We detected oxidized lipids and NADPH oxidase (visualized with the marker p22phox, a subunit of NADPH oxidase), responsible for the generation of reactive oxygen species, in inflammatory non‐demyelinating diseases other than MS, such as SSPE and HSV encephalitis, as well as demyelinating diseases such as PML and EPM. Here, CYBA is linked to progressive multifocal leukoencephalopathy.