High unrecognized SARS-CoV-2 exposure of newly admitted and hospitalized psychiatric patients.

BACKGROUND: Patients with pre-existing mental disorders are at higher risk for SARS-CoV-2 infection and adverse outcomes, and severe mental illness, including mood and psychosis spectrum disorders, is associated with increased mortality risk. Despite their increased risk profile, patients with severe mental illness have been understudied during the pandemic, with limited estimates of exposure in inpatient settings. OBJECTIVE: The aim of this study was to describe the SARS-CoV-2 seroprevalence and antibody titers, and pro-inflammatory cytokine concentrations of newly admitted or hospitalized psychiatric inpatients without known history of COVID-19 infection, using robust quantitative multi-antigen assessments, and compare patients' exposure to that of hospital staff. METHODS: This multi-centric, cross-sectional study compared SARS-CoV-2 seroprevalence and titers of 285 patients (University Psychiatric Centre Duffel [UPCD] N = 194; Assistance-Publique-Hopitaux de Paris [AP-HP] N = 91), and 192 hospital caregivers (UPCD N = 130; AP-HP N = 62) at two large psychiatric care facilities between January 1st and the May 30th 2021. Serum levels of SARS-CoV-2 antibodies against Spike proteins (full length), spike subunit 1 (S1), spike subunit 2 (S2), spike subunit 1 receptor binding domain (S1-RBD) and Nucleocapsid proteins were quantitatively determined using an advanced capillary Western Blot technique. To assess the robustness of the between-group seroprevalence differences, we performed sensitivity analyses with stringent cut-offs for seropositivity. We also assessed peripheral concentrations of IL-6, IL-8 and TNF-a using ELLA assays. Secondary analyses included comparisons of SARS-CoV-2 seroprevalence and titers between patient diagnostic subgroups, and between newly admitted (hospitalization ≤ 7 days) and hospitalized patients (hospitalization > 7 days) and correlations between serological and cytokines. RESULTS: Patients had a significantly higher SARS-CoV-2 seroprevalence (67.85 % [95% CI 62.20-73.02]) than hospital caregivers (27.08% [95% CI 21.29-33.77]), and had significantly higher global SARS-CoV-2 titers (F = 29.40, df = 2, p < 0.0001). Moreover, patients had a 2.51-fold (95% CI 1.95-3.20) higher SARS-CoV-2 exposure risk compared to hospital caregivers (Fisher's exact test, P < 0.0001). No difference was found in SARS-CoV-2 seroprevalence and titers between patient subgroups. Patients could be differentiated most accurately from hospital caregivers by their higher Spike protein titers (OR 136.54 [95% CI 43.08-481.98], P < 0.0001), lower S1 (OR 0.06 [95% CI 0.02-0.15], P < 0.0001) titers and higher IL-6 (OR 3.41 [95% CI 1.73-7.24], P < 0.0001) and TNF-α (OR 34.29 [95% CI 5.00-258.87], P < 0.0001) and lower titers of IL-8 (OR 0.13 [95% CI 0.05-0.30], P < 0.0001). Seropositive patients had significantly higher SARS-COV-2 antibody titers compared to seropositive hospital caregivers (F = 19.53, df = 2, P < 0.0001), while titers were not different in seronegative individuals. Pro-inflammatory cytokine concentrations were not associated with serological status. CONCLUSION: Our work demonstrated a very high unrecognized exposure to SARS-CoV-2 among newly admitted and hospitalized psychiatric inpatients, which is cause for concern in the context of highly robust evidence of adverse outcomes following COVID-19 in psychiatric patients. Attention should be directed toward monitoring and mitigating exposure to infectious agents within psychiatric hospitals.

Human endogenous retroviral protein triggers deficit in glutamate synapse maturation and behaviors associated with psychosis.

