidative Burst Activity of Neutrophils in Patients With Spinal Cord Injury

Abstract

ObjectiveTo evaluate phagocytic activity and neutrophil oxidative burst functions in patients with spinal cord injury (SCI) because alterations in neutrophil metabolic activity can be one of the causes of immune mechanism damage contributing to repeated bacterial infections. DesignA controlled and cross-sectional study. SettingDepartments of physical medicine and rehabilitation and immunology. ParticipantsPatients with SCI (N=34) and 28 healthy controls. InterventionsPhagocytosis and oxidative burst in whole-blood neutrophils were assessed by flow cytometry. The percentage of phagocytizing cells after in vitro incubation with Escherichia coli, phagocytic activity (mean intensity of fluorescence [MIF]) and the percentage of neutrophiloxidative burst, and the MIF value of the production of reactive oxygen intermediates (ROIs) were analyzed. In addition, clinical assessment including the level of injury, American Spinal Injury Association scores, and functional status were carried out. Main Outcome MeasuresNot applicable. ResultsAlthough the percentage of E. coli phagocytizing neutrophils was not different between groups, the MIF value of absorbed E. coli was significantly lower in patients with SCI than in controls (P<.05). The MIF value of ROI production by neutrophils with both stimulator of phorbol 12-myristate 13-acetate and E. coli was significantly higher in patients with SCI (P<.05). ConclusionsIn patients with SCI, decreased phagocytic activity of neutrophils may be a result of a regulatory mechanism to minimize the deleterious effects of increased neutrophil burst activity.