Unusual natalizumab-associated progressive multifocal leukoencephalopathy starting in the brainstem

we report on a 45-year-old German patient with relapsingremitting (RR) multiple sclerosis (MS) who was started on natalizumab (NAT) therapy in November 2007, because of ongoing disease activity despite interferon therapy. She had never been treated with immunosuppressants before. After she tested positive for anti-JCV (John Cunningham Virus)antibodies for the first time, she decided to discontinue NAT treatment in July 2011 (after 49 NAT...