Curbside Consultation in IBD: 49 Clinical Questions, Second Edition

David T Rubin, MD; Sonia Friedman, MD; Francis A Farraye, MD MSc

Question 21: When Should I Consider Anti-Integrin Therapy For My Patient With Inflammatory Bowel Disease? What Is The Updated Understanding Of Progressive Multifocal Leukoencephalopathy And John Cunningham Virus Testing? (continued)

Nitsan Maharshak, MD; Scott E. Plevy, MD

Natalizumab, an immunoglobulin G4 (IgG4) humanized anti-α4 integrin monoclonal antibody, is a US Food and Drug Administration (FDA)-approved therapy for multiple sclerosis (MS) and Crohn’s disease (CD). The α4 subunit is expressed on the surface of all leukocytes except neutrophils and forms a heterodimer composed of either α4β1 or α4β7 integrins. Natalizumab consequently inhibits the α4-mediated adhesion of leukocytes to their respective receptors: vascular cell adhesion molecule-1 (VCAM-1), expressed on activated vascular endothelium…