Autoantibodies in patients with post-COVID syndrome: a possible link with severity?

Coronavirus disease 2019 is an infectious disease associated with the respiratory system caused by the SARS-CoV-2 virus. Right now, an increasing number of patients with Post-COVID Syndrome show, without clear evidence of organ dysfunction, a plethora of severe symptoms, such as fatigue, pain, shortness of breath, cognitive impairment, and sleep disturbance. It has already been demonstrated that SARS-CoV-2 virus can disrupt the self-tolerance mechanism of the immune system, thus triggering autoimmune conditions. Several studies have recently documented the presence of autoantibodies in the sera of post-COVID patients, but until now, it is unclear whether the persistence of symptoms could be directly correlated with the presence of autoantibodies. In this study, serum autoantibodies (AAbs) levels against four G protein-coupled receptors in 78 patients with post-COVID syndrome have been analyzed. The AAbs investigated are clustered in two groups: adrenergic receptors (α1 and β2) and muscarinic acetylcholine receptors (M3 and M4). At least one or more AAbs were detected in 60.3% (47/78) of patients diagnosed with post-COVID syndrome, whereas 37.2% (29/78) of patients were positive for all receptors investigated. Interestingly, a strong correlation has been found between AAbs and pain intensity feeling by the patients measured by Visual Analogic Scale. A significant association was also obtained with insomnia and AABS-positive patients. The identification of AAbs and their correlation with pathological symptoms seriousness underly the possible role of AAbs as future therapeutic targets.