ICAM1 and progressive multifocal leukoencephalopathy: To this end, translating methodologies from mouse models of MS that have allowed to image the inflammatory status of the BBB in vivo by MRI imaging making use of micro-sized particles of iron oxide (MPIO) targeting adhesion molecules including ICAM-1 [93, 94], will be beneficial to further advance the personalized dosing of NTZ in individual MS patients ensuring therapeutic efficacy while limiting the risk for PML.