Identifying Neurological Autoantibodies in COVID-19: mGluR2 as a Marker
of Immune Dysregulation During the Omicron Outbreak in China
Abstract
Aimed to comprehensively investigate the presence of neural
autoantibodies in the cerebrospinal fluid (CSF) and plasma of COVID-19
patients experiencing neurological complications during the Omicron wave
in China. Forty consecutive COVID-19 patients with severe neurological
complications and 15 disease controls (DC) were enrolled in the study.
Neural autoantibodies were detected using both the indirect
immunofluorescence assay (IFA) on mouse brain tissue and the
Brain-neuronal-antigen microarray. A bioinformatics analysis was
conducted to evaluate the similarity between SARS-CoV-2 proteins and the
specific antigens identified by the microarray. Our results showed a
markedly elevated prevalence of neural autoantibodies in CSF (62.16%
vs. 0.0%) and in plasma of COVID-19 patients compared to DC using IFA.
Additionally, we identified 12 upregulated intrathecal IgG
autoantibodies with differential levels between COVID-19 patients and
DC, as well as 51 upregulated IgG autoantibodies in plasma. Anti-mGluR2
antibodies exhibited the highest positivity rate in COVID-19 patients, a
finding further confirmed by cell-based assays (CBA). Moreover, we
discovered a shared peptide similarity between the SARS-CoV-2 N, S
protein and mGluR2. Among two COVID-19 patients with positive
anti-mGluR2 antibodies, there were specific and prominent bindings to
both the RBD-Fc of S and mGluR2, while only weak binding was observed to
N.