Mobile genetic elements, such as human endogenous retroviruses (HERVs), produce proteins that regulate brain cell functions and synaptic transmission and have been implicated in the etiology of neurological and neurodevelopmental psychiatric disorders. However, the mechanisms by which these proteins of retroviral origin alter brain cell communication remain poorly understood. Here, we combined single-molecule tracking, calcium imaging, and behavioral approaches to demonstrate that the envelope protein (Env) of HERV type W, which is normally silenced but expressed in patients with neuropsychiatric conditions, alters the N-methyl-d-aspartate receptor (NMDAR)-mediated synaptic organization and plasticity through glia- and cytokine-dependent changes. Env expression in the developing hippocampus was sufficient to induce behavioral impairments at the adult stage that were prevented by Env neutralization or tuning of NMDAR trafficking. Thus, we show that a HERV gene product alters glutamate synapse maturation and generates behavioral deficits, further supporting the possible etiological interplay between genetic, immune, and synaptic factors in psychosis.

Human Endogenous Retroviruses and Type 1 Diabetes.

PURPOSE OF THE REVIEW: The aim of this review is to discuss recent data pointing at an involvement of human endogenous retroviruses (HERVs) in type 1 diabetes (T1D) onset and progression. RECENT FINDINGS: The envelope protein of HERV-W family, named HERV-W-Env, was detected in pancreata from T1D patients and was shown to display pro-inflammatory properties and direct toxicity toward pancreatic beta cells. The etiopathogenesis of T1D remains elusive, even if conventional environmental viral infections have been recurrently involved. Nonetheless, a new category of pathogens may provide the missing link between genetic susceptibility and environmental factors long thought to contribute to T1D onset. A number of studies have now shown that HERV sequences, which are normally inactivated or repressed in the human genome, could be activated by environmental viruses. Thus, if similarly activated by viruses associated with T1D, disregarded HERV genes may underlie T1D genetic susceptibility. Moreover, once expressed, HERV elements may display broad pathogenic properties, which identify them as potential new therapeutic targets.

Molecular characteristics of Human Endogenous Retrovirus type-W in schizophrenia and bipolar disorder.

Epidemiological and genome-wide association studies of severe psychiatric disorders such as schizophrenia (SZ) and bipolar disorder (BD), suggest complex interactions between multiple genetic elements and environmental factors. The involvement of genetic elements such as Human Endogenous Retroviruses type 'W' family (HERV-W) has consistently been associated with SZ. HERV-W envelope gene (env) is activated by environmental factors and encodes a protein displaying inflammation and neurotoxicity. The present study addressed the molecular characteristics of HERV-W env in SZ and BD. Hundred and thirty-six patients, 91 with BD, 45 with SZ and 73 healthy controls (HC) were included. HERV-W env transcription was found to be elevated in BD (P<10-4) and in SZ (P=0.012) as compared with HC, but with higher values in BD than in SZ group (P<0.01). The corresponding DNA copy number was paradoxically lower in the genome of patients with BD (P=0.0016) or SZ (P<0.0003) than in HC. Differences in nucleotide sequence of HERV-W env were found between patients with SZ and BD as compared with HC, as well as between SZ and BD. The molecular characteristics of HERV-W env also differ from what was observed in Multiple Sclerosis (MS) and may represent distinct features of the genome of patients with BD and SZ. The seroprevalence for Toxoplasma gondii yielded low but significant association with HERV-W transcriptional level in a subgroup of BD and SZ, suggesting a potential role in particular patients. A global hypothesis of mechanisms inducing such major psychoses is discussed, placing HERV-W at the crossroads between environmental, genetic and immunological factors. Thus, particular infections would act as activators of HERV-W elements in earliest life, resulting in the production of an HERV-W envelope protein, which then stimulates pro-inflammatory and neurotoxic cascades. This hypothesis needs to be further explored as it may yield major changes in our understanding and treatment of severe psychotic disorders.

Multiple sclerosis-associated retroviral agent (MSRV)-stimulated cytokine production in patients with relapsing-remitting multiple sclerosis.

