C-reactive protein in Crohn’s disease: how informative is it?

Abstract

C-reactive protein (CRP) is an important acute-phase marker, produced mainly in the liver. Its production by mesenteric adipocytes has been recently stressed in Crohn’s disease (CD). There are many factors affecting CRP levels, both environmental and genetics. The short-life of this biomarker makes it of pertinent use in the assessment of inflammation. There are inconsistent results concerning the association of clinical activity indices, mucosal healing, histological activity and CRP. This review summarizes the role of CRP in CD, namely its importance in the differential diagnosis of CD; its relationship with clinical activity indices, other markers of inflammation and endoscopic and radiological cross sectional imaging; prediction of response to anti-TNF treatment and prediction of outcome.

Keywords::

• anti-TNF
• biomarkers
• clinical activity indices
• C-reactive protein
• Crohn’s disease
• differential diagnosis
• endoscopic indices of activity
• outcome

Financial & competing interests disclosure

F Magro is a speaker to MSD, Abbvie, Laboratórios Vitória, Ferring, Dr. Falk Pharma Portugal, Abbott and Vifor. P Ministro is a medical advisor for Abbvie, Ferring, MSD and Hospira. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• The major determinant of plasma C-reactive protein (CRP) levels is the rate of synthesis, and the concentrations quickly decrease once the acute-phase stimulus disappears, making CRP a very valuable marker to detect and follow-up inflammation.

• CRP in inflammatory bowel disease is used to diagnosis purposes and to measure disease activity, response to treatment and follow-up.

• CRP has a high positive and negative predictive value for differential diagnosis between inflammatory bowel disease and irritable bowel syndrome and is not helpful for differential diagnosis from other types of colitis.

• The sensitivity of CRP in Crohn’s disease is much better than in ulcerative colitis.

• There are inconsistent results concerning the association of clinical activity indices, mucosal healing, histological activity and CRP.

• Patient selection for clinical trials should include not only patients with symptoms of active disease but also with objective evidence of inflammation measured by biomarkers as CRP.

• The likelihood of placebo response is higher in patients with low CRP.

Notes