TNF and irritable bowel syndrome: Commonly used biomarkers in clinical practice to diagnose and monitor disease activity in IBD are C-reactive protein (CRP), serum or plasma albumin, and fecal calprotectin.10 The production of CRP in the liver is triggered by cytokines (ie, interleukin-6, tumor necrosis factor, and interleukin-1β) from gut inflammation11 and albumin is depressed in the acute-phase response.12 Calprotectin is a protein found in high concentrations in neutrophil granulocytes.