Current application of proteomics in biomarker discovery for inflammatory bowel disease

Table 1 Current biomarkers and their utility in inflammatory bowel disease management[12]

Application	Biomarker	Utility
Diagnosis of IBD	Fecal calprotectin[69]	Sensitivity: 89%-98%, specificity: 81%-91%
	Fecal lactoferrin[70]	Sensitivity: 80%, specificity: 82%
	Fecal 100A12[71] (differentiating from IBS)	Sensitivity: 86%, specificity: 96%
	CRP[72-74]	Sensitivity: Approximately equal 100% in CD, approximately equal 50% in UC poor specificity
Distinguishing UC and CD	ASCA[75]	Sensitivity: 40%-50%, specificity: > 90% in CD
	pANCA[75]	Sensitivity: 57%, specificity: 92%
	Escherichia coli antibodies (Anti-OmpC, Anti-I2, Anti-CBir1)[76]	Sensitivity: 18%-55%, specificity: 76%-93%[76]
Marker of disease activity	Fecal lactoferrin[77,78]	Sensitivity: 66%-80%
		Specificity: 60%-100%
	Fecal calprotectin[77,78]	Sensitivity: 70%-100%
		Specificity: 44%-100%
	CRP[78]	Sensitivity: 48%
		Specificity: 91%
Assessing mucosal healing	Fecal calprotectin	Several studies demonstrate significant reduction in biomarker in the presence of mucosal healing with treatment
Predicting disease course	Fecal lactoferrin[77]	May be associated with complications including; structuring or fistulising disease, and small bowel disease pANCA may predict aggressive UC and pouchitis following surgery[79]
	ASCA
	pANCA Anti-I2, Anti-OmpC[12]
Predicting Relapse within 12 mo	Fecal calprotectin[80,81]	Sensitivity: 69%-90%
		Specificity: 69%-82%
		Positive predictive value: 81%/87% (UC/CD)
		Negative predictive value: 90%/43% (UC/CD)
	Fecal lactoferrin[81]	Sensitivity: 62%
		Specificity: 65%
Predicting therapeutic response	pANCA[82]	Conflicting reports, possible lower response rate to infliximab in patients with a positive serology
	Anti-I2[83]	94% responded to fecal diversion

CD: Crohn’s disease; UC: Ulcerative colitis; IBD: Inflammatory bowel disease; ASCA: Anti-Saccharomyces cerevisiae; pANCA: Perinuclear antineutrophil cytoplasmic antibodies; CRP: C-Reactive protein; PF4: Platelet factor 4.