BACKGROUND: Human endogenous retroviruses are suggested to play a pathogenic role in multiple sclerosis (MS); one of such retroviruses, the MS-associated retroviral agent (MSRV) has repeatedly been isolated in MS patients. OBJECTIVE AND METHODS: We analyzed cytokine profiles in MSRV envelope protein (MSRV ENV-SU)-stimulated peripheral blood mononuclear cells of 30 relapsing-remitting MS patients with either acute (AMS) (n = 13) or stable (SMS) (n = 17) disease. Results suggest that MSRV ENV-SU induces the production of inflammatory cytokines, including tumor necrosis factor-alpha (P < 0.05) and interferon-gamma (P < 0.004) in AMS patients and of interleukin-10 (P < 0.05), an inflammation-dampening cytokine, in SMS individuals. CONCLUSIONS: These data strengthen the hypothesis indicating that MSRV could be involved in the pathogenesis of MS.

Reduced expression of human endogenous retrovirus (HERV)-W GAG protein in the cingulate gyrus and hippocampus in schizophrenia, bipolar disorder, and depression.

The human endogenous retrovirus (HERV)-W multicopy family was identified in human DNA from the previously characterized multiple sclerosis associated retroviral element (MSRV). Upregulation of the HERV-W POL has been reported in cerebrospinal fluid of patients with schizophrenia. The expression of capsid (GAG) protein of HERV-W was studied by immunohistochemistry and western blotting in postmortem brain tissue of the anterior cingulate cortex and hippocampal formation of normal controls and of patients with schizophrenia, bipolar disorder and major depression. A physiological expression of GAG protein was detected in neurons as well as astroglial cells in normal brain both in the anterior cingulate cortex and in the hippocampal formation. There was a statistically significant reduction of this expression in neurons and astroglial cells in brains from individuals with schizophrenia, major depression, and bipolar disorder. The results from the present study confirm that GAG protein encoded by the HERV-W multicopy gene family is expressed in cells of the central nervous system under normal conditions. Our findings of a cell type-, brain region- and disease-specific reduced expression in schizophrenia, major depression, and bipolar disorder are compatible with a pathophysiological role of HERVs in human brain disorders. The causes and biological consequences of this differential regulation will be the subject of further investigations.

Multiple sclerosis-associated retrovirus particles cause T lymphocyte-dependent death with brain hemorrhage in humanized SCID mice model.

A retroviral element (multiple sclerosis-associated retrovirus, MSRV) defining a family of genetically inherited endogenous retroviruses (human endogenous retrovirus type W, HERV-W) has been characterized in cell cultures from patients with multiple sclerosis. Recently, MSRV retroviral particles or the envelope recombinant protein were shown to display superantigen activity in vitro, but no animal model has yet been set up for studying the pathogenicity of this retrovirus. In the present study, the pathogenicity of different sources of MSRV retroviral particles has been evaluated in a hybrid animal model: severe combined immunodeficiency (SCID) mice grafted with human lymphocytes and injected intraperitoneally with MSRV virion or mock controls. MSRV-injected mice presented with acute neurological symptoms and died within 5 to 10 days post injection. Necropsy revealed disseminated and major brain hemorrhages, whereas control animals did not show abnormalities (P <.001). In ill animals, reverse transcriptase-polymerase chain reaction (RT-PCR) analyses showed circulating MSRV RNA in serum, whereas overexpression of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma was evidenced in spleen RNA. Neuropathological examination confirmed that hemorrhages occurred prior to death in multifocal areas of brain parenchyma and meninges. Further series addressed the question of immune-mediated pathogenicity, by inoculating virion to SCID mice grafted with total and T lymphocyte-depleted cells in parallel: dramatic and statistically significant reduction in the number of affected mice was observed in T-depleted series (P <.001). This in vivo study suggests that MSRV retroviral particles from MS cultures have potent immunopathogenic properties mediated by T cells compatible with the previously reported superantigen activity in vitro, which appear to be mediated by an overexpression of proinflammatory cytokines.

