Abstract
Impairment of health after overcoming the acute phase of COVID-19 is being observed more and more frequently. Here different symptoms of neurological and/or cardiological origin have been reported. With symptoms, which are very similar to the ones reported but are not caused by SARS-CoV-2, the occurrence of functionally active autoantibodies (fAABs) targeting G-protein coupled receptors (GPCR-fAABs) has been discussed to be involved.We, therefore investigated, whether GPCR-fAABs are detectable in 31 patients suffering from different Long-COVID-19 symptoms after recovery from the acute phase of the disease.The spectrum of symptoms was mostly of neurological origin (29/31 patients), including post-COVID-19 fatigue, alopecia, attention deficit, tremor and others. Combined neurological and cardiovascular disorders were reported in 17 of the 31 patients. Two recovered COVID-19 patients were free of follow-up symptoms. All 31 former COVID-19 patients had between 2 and 7 different GPCR-fAABs that acted as receptor agonists. Some of those GPCR-fAABs activate their target receptors which cause a positive chronotropic effect in neonatal rat cardiomyocytes, the read-out in the test system for their detection (bioassay for GPCR-fAAB detection). Other GPCR-fAABs, in opposite, cause a negative chronotropic effect on those cells. The positive chronotropic GPCR-fAABs identified in the blood of Long-COVID patients targeted the β2-adrenoceptor (β2-fAAB), the α1-adrenoceptor (α1-fAAB), the angiotensin II AT1-receptor (AT1-fAAB), and the nociceptin—like opioid receptor (NOC-fAAB). The negative chronotropic GPCR-fAABs identified targeted the muscarinic M2-receptor (M2-fAAB), the MAS-receptor (MAS-fAAB), and the ETA-receptor (ETA-fAAB). It was analysed which of the extracellular receptor loops was targeted by the autoantibodies.
Highlights
The pandemic COVID-19 viral infection is often associated with severe respiratory and neurological complications, cardiovascular problems, microvascular and endothelial disorders, and gastrointestinal diseases
Several different G-protein coupled receptors (GPCR)-Functional autoantibody (fAAB) were identified in the 31 sera of recovered COVID-19 patients
The astonishing finding of this investigation is the fact that an unusually high number of GPCR-fAABs were detected in the serum of recovered COVID-19 patients who mostly suffered from a variety of different post-COVID-19 symptoms
Summary
The pandemic COVID-19 viral infection is often associated with severe respiratory and neurological complications, cardiovascular problems, microvascular and endothelial disorders, and gastrointestinal diseases. These symptoms are often observed in patients who have already recovered from the disease and had negative follow-up coronavirus tests. In their Italian study, Carfi et al [1] indicated that only. Most of the symptomatic post-infection COVID-19 patients suffered from neurological disorders, such as chronic fatigue syndrome, postural orthostatic tachycardia syndrome (PoTS) and dysautonomia [1]. Similar results concerning the Abbreviations: fAAB, Functional autoantibody; ACE2, Angiotensin-converting enzyme 2 receptors; α1-fAAB, Autoantibody targeting the alpha1-adrenoceptor; AT1-fAAB, Autoantibody targeting the angiotensin II AT1 receptor; β2-fAAB, Autoantibody targeting the beta2-adrenoceptor; CRPS, Complex regional pain syndrome; ETA-fAAB, Autoantibody targeting the endothelin receptor; GPCR, G-protein coupled receptors; MAS-fAAB, Autoantibody targeting the MAS receptor; M2-fAAB, Autoantibody targeting the muscarinic receptor; NOC-fAAB, Functionally active autoantibody against the nociceptin receptor; PoTS, Postural orthostatic tachycardia syndrome; SARS, Severe acute respiratory syndrome; RAS, Renin angiotensin system
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