Virus infection, antiviral immunity, and autoimmunity

Neural autoantibodies in psychiatric disorders are associated with antibodies against viral pathogens: a retrospective study of 619 patients

A history of viral infection has been associated with a higher risk for psychiatric disorders. One potential underlying mechanism is that antiviral immunological responses could trigger cross-reactivity between viral and neural antigens, which would raise the co-occurrence of antiviral antibodies and anti-neural autoantibodies. We studied 619 patients' psychiatric diagnoses from the Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Germany. Anti-neural autoantibodies and antiviral antibody specific indices were measured in serum and/or cerebrospinal fluid (CSF) from all patients. Among these 619 patients, 115 tested positive for serum and/or CSF neural autoantibodies (18.6%), with the most often identified autoantibodies being anti-GAD65 in serum (2.2%) and CSF (1.6%), and anti-NMDA in serum (0.6%) and CSF (1.3%). The three main diagnostic groups presenting neural autoantibodies were patients with organic psychiatric disorders including dementia (81 of 377; 21.7%), those with psychotic disorders (9 of 66; 13.6%), and patients with affective disorders (19 of 138; 13.9%). Logistic regression analysis revealed a significant association between the varicella zoster virus (VZV) antibody-specific index and autoantibody positivity in patients with all diagnoses (F00-F79) (p < 0.005). Furthermore, the rubella antibody-specific index proved to be significantly associated with neural autoantibody positivity (p < 0.001) across all patients (F00-F79), and in those with affective disorders (p < 0.01). Our results show that VZV and rubella antiviral antibodies are associated with a higher propensity to develop anti-neural autoantibodies, suggesting that the known association between viral infection and later developing psychiatric disorders may be partly attributable to the development of anti-neural autoimmunity.

Exploring the Contribution of TLR7 to Sex-Based Disparities in Respiratory Syncytial Virus (RSV)-Induced Inflammation and Immunity

TLR7 plays a key role in recognizing viral RNA to initiate an immune response. Sex-based differences in the severity of RSV respiratory infections have been noted, and this may be related to higher expression of X-linked toll-like receptor 7 (TLR7) in female immune cells. Indeed, TLR7 has been shown to influence sex differences in responses to other respiratory viruses; however, its role in RSV infection remains underexplored. We infected adult C57Bl/6 or TLR7 knockout mice with RSV and compared the specific lung immune responses between different sexes. Gene expression analysis revealed that infected female mice had elevated levels of type I and II interferons, proinflammatory cytokines, chemokines, and viral transcripts in their lungs compared to males. Additionally, females exhibited increased numbers of macrophages and higher antibody responses in the airways. Deletion of TLR7 diminished the sex differences in certain cytokine and antibody responses. Furthermore, ex vivo infection of male alveolar macrophages with RSV resulted in greater production of proinflammatory cytokines and viral transcripts than in female macrophages, suggesting inherent sex differences in macrophage responses. These findings provide new insights into the mechanisms underlying sex differences in RSV pathophysiology and suggest that TLR7 contributes to an enhanced inflammatory response in females.

Children who develop celiac disease are predicted to exhibit distinct metabolic pathways among their gut microbiota years before diagnosis

Celiac disease (CD) is an autoimmune disease caused by a loss of gluten tolerance in genetically predisposed individuals. While 30%-40% of people possess the predisposing alleles, only 1%-2% are diagnosed with CD, suggesting that environmental factors are involved in disease pathogenesis. To determine an association between pediatric CD and the gut microbiome, we analyzed fecal samples from a prospective cohort study (ABIS). These samples were collected from children who later developed CD (CD progressors) and age-matched healthy children (at ages 1, 2.5, and 5) with similar HLA genotypes, breastfeeding durations, and gluten exposure times. We previously reported gut microbiome differences at ages 2.5 and 5 in this cohort; here, we present findings from samples collected at age 1 (n = 5). We identified 14 ASVs differing significantly between CD progressors and controls, including taxa linked to CD pathogenesis. CD progressors had increased Firmicutes and higher alpha diversity in IgA- bacteria. Using PICRUSt, we analyzed metabolic pathways enriched in CD progressors compared to controls at ages 1, 2.5, and 5 (n = 5-16), revealing enriched inflammatory and pathogenic pathways potentially contributing to CD-related immune dysregulation. While results are based on the primary EdgeR analysis, we also applied a non-parametric method of statistical analysis, reporting those results with supplementary figures. In conclusion, our findings suggest distinct metabolic pathways enriched in the gut microbiome of CD progressors years before diagnosis, which could inform targeted therapeutics for CD. As discussed in the limitations section, this small pilot study should be replicated with larger sample sizes for broader generalization.

IMPORTANCE

We analyzed gut microbiome data from children who later developed celiac disease (CD progressors) compared to healthy children in the first 5 years of life. Using fecal samples corresponding to the three phases of gut microbiome development, we uncovered enriched functional microbial pathways in CD progressors at age 1. Some of these pathways, implicated in bacterial pathogenesis, microbiota modulation, and inflammation, have been correlated with CD. We also identified taxa in CD progressors at age 1 including Lachnospiraceae, Alistipes, and Bifidobacterium dentium that were previously associated with CD. These findings suggest a potential role for these taxa and enriched pathways in pediatric CD onset years before diagnosis, highlighting potential for early interventions. While the findings of this exploratory study should be validated with larger sample sizes, our study suggests microbial metabolic pathways related to CD onset, enhancing our understanding of CD pathogenesis and the role of gut microbiome-mediated early alterations.

The role of Epstein-Barr virus in autoimmune and autoinflammatory diseases

Epstein-Barr Virus (EBV), a dsDNA herpesvirus, is believed to play a significant role in exacerbating and potentially triggering autoimmune and autoinflammatory maladies. Around 90% of the world is infected with the virus, which establishes latency within lymphocytes. EBV is also known to cause infectious mononucleosis, a self-limited flu-like illness, in adolescents. EBV is often reactivated and it employs several mechanisms of evading the host immune system. It has also been implicated in inducing host immune dysfunction potentially resulting in exacerbation or triggering of inflammatory processes. EBV has therefore been linked to a number of autoimmune diseases, including systemic lupus erythematosus, multiple sclerosis, rheumatoid arthritis, and Sjögren's syndrome. The review examines the molecular mechanisms through which the virus alters host immune system components thus possibly resulting in autoimmune processes. Understanding the mechanisms underpinning EBV-associated autoimmunity is pivotal; however, the precise causal pathways remain elusive. Research on therapeutic agents and vaccines for EBV has been stagnant for a long number of years until recent advances shed light on potential therapeutic targets. The implications of EBV in autoimmunity underscore the importance of developing targeted therapeutic strategies and, potentially, vaccines to mitigate the autoimmune burden associated with this ubiquitous virus.

Differential roles of human CD4+ and CD8+ regulatory T cells in controlling self-reactive immune responses

Here we analyzed the relative contributions of CD4+ regulatory T cells expressing Forkhead box protein P3 (FOXP3) and CD8+ regulatory T cells expressing killer cell immunoglobulin-like receptors to the control of autoreactive T and B lymphocytes in human tonsil-derived immune organoids. FOXP3 and GZMB respectively encode proteins FOXP3 and granzyme B, which are critical to the suppressive functions of CD4+ and CD8+ regulatory T cells. Using CRISPR-Cas9 gene editing, we were able to achieve a reduction of ~90-95% in the expression of these genes. FOXP3 knockout in tonsil T cells led to production of antibodies against a variety of autoantigens and increased the affinity of influenza-specific antibodies. By contrast, GZMB knockout resulted in an increase in follicular helper T cells, consistent with the ablation of CD8+ regulatory T cells observed in mouse models, and a marked expansion of autoreactive CD8+ and CD4+ T cells. These findings highlight the distinct yet complementary roles of CD8+ and CD4+ regulatory T cells in regulating cellular and humoral responses to prevent autoimmunity.

Recent clinical and mechanistic insights into vitiligo offer new treatment options for cell-specific autoimmunity

Vitiligo is an autoimmune disease that has been recognized, stigmatized, and treated for millennia. Recent translational research has revealed key mechanisms of disease, including cellular stress, innate immune activation, T cell-mediated elimination of melanocytes from the skin resulting in clinically apparent white spots, as well as stem cell regeneration that reverses established lesions. Many of these pathways have been targeted therapeutically, leading to the first FDA-approved medication to reverse the disease, with many more in clinical trials. Despite these impressive advances, many questions remain, which will be answered through integration of additional basic, translational, and clinical research studies. This vitiligo revolution has led to great excitement for individuals with vitiligo, those who know them, and the dermatologists who care for their patients. But just as importantly, these advances have great potential to shed light on autoimmune diseases that are more difficult to study, possibly leading to treatment advances that could not be achieved otherwise.

