Plasmapheresis for Managing Natalizumab-Associated PML: A Risky Proposition

Natalizumab, a monoclonal antibody that binds to integrin receptors on the surface of leukocytes to prevent their migration out of the bloodstream, has been used successfully to treat multiple sclerosis (MS) and Crohn disease. At least 14 patients with MS and one with Crohn disease treated with natalizumab have developed progressive multifocal leukoencephalopathy (PML). PML is a usually deadly demyelinating disease of the nervous system caused by reactivation of JC virus (JCV).

Now, two new case reports describe the management of PML that developed in two patients with MS, one after 12 months (reported by Wenning and colleagues) and another after 14 months (reported by Lindå and colleagues) of natalizumab monotherapy. In the case reported by…