Serum cytochrome c level as a prognostic indicator in patients with systemic inflammatory response syndrome

Background: Apoptosis may play an important role in the development of systemic inflammatory response syndrome (SIRS) and progression to multiple organ dysfunction syndrome (MODS). To quantify the extent of apoptosis in these morbidities, we developed a sandwich ELISA system to measure serum cytochrome c (cyt-c) levels and we investigated the prognostic significance of cyt-c concentration in SIRS/MODS patients. Methods: Cyt-c concentrations in patients with SIRS (n=53) with or at risk for MODS were measured and compared with those of control subjects (n=14). Results: Cyt-c concentrations in SIRS/MODS patients increased (0.24–210 ng/ml), whereas those in control subjects were under detection limits (0.1 ng/ml). Cyt-c concentrations in non-survivors increased significantly compared with those in survivors both on the day of admission and on the fifth hospital day. A significant positive correlation was found between cyt-c concentration and two representative organ dysfunction scores, APACHE II and multi-organ failure (MOF) score. Cyt-c concentrations increased earlier than MOF score during the exacerbation phase and rapidly decreased during the convalescence phase in a survivor, but the level continued to be high in a non-survivor. Conclusions: Determination of serum cyt-c concentrations may be useful to assess the severity of organ dysfunction and to predict the prognosis of SIRS/MODS patients.