Delayed apoptosis in patients with multiple organ dysfunction syndrome

Aged neutrophils undergo spontaneous apoptosis and delayed apoptosis is associated with persistence of inflammatory disorders through release of toxic metabolites. We evaluated spontaneous apoptosis of neutrophils in patients with multiorgan dysfunction syndrome and neutrophil respiratory burst activity. Neutrophil apoptosis was assessed at study enrollment and after 24 hours incubation in culture medium by annexin-V assay, morphology and DNA fragmentation. Respiratory burst activity was measured using dihydrorhodamine. Twenty two patients with multiple organ dysfunction syndrome admitted to an intensive care unit and 22 healthy controls were studied. After 24 hours, a profound delay in spontaneous apoptosis in organ dysfunction patients was seen compared to controls for both annexin-V (26.9% versus 52.1%, p< 0.0001) and morphological assessment (25.0% versus 61.5%, p<0.0001). Respiratory burst activity was increased (86.3% versus 27.6%, p<0.001) suggesting that the delay in apoptosis was associated with prolongation of the functional activity of the cells. We conclude that in patient with multiple organ dysfunction syndrome there is a delay in spontaneous apoptosis together with a high functional activity of neutrophils.