Biomarkers in the Critically Ill Patient: C-reactive Protein
Section snippets
Structure and history
CRP was first described in 1930, when Tillet and Francis2 reported that serum from individuals acutely ill with lobar pneumonia was able to precipitate a substance derived from the C polysaccharide of Streptococcus pneumoniae, which they called fraction C. Importantly, they noted that when serum was taken from patients when they were acutely ill there was a strong precipitation reaction but the strength of the reaction decreased as the patients recovered. This observation suggested that this
Physiologic activities
The pentraxin family is highly conserved in evolution, suggesting that members have an important physiologic role. This theory is supported by the fact that there are no known deficiencies of CRP in humans. It has been suggested that CRP may act in a proinflammatory or in an antiinflammatory capacity to aid host defense. In vitro, CRP has been shown to increase release of the antiinflammatory cytokine IL-1011 and decrease synthesis of several proinflammatory cytokines including IL-12, tumor
CRP as a biomarker of disease
CRP is an acute phase protein and as such plasma levels are increased in most forms of acute and chronic inflammatory diseases. CRP is a recognized and widely used marker in rheumatology, with levels elevated in patients with rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, polymyalgia rheumatica, to mention just a few. In such patients, CRP levels, especially when using new high-sensitivity CRP assays, can be used to assess the effectiveness of treatment and to monitor
CRP as a biomarker of infection
A useful biomarker of infection, or rather the host response to infection, should provide additional information to the clinical picture in the fields of diagnosis, disease severity stratification and prognosis, and therapeutic guidance.38 CRP has been investigated in all these 3 areas.
CRP versus procalcitonin
Several studies have suggested that procalcitonin (PCT) is a more reliable marker of sepsis than CRP,71, 72, 73, 74, 75 but not all studies support this.31, 76, 77 Luzzani and colleagues72 reported that PCT levels predicted infection and severity of disease more reliably than CRP levels in 70 critically ill patients, and 2 meta-analyses concluded that PCT was a better diagnostic indicator than CRP.73, 75 Castelli and colleagues74 reported that PCT reacts faster than CRP, thus allowing an
Summary
There is an indisputable need for better techniques to diagnose sepsis, to characterize patients with sepsis, and to monitor therapeutic effectiveness. Use of biomarkers has been suggested as a means of achieving these aims. CRP is one of the many biomarkers that have been proposed for use in patients with sepsis and has been widely studied. The main advantages of serum CRP levels as a biomarker are the availability, ease of use, and low cost of assays. The key disadvantages are that CRP is not
References (77)
- et al.
The physiological structure of human C-reactive protein and its complex with phosphocholine
Structure
(1999) - et al.
Solid phase radioimmunoassays for human C-reactive protein
Clin Chim Acta
(1981) - et al.
Regulation of complement activation by C-reactive protein
Immunopharmacology
(1999) - et al.
C-reactive protein
J Biol Chem
(2004) - et al.
Biological markers in inflammatory bowel disease: practical consideration for clinicians
Gastroenterol Clin Biol
(2009) - et al.
Procalcitonin versus C-reactive protein as predictive markers of response to antibiotic therapy in acute exacerbations of COPD
Chest
(2010) - et al.
C-reactive protein as a marker of infection in critically ill patients
Clin Microbiol Infect
(2005) - et al.
A prospective evaluation of the Infection Probability Score (IPS) in the intensive care unit
J Infect
(2008) - et al.
Serum levels of C-reactive protein and procalcitonin in critically ill patients with cirrhosis of the liver
J Lab Clin Med
(2005) - et al.
C-reactive protein for detection and follow-up of bacterial and fungal infections in severely neutropenic patients with acute leukaemia
Eur J Cancer Clin Oncol
(1985)
Contribution of C-reactive protein to the diagnosis and assessment of severity of community-acquired pneumonia
Chest
Procalcitonin levels in surgical patients at risk of candidemia
J Infect
C-reactive protein levels correlate with mortality and organ failure in critically ill patients
Chest
C-reactive protein concentration as a predictor of intensive care unit readmission: a nested case-control study
J Crit Care
CRP levels and post-intensive care unit mortality in non-surgical intensive care patients
Chest
C-reactive protein as a predictor of outcome after discharge from the intensive care: a prospective observational study
Br J Anaesth
Accuracy of procalcitonin for sepsis diagnosis in critically ill patients: systematic review and meta-analysis
Lancet Infect Dis
Sepsis biomarkers: a review
Crit Care
Serological reactions in pneumonia with a non-protein somatic fraction of pneumococcus
J Exp Med
Nonspecific precipitins for pneumococcic fraction C in acute infections
J Infect Dis
The occurrence during acute infections of a protein not normally present in the blood: I. Distribution of the reactive protein in patients’ sera and the effect of calcium on the flocculation reaction with C polysaccharide of pneumococcus
J Exp Med
The occurrence during acute infections of a protein not normally present in the blood: II. Isolation and proerties of the reactive protein
J Exp Med
Distribution and determinants of serum high-sensitive C-reactive protein in a population of young adults: the cardiovascular risk in young Finns study
J Intern Med
C-reactive protein: a critical update
J Clin Invest
Metabolic and scintigraphic studies of radioiodinated human C-reactive protein in health and disease
J Clin Invest
C-reactive protein mediates protection from lipopolysaccharide through interactions with Fc gamma R
J Immunol
Experimental allergic encephalomyelitis is inhibited in transgenic mice expressing human C-reactive protein
J Immunol
The acute-phase reactant C-reactive protein binds to phosphorylcholine-expressing Neisseria meningitidis and increases uptake by human phagocytes
Infect Immun
Generation of biologically active C-reactive protein peptides by a neutral protease on the membrane of phorbol myristate acetate-stimulated neutrophils
J Immunol
Inflammation and endothelial function: direct vascular effects of human C-reactive protein on nitric oxide bioavailability
Circulation
Interferon-gamma and lipopolysaccharide potentiate monocyte tissue factor induction by C-reactive protein: relationship with age, sex, and hormone replacement treatment
Circulation
Direct proinflammatory effect of C-reactive protein on human endothelial cells
Circulation
C-reactive protein: structural biology and host defense function
Clin Chem Lab Med
Human C-reactive protein is protective against fatal Salmonella enterica serovar typhimurium infection in transgenic mice
Infect Immun
Relationship between CRP and hypofibrinolysis: Is this a possible mechanism to explain the association between CRP and outcome in critically ill patients?
Thromb J
High sensitivity C-reactive protein as a disease activity marker in rheumatoid arthritis
J Rheumatol
Clinical relevance of C-reactive protein in ankylosing spondylitis and evaluation of the NSAIDs/coxibs’ treatment effect on C-reactive protein
Rheumatology (Oxford)
Significance of measurement of high-sensitivity C-reactive protein in acute pancreatitis
J Gastroenterol
Cited by (75)
Erythrocyte and plasma selenium in children with acute inflammatory response
2022, Journal of Trace Elements in Medicine and BiologyCitation Excerpt :No interactions between variables were observed in the final model. Considering that selenoprotein P, CRP, and procalcitonin have different kinetics [38–40], they were not included in the analysis. The hypothesis of this study was that erythrocyte selenium is not affected by the systemic inflammatory response in critically ill children.
Clinical value of alkaline phosphatase on the surface membrane of neutrophils for prediction of bacteremia in patients with systemic inflammatory response syndrome
2021, Diagnostic Microbiology and Infectious DiseasePredicting Bacterial Versus Viral Infection, or None of the Above: Current and Future Prospects of Biomarkers
2019, Clinics in Laboratory Medicine
The authors have nothing to disclose.