Zika and Dengue Virus Autoimmunity: An Overview of Related Disorders and Their Potential Mechanisms

Zika virus (ZIKV) and dengue virus (DENV) are two major mosquito-borne flaviviruses that pose a significant threat to the global public health system, particularly in tropical regions. The clinical outcomes related to these viral pathogens can vary from self-limiting asymptomatic infections to various forms of life-threatening pathological conditions such as haemorrhagic disorders. In addition to the direct effects of the viral pathogens, immune processes play also a significant function in the development of diseases mediated by ZIKV and DENV. Studing these processes is important for developing safer vaccines and targeted therapeutic strategies. These viruses have been reported to trigger various autoimmune disorders affecting different parts of human organ systems. It also has been shown that preexisting immunity to ZIKV or DENV can impact the outcome of subsequent infections caused by another virus. ZIKV and DENV infection can promote the development of autoimmune disorders by different mechanisms, such as molecular mimicry and autoantibody formation. The present review provides an overview of various autoimmune disorders associated with ZIKV and DENV infection and their potential underlying mechanisms.

Fructose-1,6-diphosphate inhibits viral replication by promoting the lysosomal degradation of HMGB1 and blocking the binding of HMGB1 to the viral genome

Fructose-1,6-diphosphate (FBP), a key glycolytic metabolite, is recognized for its cytoprotective effects during stress. However, the role of FBP in viral infections is unknown. Here, we demonstrate that virus-infected cells exhibit elevated FBP levels. Exogenous FBP inhibits both RNA and DNA virus infections in vitro and in vivo. Modulating intracellular FBP levels by regulating the expression of the metabolic enzymes FBP1 and PFK1 significantly impacts viral infections. Mechanistically, the inhibitory effects of FBP are not a result of altered viral adhesion or entry and are largely independent of type I interferon-mediated immune responses; rather, they occur through modulation of HMGB1. During viral infections, FBP predominantly reduces the protein levels of HMGB1 by facilitating its lysosomal degradation. Furthermore, FBP interacts with HMGB1 and disrupts the binding of HMGB1 to viral genomes, thereby further inhibiting viral replication. Our findings underscore the potential of FBP as a therapeutic target for controlling viral infections.

Memory inflation: Beyond the acute phase of viral infection

Memory inflation is confirmed as the most commonly dysregulation of host immunity with antigen-independent manner in mammals after viral infection. By generating large numbers of effector/memory and terminal differentiated effector memory CD8+ T cells with diminished naïve subsets, memory inflation is believed to play critical roles in connecting the viral infection and the onset of multiple diseases. Here, we reviewed the current understanding of memory inflated CD8+ T cells in their distinct phenotypic features that different from exhausted subsets; the intrinsic and extrinsic roles in regulating the formation of memory inflation; and the key proteins in maintaining the expansion and proliferation of inflationary populations. More importantly, based on the evidences from both clinic and animal models, we summarized the potential mechanisms of memory inflation to trigger autoimmune neuropathies, such as Guillain-Barré syndrome and multiple sclerosis; the correlations of memory inflation between tumorigenesis and resistance of tumour immunotherapies; as well as the effects of memory inflation to facilitate vascular disease progression. To sum up, better understanding of memory inflation could provide us an opportunity to beyond the acute phase of viral infection, and shed a light on the long-term influences of CD8+ T cell heterogeneity in dampen host immune homeostasis.

Causality between autoimmune diseases and schizophrenia: a bidirectional Mendelian randomization study

BACKGROUND

Observational studies have shown a link between autoimmune diseases and schizophrenia, with conflicting conclusions. Due to the existence of confounding factors, the causal link between autoimmune diseases and schizophrenia is still unknown.

METHOD

We conducted a comprehensive Mendelian randomization (MR) analysis of schizophrenia and ten common autoimmune diseases in individuals of European descent using genome-wide association studies (GWASs). To evaluate the relationships between autoimmune diseases and schizophrenia, inverse variance weighted, MR-RAPS, Bayesian weighted MR, constrained maximum likelihood, debiased IVW, MR-Egger, and weighted median were utilized. Several sensitivity analyses were performed to ensure the reliability of the study's results.

RESULTS

Our findings reveal that genetically predicted ankylosing spondylitis is related to an increased risk of schizophrenia, whereas celiac disease, type 1 diabetes, and systemic lupus erythematosus are associated with a lower risk of schizophrenia. In the reverse MR analysis, our study indicated that genetically predicted schizophrenia is linked to higher risks of ankylosing spondylitis, Crohn's disease, ulcerative colitis, inflammatory bowel disease, and psoriasis. Neither multiple sclerosis nor rheumatoid arthritis have been linked to schizophrenia, and vice versa.

CONCLUSION

Despite contradicting some other observational reports, this study showed support for a causal link between autoimmune diseases and schizophrenia. To gain a better understanding of the mechanisms underlying the development of immune-mediated schizophrenia, additional research is required to identify potential mechanisms identified in observational studies.

Epidemiological Characteristics of Neuro-Specific Antibodies Following Viral Infections

This study aims to explore the epidemiological characteristics of neuro-specific antibodies (ns-Ab) induced by different viral infections within the central nervous system (CNS). Additionally, it seeks to compare the autoimmune effects following several typical viral infections in CNS. We conduct a retrospective study to compare and analyze the prevalence trends of ns-Ab in patients with different viral infections. Additionally, evaluate the intensity of CNS inflammatory responses postviral infection by correlating clinical characteristics and laboratory findings, and briefly demonstrate the immune effects in CNS following various viral infections. This study retrospectively collected data from 1037 patients hospitalized with suspected CNS infections. A total of 654 patients (63.1%) were included in the final analysis. A higher proportion of patients with pathogens present in their cerebrospinal fluid (CSF) (114 out of 332, 34.3%) tested positive for ns-Ab compared to those without pathogens (70 out of 322, 21.7%) (p = 0.0004). Specifically, the screening rate for ns-Ab in patients with CNS viral infections (83 out of 165, 50.3%) and the prevalence of ns-Ab (27 out of 83, 32.5%) were significantly higher than in those with other pathogen infections (p < 0.0001 and p = 0.016, respectively). Among these, human herpesvirus 7 (HHV7) patients had the highest detection rate of ns-Ab during the disease course (11 out of 26, 42.3%), but exhibited infection characteristics distinctly different from those of herpes simplex virus 1 (HSV1). Viral infections significantly promote the development of autoimmune responses in CNS. The production of ns-Ab and the subsequent autoimmune response vary across different viral infections. There is a strong statistical correlation between HHV7 and the presence of ns-Ab, suggesting that HHV7 may serve as an early indicator of secondary autoimmune response following CNS infections.

Traumatic spinal cord injury and its correlation to risk of autoimmune/-inflammatory disease

STUDY DESIGN

Nationwide epidemiological open cohort study.

OBJECTIVES

To evaluate whether individuals with traumatic spinal cord injury (TSCI) are more prone to develop autoimmune diseases compared to a general non-TSCI population.

SETTING

Danish public national registries.

METHODS

An open nationwide cohort, including individuals born in Denmark from or alive during 1945-2018 was collected and the study period was 1980-2018. Poissons Log-linear regression estimated the incidence rate ratio (IRR) for developing eight groups of autoimmune diseases. A dose-response relationship based on the cervical/thoracic level of injury was assessed by stratification.

RESULTS

The cohort included 3,272 individuals with TSCI and 4.8 million background individuals, accounting for 50,865 and 140 million person-years respectively. The TSCI population had an overall IRR of 1.81 (95% CI, 1.59 to 2.05) of getting any autoimmune disease. Subgroup analysis found positive associations for; a) Other neurologic IRR 5.19 (95% CI, 2.79 to 9.65), b) multiple sclerosis IRR 3.70 (95% CI, 2.54 to 5.40), c) Dermatologic IRR 2.57 (95% CI, 1.86 to 3.55), d) Type 1 diabetes mellitus IRR 2.01 (95% CI, 1.54 to 2.61), e) Systemic 1.92 (95% CI, 1.44 to 2.55), and f) Gastroenterologic IRR 1.42 (95% CI, 1.05 to 1.92). Cervical levels of TSCI showed an IRR of 1.70 (95% CI, 1.43 to 2.02), while thoracic levels had an IRR 1.98 (95% CI, 1.63 to 2.39).

CONCLUSIONS

TSCI may be an individual risk factor of developing an autoimmune disease. There does not appear to exist a dose-response relationship from the level of injury.

