Epilepsia Partialis Continua as an Early Sign of Anti-Myelin Oligodendrocyte Glycoprotein Antibody-positive Encephalitis

Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies have been associated with steroid-responsive cortical encephalitis and comorbid generalized epilepsy. A 44-year-old woman developed repeated epilepsia partialis continua (EPC) without generalized seizures and was anti-MOG antibody-positive. Radiological abnormalities were detected in the bilateral medial frontoparietal cortices, but there were no cerebrospinal fluid abnormalities. She achieved remission with anti-epileptic drugs alone. However, encephalitis recurred four months later when pleocytosis appeared, and steroid therapy was effective. Altogether, EPC without typical cerebrospinal fluid features can be an early sign of anti-MOG antibody-positive encephalitis. Thus, patients with EPC of unknown etiology need to be screened for anti-MOG antibodies.

Autoantibodies and cell-mediated autoimmunity to NMDA-type GluRepsilon2 in patients with Rasmussen's encephalitis and chronic progressive epilepsia partialis continua

PURPOSE

To evaluate antibody-mediated and cytotoxic T cell-mediated pathogenicity that has been implicated as the autoimmune pathophysiological mechanism in Rasmussen's encephalitis.

METHODS

We examined autoantibodies against the N-methyl-d-aspartate glutamate receptor (NMDA-type GluR) epsilon2 subunit and its epitopes in serum and CSF samples from 20 patients [five histologically proven (definitive) Rasmussen's encephalitis with epilepsia partialis continua (EPC), four definitive Rasmussen's encephalitis without EPC, and 11 clinical Rasmussen's encephalitis with EPC]. We examined 3H-thymidine uptake into lymphocytes after stimulation by GluRs.

RESULTS

All nine definitive patients (five patients with EPC and four without EPC), and 10 of 11 clinical Rasmussen's encephalitis patients had the autoantibodies. In four patients, the autoantibodies were absent in early stage when epileptic seizures had already become frequent, and appeared subsequently. In two patients, the autoantibodies persisted in the serum after frontal lobe resection or functional hemispherectomy, although epileptic seizures were completely controlled. Autoantibodies to the C2 epitope predominated, while autoantibodies to the extracellular N epitope were rare. The mean 3H-thymidine uptake ratios (stimulation by GluRepsilon2-containing homogenates/stimulation by PHA) were significantly higher in definitive and clinical Rasmussen encephalitis patients than in controls. The mean 3H-thymidine uptake ratios (relative to PHA) were significantly higher for GluRepsilon2-containing homogenate than for control homogenate or GluRdelta2-containing homogenate.

CONCLUSIONS

Autoantibodies against GluRepsilon2 may be one of the diagnostic markers for Rasmussen's encephalitis with and without EPC. Patients have activated T cells stimulated by GluRepsilon2 in peripheral blood circulation. We speculate that cellular autoimmunity and the subsequent humoral autoimmunity against GluRepsilon2 may contribute to the pathophysiological processes in Rasmussen's encephalitis.

Autoantibodies to NMDA receptor in patients with chronic forms of epilepsia partialis continua

BACKGROUND

Antibody-mediated and cytotoxic T cell-mediated pathogenicity have been implicated as the autoimmune pathophysiologic mechanisms in Rasmussen's encephalitis.

METHODS

The authors investigated autoantibodies against the NMDA glutamate receptor (GluR) epsilon2 subunit and their epitopes in serum and CSF samples from 15 patients with chronic epilepsia partialis continua (EPC), 17 with West syndrome, 10 with Lennox-Gastaut syndrome, and 11 control subjects.

RESULTS

In 15 patients with chronic EPC, we detected NMDA-type GluR epsilon2 autoantibodies in histologically proven Rasmussen's encephalitis (3/3 patients), clinical Rasmussen's encephalitis (6/7 patients), acute encephalitis/encephalopathy (2/3 patients), and nonprogressive EPC (2/2 patients). Serum IgM autoantibodies were found in the early phase of EPC and became negative later in four patients. The autoantibodies were not detected in West syndrome, Lennox-Gastaut syndrome, or controls. Among 10 patients with histologically proven or clinical Rasmussen's encephalitis, epitope analyses showed that the autoantibodies were predominantly against C-terminal epitopes and rarely against N-terminal epitope, with inconsistency in profile during the courses of disease. Epitope recognition spectrum of autoantibodies was broader in CSF than in serum, and the serum or CSF profile showed an increase in number of epitopes as disease progressed in some patients.

