SARS-CoV-2 infection induces the production of autoantibodies in severe COVID-19 patients in an age-dependent manner (preprint)

Age is a significant risk factor for the coronavirus disease 2019 (COVID-19) outcomes due to immunosenescence and certain age-dependent medical conditions (e.g., obesity, cardiovascular disorder, diabetes, chronic respiratory disease). However, despite the well-known influence of age on autoantibody biology in health & 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 outcomes (with 71 mild, 61 moderate, and 27 severe patients) 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. Multivariate regression analysis showed that severe COVID-19 patients have a significant age-associated increase of autoantibody levels against 16 targets (e.g., amyloid beta peptide, beta catenin, cardiolipin, claudin, enteric nerve, fibulin, insulin receptor a, and platelet glycoprotein). Principal component analysis with spectrum decomposition 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 elderly COVID-19 patients. Follow-up analysis using binomial regression found that anti-cardiolipin and anti-platelet glycoprotein autoantibodies indicated a significantly increased likelihood of developing a severe COVID-19 phenotype, presenting a synergistic effect on worsening COVID-19 outcomes. These findings provide new key insights to explain why elderly patients less favorable outcomes have than young individuals, suggesting new associations of distinct autoantibody levels with disease severity.

Age-dependent impairment in antibody responses elicited by a homologous CoronaVac booster dose (preprint)

The emergence of the SARS-CoV-2 Omicron sublineages resulted in drastically increased transmission rates and reduced protection from vaccine-induced immunity. To counteract these effects, multiple booster strategies were used in different countries, although data comparing their efficiency in improving protective immunity remains sparse, especially among vulnerable populations, including older adults. The inactivated CoronaVac vaccine was among the most widely distributed worldwide, particularly in China, and South America. However, whether homologous versus heterologous booster doses in those fully vaccinated with CoronaVac induce distinct humoral responses and whether these responses vary across age groups remain unknown. We analyzed plasma antibody responses from CoronaVac-vaccinated younger or older individuals in central and south America that received a homologous CoronaVac or heterologous BNT162b2 or ChAdOx1 booster vaccines. We found that both IgG levels against SARS-CoV-2 spike or RBD, as well as neutralization titers against Omicron sublineages, were substantially reduced in participants that received homologous CoronaVac when compared to heterologous BNT162b2 or ChAdOx1 booster. This effect was specifically prominent in recipients older than 50 years of age. In this group, CoronaVac booster induced low virus-specific IgG levels and failed to elevate their neutralization titers against any omicron sublineage. Our results point to significant inefficiency in mounting protective anti-viral humoral immunity in those who were primed with CoronaVac followed by CoronaVac booster, particularly among older adults, urging a heterologous regimen in high-risk populations fully vaccinated with CoronaVac. One Sentence SummaryHomologous CoronaVac boosters do not improve neutralization responses against current VOCs in older adults in contrast to heterologous regimens.

Autoantibodies linked to autoimmune diseases associate with COVID-19 outcomes (preprint)

The 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 wide 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 248 individuals, of which 171 were COVID-19 patients (74 with mild, 65 moderate, and 32 with severe disease) and 77 were healthy controls. Dysregulated autoantibody serum levels, characterized mainly by elevated concentrations, occurred mostly in patients with moderate or severe COVID-19 infection, and was accompanied by a progressive disruption of physiologic IgG and IgA autoantibody signatures. A similar perturbation was found in patients with anosmia. Notably, autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations, being both indicated by random forest classification as strong predictors of COVID-19 outcome, together with age. Moreover, higher levels of autoantibodies (mainly IgGs) were seen in the elderly with severe disease compared with young COVID-19 patients with severe disease. These findings suggest that the SARS-CoV-2 infection induces a broader loss of self-tolerance than previously thought, providing new ideas for therapeutic interventions.

