Another patient had serum NMDAR antibodies and anti-R. typhi IgM (patient E) detected but a negative peripheral blood EDTA buffy coat PCR for R. typhi, leading to uncertainty with the diagnosis of acute murine typhus.23 One patient (patient C) had a moderate (1:500) serum NMDAR antibody level and purulent discharge from the ears with a history of chronic otitis media; hence, a primary infectious aetiology from contiguous spread was considered more likely than a primary autoimmune condition. Here, CD40LG is linked to chronic otitis media.