Association of Varying Clinical Manifestations and Positive Anti-SARS-CoV-2 IgG Antibodies: A Cross-Sectional Observational Study

Dysregulated autoantibodies targeting AGTR1 are associated with the accumulation of COVID-19 symptoms

Coronavirus disease 2019 (COVID-19) presents a wide spectrum of symptoms, the causes of which remain poorly understood. This study explored the associations between autoantibodies (AABs), particularly those targeting G protein-coupled receptors (GPCRs) and renin‒angiotensin system (RAS) molecules, and the clinical manifestations of COVID-19. Using a cross-sectional analysis of 244 individuals, we applied multivariate analysis of variance, principal component analysis, and multinomial regression to examine the relationships between AAB levels and key symptoms. Significant correlations were identified between specific AABs and symptoms such as fever, muscle aches, anosmia, and dysgeusia. Notably, anti-AGTR1 antibodies, which contribute to endothelial glycocalyx (eGC) degradation, a process reversed by losartan, have emerged as strong predictors of core symptoms. AAB levels increased with symptom accumulation, peaking in patients exhibiting all four key symptoms. These findings highlight the role of AABs, particularly anti-AGTR1 antibodies, in determining symptom severity and suggest their involvement in the pathophysiology of COVID-19, including vascular complications.

Severe COVID-19 patients exhibit elevated levels of autoantibodies targeting cardiolipin and platelet glycoprotein with age: a systems biology approach

Age is a significant risk factor for the coronavirus disease 2019 (COVID-19) severity due to immunosenescence and certain age-dependent medical conditions (e.g., obesity, cardiovascular disorder, and chronic respiratory disease). However, despite the well-known influence of age on autoantibody biology in health and disease, its impact on the risk of developing severe COVID-19 remains poorly explored. Here, we performed a cross-sectional study of autoantibodies directed against 58 targets associated with autoimmune diseases in 159 individuals with different COVID-19 severity (71 mild, 61 moderate, and 27 with severe symptoms) and 73 healthy controls. We found that the natural production of autoantibodies increases with age and is exacerbated by SARS-CoV-2 infection, mostly in severe COVID-19 patients. Multiple linear regression analysis showed that severe COVID-19 patients have a significant age-associated increase of autoantibody levels against 16 targets (e.g., amyloid β peptide, β catenin, cardiolipin, claudin, enteric nerve, fibulin, insulin receptor a, and platelet glycoprotein). Principal component analysis with spectrum decomposition and hierarchical clustering analysis based on these autoantibodies indicated an age-dependent stratification of severe COVID-19 patients. Random forest analysis ranked autoantibodies targeting cardiolipin, claudin, and platelet glycoprotein as the three most crucial autoantibodies for the stratification of severe COVID-19 patients ≥50 years of age. Follow-up analysis using binomial logistic regression found that anti-cardiolipin and anti-platelet glycoprotein autoantibodies significantly increased the likelihood of developing a severe COVID-19 phenotype with aging. These findings provide key insights to explain why aging increases the chance of developing more severe COVID-19 phenotypes.

Autoantibodies targeting G protein-coupled receptors: An evolving history in autoimmunity. Report of the 4th international symposium

G protein-coupled receptors (GPCR) are involved in various physiological and pathophysiological processes. Functional autoantibodies targeting GPCRs have been associated with multiple disease manifestations in this context. Here we summarize and discuss the relevant findings and concepts presented in the biennial International Meeting on autoantibodies targeting GPCRs (the 4th Symposium), held in Lübeck, Germany, 15-16 September 2022. The symposium focused on the current knowledge of these autoantibodies' role in various diseases, such as cardiovascular, renal, infectious (COVID-19), and autoimmune diseases (e.g., systemic sclerosis and systemic lupus erythematosus). Beyond their association with disease phenotypes, intense research related to the mechanistic action of these autoantibodies on immune regulation and pathogenesis has been developed, underscoring the role of autoantibodies targeting GPCRs on disease outcomes and etiopathogenesis. The observation repeatedly highlighted that autoantibodies targeting GPCRs could also be present in healthy individuals, suggesting that anti-GPCR autoantibodies play a physiologic role in modeling the course of diseases. Since numerous therapies targeting GPCRs have been developed, including small molecules and monoclonal antibodies designed for treating cancer, infections, metabolic disorders, or inflammatory conditions, anti-GPCR autoantibodies themselves can serve as therapeutic targets to reduce patients' morbidity and mortality, representing a new area for the development of novel therapeutic interventions.

Cross-sectional analysis reveals autoantibody signatures associated with COVID-19 severity

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased levels of autoantibodies targeting immunological proteins such as cytokines and chemokines. Reports further indicate that COVID-19 patients may develop a broad spectrum of autoimmune diseases due to reasons not fully understood. Even so, the landscape of autoantibodies induced by SARS-CoV-2 infection remains uncharted territory. To gain more insight, we carried out a comprehensive assessment of autoantibodies known to be linked to diverse autoimmune diseases observed in COVID-19 patients in a cohort of 231 individuals, of which 161 were COVID-19 patients (72 with mild, 61 moderate, and 28 with severe disease) and 70 were healthy controls. Dysregulated IgG and IgA autoantibody signatures, characterized mainly by elevated concentrations, occurred predominantly in patients with moderate or severe COVID-19 infection. Autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations while stratifying COVID-19 severity as indicated by random forest and principal component analyses. Furthermore, while young versus elderly COVID-19 patients showed only slight differences in autoantibody levels, elderly patients with severe disease presented higher IgG autoantibody concentrations than young individuals with severe COVID-19. This work maps the intersection of COVID-19 and autoimmunity by demonstrating the dysregulation of multiple autoantibodies triggered during SARS-CoV-2 infection. Thus, this cross-sectional study suggests that SARS-CoV-2 infection induces autoantibody signatures associated with COVID-19 severity and several autoantibodies that can be used as biomarkers of COVID-19 severity, indicating autoantibodies as potential therapeutical targets for these patients.

