Therapeutic plasma exchange and immunosuppressive therapy in a patient with anti-GAD antibody-related epilepsy: Quantification of the antibody response

Abstract

Antibodies to glutamic acid decarboxylase (GAD) have been associated with a host of neurological disorders including stiff person syndrome, cerebellar ataxia, limbic encephalitis, and epilepsy. Whether anti-GAD antibodies have an etiological role in these neurological disorders or simply serve as disease markers is unclear. Here, we report a case of a patient with recurrent seizures, poorly responsive to conventional treatment, associated with anti-GAD antibodies. The patient was experiencing near daily seizures at the time of presentation and had marked improvement while receiving immunosuppressive therapy and therapeutic plasma exchange (TPE). We go on to show that the patient had a substantial reduction of her GAD autoantibody burden following this therapy. Using immunostaining, we further demonstrate a progressive loss of GAD reactivity in the patient's sera to neurons and GAD-expressing HELA cells with successive TPEs. Hence, these data support the concept of an immune-mediated pathogenic component to these autoantibody-associated neurological syndromes.

Treatment of immune-mediated temporal lobe epilepsy with GAD antibodies

“…A number of previous case reports or small patient series on therapy outcome of GAD-TLE using immunotherapy produced inconsistent results [3,4,[30][31][32][33][34][35]. In a recently published study regarding seizure outcome of patients with autoimmune epilepsies, four GAD-TLE patients were included: two of them had a favourable outcome under immunotherapy with IVIG and MP gaining seizure-freedom for a period of 6-18 months [36].…”

Intrathecal-specific glutamic acid decarboxylase antibodies at low titers in autoimmune neurological disorders

“…Although there were conflicting results regarding immunotherapy responses, the successful treatment of refractory epilepsy after immunotherapy has been reported in previous cases (Farooqi et al, 2015;Kanter et al, 2008). Furthermore, cortical GABA levels were reported to decrease in patients with temporal lobe epilepsy and GAD-Abs, but there was no difference in a composite measure of glutamate and glutamine (Stagg et al, 2010).…”

Differences in epileptic symptoms depending on the type of autoimmune-mediated limbic encephalitis

“…The characteristics of these epileptic seizures were de jà vu, absence and automatism. Farooqi et al [72] reported that a 23-year-old female patient who had a 4-year history of epilepsy in the form of generalized tonic-clonic seizures was hospitalized for an increased frequency of seizures (from once a week to once a day). These seizures predominantly occurred during the night and lasted 1-2 min.…”