Dramatic worsening following plasma exchange in severe post-natalizumab withdrawal multiple sclerosis relapse.

We report the case of a young woman with multiple sclerosis who discontinued natalizumab twice and experienced a severe relapse following each natalizumab withdrawal. The first relapse was successfully treated by intravenous methylprednisolone (IVMP). In contrast the second relapse was unresponsive to IVMP. Subsequent treatment by plasma exchanges (PLEX) was followed by a dramatic neurological worsening. This case suggests that PLEX after natalizumab discontinuation may increase relapse severity.