Acute phase response of serum amyloid A protein and C reactive protein to the common cold and influenza.

Abstract

C reactive protein (CRP) and serum amyloid A protein (SAA) are sensitive and rapid acute phase reactants, and their measurement for monitoring inflammatory disease and assessing the prognosis in secondary amyloidosis is gaining widespread acceptance. The changes in these proteins in eight subjects suffering from natural colds, 15 subjects with experimentally induced colds (rhinoviruses E1, 3, 9, 14, or 31), and eight with experimentally induced influenza (A/Eng/40/83) were studied. SAA concentration increased in 21 of the 23 subjects with natural or experimental rhinovirus colds (mean increase 95 mg/l); CRP concentration increased in 11 (mean increase 11 mg/l). All subjects with influenza showed pronounced increases in SAA concentrations (mean increase 642 mg/l) while six showed increases in CRP concentration (mean increase 22 mg/l). All these increases were highly significant (p less than 0.001). Asymptomatic excretors of both rhinovirus and influenza virus showed significant increases in SAA concentration (p = 0.015 for rhinovirus and p less than 0.001 for influenza virus) but not in CRP concentration. No changes in SAA or CRP values were seen in 12 volunteers after challenge with saline. These observations suggest that caution is required in the interpretation of estimations of SAA concentration and that it may be too sensitive an acute phase protein for clinical use as its concentration may be raised in both trivial and asymptomatic viral infections.

Evaluation of the effect of simultaneous infection with E. coli O2 and H9N2 influenza virus on inflammatory factors in broiler chickens

“…In birds, changes in a few acute phase proteins have been described including alpha-1-acid glycoprotein, SAA, transferrin and ovotransferrin. 21,[37][38][39][40] Whicher et al 41 reported an elevation in SAA in all people infected with influenza virus type A and the highest concentrations of ceruloplasmin and SAA were observed on the 3 rd day. It was concluded that SAA measurement could be a valuable indicator in viral infection.…”

FebriDx Point-of-Care Testing to Guide Antibiotic Therapy for AcuteRespiratory Tract Infection in UK Primary Care: A Retrospective OutcomeAnalysis

“…As a single biomarker, CRP is less sensitive but more specific for confirming the presence of a bacterial infection at high concentrations but at lower concentrations of CRP is frequently observed during both viral and bacterial infections [32]. Certain viral infections, such as influenza, adenovirus, and others have been shown to cause substantial increases in CRP [33][34][35][36]. Using only CRP as a single biomarker at a cut off of 20 mg/L will reduce the risk of missing a clinically significant bacterial infection but simultaneously lead to overtreatment of viral infections that do not necessitate any antibiotic therapy.…”

Aspirin-triggered resolvin D1 reduces pneumococcal lung infection and inflammation in a viral and bacterial coinfection pneumonia model

“…Circulating levels of SAA markedly increase during acute infection where plasma concentrations can increase over 1000-fold. Both viral and bacterial respiratory infections increase the circulating SAA levels that typically peak at 3-5 days following infection and the levels of SAA decline with clinical recovery [11]. In addition to increased circulating levels of SAA during acute infection, we have shown that IAV and the bacterial ligand lipopolysaccharide (LPS) potently stimulate de novo synthesis of SAA transcript in the lungs, where SAA synthesis peaked on day 5 and resolved to baseline levels by day 10 in IAV-infected mice [12].…”