Lupus autoantibodies target ribosomal P proteins

RPLP1 restricts HIV-1 transcription by disrupting C/EBPβ binding to the LTR

Long-term non-progressors (LTNPs) of HIV-1 infection may provide important insights into mechanisms involved in viral control and pathogenesis. Here, our results suggest that the ribosomal protein lateral stalk subunit P1 (RPLP1) is expressed at higher levels in LTNPs compared to regular progressors (RPs). Functionally, RPLP1 inhibits transcription of clade B HIV-1 strains by occupying the C/EBPβ binding sites in the viral long terminal repeat (LTR). This interaction requires the α-helixes 2 and 4 domains of RPLP1 and is evaded by HIV-1 group M subtype C and group N, O and P strains that do not require C/EBPβ for transcription. We further demonstrate that HIV-1-induced translocation of RPLP1 from the cytoplasm to the nucleus is essential for antiviral activity. Finally, knock-down of RPLP1 promotes reactivation of latent HIV-1 proviruses. Thus, RPLP1 may play a role in the maintenance of HIV-1 latency and resistance to RPLP1 restriction may contribute to the effective spread of clade C HIV-1 strains.

CD72 is an inhibitory pattern recognition receptor that recognizes ribosomes and suppresses production of anti-ribosome autoantibody

B cell responses to nucleic acid-containing self-antigens that involve intracellular nucleic acid sensors play a crucial role in autoantibody production in SLE. CD72 is an inhibitory B cell co-receptor that down-regulates BCR signaling, and prevents the development of SLE. We previously showed that CD72 recognizes the RNA-containing self-antigen Sm/RNP, a target of SLE-specific autoantibodies, and induces B cell tolerance to Sm/RNP by specifically inhibiting B cell response to this self-antigen. Here, we address whether CD72 inhibits B cell response to ribosomes because the ribosome is an RNA-containing self-antigen and is a target of SLE-specific autoantibodies as well as Sm/RNP. We demonstrate that CD72 recognizes ribosomes as a ligand, and specifically inhibits BCR signaling induced by ribosomes. Although conventional protein antigens by themselves do not induce proliferation of specific B cells, ribosomes induce proliferation of B cells reactive to ribosomes in a manner dependent on RNA. This proliferative response is down-regulated by CD72. These results suggest that ribosomes activate B cells by inducing dual signaling through BCR and intracellular RNA sensors and that CD72 inhibits B cell response to ribosomes. Moreover, CD72-/- but not CD72+/+ mice spontaneously produce anti-ribosome autoantibodies. Taken together, CD72 induces B cell self-tolerance to ribosomes by recognizing ribosomes and inhibiting RNA-dependent B cell response to this self-antigen. CD72 appears to prevent development of SLE by inhibiting autoimmune B cell responses to multiple RNA-containing self-antigens. Because these self-antigens but not protein self-antigens induce RNA-dependent B cell activation, self-tolerance to RNA-containing self-antigens may require a distinct tolerance mechanism mediated by CD72.

Pathogenetic associations of anti-ribosomal P protein antibody titres and their subclasses in patients with systemic lupus erythematosus

OBJECTIVES

We evaluated the association between anti-ribosomal P antibody (anti-RibP) titres and disease activity in Japanese SLE patients.

METHODS

Eighty patients admitted and treated in Niigata University Hospital for new-onset or flare-up of SLE were included in this retrospective cross-sectional study. Clinical data were obtained from medical records at admission. The anti-RibP index, and cytokine and tryptophan metabolite levels were determined by ELISA.

RESULTS

Of the 80 SLE patients, 30 had anti-RibP. Anti-RibP presence was associated with a greater prevalence of skin rash and more severe inflammatory responses, demonstrated by higher inflammatory cytokine levels, hypocomplementemia, and accelerated tryptophan metabolism, in younger patients. The serum anti-RibP index was correlated with age at diagnosis, clinical indicators, initial prednisolone dose, and cytokines and tryptophan metabolite levels in univariate analysis. Multivariate analysis showed that the anti-RibP index was independently associated with the initial prednisolone dose and the prevalence of skin rash. The anti-RibP IgGs were mainly the IgG2 and IgG3 subclasses, and anti-RibP IgG3 was associated with hypocomplementemia, higher DAS, accelerated kynurenine pathway activity, and higher proinflammatory cytokine production. The coexistence of anti-dsDNA IgG and anti-RibP IgG2 or IgG3 accompanied higher IL-10 and IFN-α2 levels; furthermore, anti-RibP IgG3 coexistence with anti-dsDNA antibody contributed to the requirement for higher initial prednisolone doses and accelerated kynurenine pathway activity.

CONCLUSION

Anti-RibP was associated with clinical manifestations and parameters in SLE, and its index might be a useful indicator of disease severity. Anti-RibP IgG3 was the IgG subclass most strongly associated with the pathogenesis of SLE.

Identification of a novel alternatively spliced isoform of the ribosomal uL10 protein

Alternative splicing is one of the key mechanisms extending the complexity of genetic information and at the same time adaptability of higher eukaryotes. As a result, the broad spectrum of isoforms produced by alternative splicing allows organisms to fine-tune their proteome; however, the functions of the majority of alternatively spliced protein isoforms are largely unknown. Ribosomal protein isoforms are one of the groups for which data are limited. Here we report characterization of an alternatively spliced isoform of the ribosomal uL10 protein, named uL10β. The uL10 protein constitutes the core element of the ribosomal stalk structure within the GTPase associated center, which represents the landing platform for translational GTPases - trGTPases. The stalk plays an important role in the ribosome-dependent stimulation of GTP by trGTPases, which confer unidirectional trajectory for the ribosome, allosterically contributing to the speed and accuracy of translation. We have shown that the newly identified uL10β protein is stably expressed in mammalian cells and is primarily located within the nuclear compartment with a minor signal within the cytoplasm. Importantly, uL10β is able to bind to the ribosomal particle, but is mainly associated with 60S and 80S particles; additionally, the uL10β undergoes re-localization into the mitochondria upon endoplasmic reticulum stress induction. Our results suggest a specific stress-related dual role of uL10β, supporting the idea of existence of specialized ribosomes with an altered GTPase associated center.

Autoantibodies in Neuropsychiatric Systemic Lupus Erythematosus (NPSLE): Can They Be Used as Biomarkers for the Differential Diagnosis of This Disease?

