Introduction: Acute phase response represents an increase in hepatic production of the so-called acute phase proteins (APP). Until now, C-reactive protein (CRP) has routinely been measured as an indication of bacterial infections. Serum amyloid A (SAA) is a novel marker. It is a more conservative protein for viral etiology of the disease. We analyzed the dynamic changes of SAA and CRP during influenza infection and evaluated the role of SAA as a significant marker for viral infections.
Materials and Methods: We studied 31 patients with clinically suspected and serologically proved influenza, hospitalized in the Department of Infectious Diseases at St. Marina University Hospital, Varna. Serum levels of SAA and CRP were measured on admission and 4.23±1.03 days later by immunoturbidimetric assays, adapted on Olympus AU 400.
Results: The mean serum concentrations of SAA during the acute stage were 168.92 mg/L and those of CRP were 48.08 mg/L. In the group of bacterial complications, such as bronchitis, sinusitis and otitis media, the SAA levels were 5- to 9-fold greater than CRP. Analyses of the second measurement showed a tendency of serum SAA to disappear more quickly than CRP - 52.11 mg/L vs. 16.71 mg/L.
Conclusion: SAA is more sensitive APP than CRP in viral infection settings. In cases of bacterial superinfections, serum SAA is more predominant than CRP, indicating the necessity of an antibiotic therapy. Prompt downgrading of SAA in sera correlates with auspicious prognosis could be used as an effective treatment monitoring.
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