Multiple sclerosis retrovirus particles and recombinant envelope trigger an abnormal immune response in vitro, by inducing polyclonal Vbeta16 T-lymphocyte activation.

A retroviral element (MSRV) defining a family of genetically inherited endogenous retroviruses (HERV-W) has recently been characterized in cell cultures from patients with multiple sclerosis (MS). To address the possible relationship with MS, direct detection of circulating virion RNA was proposed but revealed technically difficult to perform in standardized conditions, in the face of multiple endogenous HERV-W copies. A parallel approach has evaluated MSRV potential pathogenicity in relation to characteristic features of multiple sclerosis, in particular, T-lymphocyte-mediated immunopathology. We report here that MSRV particles induce T-lymphocyte response with a bias in the Vbeta16 chain usage in surface receptor, whatever the HLA DR of the donor. A recombinant MSRV envelope-but not core-protein reproduced similar nonconventional activation. Molecular analysis of Vbeta CDR3 showed that Vbeta16 expansions are polyclonal. Our results thus provide evidence that MSRV envelope protein can trigger an abnormal immune response with similar characteristics to that of superantigens.

Glial toxicity in urine and multiple sclerosis.

The biochemical and biological characterization of a cytotoxic activity targeting macroglial cells (oligodendrocytes and astrocytes), in moncyte cultures and in CSF of a patient with multiple sclerosis, has previously been described. In further studies, cell-based tests have shown a good correlation between this glial cytotoxic (gliotoxic) activity, in CSF or in urine, and MS. We now present results obtained with urine samples from 102 MS patients, 51 patients with other neurological disease and 35 healthy subjects using a bioassay set up for the detection of an apoptosis-like effect induced in a glial cell-line. Significant gliotoxicity was detected in urine from 74/102 MS patients while only 4/51 neurological controls (P>0.001) and never in healthy subjects (P>0.001). Given the statistical tendency provided by this bioassay and its technical limitations for routine testing, it is now used for monitoring the molecular characterization of this 'gliotoxic factor'. Its replacement by a specific immunoassay could provide more accurate routine techniques for the detection of this biological marker in MS.

Infrequency of detection of particle-associated MSRV/HERV-W RNA in the synovial fluid of patients with rheumatoid arthritis.

OBJECTIVES: To determine whether the recently identified multiple sclerosis-associated retrovirus, MSRV, is detectable in the serum and synovial fluid of patients with rheumatoid arthritis (RA). METHODS: A reverse transcription-polymerase chain reaction (RT-PCR) assay was used to seek evidence of particle-associated MSRV/HERV-W RNA in the plasma and synovial fluid of patients with RA and controls. Stringent precautions were taken to avoid detection of contaminating human genomic DNA and cellular RNA sequences. RESULTS: Thirty-seven plasma samples were tested (20 from RA patients and 17 from controls) but none had detectable MSRV/HERV-W RNA. Synovial fluid samples were available from nine patients with RA and 10 controls. Particle-associated MSRV/HERV-W RNA was reproducibly detected in two of nine synovial fluid samples from RA patients and in one control sample. The identity of RT-PCR products was confirmed by sequencing. CONCLUSION: MSRV/HERV-W RNA sequences are detectable in the synovial fluid of a small proportion of RA patients, but this phenomenon may not be specific to RA.

Particle-associated retroviral RNA and tandem RGH/HERV-W copies on human chromosome 7q: possible components of a 'chain-reaction' triggered by infectious agents in multiple sclerosis?