Systemic lupus erythematosus is a complex immunological disease where both environmental factors and genetic predisposition lead to the dysregulation of important immune mechanisms. Eventually, the combination of these factors leads to the production of self-reactive antibodies that can target any organ or tissue of the human body. Autoantibodies can form immune complexes responsible for both the organ damage and the most severe complications. Involvement of the central nervous system defines a subcategory of the disease, generally known with the denomination of neuropsychiatric systemic lupus erythematosus. Neuropsychiatric symptoms can range from relatively mild manifestations, such as headache, to more severe complications, such as psychosis. The evaluation of the presence of the autoantibodies in the serum of these patients is the most helpful diagnostic tool for the assessment of the disease. The scientific progresses achieved in the last decades helped researchers and physicians to discover some of autoepitopes targeted by the autoantibodies, although the majority of them have not been identified yet. Additionally, the central nervous system is full of epitopes that cannot be found elsewhere in the human body, for this reason, autoantibodies that selectively target these epitopes might be used for the differential diagnosis between patients with and without the neuropsychiatric symptoms. In this review, the most relevant data is reported with regard to mechanisms implicated in the production of autoantibodies and the most important autoantibodies found among patients with systemic lupus erythematosus with and without the neuropsychiatric manifestations.

Neuropsychiatric lupus erythematosus: Focusing on autoantibodies

Patients with systemic lupus erythematosus (SLE) frequently suffer from nervous system complications, termed neuropsychiatric lupus erythematosus (NPLE). NPLE accounts for the poor prognosis of SLE. Correct attribution of NP events to SLE is the primary principle in managing NPLE. The vascular injuries and neuroinflammation are the fundamental neuropathologic changes in NPLE. Specific autoantibody-mediated central nerve system (CNS) damages distinguish NPLE from other CNS disorders. Though the central antibodies in NPLE are generally thought to be raised from the periphery immune system, they may be produced in the meninges and choroid plexus. On this basis, abnormal activation of microglia and disease-associated microglia (DAM) should be the common mechanisms of NPLE and other CNS disturbances. Improved understanding of both characteristic and sharing features of NPLE might yield further options for managing this disease.

Disease criteria of systemic lupus erythematosus (SLE); the potential role of non-criteria autoantibodies

Patients with SLE show a broad spectrum of more than 200 autoantibodies. They can be pathogenic, predictive, prognostic or even an epiphenomenon. Here, we discuss different autoantibodies that have not been included in EULAR/ACR 2019 classification criteria. Most of them have been addressed to monitor and detect disease activity and not specifically as classification criteria. Indeed, markers to assess disease activity fluctuate as compared with classification criteria and their validation is different. The development of new methods will probably bring new clinical associations and be evaluated as potential classification criteria.

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Most of the autoantibodies described in SLE are of utility in monitoring disease activity.

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The validation of activity biomarkers is different from classification criteria biomarkers.

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The new methods coming into the clinical routine will bring new associations and potentially classification criteria.

Properties of Uncommon Indirect Immunofluorescence Staining Patterns Determined during Antinuclear Antibody Detection on HEp-2 Cells

In this study, we aimed to assess the prevalence of uncommon staining patterns found during testing for the presence of antinuclear antibodies (ANA) and to determine their association with certain antibodies and clinical diagnoses. Presence of ANA and the staining pattern was determined in 10955 samples using indirect immunofluorescence (IIF) on HEp-2 cells. ANA-positive samples were assessed for presence of 14 specific antibody types using a microbead based system. Demographic data (age, sex) and clinical diagnoses were collected from the referral documentation. Particular staining patterns were then compared with a representative comparison group comprised of samples with common staining patterns using these criteria. There were 22 patterns present in less than 3% of samples each and these were jointly present in 42.43% of ANA-positive samples. Specific antibodies were found in proportions similar to the comparison group (46.06%) and varied significantly between patterns. Likewise, there were significant differences in antibody distribution in particular patterns. Some patterns were associated with presence of rheumatic diseases or inflammatory arthropathies, while in others there was a concurrent diagnosis of liver disease, or a neoplastic process. Many of the uncommon IIF patterns have distinctive characteristics that warrant further investigation in order to determine their role in diagnosing various diseases, not limited only to the illnesses of the rheumatic spectrum. IIF on HEp-2 cells remains an irreplaceable method because of the diversity of ANA, only a number of which can be detected using other standardised methods.

Hydroxychloroquine alleviates the neurotoxicity induced by anti-ribosomal P antibodies

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a wide spectrum of autoantibodies, among which anti-ribosomal P (anti-P) antibodies are considered to be closely related to the neuropsychiatric SLE (NPSLE). Hydroxychloroquine (HCQ) has been proven to be effective against a variety of autoimmune diseases and is an essential drug for the treatment of SLE. In this study, we investigated the effects of anti-ribosomal P (anti-P) antibodies on neural cells and determined whether hydroxychloroquine (HCQ) influenced the anti-P antibodies-induced changes. The results showed that the binding of anti-P antibodies with mouse neuroblastoma- 2a (N2a) cells and rat primary neurons resulted in elevated intracellular calcium levels, inducing decreased cell viability and cell apoptosis. These inhibitory effects were alleviated by HCQ in a concentration-dependent manner by reducing the intracellular calcium levels and modulating the expression of apoptotic proteins. In summary, our study demonstrates that anti-P antibodies induce neural cell damage. HCQ could ease the damage effects and may play a neuroprotective role in NPSLE.

Association of Antiribosomal P Antibody with Neurological and Systemic Manifestations in Patients with Systemic Lupus Erythematosus in Southwestern Colombia

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by heterogeneous pathogenesis, various clinical manifestations, and a broad spectrum of autoantibodies which recognize different cellular components. This study examines the clinical significance and serological associations of serum antiribosomal P antibodies (anti-P) derived from SLE patients in a population from southwestern Colombia.

METHODS

We performed a cross-sectional study of 66 SLE patients. Serum antiribosomal P0 autoantibodies were detected by line immunoassay using the ANA-LIA MAXX kit and processed on the automated HumaBlot 44FA system (Human Diagnostics, Germany).

RESULTS

Of the 66 SLE patients included in the study, 17 patients (25.76%) showed anti-P positivity by line immunoassay (IA), 47 (71.21%) were negative, and results from 2 patients were indeterminate. We did not find an association with neuropsychiatric SLE (NPSLE), renal, or hepatic disorders (P > 0.05). Laboratory findings indicated that anti-P positivity was significantly associated to anti-Smith (P = 0.001), anti-Ro60/SSA (P = 0.046), and anti-dsDNA antibodies (P = 0.034), the latter being true only when performed using indirect immunofluorescence (IIF).

