Self-Limited Cytomegalovirus Infection During Natalizumab Treatment for Multiple Sclerosis

Natalizumab is indicated as monotherapy for the treatment of relapsing-remitting multiple sclerosis; it prevents outbreaks and delays the progression of physical disability. Here, we report the case of a 30-year-old patient with multiple sclerosis receiving natalizumab as monotherapy who subsequently developed self-limited cytomegalovirus disease. Cytomegalovirus infection has been reported during treatment with natalizumab, and in this study, we use new techniques to analyze the possible association of cytomegalovirus infection with natalizumab. LEARNING POINTS: Natalizumab is a humanized recombinant monoclonal antibody (IgG4k) against α4-integrin which promotes immunocompromise by blocking the adhesion interactions necessary for lymphocyte trafficking. Cytomegalovirus infection has been described during natalizumab treatment, although the pathogenesis and mechanisms are not complete understood. This case highlights the importance of awareness of this association and possible complications.