SPONSORSHIP

None.

Pediatric acute-onset neuropsychiatric syndrome and pediatric autoimmune neuropsychiatric disorder associated with streptococcal infections: a delphi study and consensus document about definition, diagnostic criteria, treatment and follow-up

Pediatric Autoimmune Neuropsychiatric Disorder Associated with Streptococcal Infections (PANDAS) and Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) are broad diagnoses that encompass a range of sudden-onset neuropsychiatric symptoms in children, which can include obsessive-compulsive disorder (OCD), tics, anxiety, emotional instability, and cognitive difficulties. Unlike PANDAS, PANS is not strictly linked to group A streptococcal infections but can be triggered by various infectious or environmental factors. Lights and shadows remain upon the management of children with PANS and PANDAS and there is no clear consensus regarding definition, diagnostic criteria, treatment, and follow-up. The aim of the present study was to evaluate the level of agreement on PANS and PANDAS definition, diagnostic criteria, treatment and follow-up and to assess on the basis of recent studies whether there is a need to modify the current recommendations used by primary care pediatricians and hospital pediatricians in clinical practice in order to improve outcomes. Using the Delphi method, this consensus provides shared indications on PANS and PANDAS management in pediatric age, based on the most updated literature. This work represents, in our opinion, the most complete and up-to-date information on the diagnosis of PANS and PANDAS, as well as consensus statements about several aspects of clinical care. Undoubtedly, more randomized and controlled trials are needed in the pediatric population to better define the best management, also in terms of adequate follow-up examinations and period of observation.

Infection, vaccination and narcolepsy type 1: Evidence and potential molecular mechanisms

NT1 is a rare, chronic and disabling neurological disease causing excessive daytime sleepiness and cataplexy. NT1 is characterized pathologically by an almost complete loss of neurons producing the hypocretin (HCRT)/orexin neuropeptides in the lateral hypothalamus. While the exact etiology of NT1 is still unknown, numerous studies have provided compelling evidence supporting its autoimmune origin. The prevailing hypothetical view on the pathogenesis of NT1 involves an immune-mediated loss of HCRT neurons that can be triggered by Pandemrix® vaccination and/or by infection in genetically susceptible patients, specifically carriers of the HLA-DQB1*06:02 MHC class II allele. The molecular mechanisms by which infection/vaccination can induce autoimmunity in the case of NT1 remain to be elucidated. In this review, evidence regarding the involvement of vaccination and infection and the potential mechanisms by which it could be linked to the pathogenesis of NT1 will be discussed in light of the existing findings in other autoimmune diseases.

From tumor to tolerance: A comprehensive review of immune checkpoint inhibitors and immune-related adverse events

The advent of immune checkpoint inhibitors (ICIs) has revolutionized the treatment landscape for various malignancies by harnessing the body's immune system to target cancer cells. However, their widespread use has unveiled a spectrum of immune-related adverse events, highlighting a critical balance between antitumor immunity and autoimmunity. This review article delves into the molecular immunology of ICIs, mapping the journey from their therapeutic action to the unintended induction of immune-related adverse events. We provide a comprehensive overview of all available ICIs, including cytotoxic T-lymphocyte-associated protein 4, programmed cell death protein 1, programmed death-ligand 1 inhibitors, and emerging targets, discussing their mechanisms of action, clinical applications, and the molecular underpinnings of associated immune-related adverse events. Special attention is given to the activation of autoreactive T cells, B cells, cytokine release, and the inflammatory cascade, which together contribute to the development of immune-related adverse events. Through a molecular lens, we explore the clinical manifestations of immune-related adverse events across organ systems, offering insights into diagnosis, management, and strategies to mitigate these adverse effects. The review underscores the importance of understanding the delicate interplay between enhancing antitumor responses and minimizing immune-related adverse events, aiming to guide future research and the development of next-generation ICIs with improved drug safety profiles.

New-onset sarcoidosis in a patient with long COVID

Long COVID, often following SARS-CoV-2 infection, may stem from sustained inflammation, overlapping with autoimmune diseases like sarcoidosis. Though specific treatments lack, this link could shape future diagnostic and therapeutic methods.

Association between heavy metals exposure and persistent infections: the mediating role of immune function

Introduction

Persistent infections caused by certain viruses and parasites have been associated with multiple diseases and substantial mortality. Heavy metals are ubiquitous environmental pollutants with immunosuppressive properties. This study aimed to determine whether heavy metals exposure suppress the immune system, thereby increasing the susceptibility to persistent infections.

Methods

Using data from NHANES 1999-2016, we explored the associations between heavy metals exposure and persistent infections: Cytomegalovirus (CMV), Epstein-Barr Virus (EBV), Hepatitis C Virus (HCV), Herpes Simplex Virus Type-1 (HSV-1), Toxoplasma gondii (T. gondii), and Toxocara canis and Toxocara cati (Toxocara spp.) by performing logistic regression, weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models. Mediation analysis was used to determine the mediating role of host immune function in these associations.

Results

Logistic regression analysis revealed positive associations between multiple heavy metals and the increased risk of persistent infections. In WQS models, the heavy metals mixture was associated with increased risks of several persistent infections: CMV (OR: 1.58; 95% CI: 1.17, 2.14), HCV (OR: 2.94; 95% CI: 1.68, 5.16), HSV-1 (OR: 1.25; 95% CI: 1.11, 1.42), T. gondii (OR: 1.97; 95% CI: 1.41, 2.76), and Toxocara spp. (OR: 1.76; 95% CI: 1.16, 2.66). BKMR models further confirmed the combined effects of heavy metals mixture and also identified the individual effect of arsenic, cadmium, and lead. On mediation analysis, the systemic immune inflammation index, which reflects the host's immune status, mediated 12.14% of the association of mixed heavy metals exposure with HSV-1 infection.

Discussion

The findings of this study revealed that heavy metals exposure may increase susceptibility to persistent infections, with the host's immune status potentially mediating this relationship. Reducing exposure to heavy metals may have preventive implications for persistent infections, and further prospective studies are needed to confirm these findings.

Asymptomatic herpes simplex virus brain infection elicits cellular senescence phenotypes in the central nervous system of mice suffering multiple sclerosis-like disease

Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease affecting the central nervous system (CNS) in animals that parallels several clinical and molecular traits of multiple sclerosis in humans. Herpes simplex virus type 1 (HSV-1) infection mainly causes cold sores and eye diseases, yet eventually, it can also reach the CNS, leading to acute encephalitis. Notably, a significant proportion of healthy individuals are likely to have asymptomatic HSV-1 brain infection with chronic brain inflammation due to persistent latent infection in neurons. Because cellular senescence is suggested as a potential factor contributing to the development of various neurodegenerative disorders, including multiple sclerosis, and viral infections may induce a premature senescence state in the CNS, potentially increasing susceptibility to such disorders, here we examine the presence of senescence-related markers in the brains and spinal cords of mice with asymptomatic HSV-1 brain infection, EAE, and both conditions. Across all scenarios, we find a significant increases of senescence biomarkers in the CNS with some differences depending on the analyzed group. Notably, some senescence biomarkers are exclusively observed in mice with the combined conditions. These results indicate that asymptomatic HSV-1 brain infection and EAE associate with a significant expression of senescence biomarkers in the CNS.

Cellular pathways and molecular events that shape autoantibody production in COVID-19

A hallmark of COVID-19 is the variety of complications that follow SARS-CoV-2 infection in some patients, and that target multiple organs and tissues. Also remarkable are the associations with several auto-inflammatory disorders and the presence of autoantibodies directed to a vast array of antigens. The processes underlying autoantibody production in COVID-19 have not been completed deciphered. Here, we review mechanisms involved in autoantibody production in COVID-19, multisystem inflammatory syndrome in children, and post-acute sequelae of COVID19. We critically discuss how genomic integrity, loss of B cell tolerance to self, superantigen effects of the virus, and extrafollicular B cell activation could underly autoantibody proaction in COVID-19. We also offer models that may account for the pathogenic roles of autoantibodies in the promotion of inflammatory cascades, thromboembolic phenomena, and endothelial and vascular deregulations.

