Autoantibody-Driven Monocyte Dysfunction in Post-COVID Syndrome with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract

Post-COVID syndrome (PCS) has emerged as a significant health concern with persisting symptoms. A subset of PCS patients develops severe myalgic encephalomyelitis/chronic fatigue syndrome (pcME/CFS). Dysregulated autoantibodies (AABs) have been implicated in PCS, contributing to immune dysregulation, impairment of autonomous nerve and vascular function. As recently shown in autoimmune diseases, IgG fractions translate disease-specific pathways into various cells. Therefore, we asked whether IgG fractions from PCS patients could be applied in vitro to identify specific cytokine rersponses for PCS patients without (nPCS) and with pcME/CSF. To assess this, we have stimulated monocyte cell lines with IgG fractions from PCS patients. Our findings reveal distinct patterns of immune regulation by AABs in vascular and immune dysfunction. In contrast to nPCS, pcME/CSF AABs induced enhanced neurotrophic responses, characterized by significant cytokine correlations involving brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF) and LIGHT. AAB-induced cytokine levels correlate with clinical symptoms. Further, this study emphasizes a contribution of AAB in PCS, in mitigating long-term immune dysregulation, and a need for therapies modulating IgG-induced pathways.