Multi-Layered Transcriptomic Holistic Analyses Reveal an Immunological Overlap between COVID-19 and Hemophagocytic Lymphohistiocytosis Associated with Disease Severity (preprint)

Clinical and hyperinflammatory overlap between COVID-19 and hemophagocytic lymphohistiocytosis (HLH) has been reported. However, the underlying mechanisms are unclear. Here we show that COVID-19 and HLH have an overlap of signaling pathways and gene signatures commonly dysregulated, which were defined by investigating the transcriptomes of 1253 subjects (controls, COVID-19, and HLH patients) using microarray, bulk RNA-sequencing (RNAseq), and single-cell RNAseq (scRNAseq). COVID-19 and HLH share pathways involved in cytokine and chemokine signaling as well as neutrophil-mediated immune responses that associate with COVID-19 severity. These genes are dysregulated at protein level across several COVID-19 studies and form an interconnected network with differentially expressed plasma proteins which converge to neutrophil hyperactivation in COVID-19 patients admitted to the intensive care unit. scRNAseq analysis indicated that these genes are specifically upregulated across different leukocyte populations, including lymphocyte subsets and immature neutrophils. Artificial intelligence modeling confirmed the strong association of these genes with COVID-19 severity. Thus, our work indicates putative therapeutic pathways for intervention.Funding: We acknowledge the Latin American Society of Immunodeficiencies (LASID) for providing the research funding of LFS (LASID Fellowship award 2020), and the São Paulo Research Foundation (FAPESP grants 2018/18886-9, 2020/01688-0, and 2020/07069-0 to OCM) for financial support. Computational analysis was supported by FAPESP and partially by the grants from Ontario Research Fund (#34876), Natural Sciences Research Council (NSERC #203475), Canada Foundation for Innovation (CFI #29272, #225404, #33536), and IBM granted to IJ, the National Institutes of Health (NHLBI) through award HL130704 granted to AJ, as well as the NIH P4 GM108538 granted to KAO and JJC. This study was financed in part by the coordination for the improvement of higher education personnel – Brazil (CAPES) – finance code 001.Declaration of Interests: The authors have declared that no conflict of interest exists.

The relationship between autoantibodies targeting GPCRs and the renin-angiotensin system associates with COVID-19 severity (preprint)

The coronavirus disease 2019 (COVID-19) can evolve to clinical manifestations resembling systemic autoimmune diseases, with the presence of autoantibodies that are still poorly characterized. To address this issue, we performed a cross-sectional study of 246 individuals to determine whether autoantibodies targeting G protein-coupled receptors (GPCRs) and renin-angiotensin system (RAS)-related molecules were associated with COVID-19-related clinical outcomes. Moderate and severe patients exhibited the highest autoantibody levels, relative to both healthy controls and patients with mild COVID-19 symptoms. Random Forest, a machine learning model, ranked anti-GPCR autoantibodies targeting downstream molecules in the RAS signaling pathway such as the angiotensin II type 1 and Mas receptor, and the chemokine receptor CXCR3 as the three strongest predictors of severe disease. Moreover, while the autoantibody network signatures were relatively conserved in patients with mild COVID-19 compared to healthy controls, they were disrupted in moderate and most perturbed in severe patients. Our data indicate that the relationship between autoantibodies targeting GPCRs and RAS-related molecules associates with the clinical severity of COVID-19, suggesting novel molecular pathways for therapeutic interventions.

Specific immune-regulatory transcriptional signatures reveal sex and age differences in SARS-CoV-2 infected patients (preprint)

The coronavirus disease 2019 (COVID-19) fatality rate varies in different patient groups. However, the underlying mechanisms that explain this variation are poorly understood. Here, we reanalyzed and integrated public RNAseq datasets of nasopharyngeal swabs and peripheral blood leukocytes from patients with SARS-CoV-2, comparing transcription patterns according to sex, age, and viral load. We found that female and young patients infected by SARS-CoV-2 exhibited a similar transcriptomic pattern with a larger number of total (up- and downregulated) differentially expressed genes (DEGs) compared to males and elderly patients. The transcriptional analysis showed a sex-specific profile with a higher transcriptional modulation of immune response-associated genes in female and young subjects against SARS-CoV-2. The functional clustering was characterized by a highly correlated interferome network of cytokine/chemokine- and neutrophil-associated genes that were enriched both in nasopharyngeal cells and peripheral blood of COVID-19 patients. Females exhibited reduced transcriptional levels of key pro-inflammatory/neutrophil-related genes such as CXCL8 receptors (CXCR1/CXCR2), IL-1{beta}, S100A9, ITGAM, and DBNL compared to males, which correlate with a protective gene expression profile against inflammatory damage. Our data indicate specific immune-regulatory pathways associated with sex and age of patients infected with SARS-CoV-2. These results point out therapeutic targets to reduce morbidity and mortality of COVID-19.