CONCLUSION

The anti-P antibodies are not associated with clinical manifestations such as NPSLE, lupus nephritis, or hepatic involvement in the southwest Colombian SLE population. Moreover, we confirmed previously reported association between anti-P antibody, serum anti-dsDNA, and anti-Smith.

Immune Response to Enterococcus gallinarum in Lupus Patients Is Associated With a Subset of Lupus-Associated Autoantibodies

Interactions between gut microbes and the immune system influence autoimmune disorders like systemic lupus erythematosus (SLE). Recently, Enterococcus gallinarum, a gram-positive commensal gut bacterium, was implicated as a candidate pathobiont in SLE. The present study was undertaken to evaluate the influence of E. gallinarum exposure on clinical parameters of SLE. Since circulating IgG antibodies to whole bacteria have been established as a surrogate marker for bacterial exposure, anti-E. gallinarum IgG antibodies were measured in banked serum samples from SLE patients and healthy controls in the Oklahoma Cohort for Rheumatic Diseases. The associations between anti-E. gallinarum antibody titers and clinical indicators of lupus were studied. Antibodies to human RNA were studied in a subset of patients. Our results show that sera from both patients and healthy controls had IgG and IgA antibodies reactive with E. gallinarum. The antibody titers between the two groups were not different. However, SLE patients with Ribosomal P autoantibodies had higher anti-E. gallinarum IgG titers compared to healthy controls. In addition to anti-Ribosomal P, higher anti-E. gallinarum titers were also significantly associated with the presence of anti-dsDNA and anti-Sm autoantibodies. In the subset of patients with anti-Ribosomal P and anti-dsDNA, the anti-E. gallinarum titers correlated significantly with antibodies to human RNA. Our data show that both healthy individuals and SLE patients were sero-reactive to E. gallinarum. In SLE patients, the immune response to E. gallinarum was associated with antibody response to a specific subset of lupus autoantigens. These findings provide additional evidence that E. gallinarum may be a pathobiont for SLE in susceptible individuals.

Cognitive Impairment in SLE: Mechanisms and Therapeutic Approaches

A wide range of patients with systemic lupus erythematosus (SLE) suffer from cognitive dysfunction (CD) which severely impacts their quality of life. However, CD remains underdiagnosed and poorly understood. Here, we discuss current findings in patients and in animal models. Strong evidence suggests that CD pathogenesis involves known mechanisms of tissue injury in SLE. These mechanisms recruit brain resident cells, in particular microglia, into the pathological process. While systemic immune activation is critical to central nervous system injury, the current focus of therapy is the microglial cell and not the systemic immune perturbation. Further studies are critical to examine additional potential therapeutic targets and more specific treatments based on the cause and progress of the disease.

Association of coexisting anti-ribosomal P and anti-dsDNA antibodies with histology and renal prognosis in lupus nephritis patients

OBJECTIVES

Anti-ribosomal P protein autoantibodies (anti-P) specifically develop in patients with systemic lupus erythematosus. Associations of anti-P with lupus nephritis (LN) histological subclass and renal outcome remain inconclusive. We sought to determine the association of anti-P and anti-double-stranded DNA antibody (anti-dsDNA) with renal histology and prognosis in LN patients.

METHODS

Thirty-four patients with LN, having undergone kidney biopsy, were included. The 2018 revised ISN/RPS classification system was used for pathophysiological evaluation. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate < 60 mL/min/1.73 m² for > 3 months.

RESULTS

Six patients (17.6%) were positive for anti-P and 26 (76.5%) for anti-dsDNA. Among the six patients with anti-P, one did not have anti-dsDNA, but did have anti-Sm antibody, and showed a histological subtype of class V. This patient maintained good renal function for over 14 years. The remaining five patients, who had both anti-P and anti-dsDNA, exhibited proliferative nephritis and were associated with prolonged hypocomplementemia, and the incidence of CKD did not differ from patients without anti-P.

CONCLUSION

Although this study included a small number of patients, the results indicated that histology class and renal prognosis associated with anti-P depend on the coexistence of anti-dsDNA. Further studies with a large number of patients are required to confirm this conclusion.

iTRAQ®-based quantitative proteomics reveals the proteomic profiling of methicillin-resistant Staphylococcus aureus-derived extracellular vesicles after exposure to imipenem

This study sought to reveal the proteomic profiling of methicillin-resistant Staphylococcus aureus (MRSA)-derived extracellular vesicles (EVs) after exposure to imipenem. The advanced isobaric tags for relative and absolute quantitation (iTRAQ®) proteomic approach were used to analyze the alterations in MRSA-derived EV protein patterns upon exposure to imipenem. A total of 1260 EV proteins were identified and quantified. Among these, 861 differentially expressed exosome proteins (P < 0.05) were found. Multivariate analysis, Gene Ontology (GO) annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to analyze the identified proteins. Enrichment analysis of GO annotations indicated that imipenem primarily regulated the metabolic processes in MRSA. The metabolism of differentially expressed proteins was found to be the most significant in the combined analysis of the KEGG pathway analysis. Based on the results from the STRING analysis, 50S ribosomal protein L16 (RplP) and 30S ribosomal protein S8 (RpsH) were involved in the imipenem-induced MRSA-derived EVs. These results provide vital information on MRSA-derived EVs, increasing our knowledge of the proteome level changes in EVs upon exposure to imipenem. Moreover, these results pave the way for developing novel MRSA treatments.

Omega-3 fatty acid intake suppresses induction of diverse autoantibody repertoire by crystalline silica in lupus-prone mice

