ABSTRACT
Approximately 30% of individuals with severe SARS-CoV-2 infections also develop neurological and psychiatric complaints. In rare cases, the occurrence of autoimmune encephalitis has been reported after SARS-CoV-2 infection. In this systematic review, we have identified eight SARS-CoV-2-associated cases of anti-NMDA receptor encephalitis. All had cerebrospinal fluid antibodies against the NMDA receptor and a recent onset of working memory deficits, altered mental status, or psychiatric symptoms, such as confusion, agitation, auditory hallucination, catatonia and speech dysfunction. All patients received high-dose steroid and immunoglobulin therapeutics and conditions improved in each case. These findings suggest that clinical attention should be paid to warning signs of autoimmune encephalitis in severe COVID-19 cases. If characteristic features of autoimmune encephalitis are present, autoantibody diagnostics should be performed and confirmed cases should be treated with immunotherapy to minimize neurological impairments.
Subject(s)
Anti-N-Methyl-D-Aspartate Receptor Encephalitis/virology , COVID-19/complications , Mental Disorders/virology , Receptors, N-Methyl-D-Aspartate/immunology , Adolescent , Adult , Autoantibodies/immunology , COVID-19/immunology , Child , Female , Humans , Infant , Male , Middle Aged , Molecular Mimicry , SARS-CoV-2/immunology , Young AdultABSTRACT
The role of autoimmunity in central nervous system (CNS) disorders is rapidly expanding. In the last twenty years, different types of autoantibodies targeting subunits of ionotropic glutamate receptors have been found in a variety of patients affected by brain disorders. Several of these antibodies are directed against NMDA receptors (NMDAR), mostly in autoimmune encephalitis, whereas a growing field of research has identified antibodies against AMPA receptor (AMPAR) subunits in patients with different types of epilepsy or frontotemporal dementia. Several in vitro and in vivo studies performed in the last decade have dramatically improved our understanding of the molecular and functional effects induced by both NMDAR and AMPAR autoantibodies at the excitatory glutamatergic synapse and, consequently, their possible role in the onset of clinical symptoms. In particular, the method by which autoantibodies can modulate the localization at synapses of specific target subunits leading to functional impairments and behavioral alterations has been well addressed in animal studies. Overall, these preclinical studies have opened new avenues for the development of novel pharmacological treatments specifically targeting the synaptic activation of ionotropic glutamate receptors.