key: cord-1048939-xt9lbbnd
authors: Lee, E.; Tyler, R. E.; Johnson, D.; Koh, N.; Ong, B. C.; Foo, S. Y.; Tan, J.
title: High frequency and persistence of Anti-DSG2 antibodies in post COVID-19 serum samples
date: 2022-03-08
journal: nan
DOI: 10.1101/2022.02.23.22271045
sha: 4280b84666226211f2523b75fd5a397345f7ce68
doc_id: 1048939
cord_uid: xt9lbbnd

Background: There is growing recognition that COVID-19 does cause cardiac sequelae. The underlying mechanisms involved are still poorly understood to date. Viral infections, including COVID-19, have been hypothesized to contribute to autoimmunity, by exposing previously hidden cryptic epitopes on damaged cells to an activated immune system Given the high incidence of cardiac involvement seen in COVID-19, our aim was to determine the frequency of anti-DSG2 antibodies in a population of post COVID-19 patients. Methods and Results: 300 convalescent serum samples were obtained from a group of post COVID-19 infected patients from October 2020 to February 2021. 154 samples were drawn 6 months post-COVID-19 infection and 146 samples were drawn 9 months post COVID infection. 17 samples were obtained from the same patient at the 6- and 9-month mark. An electrochemiluminescent-based immunoassay utilizing the extracellular domain of DSG2 for antibody capture was used. The mean signal intensity of anti-DSG2 antibodies in the post COVID-19 samples was significantly higher than that of a healthy control population (19+/-83.2 vs. 2.1+/-6.8, P value <0.001). Of note, 29.3% of the post COVID-19 infection samples demonstrated a signal higher than the 90th percentile of the control population and 8.7% were higher than the median found in ARVC patients. The signal intensity between the 6-month and 9-month samples did not differ significantly. Conclusions: We report for the first time that recovered COVID-19 patients demonstrate significantly higher and sustained levels of anti-DSG2 autoantibodies as compared to a healthy control population, comparable to that of a diagnosed ARVC group.

a depressed ejection fraction after COVID-19 recovery are not well-understood, although frank cardiomyopathy has been described in post-COVID-19 patients. A recent study (PROLUN study; ref. 1) demonstrated right ventricular and diastolic dysfunction in approximately half of the patients, with arrhythmias in ~27%, 3 months after COVID-19 (1) .

The findings of right-sided cardiomyopathy and increased predilection for arrhythmias are also features of arrhythmogenic right ventricular cardiomyopathy (ARVC). Antibodies to the desmosome protein desmoglein-2 (DSG2) have been shown to be present in some patients with ARVC (2) . Concentrations of anti-DSG2 antibodies correlate positively to arrhythmia burden, and presence of these antibodies in borderline ARVC cases predicts the development of fulminant ARVC (2) . Exposure of cardiomyocytes to anti-DSG2 antibodies in vitro results in a reduction in gap junction function. Together, these data suggest that anti-DSG2 antibodies may play a functional role in cardiac pathology. Viral infections, including COVID-19, have been hypothesized to contribute to autoimmunity, e.g., by exposing previously hidden cryptic epitopes on damaged cells to an activated immune system (3) . Given the high incidence of cardiac involvement seen in COVID-19, we hypothesized that anti-DSG2 autoantibodies might be generated as a result. We developed an electrochemiluminescent-based immunoassay utilizing the extracellular domain of DSG2 for antibody capture; assay performance was validated by appropriate capture of commercially available anti-DSG2 antibodies (polyclonal goat anti-human DSG2 antibody; R&D Systems) (Fig.  1A) . 300 convalescent serum samples were obtained from a group of post-COVID-19 infected patients from October 2020 to February 2021 as part of an ongoing epidemiological study of a young, East Asian-populated dormitory in Singapore. The mean age of our study population was 37 years old (range 21-65). 154 samples were drawn 6 months post-COVID-19 and 146 samples were drawn 9 months post COVID. 17 samples were obtained from the same patient at the 6and 9-month mark. The negative control group sera were obtained from a commercial source (BioIVT) of self-declared healthy individuals. Positive control ARVC sera were obtained from a prior study (4) . The mean signal intensity of anti-DSG2 antibodies in the post COVID-19 samples was significantly higher than that of a healthy control population (19±83.2 in the post COVID-19 sample vs. 2.1±6.8 in the healthy control population, P value <0.001). Of note, 29.3% of the post COVID-19 samples demonstrated a signal higher than the 90 th percentile of the control population and 8.7% were higher than the median found in ARVC patients. The signal intensity between the 6-month and 9-month samples did not differ significantly (p=0.529; Fig. 1B ). The caveat to this comparison is that the separate groups of samples (post-COVID-19, healthy controls and ARVC sera) were assessed non-contemporaneously; however, same-group repeat testing (for positive controls, healthy controls and ARVC groups) has demonstrated high repeatability; negative control samples demonstrated minimal variation across tests and were used to normalize all data.

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The copyright holder for this preprint this version posted March 8, 2022. ; https://doi.org/10.1101/2022.02.23.22271045 doi: medRxiv preprint

We report for the first time that recovered COVID-19 patients demonstrate significantly higher levels of anti-DSG2 autoantibodies, and that these antibody levels are sustained well into recovery from COVID-19 -up to 6 and 9 months. While other groups (4) have demonstrated increased overall levels of autoantibodies during the acute/subacute phases of COVID-19, our data demonstrates the prolonged and robust elevation of a specific autoantibody; in addition, as anti-DSG2 antibodies from ARVC patients appear to cause direct cardiac pathology in vitro (2) , this has implications for long-term, post-COVID-19 cardiac compromise. Of note, ~29% of our patients had levels of anti-DSG2 autoantibodies above the 90 th percentile of a comparator normal control group, whereas ~27% of post-COVID-19 patients had notable arrhythmia in the PROLUN stud (1) .

The limitations to this study are that we were unable to analyze the relationship between anti-DSG2 autoantibody levels and current symptoms, given the lack of available clinical data for these patients, and that it is not known if COVID-19 vaccinations generate similar frequencies of anti-DSG2 antibodies. The presence of anti-DSG2 antibodies after COVID-19 recovery may have important risk stratification implications in determining vocational suitability and fitness for competitive sports. Further work is required to demonstrate that the anti-DSG2 autoantibodies found in post-COVID-19 patients have direct cardiotoxicity. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted March 8, 2022. ; https://doi.org/10.1101/2022.02.23.22271045 doi: medRxiv preprint

Cardiac dysfunction and arrhythmias 3 Months after hospitalization for COVID-19

An autoantibody identifies arrhythmogenic right ventricular cardiomyopathy and participates in its pathogenesis

Collection of ARVC serum by Arvada Therapeutics under ICH guidelines

Diverse functional autoantibodies in patients with COVID-19