Inhalation of crystalline silica (cSiO2) in the workplace is etiologically linked to lupus and other autoimmune diseases. Exposing lupus-prone NZBWF1 mice to respirable cSiO2 unleashes a vicious cycle of inflammation and cell death in the lung that triggers interferon-regulated gene expression, ectopic lymphoid structure (ELS) development, elevation of local and systemic autoantibodies (AAbs), and glomerulonephritis. However, cSiO2-induced inflammation and onset of autoimmunity can be prevented by inclusion of the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) into the diet of these mice. Since cSiO2 both causes cell death and interferes with efferocytosis, secondary necrosis of residual cell corpses might provide a rich and varied autoantigen (AAg) source in the lung. While it is known that the particle induces anti-nuclear and anti-dsDNA AAbs in NZBWF1 mice, the full extent of the cSiO2-induced AAb response relative to specificity and isotype is not yet understood. The purpose of this study was to test the hypotheses that cSiO2 exposure induces a wide spectrum of AAbs in the pulmonary and systemic compartments, and that dietary DHA intervention prevents these changes. Archived tissue fluid samples were obtained from a prior study in which NZBWF1 mice were fed purified isocaloric diets containing no DHA (control) or DHA corresponding calorically to human doses of 2 and 5 g/day. Mice were intranasally instilled with 1 mg cSiO2 or saline vehicle weekly for 4 weeks, then groups euthanized 1, 5, 9, or 13 weeks post-instillation (PI) of the last cSiO2 dose. Bronchoalveolar lavage fluid (BALF) and plasma from each time point were subjected to AAb profiling using a microarray containing 122 AAgs. cSiO2 triggered robust IgG and IgM AAb responses against lupus-associated AAgs, including DNA, histones, ribonucleoprotein, Smith antigen, Ro/SSA, La/SSB, and complement as early as 1 week PI in BALF and 5 weeks PI in plasma, peaking at 9 and 13 weeks PI, respectively. Importantly, cSiO2 also induced AAbs to AAgs associated with rheumatoid arthritis (collagen II, fibrinogen IV, fibrinogen S, fibronectin, and vimentin), Sjögren's syndrome (α-fodrin), systemic sclerosis (topoisomerase I), vasculitis (MPO and PR3), myositis (Mi-2, TIF1-γ, MDA5), autoimmune hepatitis (LC-1), and celiac disease (TTG). cSiO2 elicited comparable but more modest IgA AAb responses in BALF and plasma. cSiO2-induced AAb production was strongly associated with time dependent inflammatory/autoimmune gene expression, ELS development, and glomerulonephritis. AAb responses were dose-dependently suppressed by DHA supplementation and negatively correlated with the ω-3 index, an erythrocyte biomarker of ω-3 content in tissue phospholipids. Taken together, these findings suggest that cSiO2 exposure elicits a diverse multi-isotype repertoire of AAbs, many of which have been reported in individuals with lupus and other autoimmune diseases. Furthermore, induction of this broad AAb spectrum could be impeded by increasing ω-3 tissue content via dietary DHA supplementation.

Lupus hepatitis, more than just elevated liver enzymes

Systemic lupus erythematosus (SLE), a multisystem autoimmune inflammatory disease, may involve any organs, including the liver. Liver involvement in SLE is not part of the American College of Rheumatology criteria and is relatively rare. Liver disease is usually mild, manifesting as subtle elevation of liver enzymes. Jaundice and hepatomegaly can be seen in some patients; advanced liver disease with cirrhosis is extremely rare. Precise pathology remains obscure. SLE may cause non-specific changes, including hepatocellular, cholestatic, or vascular changes. Alcohol, drugs, viral infections, metabolic disorders, autoimmune hepatitis, and other common causes of liver dysfunction should be excluded. Corticosteroids may expedite the recovery process, but may lead to non-alcoholic fatty liver disease and liver damage. Several large-scale multicentre studies have shown that liver involvement is not the major cause of morbidity and mortality in SLE patients. In this review, we discuss the pathogenesis, diagnosis, differential diagnosis, clinical manifestations, management, complications, and prognosis of lupus hepatitis.

The immunologic etiology of psychiatric manifestations in systemic lupus erythematosus: A narrative review on the role of the blood brain barrier, antibodies, cytokines and chemokines

INTRODUCTION

The aim of this narrative review is to provide an overview of the literature on the possible immunologic pathophysiology of psychiatric manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

A systematic search on PubMed was conducted. English studies with full text availability that investigated the correlation between blood-brain barrier (BBB) dysfunction, intrathecal synthesis of antibodies, antibodies, cytokines, chemokines, metalloproteinases, complement and psychiatric NPSLE manifestations in adults were included.

RESULTS

Both transient BBB-dysfunction with consequent access of antibodies to the cerebrospinal fluid (CSF) and intrathecal synthesis of antibodies could occur in psychiatric NPSLE. Anti-phospholipid antibodies, anti-NMDA antibodies and anti-ribosomal protein p antibodies seem to mediate concentration dependent neuronal dysfunction. Interferon-α may induce microglial engulfment of neurons, direct neuronal damage and production of cytokines and chemokines in psychiatric NPSLE. Several cytokines, chemokines and matrix metalloproteinase-9 may contribute to the pathophysiology of psychiatric NPSLE by attracting and activating Th1-cells and B-cells.

DISCUSSION

This potential pathophysiology may help understand NPSLE and may have implications for the diagnostic management and therapy of psychiatric NPSLE. However, the presented pathophysiological model is based on correlations between potential immunologic etiologies and psychiatric NPSLE that remain questionable. More research on this topic is necessary to further elucidate the pathophysiology of NPSLE.

Diversity of neuropsychiatric manifestations in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease characterised by diverse organ damages resulting from various autoantibodies, such as antinuclear or anti-DNA antibodies. Neuropsychiatric lupus (NPSLE) refers to the neurological and psychiatric disorders complicated with SLE and can be challenging for physicians to manage. NPSLE has a broad spectrum and high heterogeneity of clinical phenotypes, including headaches, psychiatric symptoms and peripheral neuropathy. Additionally, various immune effectors have been reported to contribute to the pathogenesis, including cytokines, cell-mediated inflammation and brain-reactive autoantibodies. In some patients with SLE, neuropsychiatric symptoms develop for the first time after the initiation of the steroid treatment, hindering the differentiation from steroid psychosis. The administration of high doses of steroids in patients with SLE is believed to trigger psychiatric symptoms. No clear evidence has yet been found regarding the treatment of NPSLE. Therefore, NPSLE-specific markers need to be developed, and treatment guidelines should be established. This article provides an overview of NPSLE as well as its pathogenesis and treatment.

Neuropsychiatric lupus: new mechanistic insights and future treatment directions

Patients with systemic lupus erythematosus (SLE) frequently show symptoms of central nervous system (CNS) involvement, termed neuropsychiatric SLE (NPSLE). The CNS manifestations of SLE are diverse and have a broad spectrum of severity and prognostic implications. Patients with NPSLE typically present with nonspecific symptoms, such as headache and cognitive impairment, but might also experience devastating features, such as memory loss, seizures and stroke. Some features of NPSLE, in particular those related to coagulopathy, have been characterized and an evidence-based treatment algorithm is available. The cognitive and affective manifestations of NPSLE, however, remain poorly understood. Various immune effectors have been evaluated as contributors to its pathogenesis, including brain-reactive autoantibodies, cytokines and cell-mediated inflammation. Additional brain-intrinsic elements (such as resident microglia, the blood-brain barrier and other neurovascular interfaces) are important facilitators of NPSLE. As yet, however, no unifying model has been found to underlie the pathogenesis of NPSLE, suggesting that this disease has multiple contributors and perhaps several distinct aetiologies. This heterogeneity presents a challenge for clinicians who have traditionally relied on empirical judgement in choosing treatment modalities for patients with NPSLE. Improved understanding of this manifestation of SLE might yield further options for managing this disease.

