LGI1 and viral encephalitis: Serum LGI1 antibodies titers were on average 127-fold higher than CSF LGI1 antibody titers by live cell–based assay using a membrane-tethered LGI1 construct in all 6 patients with LGI1 antibody encephalitis (table), none of whom were asymptomatic at follow-up.12 None of the 6 patients showed a CSF lymphocytosis or oligoclonal bands on routine CSF analysis.