We report two patients with
encephalitis associated with
antibodies against NR1-NR2 heteromers of the
NMDA receptor that showed dramatic improvement after immunomodulating
therapies. A 38-year old woman (case 1) suddenly developed
seizures and short term memory loss. Brain MRI appeared almost normal except for a small number of high intensity spots of white matter on T(2) weighted images. Cerebrospinal fluid examination (CFS) disclosed lymphocytic
pleocytosis (61/µl) and Qualitative analysis of NR1-NR2
antibodies in both CFS and serum were positive. Although an initial treatment with high-dose
methylprednisolone was not beneficial for clinical improvement,
intravenous immunoglobulin (
IVIg)
therapy led to complete recovery from her neurological problems. Repeated general surveys showed no evidence of
tumors including
ovarian teratoma. A 71-year old man (case 2) suddenly developed
seizures and short-term memory loss three days after receiving an
influenza vaccination. Brain MRI appeared normal. CSF analysis revealed no
pleocytosis and a slight elevation of
protein value accompanying
oligoclonal IgG band. Qualitative analysis of NR1-NR2
antibodies in both CFS and serum were positive. Intravenous high-dose
methylprednisolone caused dramatic improvement and his neurological problems immediately disappeared. Repeated general surveys showed no evidence of
tumors, as in case 1. These two cases showed relatively benign clinical courses with no evidence of
tumors and were quite different from the well-known
encephalitis associated with
antibodies against NR1-NR2 heteromers of the
NMDA receptor. Our clinical experience in these two cases suggests that the disease spectrum of anti-
NMDA-receptor associated
encephalitis might be broader than was once considered.