Neuroprotective effect of microglia against impairments of auditory steady-state response induced by anti-P IgG from SLE patients in naïve mice

OBJECTIVE

Autoantibodies against ribosomal P proteins (anti-P antibodies) are strongly associated with the neuropsychiatric manifestations of systemic lupus erythematosus (NPSLE). The present study was designed to assess whether anti-P antibodies can induce abnormal brain electrical activities in mice and investigate the potential cytopathological mechanism.

METHODS

Affinity-purified human anti-ribosomal P antibodies were injected intravenously into mice after blood-brain barrier (BBB) disruption. The auditory steady-state response (ASSR) was evaluated based on electroencephalography (EEG) signals in response to 40-Hz click-train stimuli, which were recorded from electrodes implanted in the skull of mice. Immunofluorescence staining was used to examine the morphology and density of neurons and glia in the hippocampus and cortex. The presence of apoptosis in the brain tissues was studied using the TUNEL assay. A PLX3397 diet was used to selectively eliminate microglia from the brains of mice.

RESULTS

Circulating anti-P antibodies caused an enhancement of the ASSR and the activation of microglia through the disrupted BBB, while no obvious neural apoptosis was observed. In contrast, when microglia were depleted, anti-P antibodies induced a serious reduction in the ASSR and neural apoptosis.

CONCLUSION

Our study indicates that anti-P antibodies can directly induce the dysfunction of auditory-evoked potentials in the brain and that microglia are involved in the protection of neural activity after the invasion of anti-P antibodies, which could have important implications for NPSLE.

A review and meta-analysis of anti-ribosomal P autoantibodies in systemic lupus erythematosus

The discovery of autoantibodies to ribosomal proteins (anti-RibP) dates back more than fifty years when antibodies to ribosomes were identified in systemic lupus erythematosus (SLE) sera. Over the years, anti-RibP autoantibodies have been the subject of extensive study and became known as a highly specific biomarker for the diagnosis of SLE and were associated with neuropsychiatric SLE (NPSLE), lupus nephritis (LN) and hepatitis (LH). As demonstrated by studies on cultured human cells and of murine models, there is evidence to suggest that anti-RibP may have a pathogenic role in LN and NPSLE. Despite a wealth of evidence, in comparison to other SLE autoantibodies such as anti-Sm and anti-dsDNA, anti-RibP has not been included in classification criteria for SLE. A significant challenge is the variability of assays used to detect anti-RibP, including the antigens and diagnostic platforms employed. This may account for the marked variation in frequencies (10-47%) in SLE and its association with clinical and demographic features reported in SLE cohorts. We performed a systematic literature review and meta-analysis to help clarify its prevalence, various clinical and serological associations in SLE based on the different RibP antigens and assay platforms used.

Assessing cognitive impairment in SLE: examining relationships between resting glucose metabolism and anti-NMDAR antibodies with navigational performance

OBJECTIVE

Resting Fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) brain imaging and neuropsychological testing were used to investigate the usefulness of a spatial navigation task (SNT) as a performance benchmark for cognitive impairment related to anti-N-methyl D-aspartate (anti-NMDA) receptor antibodies (DNRAb) in SLE.

METHODS

Neuropsychological assessments, including a desktop 3-D virtual SNT, were performed on 19 SLE participants and 9 healthy control (HC) subjects. SLE participants had stable disease activity and medication doses and no history of neuropsychiatric illness or current use of mind-altering medications. Resting FDG-PET scans were obtained on all SLE participants and compared with a historical set from 25 age-matched and sex-matched HCs. Serum DNRAb titres were measured by ELISA.

RESULTS

11/19 (58%) of SLE participants failed to complete the SNT (SNT-) compared with 2/9 (22%) of HCs. Compared with 7/9 (78%) in HCs, only 2/9 (22%; p=0.037) of SLE participants with high serum DNRAb titres completed the SNT, in contrast to 6/10 (60%; p=0.810) in SLE participants with low DNRAb titres. Voxel-wise comparison of FDG-PET scans between the 8 SLE participants successfully completing the SNT task (SNT+) and the 11 SNT- SLE participants revealed increased metabolism in the SNT+ participants (p<0.001) in the left anterior putamen/caudate, right anterior putamen, left prefrontal cortex (BA 9), right prefrontal cortex (BA 9/10) and left lateral and medial frontal cortex (BA 8). Compared with HCs, the SNT+ group demonstrated increased metabolism in all regions (p<0.02) except for the right prefrontal cortex (BA 9), whereas the SNT- group demonstrated either significantly decreased or similar metabolism in these seven regions.

CONCLUSIONS

SNT performance is associated with serum DNRAb titres and resting glucose metabolism in the anterior putamen/caudate and frontal cortex, suggesting compensatory neural recruitment in SNT-associated regions is necessary for successful completion of the task. The SNT therefore has potential for use as a marker for SLE-mediated cognitive impairment.

From Systemic Inflammation to Neuroinflammation: The Case of Neurolupus

It took decades to arrive at the general consensus dismissing the notion that the immune system is independent of the central nervous system. In the case of uncontrolled systemic inflammation, the relationship between the two systems is thrown off balance and results in cognitive and emotional impairment. It is specifically true for autoimmune pathologies where the central nervous system is affected as a result of systemic inflammation. Along with boosting circulating cytokine levels, systemic inflammation can lead to aberrant brain-resident immune cell activation, leakage of the blood⁻brain barrier, and the production of circulating antibodies that cross-react with brain antigens. One of the most disabling autoimmune pathologies known to have an effect on the central nervous system secondary to the systemic disease is systemic lupus erythematosus. Its neuropsychiatric expression has been extensively studied in lupus-like disease murine models that develop an autoimmunity-associated behavioral syndrome. These models are very useful for studying how the peripheral immune system and systemic inflammation can influence brain functions. In this review, we summarize the experimental data reported on murine models developing autoimmune diseases and systemic inflammation, and we explore the underlying mechanisms explaining how systemic inflammation can result in behavioral deficits, with a special focus on in vivo neuroimaging techniques.