Different groups have observed retrovirus particle (RVP) production in cell cultures from patients with multiple sclerosis (MS). This in vitro production appeared relatively specific for MS versus healthy controls, but was likely to be enhanced or activated by infectious triggers such as Herpesviruses (e.g. HSV, EBV). Independent molecular analysis of retroviral RNA associated with RVP revealed two different genetic families of endogenous retroviral elements (HERV): MSRV/HERV-W and RGH/HERV-H. Interestingly, these sequences were detected by mutually exclusive primers in RT - PCR amplifications. Surprisingly, these two HERV families both contain an ancestral proviral copy inserted in chromosome 7q21-22 region at about 1 kb of distance of each other. Another HERV-W proviral sequence is located within a T-cell alpha-delta receptor (TCR) gene in chromosome 14q11.2 region. Interestingly, these two regions correspond to genetic loci previously identified as potentially associated with 'multigenic' susceptibility to MS and TCR alpha chain genetic determinants have been reported to be statistically associated with MS. A plausible role for infectious agents triggering a co-activation of the chromosome 7q HERV tandem (replicative retrovirus and/or other virus and/or intracellular bacteria) and, eventually, other HERV copies, is discussed. The role of particular HERV polymorphism and the production of pathogenic molecules (gliotoxin and superantigen) possibly associated with retroviral expression are also evoked. An integrative concept of pathogenic 'chain-reaction' in MS involving several step-specific pathogenic 'agents' and 'products' somewhat interacting with particular genetic elements would federate most partial data obtained on MS, including retroviral expression.

Phylogeny of a novel family of human endogenous retrovirus sequences, HERV-W, in humans and other primates.

A novel human endogenous retrovirus, HERV-W, has been characterized on the basis of multiple sclerosis-associated retrovirus (MSRV) probes. We have analyzed the phylogenetic distribution of HERV-W in humans and other primate species. As HERV-W presents a C/D chimeric nature and is largely composed of deleted elements, Southern blots were performed using gag, pol, env, and LTR probes. The relative complexities observed for gag, pol, env, and LTR regions were similar in humans, apes, and Old World monkeys, the minimal number of bands observed after Southern blot analysis being 25, 50, 10, and at least 100, respectively. The HERV-W family entered the genome of catarrhines more than 25 million years ago.

Human retroviral sequences associated with extracellular particles in autoimmune diseases: epiphenomenon or possible role in aetiopathogenesis?

Publications describing retroviral sequences associated with extracellular particles in Sjögren's syndrome or systemic lupus erythematosus, multiple sclerosis, and type I diabetes present novel arguments and raise complex questions about eventual relationships between retroviruses and autoimmunity. They are presented and discussed in the present review, preceded by an overview of the biology of retroviral elements.

Specificities of multiple sclerosis cerebrospinal fluid and serum antibodies against mimotopes.

In order to characterize antigenic epitopes specifically targeted by the immune response of patients with multiple sclerosis (MS), the antibody specificities of cerebrospinal fluids (CSF) and sera from the same MS patients have been analyzed using a random pentadecapeptide library displayed on phage. The 3 peptides (mimotopes) selected with MS sera were not disease-specific. In contrast, the combination of 4 MS CSF selected mimotopes, allowed the detection of specific antibodies in 21 of 60 MS CSF whereas only 2 of 27 CSF from patients with other neurological diseases equally recognized the 4 mimotopes. Some amino acid similarities were found between two MS CSF selected mimotopes and two envelope regions (319-329 and 433-443, respectively) of MSRV (multiple-sclerosis-associated retrovirus) and the related endogenous retrovirus HERV-W.

Molecular cloning and characterization of MSRV-related sequences associated with retrovirus-like particles.

New sequences have been obtained by successive overlapping RT-PCR extensions from the pol region of a retroviral RNA (multiple sclerosis-associated retroviral element, MSRV) amplified in retrovirus-like particles from patients with multiple sclerosis. gag and pol sequences are related to type C oncoviruses, whereas the env sequence is closer to type D. A tryptophan-like (W) tRNA primer-binding site was identified downstream of the RU5 region in the 5'LTR, and the U3R region cloned in the 3'LTR exhibited potent promoter activity. MSRV clones define a novel family of endogenous elements, HERV-W. From our data, HERV-W RNAs are copackaged in extracellular particles which might be produced by replication-competent or transcomplemented HERV-W copies or by an exogenous member of the HERV-W family.

Molecular characterization and placental expression of HERV-W, a new human endogenous retrovirus family.