Exploring the impact of acute viral exposure on clinical characteristics and antibody profiles in antiphospholipid syndrome: a study in CAPSTONE

The relationship between antiphospholipid syndrome (APS) and acute viral infection, such as SARS-CoV-2, is unclear. This study aims to assess symptoms, antiphospholipid antibody (aPL) fluctuations, and complication risks in APS patients infected with SARS-CoV-2. APS patients from Peking Union Medical College Hospital during the COVID-19 outbreak (October-December 2022) were included. Age- and gender-matched APS patients without infection served as controls. Data on demographics, symptoms, treatments, and serum aPL levels were analyzed. Of 234 APS patients, 107 (45.7%) were infected with SARS-CoV-2. Typical symptoms included high fever (81.3%), cough/expectoration (70.1%), and pharyngalgia (52.3%). Age- and gender-based matching selected 97 patients in either infected or uninfected group. After infection, anti-β-2-glycoprotein I-IgG (aβ2GP1-IgG) increased from 4.14 to 4.18 AU/ml, aβ2GP1-IgM decreased from 9.85 to 7.38 AU/ml, and anticardiolipin-IgA (aCL-IgA) significantly increased with a median remaining at 2.50 APLU/ml. Lupus anticoagulants and other aPLs remained stable. Arterial thrombosis incidence increased from 18 (18.6%) to 21 (21.6%), while venous thrombosis incidence did not change. Additionally, 7 (6.5%) patients presented either new-onset or worsening thrombocytopenia, characterized by a significant decline in platelet count (no less than 10 × 109/L) within two weeks of SARS-CoV-2 infection, all of which recovered within 2 weeks. Acute SARS-CoV-2 infection may induce or worsen thrombocytopenia but does not substantially increase thrombotic events in APS. The process of SARS-CoV-2 infection was related to mild titer fluctuation of aβ2GP1-IgG, aβ2GP1-IgM and aCL-IgA in APS patients, necessitating careful monitoring and management.

Innate acting memory Th1 cells modulate heterologous diseases

Through immune memory, infections have a lasting effect on the host. While memory cells enable accelerated and enhanced responses upon rechallenge with the same pathogen, their impact on susceptibility to unrelated diseases is unclear. We identify a subset of memory T helper 1 (Th1) cells termed innate acting memory T (TIA) cells that originate from a viral infection and produce IFN-γ with innate kinetics upon heterologous challenge in vivo. Activation of memory TIA cells is induced in response to IL-12 in combination with IL-18 or IL-33 but is TCR independent. Rapid IFN-γ production by memory TIA cells is protective in subsequent heterologous challenge with the bacterial pathogen Legionella pneumophila. In contrast, antigen-independent reactivation of CD4+ memory TIA cells accelerates disease onset in an autoimmune model of multiple sclerosis. Our findings demonstrate that memory Th1 cells can acquire additional TCR-independent functionality to mount rapid, innate-like responses that modulate susceptibility to heterologous challenges.

Identification and Analysis of Biomarkers Associated with Lipophagy and Therapeutic Agents for COVID-19

BACKGROUND

Lipids, as a fundamental cell component, play an regulating role in controlling the different cellular biological processes involved in viral infections. A notable feature of coronavirus disease 2019 (COVID-19) is impaired lipid metabolism. The function of lipophagy-related genes in COVID-19 is unknown. The present study aimed to investigate biomarkers and drug targets associated with lipophagy and lipophagy-based therapeutic agents for COVID-19 through bioinformatics analysis.

METHODS

Lipophagy-related biomarkers for COVID-19 were identified using machine learning algorithms such as random forest, Support Vector Machine-Recursive Feature Elimination, Generalized Linear Model, and Extreme Gradient Boosting in three COVID-19-associated GEO datasets: scRNA-seq (GSE145926) and bulk RNA-seq (GSE183533 and GSE190496). The cMAP database was searched for potential COVID-19 medications.

RESULTS

The lipophagy pathway was downregulated, and the lipid droplet formation pathway was upregulated, resulting in impaired lipid metabolism. Seven lipophagy-related genes, including ACADVL, HYOU1, DAP, AUP1, PRXAB2, LSS, and PLIN2, were used as biomarkers and drug targets for COVID-19. Moreover, lipophagy may play a role in COVID-19 pathogenesis. As prospective drugs for treating COVID-19, seven potential downregulators (phenoxybenzamine, helveticoside, lanatoside C, geldanamycin, loperamide, pioglitazone, and trichostatin A) were discovered. These medication candidates showed remarkable binding energies against the seven biomarkers.

CONCLUSIONS

The lipophagy-related genes ACADVL, HYOU1, DAP, AUP1, PRXAB2, LSS, and PLIN2 can be used as biomarkers and drug targets for COVID-19. Seven potential downregulators of these seven biomarkers may have therapeutic effects for treating COVID-19.

Metabolomics analysis of CEF cells infected with avian leukosis virus subgroup J based on UHPLC-QE-MS

Avian leukosis virus subgroup J (ALV-J) is a retrovirus that can cause immunosuppression and tumors in chicken. However, relative pathogenesis is still not clear. At present, metabolomics has shown great potential in the screening of tumor metabolic markers, prognostic evaluation, and drug target design. In this study, we utilize an untargeted metabolomics approach based on ultrahigh-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS) to analyze the metabolic changes in chicken embryo fibroblast (CEF) cells infected by ALV-J. We found that ALV-J infection significantly altered a wealth of metabolites compared with control group. Additionally, most of the differentially expressed metabolites belonged to lipid metabolism, purine nucleotide metabolism and amino acid metabolism. Among them, the proportion of lipid metabolites account for the highest proportion (around 31%). Results suggest that these changes may be conductive to the formation of virion, thereby promoting the replication of ALV-J. These data provided metabolic evidence and potential biomarkers for the cellular metabolic changes induced by ALV-J, and provided important insight for further understanding the replication needs and pathogenesis of ALV-J.

Single-Cell Sequencing: High-Resolution Analysis of Cellular Heterogeneity in Autoimmune Diseases

Autoimmune diseases (AIDs) are complex in etiology and diverse in classification but clinically show similar symptoms such as joint pain and skin problems. As a result, the diagnosis is challenging, and usually, only broad treatments can be available. Consequently, the clinical responses in patients with different types of AIDs are unsatisfactory. Therefore, it is necessary to conduct more research to figure out the pathogenesis and therapeutic targets of AIDs. This requires research technologies with strong extraction and prediction capabilities. Single-cell sequencing technology analyses the genomic, epigenomic, or transcriptomic information at the single-cell level. It can define different cell types and states in greater detail, further revealing the molecular mechanisms that drive disease progression. These advantages enable cell biology research to achieve an unprecedented resolution and scale, bringing a whole new vision to life science research. In recent years, single-cell technology especially single-cell RNA sequencing (scRNA-seq) has been widely used in various disease research. In this paper, we present the innovations and applications of single-cell sequencing in the medical field and focus on the application contributing to the differential diagnosis and precise treatment of AIDs. Despite some limitations, single-cell sequencing has a wide range of applications in AIDs. We finally present a prospect for the development of single-cell sequencing. These ideas may provide some inspiration for subsequent research.

Autoimmunity against Nucleus Ambiguous Is Putatively Possible in Both Long-COVID-19 and Vaccinated Subjects: Scientific Evidence and Working Hypothesis

As reported by the World Health Organization (WHO), about 10-20% of people have experienced mid- to long-term effects following SARS-CoV-2 infection, collectively referred to as post-COVID-19 condition or long-COVID, including some neurovegetative symptoms. Numerous findings have suggested that the onset of these neurovegetative symptoms upon viral infection may be caused by the production of autoantibodies through molecular mimicry phenomena. Accordingly, we had previously demonstrated that 22 of the human proteins sharing putatively immunogenic peptides with SARS-CoV-2 proteins are expressed in the dorsal motor nucleus and nucleus ambiguous. Therefore, if molecular mimicry occurs following severe forms of COVID-19, there could be transitory or permanent damage in some vagal structures, resulting in a lower vagal tone and all the related clinical signs. We investigated the presence of autoantibodies against two proteins of vagal nuclei sharing a peptide with SARS-CoV-2 spike glycoprotein using an immunoassay test on blood obtained from patients with cardiorespiratory symptoms in patients affected by ongoing symptomatic COVID-19 (long-COVID), subjects vaccinated without a history of SARS-CoV-2 infection, and subjects not vaccinated without a history of SARS-CoV-2 infection. Interestingly, putative autoantibodies were present in both long-COVID-19 and vaccinated groups, opening interesting questions about pathogenic mechanisms of the disease.