Interactions of antisera to different Chlamydia and Chlamydophila species with the ribosomal protein RPS27a correlate with impaired protein synthesis in a human choroid plexus papilloma cell line

Chlamydia trachomatis (CT) and the Chlamydophila species (CS) Chlamydophila pneumoniae (CPn), and Chlamydophila psittaci (CPs) are suggested to induce autoantibodies causative of several human autoimmune disorders like rheumatoid arthritis and systemic lupus erythematosus (SLE). The aim of the present study was therefore to identify cellular protein interaction partners with antisera to CT (α-CT) or CS (α-CS) and to identify functional consequences of such interaction in vitro. As detected with a commercial first trimester human prenatal brain multiprotein array (hEXselect, Engine, Germany), the most frequent interaction partner with both α-CT and α-CS was the ribosomal small subunit protein RPS27a. This could be confirmed by Western blot analysis with a recombinant RPS27a sample. In addition, immunocytochemistry with both antisera in the human choroid plexus papilloma cell line HIBCPP revealed a granular cytoplasmic staining, and Western blot analysis with whole-cell protein samples of HIBCPP cells revealed both antisera to label protein bands of different molecular weights and intensity. By 2D Western blot analysis and mass spectrometry, one of the protein spots interacting with α-CT could be identified as the RPS27a. Finally, two different methods for the detection of protein synthesis activity, the SUnSET technique and an HPG fluorescence assay revealed both antisera to cause reduced translational activity in HIBCPP cells. Together with previous findings of RPS27a as an autoimmune target in a mouse model of systemic lupus erythematosus (SLE), these results suggest that infections with CT and/or CS could induce SLE-associated immune modifications. However, direct evidence for a pathogenic role of these interactions for SLE demands further investigations.

Electrophysiological dysfunction induced by anti-ribosomal P protein antibodies injection into the lateral ventricle of the rat brain

Objective Anti-ribosomal P antibodies (anti-P) are strongly associated with neuropsychiatric lupus. This study was designed to determine whether these antibodies are capable of causing electro-oscillogram (EOSG) and behavior alterations in rats. Methods IgG fraction anti-P positive and affinity-purified anti-P antibodies were injected intraventricularly in rats. Sequential cortical and subcortical EOSGs were analyzed during 30 days. IgG anti-Ro/SS-A and normal IgG were used as controls. Results All 13 animals injected with IgG anti-P demonstrated a high prevalence of polyspikes, diffusely distributed in hippocampal fields and cerebral cortex. These abnormalities persisted approximately a month. Remarkably, an identical electrical disturbance was observed with the inoculation of affinity-purified anti-P antibodies. The EOSG alterations were associated with behavioral disorders with varying degrees of severity in every animal injected with anti-P. In contrast, no changes in EOSG or behavioral disturbances were observed in the control group. Conclusion Our study indicates that anti-P antibodies can directly induce electrophysiological dysfunction in central nervous system particularly in hippocampus and cortex associated with behavior disturbances.

Microtubule-dependent ribosome localization in C. elegans neurons

Subcellular localization of ribosomes defines the location and capacity for protein synthesis. Methods for in vivo visualizing ribosomes in multicellular organisms are desirable in mechanistic investigations of the cell biology of ribosome dynamics. Here, we developed an approach using split GFP for tissue-specific visualization of ribosomes in Caenorhabditis elegans. Labeled ribosomes are detected as fluorescent puncta in the axons and synaptic terminals of specific neuron types, correlating with ribosome distribution at the ultrastructural level. We found that axonal ribosomes change localization during neuronal development and after axonal injury. By examining mutants affecting axonal trafficking and performing a forward genetic screen, we showed that the microtubule cytoskeleton and the JIP3 protein UNC-16 exert distinct effects on localization of axonal and somatic ribosomes. Our data demonstrate the utility of tissue-specific visualization of ribosomes in vivo, and provide insight into the mechanisms of active regulation of ribosome localization in neurons.

Next-Generation Autoantibody Testing by Combination of Screening and Confirmation-the CytoBead® Technology

Occurrence of autoantibodies (autoAbs) is a hallmark of autoimmune diseases, and the analysis thereof is an essential part in the diagnosis of organ-specific autoimmune and systemic autoimmune rheumatic diseases (SARD), especially connective tissue diseases (CTDs). Due to the appearance of autoAb profiles in SARD patients and the complexity of the corresponding serological diagnosis, different diagnostic strategies have been suggested for appropriate autoAb testing. Thus, evolving assay techniques and the continuous discovery of novel autoantigens have greatly influenced the development of these strategies. Antinuclear antibody (ANA) analysis by indirect immunofluorescence (IIF) on tissue and later cellular substrates was one of the first tests introduced into clinical routine and is still an indispensable tool for CTD serology. Thus, screening for ANA by IIF is recommended to be followed by confirmatory testing of positive findings employing different assay techniques. Given the continuous growth in the demand for autoAb testing, IIF has been challenged as the standard method for ANA and other autoAb analyses due to lacking automation, standardization, modern data management, and human bias in IIF pattern interpretation. To address these limitations of autoAb testing, the CytoBead® technique has been introduced recently which enables automated interpretation of cell-based IIF and quantitative autoAb multiplexing by addressable microbead immunoassays in one reaction environment. Thus, autoAb screening and confirmatory testing can be combined for the first time. The present review discusses the history of autoAb assay techniques in this context and gives an overview and outlook of the recent progress in emerging technologies.

Ribosomal P antibody: 30 years on the road

The identity of the protein antigens targeted by anti-cytoplasmic antibodies in lupus was discovered 30 years ago. These antigens are three acidic ribosomal phosphoproteins, P0, P1, and P2. Precise identification of the shared epitope on these three proteins enabled sensitive and specific immunoassays to be developed. Anti-P antibodies are highly specific for systemic lupus erythematosus (SLE) and occur in 15%–35% of patients, depending on ethnicity as well as the age of onset. Increased frequencies of detection of anti-P have been reported in childhood SLE as well as in neuropsychiatric, renal, and hepatic disease. While longitudinal studies by the Systemic Lupus International Collaborating Clinics (SLICC) consortium supported the association of anti-P with neuropsychiatric lupus, the predictive value of antibody determination remains controversial. This is likely explained by the heterogeneity of neuropsychiatric lupus as well as by the different methodologies used for assay. A number of experimental studies have suggested a direct pathogenic role for anti-P antibodies in brain disease. Findings include cross reactivity between anti-P and a neuronal surface antigen, which was detected in areas of the brain involved in memory, cognition, and emotion. Direct injection of anti-P antibodies into the brains of rodents was also associated with abnormal electrical activity and behavioral disturbances. Taken together, research over the last 30 years has established anti-P antibodies as a useful diagnostic marker of SLE and at least a subset of patients with neuropsychiatric disease. Further research is required to fine tune the association of anti-P with clinical manifestations and establish beyond high probability a pathophysiologic role for the antibodies.

