A. Non–herpetic acute limbic encephalitis & anti–NMDAR encephalitis
Non–herpetic acute limbic encephalitis is diagnosed with the characteristic onset symptom of limbic system and absence of herpes simplexes virus in CSF. Anti–NMDAR encephalitis is diagnosed with presence of antibodies to complex of NMDA–type GluR subunits by cell–based assay. Non–herpetic acute limbic encephalitis & anti–NMDAR encephalitis are causally related with antibodies to NMDA–type GluR, which internalize complex of NMDA–type GluR subunits on neural cell surface. Internalization may lead to protection from apoptosis by excitotoxicity related with increased glutamate and cytokines, and less phosphorylation of Akt in these encephalitides. Passive transfer of rabbit antibodies to n–terminal of human GluN2B into hippocampi of mice caused probable excited behavior and impairment of memory in behavioral analysis, and decreased expression of pam gene in microarray analyses and quantitative analyses of gene expression. In non–herpetic acute limbic encephalitis, factors including granzyme B, glutamate, etc., other than antibodies are causally related with neuronal cell death.
B. Encephalitis mediated by antibodies to voltage–gated potassium channel (VGKC)
In encephalitides mediated by antibodies to VGKC, patients with antibodies to leucine–rich glioma–inactivated 1 (LGI1) show characteristics of limbic encephalitis, and patients with antibodies to contactin–associate protein (Caspr) 2 show Morvan's syndrome with thymoma.
C. Acute disseminated encephalomyelitis (ADEM)
ADEM is the most common immune–mediated encephalitis, and its immune–mediated pathophysiology was not revealed. Recently, antibodies to myelin–oligodendrocyte glycoprotein were found in a few pediatric patients.