Unraveling the intricate dance of the Mediterranean diet and gut microbiota in autoimmune resilience

The nutritional habits regulate the gut microbiota and increase risk of an autoimmune disease. Western diet is rich in sugars, meat, and poly-unsaturated fatty acids, which lead to dysbiosis of intestinal microbiota, disruption of gut epithelial barrier and chronic mucosal inflammation. In contrast, the Mediterranean Diet (MedDiet) is abundant in ω3 fatty acids, fruits, and vegetables, possessing anti-inflammatory properties that contribute to the restoration of gut eubiosis. Numerous studies have extensively examined the impact of MedDiet and its components on both health and various disease states. Additionally, specific investigations have explored the correlation between MedDiet, microbiota, and the risk of autoimmune diseases. Furthermore, the MedDiet has been linked to a reduced risk of cardiovascular diseases, playing a pivotal role in lowering mortality rates among individuals with autoimmune diseases and comorbidities. The aim of the present review is to specifically highlight current knowledge regarding possible interactions of MedDiet with the patterns of intestinal microbiota focusing on autoimmunity and a blueprint through dietary modulations for the prevention and management of disease's activity and progression.

Thyroid tuberculosis and cold abscess after infection with COVID-19: A case report

There is mounting evidence that coronavirus disease 2019 (COVID-19) can cause immune dysregulation. The consequence of this immune dysregulation may contribute to susceptibility to tuberculosis (TB). Thyroid gland involvement by TB is extremely uncommon and typically the result of disseminated infection. It can be hard to diagnose because there are no identifiable symptoms. We present the case of a Chinese patient who had a fever again after COVID-19 infection that was finally diagnosed as thyroid tuberculosis with a cold abscess. Clinicians should maintain a high index of suspicion for high-risk patients from endemic regions with medical comorbidities, such as immunocompromised disease and malnutrition.

Clinical features and outcomes of COVID-19 patients with concomitant herpesvirus co-infection or reactivation: A systematic review

Background

Since the first case of COVID-19 was diagnosed in Wuhan, China in late 2019, concomitant infections with Herpesviridae were documented that were presented from simple skin manifestations to severe life-threatening conditions that may lead to mortality. In this systematic review, we have included studies conducted in different parts of the world to find out the association of clinical features and outcomes of COVID-19 infection and concomitant Herpesviridae infection.

Methods

A comprehensive search was conducted in electronic databases including Medline through PubMed, Cochrane database, Scopus and Web of science (core collection). Two review authors independently screened the articles and extracted data. The Risk of bias assessment was done by using RoBANS tool.

Results

A total of 919 studies were retrieved and 19 studies were included having data of 539 patients who were infected with both COVID-19 and Herpesviridae. Herpes Simplex-1, Varicella Zoster, Cytomegalovirus, Epstein-Barr virus and Human Herpes Virus-6 were the detected viruses in the included studies. Cytomegalovirus (CMV) reactivation was the most detected concomitant infection. In case of reactivation with more than one Herpes virus mortality among patients were detected along with single viral infection in some studies. Significant association was noted in dosage and usage of steroid and Herpesviridae reactivation in COVID-19 patients. Blood markers such as D-dimer, CRP along with length of stay in the ICU and usage of invasive mechanical ventilation were found to be the significantly associated markers.

Conclusion

Findings from this study will aid clinicians to assess and treat COVID-19 cases with co-infections.

Possible temporal relationship between SARS-CoV-2 infection and anti-NMDA receptor encephalitis: a meta-analysis

The global impact of SARS-CoV-2 infection has raised concerns about secondary diseases beyond acute illness. This review explores the significance and potential underlying mechanisms of how SARS-CoV-2 infection might elicit an immune response targeting N-methyl-D-aspartate (NMDA) receptors, and its implications for autoimmune-driven neuropsychiatric manifestations. We identified 19 published case reports of NMDA receptor encephalitis associated with SARS-CoV-2 infection or vaccination by a systematic literature search. The significance of these reports was limited since it is not clear if a coincidental or causal relationship exists between SARS-CoV-2 infection or vaccination and manifestation of NMDA receptor encephalitis. The included studies were hampered by difficulties in establishing if these patients had pre-existing NMDA receptor antibodies which entered the brain by infection- or vaccination-associated transient blood-brain barrier leakage. In addition, four cases had comorbid ovarian teratoma, which is a known trigger for development of NMDA receptor encephalitis. Considering that billions of people have contracted COVID-19 or have been vaccinated against this virus, the publication of only 19 case reports with a possible link to NMDA receptor encephalitis, indicates that it is rare. In conclusion, these findings do not support the case that SARS-CoV-2 infection or vaccination led to an increase of existing or de novo encephalitis mediated by an autoimmune response targeting NMDA receptor function. Nevertheless, this work underscores the importance of ongoing vigilance in monitoring viral outbreaks and their potential impact on the central nervous system through basic, epidemiological and translational research.

Human autoantibodies neutralizing type I IFNs: From 1981 to 2023

Human autoantibodies (auto-Abs) neutralizing type I IFNs were first discovered in a woman with disseminated shingles and were described by Ion Gresser from 1981 to 1984. They have since been found in patients with diverse conditions and are even used as a diagnostic criterion in patients with autoimmune polyendocrinopathy syndrome type 1 (APS-1). However, their apparent lack of association with viral diseases, including shingles, led to wide acceptance of the conclusion that they had no pathological consequences. This perception began to change in 2020, when they were found to underlie about 15% of cases of critical COVID-19 pneumonia. They have since been shown to underlie other severe viral diseases, including 5%, 20%, and 40% of cases of critical influenza pneumonia, critical MERS pneumonia, and West Nile virus encephalitis, respectively. They also seem to be associated with shingles in various settings. These auto-Abs are present in all age groups of the general population, but their frequency increases with age to reach at least 5% in the elderly. We estimate that at least 100 million people worldwide carry auto-Abs neutralizing type I IFNs. Here, we briefly review the history of the study of these auto-Abs, focusing particularly on their known causes and consequences.

Newcastle disease virus activates the PI3K/AKT signaling pathway by targeting PHLPP2 degradation to delay cell apoptosis and promote viral replication

Newcastle disease (ND) is a highly pathogenic, contagious, and fatal infectious disease in poultry caused by the Newcastle disease virus (NDV). The PI3K/AKT signaling pathway is a phosphorylation cascade that participates in regulating several cellular functions. Viruses reportedly regulate the course of infection through the PI3K/AKT axis. Here, we aimed to analyze the pathogenesis of NDV infection mediated by the PI3K/AKT signaling pathway activation. We found that NDV infection can phosphorylate AKT to activate the PI3K/AKT axis both in vitro and in vivo. Flow cytometry and Caspase-3 activity assay showed that NDV infection could inhibit cell apoptosis. The activation or inhibition of the PI3K/AKT signaling pathway activity significantly inhibited or promoted NDV-mediated apoptosis. Furthermore, inhibition of cell apoptosis significantly promoted NDV replication. Overall, our results showed that NDV infection activates the PI3K/AKT signaling pathway and inhibits cell apoptosis, thus promoting viral replication. In this context, the reduced expression of PHLPP2 protein mediated by NDV infection could be inhibited by MG132. PHLPP2 expression reversely and positively regulated NDV replication and cell apoptosis, respectively. These results indicated that NDV infection-mediated activation of the PI3K/AKT signaling pathway and the inhibition of apoptosis depend on the ubiquitin-proteasome degradation of the PHLPP2 protein. Co-IP and indirect immunofluorescence results showed that NDV V protein could interact with PHLPP2 protein, indicating that NDV targeted PHLPP2 protein degradation through V protein to activate the PI3K/AKT signaling pathway. This study deepens our understanding of the molecular mechanisms of NDV infection, providing a theoretical basis for ND prevention and control.

Autoimmune diseases and risk of non-Hodgkin lymphoma: A Mendelian randomisation study

Objective

To examine whether genetically predicted susceptibility to ten autoimmune diseases (Behçet's disease, coeliac disease, dermatitis herpetiformis, lupus, psoriasis, rheumatoid arthritis, sarcoidosis, Sjögren's syndrome, systemic sclerosis, and type 1 diabetes) is associated with risk of non-Hodgkin lymphoma (NHL).

Design

Two sample Mendelian randomization (MR) study.

Setting

Genome wide association studies (GWASs) of ten autoimmune diseases, NHL, and four NHL subtypes (i.e., follicular lymphoma, mature T/natural killer-cell lymphomas, non-follicular lymphoma, and other and unspecified types of NHL).

Analysis

We used data from the largest publicly available GWASs of European ancestry for each autoimmune disease, NHL, and NHL subtypes. For each autoimmune disease, we extracted single nucleotide polymorphisms (SNPs) strongly associated (P < 5×10-8) with that disease and that were independent of one another (R2 < 1×10-3) as genetic instruments. SNPs within the human leukocyte antigen region were not considered due to potential pleiotropy. Our primary MR analysis was the inverse-variance weighted analysis. Additionally, we conducted MR-Egger, weighted mode, and weighted median regression to address potential bias due to pleiotropy, and robust adjusted profile scores to address weak instrument bias. We carried out sensitivity analysis limited to the non-immune pathway for nominally significant findings. To account for multiple testing, we set the thresholds for statistical significance at P < 5×10-3.