Association of anosmia and neutralizing antibody production in adolescents with SARS-CoV-2

BACKGROUND

To monitor olfactory/gustatory dysfunction and its relationship to SARS-CoV-2 IgG antibody responses in an adolescent population.

METHODS

Adolescents with changes in olfactory/gustatory functions were enrolled in a 15-month study. The patients were evaluated with 1) SNOT-22, 2) pediatric smell wheel, and 3) SARS-CoV-2 antibody testing. The relationship between these scores and length of anosmia, and the amount of SARS-CoV-2 IgG antibodies were assessed. A brain MRI was performed in cases of persistent special sensory symptoms.

RESULTS

Eighteen patients were identified with smell and/or taste complaints. Most of the patients were female (67%) and median age was 15 years (range 11-17). Twelve patients had prior SARS-CoV-2 PCR testing, with only five patients with a positive result. The median SNOT-22 score was 16 (range 0-52) and the median smell wheel score was 6.5 (range 1-11). Patients with taste difficulty were more likely to have a score less than eight. 78% of the patients tested positive for antibodies and there was a strong negative correlation between smell wheel score and antibody level (Spearman, ρ = -0.798, p = 0.002). Five patients underwent MRI scan, and all resulted as normal olfactory bulb structures. 66% received nasal corticosteroids. 11 patients presented in follow up.

CONCLUSIONS

Adolescents presenting to a pediatric ENT clinic during the SARS-CoV-2 pandemic were likely to have prolonged (>6 weeks) symptoms of SARS-CoV-2. The majority do not report positive PCR testing result but do report systemic symptoms including anosmia. This suggests that anosmia may be both a late and prolonged symptom of SARS-CoV-2.

SARS-CoV-2 Infection in Winter 2021/2022: The Association of Varying Clinical Manifestations With and Without Prior Vaccination

Importance SARS-CoV-2 is a rapidly evolving virus with many strains. Although vaccines have proven to be effective against earlier strains of the virus, the efficacy of vaccination status against later strains is still an area of active research. Objective To determine if vaccination status was associated with symptomatology due to infection by later strains of SARS-CoV-2. Design This cross-sectional survey was sent to an adult Jewish population from December 2021 to March 2022. Setting This is a population-based study of Jewish communities throughout the tristate area. The subjects were recruited by local Jewish not-for-profit and social service organizations. Participants Surveys were sent to 14,714 adults who were recruited by local Jewish not-for-profit and social service organizations; 966 respondents completed the survey (6.57%). Only participants who received a positive COVID-19 nasal swab 10 weeks since December 1, 2021, were included in the main outcome. Exposure Participants were grouped by vaccine type (i.e., Johnson & Johnson {J&J}, Moderna, or Pfizer) and vaccination status (i.e., unvaccinated, single, full, or booster). Main outcomes and measures The primary study outcome was an association between immunization status and somatological presentation. Symptom severity classes were built using latent class analysis (LCA). Results Out of 14,714 recipients, 966 completed the survey (6.57%). The participants were mainly self-described Ashkenazi Jewish (97%) with a median age of 41. The LCA resulted in four classes: highly symptomatic (HS), less symptomatic (LS), anosmia, and asymptomatic (AS). Vaccinated participants were less likely to be in symptomatic groups than the unvaccinated participants (odds ratio {OR}: 0.326; 95% confidence interval {CI}: 0.157-0.679; p=0.002). Boosted participants were less likely to be in symptomatic groups than fully vaccinated participants (OR: 0.267; 95% CI: 0.122-0.626; p=0.002). Additionally, there was no association between symptomatology and vaccination type (p=0.353). Conclusions and relevance Participants who received COVID-19 vaccinations or booster shots were less likely to be symptomatic after Omicron infection compared to unvaccinated participants and vaccinated participants without boosters, respectively. There's no association between vaccination type and symptomatology. These results enhance our understanding that COVID-19 vaccinations improve clinical symptomatology, even in an unforeseen COVID-19 strain.

Autoantibodies targeting GPCRs and RAS-related molecules associate with COVID-19 severity

COVID-19 shares the feature of autoantibody production with systemic autoimmune diseases. In order to understand the role of these immune globulins in the pathogenesis of the disease, it is important to explore the autoantibody spectra. Here we show, by a cross-sectional study of 246 individuals, that autoantibodies targeting G protein-coupled receptors (GPCR) and RAS-related molecules associate with the clinical severity of COVID-19. Patients with moderate and severe disease are characterized by higher autoantibody levels than healthy controls and those with mild COVID-19 disease. Among the anti-GPCR autoantibodies, machine learning classification identifies the chemokine receptor CXCR3 and the RAS-related molecule AGTR1 as targets for antibodies with the strongest association to disease severity. Besides antibody levels, autoantibody network signatures are also changing in patients with intermediate or high disease severity. Although our current and previous studies identify anti-GPCR antibodies as natural components of human biology, their production is deregulated in COVID-19 and their level and pattern alterations might predict COVID-19 disease severity.