LGI1 and viral encephalitis: This is of interest because despite the majority of LGI1 antibodies being of the IgG4 subclass, a proportion of patients with LGI1 IgG1 antibodies are over-represented in those with cognitive impairment, suggesting that some irreversible sequelae in LGI1-antibody encephalitis may be associated with complement-mediated effects [8].