Autopsy showed ongoing severe PML-IRIS, with massive cavitary brain lesions containing abundant perivascular and parenchymal CD8-positive T-cell infiltrates.     ///    This report provides an update on PML in natalizumab-treated patients and reviews what is currently known about PML-IRIS in this setting.     ///    Update on PML and PML-IRIS occurring in multiple sclerosis patients treated with natalizumab.. 