Abstract
Despite proven clinical efficacy of vedolizumab (VDZ) for inducing and maintaining remission in patients with Crohn's disease (CD) and ulcerative colitis (UC), subgroups of patients have no therapeutic benefit from anti-α4β7 integrin therapy with VDZ. Within this study, we aimed to identify genetic, cellular, and immunological mechanisms that define response and failure to VDZ treatment. Intestinal RNA sequencing was performed in UC and CD patients before and at week 14 of VDZ therapy. α4β7 expression on peripheral and mucosal immune cells was assessed by flow cytometry and immunohistochemistry. Cellular modes of VDZ-mediated action were analyzed ex vivo and in VDZ-treated inflammatory bowel disease patients. Transcriptome analysis showed an impairment of signaling cascades associated with adhesion, diapedesis, and migration of granulocytes and agranulocytes upon VDZ therapy. In non-remitters to VDZ therapy, a tissue destructive and leukocyte-mediated inflammatory activity with activation of TNF-dependent pathways was present, all of which were inhibited in remitters to VDZ. Clinical remission was associated with a significant reduction of α4β7 expression on Th2 and Th17 polarized mucosal CD4+ T cells at week 14 of VDZ therapy and with significantly higher numbers of α4β7-expressing mucosal cells prior to the initiation of VDZ therapy compared with non-remitters. Intestinal α4β7 expression prior to VDZ therapy might represent a biomarker that predicts therapeutic response to subsequent VDZ treatment. Due to high activation of TNF signaling in VDZ non-remitters, anti-TNF treatment might represent a promising therapeutic strategy in VDZ refractory patients.
Highlights
Rapid recruitment of leukocytes from the blood stream into the intestinal lamina propria is a key process for the homeostatic immune surveillance and the exaggerated mucosal immune response that is observed in inflammatory bowel diseases (IBD) such as Crohn’s disease (CD) and ulcerative colitis (UC)
Since marked lymphocyte accumulation within the lamina propria is one of the pathogenic and histologic hallmarks observed in IBD patients, targeting T cell homing to the gut has emerged as a novel and promising therapeutic option in IBD patients
Homing of α4β7-expressing T cells is mediated by the specific interaction between α4β7 and its ligand mucosal addressin cell adhesion molecule-1 (MAdCAM-1), which is expressed under steady-state conditions by gut endothelial cells [3]
Summary
Rapid recruitment of leukocytes from the blood stream into the intestinal lamina propria is a key process for the homeostatic immune surveillance and the exaggerated mucosal immune response that is observed in inflammatory bowel diseases (IBD) such as Crohn’s disease (CD) and ulcerative colitis (UC). Since marked lymphocyte accumulation within the lamina propria is one of the pathogenic and histologic hallmarks observed in IBD patients, targeting T cell homing to the gut has emerged as a novel and promising therapeutic option in IBD patients. This is relevant for the integrin α4β7 that is expressed on the surface of gut-tropic effector lymphocytes. We aimed to identify genetic, cellular, and immunological mechanisms that define response and failure to VDZ treatment
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