Participants

The number of cases and controls identified in the relevant GWASs were 437 and 3,325 for Behçet's disease, 4,918 and 5,684 for coeliac disease, 435 and 341,188 for dermatitis herpetiformis, 4,576 and 8,039 for lupus, 11,988 and 275,335 for psoriasis, 22,350 and 74,823 for rheumatoid arthritis, 3,597 and 337,121 for sarcoidosis, 2,735 and 332,115 for Sjögren's syndrome, 9,095 and 17,584 for systemic sclerosis, 18,942 and 501,638 for type 1 diabetes, 2,400 and 410,350 for NHL; and 296 to 2,340 cases and 271,463 controls for NHL subtypes.

Exposures

Genetic variants predicting ten autoimmune diseases: Behçet's disease, coeliac disease, dermatitis herpetiformis, lupus, psoriasis, rheumatoid arthritis, sarcoidosis, Sjögren's syndrome, systemic sclerosis, and type 1 diabetes.

Main outcome measures

Estimated associations between genetically predicted susceptibility to ten autoimmune diseases and the risk of NHL.

Results

The variance of each autoimmune disease explained by the SNPs ranged from 0.3% to 3.1%. Negative associations between type 1 diabetes and sarcoidosis and the risk of NHL were observed (odds ratio [OR] 0.95, 95% confidence interval [CI]: 0.92 to 0.98, P = 5×10-3, and OR 0.92, 95% CI: 0.85 to 0.99, P = 2.8×10-2, respectively). These findings were supported by the sensitivity analyses accounting for potential pleiotropy and weak instrument bias. No significant associations were found between the other eight autoimmune diseases and NHL risk. Of the NHL subtypes, type 1 diabetes was most strongly associated with follicular lymphoma (OR 0.91, 95% CI: 0.86 to 0.96, P = 1×10-3), while sarcoidosis was most strongly associated with other and unspecified NHL (OR 0.86, 95% CI: 0.75 to 0.97, P = 1.8×10-2).

Conclusions

These findings suggest that genetically predicted susceptibility to type 1 diabetes, and to some extent sarcoidosis, might reduce the risk of NHL. However, future studies with different datasets, approaches, and populations are warranted to further examine the potential associations between these autoimmune diseases and the risk of NHL.

Oncolytic Virotherapy: A New Paradigm in Cancer Immunotherapy

Oncolytic viruses (OVs) are emerging as potential treatment options for cancer. Natural and genetically engineered viruses exhibit various antitumor mechanisms. OVs act by direct cytolysis, the potentiation of the immune system through antigen release, and the activation of inflammatory responses or indirectly by interference with different types of elements in the tumor microenvironment, modification of energy metabolism in tumor cells, and antiangiogenic action. The action of OVs is pleiotropic, and they show varied interactions with the host and tumor cells. An important impediment in oncolytic virotherapy is the journey of the virus into the tumor cells and the possibility of its binding to different biological and nonbiological vectors. OVs have been demonstrated to eliminate cancer cells that are resistant to standard treatments in many clinical trials for various cancers (melanoma, lung, and hepatic); however, there are several elements of resistance to the action of viruses per se. Therefore, it is necessary to evaluate the combination of OVs with other standard treatment modalities, such as chemotherapy, immunotherapy, targeted therapies, and cellular therapies, to increase the response rate. This review provides a comprehensive update on OVs, their use in oncolytic virotherapy, and the future prospects of this therapy alongside the standard therapies currently used in cancer treatment.

Autoimmunity and long COVID in children

Numerous hypotheses regarding the pathogenetic mechanisms of long COVID have been proposed. Immune dysregulation and autoimmunity are among the leading hypotheses. In this article, we present two clinical cases of long COVID. The first case demonstrates the phenotype of long COVID with pain and musculoskeletal symptoms, which is often associated with autoimmunity and mimics systemic connective tissue diseases. In the second case, a high titer of antinuclear antibodies was observed after SARS-CoV-2 infection, but the clinical symptoms were limited to fever and headache. Only a comprehensive evaluation of clinical symptoms and thorough objective examination can confirm or exclude autoimmune diseases after a previous SARS-CoV-2 infection. A systematic search in the PubMed Medline database was carried out for studies focusing on immune dysregulation, autoimmunity, and its association with the clinical phenotype of long COVID. The question of the role of autoimmunity in the development of long COVID and the management approaches are discussed.

Tertiary lymphoid structures in autoimmune diseases

Tertiary lymphoid structures (TLSs) are organized lymphoid-like aggregations in non-lymphoid tissues. Tissues with chronic and persistent inflammation infiltration may drive and form ectopic germinal center-like structures, which are very common in autoimmune diseases, chronic infections, and tumor microenvironments. However, the mechanisms governing the formation of TLSs are still being explored. At present, it is not clear whether the formation of TLSs is associated with local uncontrolled immune inflammatory responses. While TLSs suggest a good prognosis in tumors, the opposite is true in autoimmune diseases. This review article will discuss the current views on initiating and maintaining TLSs and the potential therapeutic target in autoimmune diseases.

CD4+ T-Cell Legumain Deficiency Attenuates Hypertensive Damage via Preservation of TRAF6

BACKGROUND

T cells are central to the immune responses contributing to hypertension. LGMN (legumain) is highly expressed in T cells; however, its role in the pathogenesis of hypertension remains unclear.

METHODS

Peripheral blood samples were collected from patients with hypertension, and cluster of differentiation (CD)4+ T cells were sorted for gene expression and Western blotting analysis. TLGMNKO (T cell-specific LGMN-knockout) mice (Lgmnf/f/CD4Cre), regulatory T cell (Treg)-specific LGMN-knockout mice (Lgmnf/f/Foxp3YFP Cre), and RR-11a (LGMN inhibitor)-treated C57BL/6 mice were infused with Ang II (angiotensin II) or deoxycorticosterone acetate/salt to establish hypertensive animal models. Flow cytometry, 4-dimensional label-free proteomics, coimmunoprecipitation, Treg suppression, and in vivo Treg depletion or adoptive transfer were used to delineate the functional importance of T-cell LGMN in hypertension development.

RESULTS

LGMN mRNA expression was increased in CD4+ T cells isolated from hypertensive patients and mice, was positively correlated with both systolic and diastolic blood pressure, and was negatively correlated with serum IL (interleukin)-10 levels. TLGMNKO mice exhibited reduced Ang II-induced or deoxycorticosterone acetate/salt-induced hypertension and target organ damage relative to wild-type (WT) mice. Genetic and pharmacological inhibition of LGMN blocked Ang II-induced or deoxycorticosterone acetate/salt-induced immunoinhibitory Treg reduction in the kidneys and blood. Anti-CD25 antibody depletion of Tregs abolished the protective effects against Ang II-induced hypertension in TLGMNKO mice, and LGMN deletion in Tregs prevented Ang II-induced hypertension in mice. Mechanistically, endogenous LGMN impaired Treg differentiation and function by directly interacting with and facilitating the degradation of TRAF6 (tumor necrosis factor receptor-associated factor 6) via chaperone-mediated autophagy, thereby inhibiting NF-κB (nuclear factor kappa B) activation. Adoptive transfer of LGMN-deficient Tregs reversed Ang II-induced hypertension, whereas depletion of TRAF6 in LGMN-deficient Tregs blocked the protective effects.

CONCLUSIONS

LGMN deficiency in T cells prevents hypertension and its complications by promoting Treg differentiation and function. Specifically targeting LGMN in Tregs may be an innovative approach for hypertension treatment.

COVID-19 and SLE: Infection and autoimmunity at its best

If one had any doubts before the pandemic regarding the correlation between infections and autoimmunity, COVID-19 left us fascinated on the strong bond between the two entities. The immune and autoimmune reactions seen in patients infected with SARS-CoV-2 have served as a base for this assumption. Later on, the use of immunosuppressants such as systemic glucocorticoids, among other biological agents, turned this assumption to a fact. This was no different when it comes to the vaccines against COVID-19. Through several postulated mechanisms these vaccines, although generally considered safe, are thought to have the potential to result in autoimmune reactions making them not more innocent than the infection itself. When systemic lupus erythematous (SLE) is viewed as a classical autoimmune multisystemic disorder, the connection with SARS-CoV-2 infection and COVID-19 vaccination is of extreme importance. This is because early reports during the pandemic have shown increased rates of SARS-CoV-2 infection among patients known previously to have SLE and much more interestingly, cases of new-onset SLE after COVID-19 have been documented in the literature. Subsequently vaccines against COVID-19, those mRNA-based and adenovirus-vector based, were reported to induce new SLE cases, trigger immune thrombocytopenia or lupus nephritis, two common presentations of SLE, or exacerbate flares. In our paper, we concluded various aspects of available and recent data regarding SLE and COVID-19 as both an infection and vaccination.

