Which of the following biologics targets integrin α4β7 and is used in small bowel Crohn’s disease?
A. Infliximab
B. Vedolizumab ✅
C. Ustekinumab
D. Adalimumab
✅ Correct Answer: B. Vedolizumab
❌ Why the Other Options Are Wrong
A. Infliximab
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Mechanism: Anti-TNF-α monoclonal antibody
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Indications: Moderate-to-severe Crohn’s disease and ulcerative colitis
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Why it's wrong:
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Infliximab does not target integrins.
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It works by neutralizing TNF-α, a pro-inflammatory cytokine, not by affecting leukocyte trafficking like vedolizumab does.
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C. Ustekinumab
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Mechanism: Targets the p40 subunit shared by IL-12 and IL-23
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Indications: Moderate-to-severe Crohn’s disease (including small bowel involvement) and psoriasis
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Why it's wrong:
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Ustekinumab modulates cytokine signaling, not integrins.
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It’s part of the Th1/Th17 pathway inhibition, not integrin-mediated gut-specific trafficking.
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D. Adalimumab
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Mechanism: Fully human monoclonal antibody against TNF-α
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Indications: Similar to infliximab—used for Crohn’s disease, ulcerative colitis, rheumatoid arthritis, etc.
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Why it's wrong:
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Like infliximab, it targets TNF-α, not integrins.
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🔍 More on Vedolizumab (Correct Answer)
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Mechanism: Binds to α4β7 integrin on gut-homing T cells
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Blocks interaction with MAdCAM-1 (mucosal vascular addressin), which is mainly expressed in gut endothelial tissue
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Result: Prevents T cell migration into inflamed GI tissue
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Key advantage: Gut-specific, so fewer systemic immunosuppressive effects