The multiple sclerosis-associated retrovirus (MSRV) isolated from plasma of MS patients was found to be phylogenetically and experimentally related to human endogenous retroviruses (HERVs). To characterize the MSRV-related HERV family and to test the hypothesis of a replication-competent HERV, we have investigated the expression of MSRV-related sequences in healthy tissues. The expression of MSRV-related transcripts restricted to the placenta led to the isolation of overlapping cDNA clones from a cDNA library. These cDNAs spanned a 7.6-kb region containing gag, pol, and env genes; RU5 and U3R flanking sequences; a polypurine tract; and a primer binding site (PBS). As this PBS showed similarity to avian retrovirus PBSs used by tRNATrp, this new HERV family was named HERV-W. Several genomic elements were identified, one of them containing a complete HERV-W unit, spanning all cDNA clones. Elements of this multicopy family were not replication competent, as gag and pol open reading frames (ORFs) were interrupted by frameshifts and stop codons. A complete ORF putatively coding for an envelope protein was found both on the HERV-W DNA prototype and within an RU5-env-U3R polyadenylated cDNA clone. Placental expression of 8-, 3.1-, and 1.3-kb transcripts was observed, and a putative splicing strategy was described. The apparently tissue-restricted HERV-W long terminal repeat expression is discussed with respect to physiological and pathological contexts.

[MSRV retrovirus and gliotoxin protein: potential biological markers in multiple sclerosis?]. / Rétrovirus MSRV et protéine gliotoxique: marqueurs biologiques potentiels dans la sclérose en plaques?

The aetiopathogeny of multiple sclerosis, a neurological disease which prevalence and duration generate an important problem of public health in industrialized countries where it is most frequent, is not clearly understood. The keys for the diagnosis and therapeutic strategies of MS are nonetheless dependent upon the identification of a well-defined aetiology and upon the understanding of the mechanisms and pathogenic connexions which lead to the demyelinating lesions of the central nervous system and to the dysfunctions of the immune system (autoimmunity) characteristic for the disease. The recent identification of a retroviral agent (MSRV) which produces extracellular particles detectable in the plasma, the CSF, and in some cell cultures from patients with MS, as well as of a cytotoxic factor targeting glial cells (gliotoxin) detected in parallel, could help elucidating the aetiopathogeny of MS. The usefulness of biological markers and targets derived from MSRV retrovirus and this gliotoxin, in the diagnostic and therapeutic perspectives for MS, is discussed in the light of the different aetiopathogenic hypotheses for the disease. From our results it is conceivable that a retroviral agent and pathogenic molecules such as this gliotoxin and an eventual MSRV-associated retroviral superantigen might initiate and perpetuate the cascade of events leading to MS. However, similar data on different simple retroviruses were recently published concerning autoimmune diseases such as diabetes type 1, Sjögren's syndrome and systemic lupus erythematosis, which could prefigurate a broader concept for the role of such retroviruses in the aetiopathogenesis of autoimmune diseases.

Case report: DNA fragmentation in glial cells in a cerebral biopsy from a multiple sclerosis patient.

Multiple sclerosis is characterized by myelin destruction and oligodendrocyte loss. The neuropathological hallmark of the disease is the presence of demyelinated plaques in the central nervous system. We have recently found a gliotoxic factor in MS cerebrospinal fluid which induces programmed cell death in vitro, in glial cells. Here we show DNA fragmentation and glial cell death in biopsy samples, obtained from a patient who underwent surgery with suspicion of tumor, and whose disease record, including brain autopsy, demonstrated an active multiple sclerosis. We used the in situ TUNEL technique, a method which sensitively detects the DNA fragmentation accompanying programmed cell death in tissue sections, and compatible with classical fixation techniques. We found intense DNA fragmentation in nuclei of glial cells at-or very near-to the site of demyelination. A double labeling technique showed that glial fibrillary associated protein positive astrocytes may undergo programmed cell death in multiple sclerosis.