The prospective use of cytokine markers for inflammatory bowel disease evaluation

Stool is stable at room temperature, resistant to multiple freezing and thawing cycles, and easily processable. Some stool metabolites have approved quantitative point of care test kits.14 Fecal calprotectin Calprotectin is released by neutrophils at an inflamed site, so fecal measurement of calprotectin is an indirect measurement of neutrophil infiltration of the gastrointestinal tract.15 CD stool specimens have four times the mean fecal calprotectin (FC) compared to the healthy stool; high FC is associated with reduced microbial diversity in severely inflamed patients.9 FC can detect lower inflammatory activity better than CRP and can distinguish between active versus quiescent IBD and IBD versus irritable bowel syndrome (IBS).16 Compared to all other noninvasive procedures, FC dominates with a 64% to 95% sensitivity and a 79% to 93% specificity.17 Furthermore, unlike CRP, FC can grade the severity of most IBD subtypes. Fecal lactoferrin Changes in fecal lactoferrin (FL) levels are proportional with leukocyte margination and diapedesis into the gut mucosa and exhibit a close correlation with inflammatory endoscopic and histological activity.19, 20 Comparable to histologic analysis, FL was reported to increase within 2 months of pouchitis development. Furthermore, the distinctive fecal microbial signatures of all IBD subtypes need to be mapped in the future.26 Autoantibodies The presence of autoantibodies suggests a loss of tolerance to commensal bacteria. [...]the reduction of intestinal bacteria in IBD affects the proper development of gut immune tolerance.5 Antineutrophil Cytoplasmic Antibody Antineutrophil cytoplasmic antibody (ANCA) is categorized based on two staining patterns: cytoplasmic ANCA and peripheral ANCA (pANCA).27 26.19% of CD and 66.05% of UC individuals are ANCA positive which show that not all IBD cases will produce ANCA.28 A positive pANCA test has an 86% specificity to UC patients and 66% specificity to CD patients, suggesting that pANCA is a poor IBD screening test but a strong UC discriminator.29 Although ANCA is a potent UC discriminator, no evidence suggests that ANCA can pinpoint the location of inflammatory involvement nor can pANCA predict postoperative relapse, proving this marker to be inferior to endoscopy.29, 30 Anti-Saccharomyces cerevisiae antibody Anti-Saccharomyces cerevisiae Antibody (ASCA) was initially discovered to target the cell wall of Saccharomyces cerevisiae, but it is now observed in some instances of IBD.