[Oxidative metabolism in polymorphonuclear granulocytes of children with trisomy 21]

In response to certain stimuli, polymorphonuclear leukocytes (PMNs) undergo an oxidative burst during which a series of reactive oxygen metabolites are generated. The importance of the release of these oxygen metabolites by polymorphonuclear leukocytes, is recognized to be a key event in the function of these cells during infection and inflammation. We have evaluated the release of reactive oxygen species during the activation of respiratory burst (RB) of PMNs obtained from children with trisomy 21 using chemiluminescence techniques. As chemiluminogenic probes we have employed lucigenin and luminon that are know to be sensitive to the superoxide anion and the H2O2-myeloperoxidase-halide system of PMNs, respectively. Activated PMNs from children with trisomy 21 exhibited a low level of superoxide and a reduced activity of H2O2-myeloperoxidase-halide system compared to the control group. No significant difference in extracellular H2O2 release was observed. It seems likely that alterations in the enzymatic activities of the Cu/Zn-Superoxide dismutase and myeloperoxidase induce imbalance in the release of reactive oxygen species in activated PMNs from children with trisomy 21. This imbalance could be on the basis of the increased oxidative injury reported in trisomy 21.