Co-occurrence of two cases of progressive multifocal leukoencephalopathy in a natalizumab "infusion group" Havla J, Berthele A, Kümpfel T, Krumbholz M, Jochim A, Kronsbein H, Ryschkewitsch C, Jensen P, Lippmann K, Hemmer B, et al. Mult Scler. 2012 Nov 1. PMID: 23124790. Abstract CommentRecommendBookmarkWatch