A Case of Postcoronavirus Disease 2019 Antineutrophil Cytoplasmic Antibody-associated Vasculitis Successfully Treated with Rituximab

We report a case of a 69-year-old Caucasian male with a history of hypertension, Type 2 diabetes, and Stage IIIa chronic kidney disease (CKD), who presented to the emergency department with positional dizziness, generalized weakness, weight loss, and suppressed appetite. Two months earlier, the patient was diagnosed with coronavirus disease 2019 (COVID-19). The patient had non-oliguric acute kidney injury alongside preexisting CKD. The urinalysis showed hematuria and significant non-nephrotic proteinuria. His serological markers were positive for antineutrophil cytoplasmic antibodies with high titers. A kidney biopsy showed focal crescentic glomerulonephritis of the pauci-immune type. Initially, treatment with immunosuppressive medication was deferred because the biopsy findings suggested a poor renal outcome, as the cortical sample showed tubular atrophy and interstitial fibrosis of more than 50%. The patient was discharged but was later readmitted with worsening renal function, deep venous thrombosis in the lower extremities, and patchy lung consolidation suggesting possible pneumonia, which was ruled out. He required dialysis and brief empiric antibiotics for pneumonia, and anticoagulation for deep venous thrombosis, and was treated with intravenous (IV) pulsed steroids, followed by gradually tapering oral steroids and rituximab induction therapy. He continued dialysis three times a week. Three months after discharge, his renal function improved to near-baseline level, and he no longer required hemodialysis. He continues to be on maintenance IV rituximab therapy and low-dose oral steroids and is followed closely by a rheumatologist. Our case reflects the evolving state of understanding how COVID-19 impacts the immune system, its varying manifestations, and its management.

Effect of serum autoantibodies on the COVID-19 patient's prognosis

Objectives

Virus infection closely associated with autoimmune disease. The study aimed to explore the autoantibody profiles and the correlation of autoantibodies with the disease severity and the prognosis of the coronavirus disease 2019 (COVID-19) patients.

Methods

Three hundred thirty-seven hospitalized COVID-19 patients from 6th to 23rd January 2023 were enrolled. Logistic and Cox regression analyses were used to analyze the risk factors for the patient's disease severity and outcome. The association between Anti-extractable nuclear antigen antibody (ENA) positivity and the prognosis of COVID-19 patients was analyzed using Kaplan-Meier survival curves.

Results

137 of COVID-19 patients were detected positive for antinuclear antibody (ANA), 61 had positive results for ENA, and 38 were positive for ANA and ENA. ANA positivity rate was higher in non-severe illness group (p = 0.032). COVID-19 patients who died during hospitalization had a high rate of ENA positivity than convalescent patients (p = 0.002). Multivariate logistic regression showed that ANA positivity was a protective factor for the disease severity of COVID-19. Multivariate Cox regression analysis revealed that ENA positivity, white blood cells count (WBC), aspartate aminotransferase (AST), Creatinine (CREA), and CRP were independent risk factors for the outcome of COVID-19 patients, and that COVID-19 patients with ENA positivity had a lower cumulative survival rate (p = 0.002).

Conclusion

A spectrum of autoantibodies were expressed in COVID-19 patients, among which ANA and ENA positivity was associated with the severity and prognosis of COVID-19. Therefore, autoantibodies may help to assess the disease severity and prognosis of COVID-19 patients.

Undervalued and novel roles of heterogeneous nuclear ribonucleoproteins in autoimmune diseases: Resurgence as potential biomarkers and targets

Autoimmune diseases are mainly characterized by the abnormal autoreactivity due to the loss of tolerance to specific autoantigens, though multiple pathways associated with the homeostasis of immune responses are involved in initiating or aggravating the conditions. The heterogeneous nuclear ribonucleoproteins (hnRNPs) are a major category of RNA-binding proteins ubiquitously expressed in a multitude of cells and have attracted great attentions especially with their distinctive roles in nucleic acid metabolisms and the pathogenesis in diseases like neurodegenerative disorders and cancers. Nevertheless, the interplay between hnRNPs and autoimmune disorders has not been fully elucidated. Virtually various family members of hnRNPs are increasingly identified as immune players and are pertinent to all kinds of immune-related processes including immune system development and innate or adaptive immune responses. Specifically, hnRNPs have been extensively recognized as autoantigens within and even beyond a myriad of autoimmune diseases, yet their diagnostic and prognostic values are seemingly underestimated. Molecular mimicry, epitope spreading and bystander activation may represent major putative mechanisms underlying the presence of autoantibodies to hnRNPs. Besides, hnRNPs play critical parts in regulating linchpin genes expressions that control genetic susceptibility, disease-linked functional pathways, or immune responses by interacting with other components particularly like microRNAs and long non-coding RNAs, thereby contributing to inflammation and autoimmunity as well as specific disease phenotypes. Therefore, comprehensive unraveling of the roles of hnRNPs is conducive to establishing potential biomarkers and developing better intervention strategies by targeting these hnRNPs in the corresponding disorders. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.

Molecular detection of Epstein-Barr virus among Sudanese patients diagnosed with Hashimoto's thyroiditis

OBJECTIVES

Hashimoto's thyroiditis (HT) is the most common cause of hypothyroidism. The exact mechanism initiating the development of HT is not yet clear. This study aimed to investigate the correlation between HT and the presence of Epstein-Barr virus (EBV) in a Sudanese population.

RESULTS

EBV-LMP1 was detected in 11.1% of HT cases, which is consistent with previous studies. Studies have reported a wide range of frequencies indicating the presence of EBV in HT, and patients with autoimmune thyroiditis have increased titers of anti-EBV antibodies in their sera compared to healthy subjects. Intrathyroidal EBV-infected B cells may be responsible for the increased risk of development of B-cell lymphoma in the thyroid gland in patients with autoimmune thyroiditis. Our study suggests that regular follow-up is necessary for patients diagnosed with HT and are positive for EBV, as antiviral therapy is not applicable due to the risk of thyroid dysfunction. The study suggests an association between EBV and HT, but causation cannot be determined. The study also highlights the need for further research to determine the viral role and correlate it with the severity and progression of HT.

Immune Repertoire Profiling Reveals Its Clinical Application Potential and Triggers for Neuromyelitis Optica Spectrum Disorders

BACKGROUND AND OBJECTIVES

Neuromyelitis optica spectrum disorders (NMOSD) is widely recognized as a CNS demyelinating disease associated with AQP4-IgG (T cell-dependent antibody), and its trigger is still unclear. In addition, although the treatment of NMOSD currently can rely on traditional immunosuppressive and modulating agents, effective methods to predict the efficacy of these therapeutics are lacking.

METHODS

In this study, high-throughput T-cell receptor (TCR) sequencing was performed on peripheral blood from 151 pretreatment patients with AQP4-IgG⁺ NMOSD and 151 healthy individuals. We compared the TCR repertoire of those with NMOSD with that of healthy individuals and identified TCR clones that were significantly enriched in NMOSD. In addition, we treated 28 patients with AQP4-IgG⁺ NMOSD with immunosuppressants and followed up for 6 months to compare changes in NMOSD-specific TCRs (NMOSD-TCRs) before and after treatment. Moreover, we analyzed transcriptome and single-cell B-cell receptor (BCR) data from public databases and performed T-cell activation experiments using antigenic epitopes of cytomegalovirus (CMV) to further explore the triggers of AQP4-IgG⁺ NMOSD.

RESULTS

Compared with healthy controls, patients with AQP4-IgG⁺ NMOSD had significantly reduced diversity and shorter CDR3 length of TCRβ repertoire. Furthermore, we identified 597 NMOSD-TCRs with a high sequence similarity that have the potential to be used in the diagnosis and prognosis of NMOSD. The characterization of NMOSD-TCRs and pathology-associated clonotype annotation indicated that the occurrence of AQP4-IgG⁺ NMOSD may be associated with CMV infection, which was further corroborated by transcriptome and single-cell BCR analysis results from public databases and T-cell activation experiments.

DISCUSSION

Our findings suggest that the occurrence of AQP4-IgG⁺ NMOSD may be associated with CMV infection. In conclusion, our study provides new clues to uncover the causative factors of AQP4-IgG⁺ NMOSD and provides a theoretical foundation for treating and monitoring the disease.

