VGKC-Complex Antibody Encephalitis: Clinical Manifestations and Response to Immunotherapy (P2.251)

Objective: To determine, in patients identified as seropositive for neuronal Voltage gated potassium channel (VGKC) complex autoantibodies, the spectrum of clinical presentations and response to immunotherapy. Background: VGKC encephalitis is a recently recognized autoimmune condition with antibodies against components of the VGKC protein complex. Clinical presentation can vary, but patients typically present with limbic encephalitis involving cognitive impairment, seizures and psychiatric symptoms. Methods: 6 patients with positive VGKC antibodies were included in this study. In all cases, the diagnosis was based on the clinical presentation, MRI findings, and blood and CSF laboratory test results. All patients were assessed at symptom onset and after treatment using the modified Rankin Scale (mRS) and neuropsychological testing. Results: All patients were male and the median age at diagnosis was 65 years (range 61-74 years). All had cognitive impairment and 83[percnt] (n=5) presented associated psychiatric symptoms (delusions, hallucinations, depression and aggression) . 33[percnt] (n=2) showed epileptic discharges in electroencephalogram and 66[percnt] (n=4) had medial bitemporal hyperintensities in their Brain MRI, compatible with limbic encephalitis. In 3 patients we could define the subtype of VGKC: LGI-1 in 2 and CASPR-2 in 1. The remaining patients showed a mean VGKC titer of 186 using radioimmunoassay techiques. An additional serum positive ATPO antibodies was detected in one patient. Three patients were treated with methylprednisolone plus Intravenous immunoglobulin (IGIV), 2 with IGIV alone and one case received IGIV plus rituximab. After treatment 83,3[percnt] had a mRS score <2 and 16[percnt] = 4. The cognitive profile was predominantly cortico-subcortical. Conclusions: VGKC encephalitis should be suspected in all patients with a rapidly cognitive impairment with or without psychiatric symptoms. As antibody testing becomes more widely available it should be performed routinely in this kind of patients. In our sample most of them had a good recovery after treatment. Disclosure: Dr. Rojas has nothing to disclose. Dr. Demey has nothing to disclose. Dr. Quiroga has nothing to disclose. Dr. Leon Cejas has nothing to disclose. Dr. Bonardo has nothing to disclose. Dr. Uribe Roca has nothing to disclose. Dr. Parisi has nothing to disclose. Dr. Gatto has received personal compensation for activities with Tuteur, Bago, Novartis, and Glaxo-Smith Klein as a speaker and a scientific advisor. Dr. Rugilo has nothing to disclose. Dr. Ollari has nothing to disclose. Dr. Fernandez Pardal has nothing to disclose. Dr. Reisin has received personal compensation for activities with Shire HGT.