CNTNAP2 and autoimmune encephalitis: Voltage-gated potassium channel complex antibody positivity without LGI1 or CASPR2 reactivity are not useful for autoimmune encephalitis diagnosis,43,44 while low-titer CASPR2 antibodies are also problematic and only high titers support autoimmune encephalitis.45,46,47 Serum NMDAR antibodies with negative CSF results were a red flag here, as noted previously.48 Rarely, CSF NMDAR antibodies by cell-based assay alone led to misdiagnosis.