Eculizumab-related progressive multifocal leukoencephalopathy

Abstract

Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection of the CNS caused by reactivation of the polyomavirus JC (JCV). In the context of immunosuppression, JCV can reactivate and spread to brain infecting oligodendrocytes. Eculizumab is a first-in-class humanized monoclonal antibody developed to target the cleavage of C5, preventing the release of C5a and activation of the terminal complement pathway. It has been shown to be effective in the treatment of paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome (aHUS). Eculizumab can impair neutro- phil and monocyte functions and predispose to encapsulated bacteria infections. We report the novel finding of PML in a patient receiving eculizumab.