Correlation between plasma peroxides and procalcitonin levels in patients with severe streptococcal community acquired pneumonia

Introduction

During lower respiratory tract infection, massive influx and activation of phagocytes and release of reactive oxygen species (ROS) is observed. As a consequence, the lipid peroxidation in plasma may increase. The aim of this study was to estimate the plasma concentration of lipid peroxides in combination with a biochemical indicator of inflammation and to assess a possible correlation between infection and oxidative stress. Plasma procalcitonin (PCT) and peroxides (PEROX) concentrations were measured in 15 patients hospitalised for radiologically confirmed severe streptococcal community acquired pneumonia (CAP). As control values, PCT and PEROX were also measured in 10 healthy subjects.

Methods

Plasma samples for PCT and PEROX were obtained the first day of hospitalisation. PCT was determined by immunoluminescence method (LUMITEST PCT, Brahms Diagnostica, Berlin, Germany). PEROX were analysed by a colorimetric assay (OXYSTAT, Biomedica, Wien, Austria).

Results

All control subjects showed a PCT level below 0.5 ng/ml (mean value: 0.32 ± 0.1 ng/ml). Mean patients PCT values was 4.9 ± 2.9 ng/ml (P < 0.01 vs control). Plasma peroxides were higher in patients respect to controls (860 ± 130 μmol/l vs 278 ± 46 μmol/l, P < 0.01). A good correlation was found between PCT and PEROX values (r² = 0.91) in patients.

Conclusion

Process of lipid peroxidation seems to correlate with the degree of infection as indicate by PCT levels.