Receptor and non-receptor mediated formation of superoxide anion and hydrogen peroxide in neutrophils of intensive care patients

Generation of reactive oxygen interme diates (ROI) has been implicated in t issue damage in a variety of disease states including sepsis and trauma. On the other hand, generation of ROI in polymorphonuclear granulocytes (PMN) presents a crucial element in the defence of the host against invading micr oorganisms. In the present study we investigated the generation of superoxide anions (O -2(-)) and hydrogen peroxide (H2O2) by neutrophils (PMN)(5) of 17 criticall y ill patients treated at a intensive care unit (ICU) after polytrauma (n=6 ), heart operation (n=6) or during septic shock (n=5) using flow cytometry. O-2(-) production Of PMN from ICU patients was significantly lower (p<0,01) than that in healthy volunteers (HV) during non-receptor mediated stimulat ion with phorbol-myristate-acetate (PMA) but higher (p<0,001) during recept or mediated stimulation with formylmethionine-leucine-phenylalanine (FMLP). H2O2 generation of PMN from ICU patients was increased after stimulation w ith FMLP ( p<0.01) and remained unchanged after stimulation with PMA. Patie nts in septic shock had lower O-2(-)-generation of PMN than did injured pat ients and patients after heart operations. We conclude that receptor mediated formation of O-2(-) and H2O2 is stimulat ed in ICU patients. However, in patients in septic shock O-2(-)-generation decreases, which potentially might contribute to the immunoparalysis presen t in septic shock.