CONCLUSIONS

The presence of autoantibodies against NMDA GluR epsilon2 suggests autoimmune pathologic mechanisms but is not a hallmark of Rasmussen's encephalitis. Patients with Rasmussen's encephalitis may have autoantibodies against several neural molecules, and these autoantibodies may be produced in the CNS after cytotoxic T cell-mediated neuronal damage.

A patient with epilepsia partialis continua with anti-glutamate receptor epsilon 2 antibodies

This report concerns a 6-year-old female with epilepsia partialis continua. Autoantibodies against amino- and carboxyl-terminal regions of the N-methyl-D-aspartate receptor subunit glutamate receptor epsilon 2 were detected in the serum and cerebrospinal fluid. The anti-glutamate receptor epsilon 2 subunit antibodies have been demonstrated in the serum and cerebrospinal fluid in some patients with chronic progressive epilepsia partialis continua of childhood and those with Rasmussen's encephalitis. The patient, however, did not develop any neurologic deterioration or intractable seizures. Therefore, anti-glutamate receptor epsilon 2 subunit antibodies are not specific for chronic progressive epilepsia partialis continua of childhood and Rasmussen's encephalitis.

[Intrathecal glutamate receptor antibodies in a patient with elderly-onset refractory epilepsy]

Antibodies against a glutamate receptor in the central nervous system are reported to be an important autoimmune factor in infantile or childhood refractory epilepsy and in adult-onset paraneoplasstic cerebellar ataxia. We here reported a patient with glutamate receptor antibodies-positive elderly-onset intractable epilepsy and advanced-stage stomach cancer. A 77-year-old man with a history of resected bladder cancer suddenly developed an attack of epilepsia partialis continua in the right arm, followed by a generalized epileptic status. The ictal EEG showed spikes in the left parietal region with diffuse slow wave backgrounds. The brain MRI demonstrated a focal high signal intensity in the left postcentral gyrus on the T2-weighted and FLAIR images. The SPECT showed a high uptake in the focal area corresponding to the MRI lesion, suggesting a seizure focus. The routine analysis in the CSF was normal, but the glutamate receptor antibodies (IgG, IgM and C-terminal) were all positive. The status epilepticus was refractory to anticonvalsants, and the barbiturate anesthesia was introduced. Subsequently, the epilepsy has been fairly controlled by valproic acid and phenobarbital. The post ictal MRI demonstrated a focal atrophy in the left postcentral gyrus. The systemic evaluations revealed an advanced-stage stomach cancer. The glutamate receptor antibodies may play a role in late-onset refractory epilepsy, and may be an autoimmune factor in paraneoplstic neurologic syndrome presenting with epilepsy.

Type 1 diabetes mellitus and epilepsia partialis continua in a 6-year-old boy with elevated anti-GAD65 antibodies

A 6-year-old boy presented with epilepsia partialis continua 6 months after diagnosis of type 1 diabetes. Anti-glutamic acid decarboxylase 65 antibodies were found in his serum and cerebrospinal fluid. Anti-epileptic agents did not improve his seizures. High-dose steroids, plasmapheresis, and intravenous immunoglobulin resulted in decreased anti-glutamic acid decarboxylase 65 antibody levels and resolution of his seizures.

Long-term selective IgG immuno-adsorption improves Rasmussen's encephalitis

We report that long-term selective immunoglobulin G immunoadsorption by protein A (PAI) improved seizure frequency and neuropsychological deficits in a 16-year-old patient with severe treatment-resistant Rasmussen's encephalitis (RE). Clinical improvement correlated with reduction of antiglutamate receptor 3 antibodies. The efficacy of PAI in our patient supports the autoimmune hypothesis of RE and suggests its application to avoid, or at least delay, functional hemispherectomy in selected cases.