Lupus brain fog: a biologic perspective on cognitive impairment, depression, and fatigue in systemic lupus erythematosus

Cognitive disturbances, mood disorders and fatigue are common in SLE patients with substantial adverse effects on function and quality of life. Attribution of these clinical findings to immune-mediated disturbances associated with SLE remains difficult and has compromised research efforts in these areas. Improved understanding of the role of the immune system in neurologic processes essential for cognition including synaptic plasticity, long term potentiation and adult neurogenesis suggests multiple potential mechanisms for altered central nervous system function associated with a chronic inflammatory illness such as SLE. This review will focus on the biology of cognition and neuroinflammation in normal circumstances and potential biologic mechanisms for cognitive impairment, depression and fatigue attributable to SLE.

Anti-ribosomal P-protein and its role in psychiatric manifestations of systemic lupus erythematosus: myth or reality?

Systemic lupus erythematosus (SLE) is an autoimmune disease that may involve the central nervous system (CNS) resulting in neuropsychiatric manifestations. The associated psychiatric disorders include depression, psychosis, mood disorders, anxiety, cognitive dysfunction, and delirium/encephalopathy. Several autoantibodies may play a role in the pathogenesis of psychiatric complications of SLE, particularly antibodies against ribosomal P-proteins (anti-P) and possibly antibodies against endothelial cells (AECA). The reported prevalence of anti-P is highly variable in SLE patients and is dependent on different ethnic backgrounds, sensitivity and specificity of the assays employed for autoantibody detection, and the time at which sera were analysed in relation to the clinical event. Controversial data exist on the association of anti-P with psychiatric manifestations of SLE. These autoantibodies have been suggested to be specific markers of the psychiatric manifestations of SLE, particularly of the psychosis and depression, and the antibody level varied with the clinical activity of the disease. Some studies have confirmed the hypothesis of an association of anti-P antibodies with psychiatric manifestations of neuropsychiatric SLE (NPSLE) while others have disputed this relationship. This review summarizes the recent studies about relationship between anti-P antibodies and psychiatric manifestation of SLE.

Disruption of the ribosomal P complex leads to stress-induced autophagy

The human ribosomal P complex, which consists of the acidic ribosomal P proteins RPLP0, RPLP1, and RPLP2 (RPLP proteins), recruits translational factors, facilitating protein synthesis. Recently, we showed that overexpression of RPLP1 immortalizes primary cells and contributes to transformation. Moreover, RPLP proteins are overexpressed in human cancer, with the highest incidence in breast carcinomas. It is thought that disruption of the P complex would directly affect protein synthesis, causing cell growth arrest and eventually apoptosis. Here, we report a distinct mechanism by which cancer cells undergo cell cycle arrest and induced autophagy when RPLP proteins are downregulated. We found that absence of RPLP0, RPLP1, or RPLP2 resulted in reactive oxygen species (ROS) accumulation and MAPK1/ERK2 signaling pathway activation. Moreover, ROS generation led to endoplasmic reticulum (ER) stress that involved the EIF2AK3/PERK-EIF2S1/eIF2α-EIF2S2-EIF2S3-ATF4/ATF-4- and ATF6/ATF-6-dependent arms of the unfolded protein response (UPR). RPLP protein-deficient cells treated with autophagy inhibitors experienced apoptotic cell death as an alternative to autophagy. Strikingly, antioxidant treatment prevented UPR activation and autophagy while restoring the proliferative capacity of these cells. Our results indicate that ROS are a critical signal generated by disruption of the P complex that causes a cellular response that follows a sequential order: first ROS, then ER stress/UPR activation, and finally autophagy. Importantly, inhibition of the first step alone is able to restore the proliferative capacity of the cells, preventing UPR activation and autophagy. Overall, our results support a role for autophagy as a survival mechanism in response to stress due to RPLP protein deficiency.

Autoantibodies in SLE: Specificities, Isotypes and Receptors

Systemic Lupus Erythematosus (SLE) is characterized by a wide spectrum of auto-antibodies which recognize several cellular components. The production of these self-reactive antibodies fluctuates during the course of the disease and the involvement of different antibody-secreting cell populations are considered highly relevant for the disease pathogenesis. These cells are developed and stimulated through different ways leading to the secretion of a variety of isotypes, affinities and idiotypes. Each of them has a particular mechanism of action binding to a specific antigen and recognized by distinct receptors. The effector responses triggered lead to a chronic tissue inflammation. DsDNA autoantibodies are the most studied as well as the first in being characterized for its pathogenic role in Lupus nephritis. However, others are of growing interest since they have been associated with other organ-specific damage, such as anti-NMDAR antibodies in neuropsychiatric clinical manifestations or anti-β2GP1 antibodies in vascular symptomatology. In this review, we describe the different auto-antibodies reported to be involved in SLE. How autoantibody isotypes and affinity-binding to their antigen might result in different pathogenic responses is also discussed.

Antibodies as Mediators of Brain Pathology

The brain is normally sequestered from antibody exposure by the blood brain barrier. However, antibodies can access the brain during fetal development before the barrier achieves full integrity, and in disease states when barrier integrity is compromised. Recent studies suggest that antibodies contribute to brain pathology associated with autoimmune diseases such as systemic lupus erythematosus and neuromyelitis optica, and can lead to transient or permanent behavioral or cognitive abnormalities. We review these findings here and examine the circumstances associated with antibody entry into the brain, the routes of access and the mechanisms that then effect pathology. Understanding these processes and the nature and specificity of neuronal autoantibodies may reveal therapeutic strategies toward alleviating or preventing the neurological pathologies and behavioral abnormalities associated with autoimmune disease.

In vivo formation of Plasmodium falciparum ribosomal stalk - a unique mode of assembly without stable heterodimeric intermediates

BACKGROUND

The ribosomal stalk composed of P-proteins constitutes a structure on the large ribosomal particle responsible for recruitment of translation factors and stimulation of factor-dependent GTP hydrolysis during translation. The main components of the stalk are P-proteins, which form a pentamer. Despite the conserved basic function of the stalk, the P-proteins do not form a uniform entity, displaying heterogeneity in the primary structure across the eukaryotic lineage. The P-proteins from protozoan parasites are among the most evolutionarily divergent stalk proteins.

