In this letter recently published in Brain, the authors report a case series of five patients (from an observational cohort: the CoCo Neurosciences Study) with severe COVID-19-related encephalitis (impaired consciousness/unresponsive and mechanically ventilated) treated with plasma exchange (PLEX) and corticosteroids. They argue that dramatic improvement in three out of five patients reinforces the hypothesis of an immune-related mechanism, as previously evoked in other papers. The authors underlined that neurologists and intensivists should be aware that this life-threatening COVID-19 neurological syndrome has a potentially favourable outcome after immunotherapy, and should not motivate systematic limitation in active patient care.