Shared Pathogenicity Features and Sequences between EBV, SARS-CoV-2, and HLA Class I Molecule-binding Motifs with a Potential Role in Autoimmunity

Epstein-Barr virus (EBV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are extraordinary in their ability to activate autoimmunity as well as to induce diverse autoimmune diseases. Here we reviewed the current knowledge on their relation. Further, we suggested that molecular mimicry could be a possible common mechanism of autoimmunity induction in the susceptible individuals infected with SARS-CoV-2. Molecular mimicry between SARS-CoV-2 and human proteins, and EBV and human proteins, are present. Besides, relation of the pathogenicity associated with both coronavirus diseases and EBV supports the notion. As a proof-of-the-concept, we investigated 8mer sequences with shared 5mers of SARS-CoV-2, EBV, and human proteins, which were predicted as epitopes binding to the same human leukocyte antigen (HLA) supertype representatives. We identified significant number of human peptide sequences with predicted-affinities to the HLA-A*02:01 allele. Rest of the peptide sequences had predicted-affinities to the HLA-A*02:01, HLA-B*40:01, HLA-B*27:05, HLA-A*01:01, and HLA-B*39:01 alleles. Carriers of these serotypes can be under a higher risk of autoimmune response induction upon getting infected, through molecular mimicry-based mechanisms common to SARS-CoV-2 and EBV infections. We additionally reviewed established associations of the identified proteins with the EBV-related pathogenicity and with the autoimmune diseases.

COVID-19 infection: a possible induction factor for development of autoimmune diseases?

Following the global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the importance of investigation of the pathogenesis and immunological characteristics of COVID-19 became quite clear. Currently, there are reports indicating that COVID-19 is able to induce autoimmune responses. Abnormal immune reactions are a cornerstone in the pathogenicity of both conditions. Detection of autoantibodies in COVID-19 patients may suggest a link between COVID-19 and autoimmunity. In this study, we focused on the similarities and possible differences between COVID-19 and autoimmune disorders to explore the relationship between them. Comparing the pathogenicity of SARS-CoV-2 infection with autoimmune conditions revealed significant immunological properties of COVID-19 including the presence of several autoantibodies, autoimmunity-related cytokines, and cellular activities that could be useful in future clinical studies aiming at managing this pandemic.

Divergent adaptive immune responses define two types of long COVID

Background

The role of adaptive immune responses in long COVID remains poorly understood, with contrasting hypotheses suggesting either an insufficient antiviral response or an excessive immune response associated with inflammatory damage. To address this issue, we set to characterize humoral and CD4+ T cell responses in long COVID patients prior to SARS-CoV-2 vaccination.

Methods

Long COVID patients who were seropositive (LC+, n=28) or seronegative (LC-, n=23) by spike ELISA assay were recruited based on (i) an initial SARS-CoV-2 infection documented by PCR or the conjunction of three major signs of COVID-19 and (ii) the persistence or resurgence of at least 3 symptoms for over 3 months. They were compared to COVID patients with resolved symptoms (RE, n=29) and uninfected control individuals (HD, n=29).

Results

The spectrum of persistent symptoms proved similar in both long COVID groups, with a trend for a higher number of symptoms in the seronegative group (median=6 vs 4.5; P=0.01). The use a highly sensitive S-flow assay enabled the detection of low levels of SARS-CoV-2 spike-specific IgG in 22.7% of ELISA-seronegative long COVID (LC-) patients. In contrast, spike-specific IgG levels were uniformly high in the LC+ and RE groups. Multiplexed antibody analyses to 30 different viral antigens showed that LC- patients had defective antibody responses to all SARS-CoV-2 proteins tested but had in most cases preserved responses to other viruses. A sensitive primary T cell line assay revealed low but detectable SARS-CoV-2-specific CD4 responses in 39.1% of LC- patients, while response frequencies were high in the LC+ and RE groups. Correlation analyses showed overall strong associations between humoral and cellular responses, with exceptions in the LC- group.

Conclusions

These findings provide evidence for two major types of antiviral immune responses in long COVID. Seropositive patients showed coordinated cellular and humoral responses at least as high as those of recovered patients. In contrast, ELISA-seronegative long COVID patients showed overall low antiviral responses, with detectable specific CD4+ T cells and/or antibodies in close to half of patients (52.2%). These divergent findings in patients sharing a comparable spectrum of persistent symptoms raise the possibility of multiple etiologies in long COVID.

Are the integrin binding motifs within SARS CoV-2 spike protein and MHC class II alleles playing the key role in COVID-19?

The previous studies on the RGD motif (aa403-405) within the SARS CoV-2 spike (S) protein receptor binding domain (RBD) suggest that the RGD motif binding integrin(s) may play an important role in infection of the host cells. We also discussed the possible role of two other integrin binding motifs that are present in S protein: LDI (aa585-587) and ECD (661-663), the motifs used by some other viruses in the course of infection. The MultiFOLD models for protein structure analysis have shown that the ECD motif is clearly accessible in the S protein, whereas the RGD and LDI motifs are partially accessible. Furthermore, the amino acids that are present in Epstein-Barr virus protein (EBV) gp42 playing very important role in binding to the HLA-DRB1 molecule and in the subsequent immune response evasion, are also present in the S protein heptad repeat-2. Our MultiFOLD model analyses have shown that these amino acids are clearly accessible on the surface in each S protein chain as monomers and in the homotrimer complex and bind to HLA-DRB1 β chain. Therefore, they may have the identical role in SARS CoV-2 immune evasion as in EBV infection. The prediction analyses of the MHC class II binding peptides within the S protein have shown that the RGD motif is present in the core 9-mer peptide IRGDEVRQI within the two HLA-DRB1*03:01 and HLA-DRB3*01.01 strong binding 15-mer peptides suggesting that RGD motif may be the potential immune epitope. Accordingly, infected HLA-DRB1*03:01 or HLA-DRB3*01.01 positive individuals may develop high affinity anti-RGD motif antibodies that react with the RGD motif in the host proteins, like fibrinogen, thrombin or von Willebrand factor, affecting haemostasis or participating in autoimmune disorders.

Clinical and Biomarker Profile Responses to Rehabilitation Treatment in Patients with Long COVID Characterized by Chronic Fatigue

Long COVID (LC) syndrome is a complex multiorgan symptom that persists beyond >12 weeks after SARS-CoV-2 infection. The most frequently associated symptom is fatigue. Physical activity and exercise are recommended, although specific studies are lacking. The objectives of the present work are to analyze the impact of a supervised exercise program on the clinical evolution of LC with fatigue patients and to identify whether certain circulating biomarkers could predict the response to rehabilitation. The rehabilitation treatment response was analyzed in 14 women diagnosed with LC and fatigue, based on the changes in the 6 min walk test and Borg/Fatigue Impact scales. Patients who showed improvement in the meters walked were considered "responders" to the therapy. A total of 65% of patients responded to the exercise program, with an improvement in the meters walked and in oxygen saturation, with stability in the percentage of meters walked. Participants with obesity and those double-vaccinated against SARS-CoV-2 presented a lower degree of fatigue. LC patients presented a favorable response to a supervised exercise program. Differences in creatinine and protein levels were observed between rehabilitation therapy "responders" and "nonresponders". A good state of protein nutrition was related to a better rehabilitation response. The results are promising regarding possible predictive biomarkers of rehabilitation response, such as creatinine.

Proteome-wide comparison of tertiary protein structures reveals molecular mimicry in Plasmodium-human interactions

Introduction

Molecular mimicry is a strategy used by parasites to evade the host's immune system and facilitate transmission to a new host. To date, high-throughput examples of molecular mimicry have been limited to comparing protein sequences. However, recent advances in the prediction of tertiary structural models, led by Deepmind's AlphaFold, enable the comparison of thousands of proteins from parasites and their hosts at the structural level, allowing for the identification of more mimics. Here, we present the first proteome-level search for tertiary structure similarity between proteins from Plasmodium falciparum, a malaria-causing parasite, and humans.

Methods

We assembled a database of experimentally-characterized protein tertiary structures (from the Protein Data Bank) and AlphaFold-generated protein tertiary structures from P. falciparum, human, and 15 negative control species, i.e., species not infected by P. falciparum. We aligned human and control structures to the parasite structures using Foldseek.

Results

We identified molecular mimicry in three proteins that have been previously proposed as mediators of Plasmodium-human interactions. By extending this approach to all P. falciparum proteins, we identified an additional 41 potential mimics that are supported by additional experimental data.

Discussion

Our findings demonstrate a valuable application of AlphaFold-derived tertiary structural models, and we discuss key considerations for its effective use in other host-parasite systems.