A Chinese female patient with LGI1 and mGluR5 antibodies: A case report

Abstract

Rationale: Anti-LGI1 antibody encephalitis and anti-mGluR5 are both uncommon encephalitis, and we report the first case of autoimmune encephalitis (AE) with dual seropositive antibodies of leucine-rich glioma-inactivated 1 (LGI1) and mGluR5.Patient concerns: We present a case of AE with dual seropositive antibodies of LGI1 and mGluR5 in a 65-year-old woman who presented with sudden onset left faciobrachial dystonic seizures and unresponsive for 5 hours. Diagnosis:The patient was diagnosed with anti-LGI1 AE and anti-mGluR5 AE mainly based on the clinical symptoms and further test of the antibody in serum and cerebral spinal fluid (CSF). Interventions and outcomes:The patient was treated with glucocorticoid intravenous drip. We also gave her the therapy of immunoglobulin (25 g q.d) for 5 days and anti-epileptic therapy. She had no more convulsions on the left side of the face and limbs. She did not complain of any uncomfort until July 18.Lessons: Early recognition of AE is crucial. Specific autoantibodies are associated with corresponding syndromes. Our patient was initially diagnosed with acute ischemic stroke. Therefore, we should conduct further study on the related symptoms of AE.Abbreviations: AE = autoimmune encephalitis, CSF = cerebral spinal fluid, FBDS = facial-brachial dystonia episodes, LGI1 = leucine-rich glioma-inactivated 1, mGluR5 = metabotropic glutamate receptor 5, PNHS = peripheral nerve hyperexcitability syndrome, VGKC = voltage-gated potassium channel complex.

Autoimmune encephalitis with mGluR5 antibodies: A case series from China and review of the literature

“…Although most patients in our case series showed pleocytosis or increased IgG index in CSF analysis, two patients had normal CSF findings in routine examination, as mentioned in some patients with anti-mGluR5 encephalitis in the previous study or other types of autoimmune encephalitis (e.g., mGluR1, NMDAR) ( 12 , 14 , 18 ). Therefore, mGluR5 antibodies should be screened in suspected patients despite having normal results in routine CSF examination.…”

“…We noticed that two patients in our case series found additional antibodies in the samples, as observed in many other types of autoimmune encephalitis, such as anti-AMPAR encephalitis and anti-GABA B R encephalitis ( 19 , 20 ). Taking together with the previous studies, five patients with anti-mGluR5 encephalitis had additional antibodies and all showed atypical symptoms: the patient with SOX1 antibodies had progressive ophthalmoplegia ( 7 ), the patient with Recoverin antibodies had visual deficits and confirmed retinopathy, the patient with NMDAR+AMPAR antibodies had refractory status epilepticus, the patient with NMDAR+MOG antibodies had cerebral cortical encephalitis ( 11 ), and the patient with LGI1 antibodies had faciobrachial dystonic seizures ( 12 ). In some of these cases, additional antibodies were pathogenically relevant, resulting a complex clinical pictures (e.g., Recoverin antibodies and retinopathy ( 21 ), MOG antibodies and cerebral cortical encephalitis ( 22 ), and LGI1 antibodies and faciobrachial dystonic seizures ( 23 )).…”

“…autoimmune encephalitis, such as anti-AMPAR encephalitis and anti-GABA B R encephalitis (19,20). Taking together with the previous studies, five patients with anti-mGluR5 encephalitis had additional antibodies and all showed atypical symptoms: the patient with SOX1 antibodies had progressive ophthalmoplegia (7), the patient with Recoverin antibodies had visual deficits and confirmed retinopathy, the patient with NMDAR+AMPAR antibodies had refractory status epilepticus, the patient with NMDAR+MOG antibodies had cerebral cortical encephalitis (11), and the patient with LGI1 antibodies had faciobrachial dystonic seizures (12). b Based on the Hodges-Lehmann method for median differences (15,16).…”

“…A recent study in an animal model has confirmed the pathogenicity of mGluR5 antibodies, which causes a reduction of mGluR5 clusters in neurons (6). However, as far as we know, since 2011, only 15 autoimmune encephalitis patients with mGluR5 antibodies from 8 studies have been reported worldwide, including three case reports from China (4,(7)(8)(9)(10)(11)(12)(13). Given the rarity of anti-mGluR5 encephalitis, additional studies in patients with different genetic backgrounds are necessary to further clarify the clinical spectrum and the disease prognosis.…”