Superoxide dismutase, copper and zinc concentrations in platelet-rich plasma of pneumonia patients.

ABSTRACT

BACKGROUND: The aim of this study was to analyse platelet superoxide dismutase (SOD) activities (total SOD, manganese SOD and copper zinc SOD) and copper (Cu) and zinc (Zn) concentrations during the course of community-acquired pneumonia (CAP), and to compare them between patients with normal platelet count and those who have developed reactive thrombocytosis (RT). METHODS: Platelet count, SOD activities and Cu and Zn concentrations in platelet-rich plasma were measured in patients with CAP on admission and at discharge. RESULTS: Post-therapeutic platelet count increased significantly from the value recorded on admission. By the end of treatment, 42% of patients developed RT. All platelet SOD activities as well as Cu concentration were significantly lower in CAP patients than in control subjects. The initial Zn concentration was greater in CAP patients compared with controls and showed a decrease at discharge. On admission, there was no difference in all SOD activities between either subgroup with normal platelet count or subgroup with RT. At discharge all SOD activities were significantly lower in patients with RT. Also, catalytic activities of those enzymes were significantly lower in both subgroups in comparison with the initial values. Post-therapeutic Cu value was lower in patients with RT in comparison with patients having normal platelet count. Zn concentration decreased significantly at discharge when compared with the initial values only in patients with RT. CONCLUSION: The pattern of changes might be indicative of a certain role of platelets in antioxidant response during treatment in CAP patients.