Cytomegalovirus esophagitis in a patient on ocrelizumab therapy: A case report

Cytomegalovirus (CMV) can infect multiple areas of the gastrointestinal tract, most commonly the esophagus and colon.1 CMV esophagitis is the third leading cause of infectious esophagitis, after Candida and herpes simplex virus (HSV).2 It occurs predominantly in immunocompromised patients (eg, due to chemotherapy, corticosteroid use, HIV infection) or in the context of host microbiome alterations (eg, antibiotic use). The diagnosis of CMV esophagitis is made using a combination of clinical history, endoscopic findings, and histologic features. Cytomegalovirus esophageal ulcers are typically either shallow or of intermediate depth, with only a minority having a deep depth or heaped-up appearance.3 Overall, symptoms are more gradual when compared to esophagitis caused by HSV. The development of CMV esophagitis is associated with a poor overall prognosis.1 Ocrelizumab (Ocrevus, Genentech) is a recombinant humanized monoclonal antibody indicated for the treatment of multiple sclerosis to include clinically isolated syndrome, relapsing-remitting disease, and active secondary progressive disease in adults. The exact mechanism by which ocrelizumab works in multiple sclerosis is unknown but is presumed to involve binding to CD20, a cell surface antigen present on pre-B and mature B lymphocytes. Following cell surface binding to B lymphocytes, ocrelizumab results in antibody-dependent cellular cytolysis and complement-mediated lysis. Known adverse reactions include an increased risk for malignancy and infection due to the immunosuppressing mechanism.4