METHODS

We have assembled P-stalk complex of Plasmodium falciparum in vivo in bacterial system using tricistronic expression cassette and provided its characteristics by biochemical and biophysical methods.

RESULTS

All three individual P-proteins, namely uL10/P0, P1 and P2, are indispensable for acquisition of a stable structure of the P stalk complex and the pentameric uL10/P0-(P1-P2)₂form represents the most favorable architecture for parasite P-proteins.

CONCLUSION

The formation of P. falciparum P-stalk is driven by trilateral interaction between individual elements which represents unique mode of assembling, without stable P1-P2 heterodimeric intermediate.

GENERAL SIGNIFICANCE

On the basis of our mass-spectrometry analysis supported by the bacterial two-hybrid assay and biophysical analyses, a unique pathway of the parasite stalk assembling has been proposed. We suggest that the absence of P1/P2 heterodimer, and the formation of a stable pentamer in the presence of all three proteins, indicate a one-step formation to be the main pathway for the vital ribosomal stalk assembly, whereas the P2 homo-oligomer may represent an off-pathway product with physiologically important nonribosomal role.

Anti-N-methyl-D-aspartate receptor and anti-ribosomal-P autoantibodies contribute to cognitive dysfunction in systemic lupus erythematosus

Objective

Autoantibodies against N-methyl-D-aspartate receptor (anti-NMDAR) and ribosomal-P (anti-P) antigens are potential pathogenic factors in the frequently observed diffuse brain dysfunctions in patients with systemic lupus erythematosus (SLE). Although studies have been conducted in this area, the role of anti-NMDAR antibodies in SLE cognitive dysfunction remains elusive. Moreover, the specific contribution of anti-P antibodies has not been reported yet. The present study attempts to clarify the contribution of anti-NMDAR and anti-P antibodies to cognitive dysfunction in SLE.

Methods

The Cambridge Neuropsychological Test Automated Battery (CANTAB) was used to assess a wide range of cognitive function areas in 133 Chilean women with SLE. ANCOVA models included autoantibodies, patient and disease features.

Results

Cognitive deficit was found in 20%. Higher SLEDAI-2K scores were associated with impairment in spatial memory and learning abilities, whereas both anti-NMDAR and anti-P antibodies contributed to deficits in attention and spatial planning abilities, which reflect fronto-parietal cortex dysfunctions.

Conclusions

These results reveal an association of active disease together with specific circulating autoantibodies, such as anti-NMDAR and anti-P, with cognitive dysfunction in SLE patients.

Virus-mediated compartmentalization of the host translational machinery

Viruses require the host translational apparatus to synthesize viral proteins. Host stress response mechanisms that suppress translation, therefore, represent a significant obstacle that viruses must overcome. Here, we report a strategy whereby the mammalian orthoreoviruses compartmentalize the translational machinery within virus-induced inclusions known as viral factories (VF). VF are the sites of reovirus replication and assembly but were thought not to contain ribosomes. It was assumed viral mRNAs exited the VF to undergo translation by the cellular machinery, and proteins reentered the factory to participate in assembly. Here, we used ribopuromycylation to visualize active translation in infected cells. These studies revealed that active translation occurs within VF and that ribosomal subunits and proteins required for translation initiation, elongation, termination, and recycling localize to the factory. Interestingly, we observed components of the 43S preinitiation complex (PIC) concentrating primarily at factory margins, suggesting a spatial and/or dynamic organization of translation within the VF. Similarly, the viral single-stranded RNA binding protein σNS localized to the factory margins and had a tubulovesicular staining pattern that extended a short distance from the margins of the factories and colocalized with endoplasmic reticulum (ER) markers. Consistent with these colocalization studies, σNS was found to associate with both eukaryotic translation initiation factor 3 subunit A (eIF3A) and the ribosomal subunit pS6R. Together, these findings indicate that σNS functions to recruit 43S PIC machinery to the primary site of viral translation within the viral factory. Pathogen-mediated compartmentalization of the translational apparatus provides a novel mechanism by which viruses might avoid host translational suppression.

Viruses lack biosynthetic capabilities and depend upon the host for protein synthesis. This dependence requires viruses to evolve mechanisms to coerce the host translational machinery into synthesizing viral proteins in the face of ongoing cellular stress responses that suppress global protein synthesis. Reoviruses replicate and assemble within cytoplasmic inclusions called viral factories. However, synthesis of viral proteins was thought to occur in the cytosol. To identify the site(s) of viral translation, we undertook a microscopy-based approach using ribopuromycylation to detect active translation. Here, we report that active translation occurs within viral factories and that translational factors are compartmentalized within factories. Furthermore, we find that the reovirus nonstructural protein σNS associates with 43S preinitiation complexes at the factory margins, suggesting a role for σNS in translation. Together, virus-induced compartmentalization of the host translational machinery represents a strategy for viruses to spatiotemporally couple viral protein synthesis with viral replication and assembly.

Anti-ribosomal-P antibodies in lupus nephritis, neuropsychiatric lupus, lupus hepatitis, and Chagas' disease: promising yet limited in clinical utility

Anti-P antibodies have been associated with organ involvement in SLE, such as in autoimmune hepatitis, and have been suggested to be directly pathogenic. Neuropsychiatric lupus, lupoid hepatitis, autoimmune hepatitis, lupus nephritis, and Chagas' disease have been associated with the presence of anti-P antibody. This review seeks to look into the current literature on anti-P antibody and the association between SLE and non-SLE autoimmune connective tissue disorder.

A 17-Year-Old Female with Systemic Lupus Presents with Complex Movement Disorder: Possible Relationship with Antiribosomal P Antibodies

Complex movement disorder is a relatively rare presentation of neurolupus. Antiphospholipid antibodies are associated with movement disorders likely via aberrant neuronal stimulation. Antiribosomal P antibodies have been previously associated with neuropsychiatric disorders but their correlation with movement disorder was not previously established. Our case report involves a 17-year-old Caucasian female patient positive for only antiribosomal P antibody and lupus anticoagulant who presented with a sudden onset of complex movement disorder. After complete cessation of physical signs with olanzapine, anticardiolipin and anti-β2 glycoprotein I antibodies became positive which indicates a likely discordance between movement disorder and antiphospholipid antibodies. This also indicates a potential causal role of antiribosomal P antibodies in inducing movement disorder.

Prevalence and clinical significance of anti-ribosomal P antibody in childhood-onset systemic lupus erythematosus

Objective: To investigate the prevalence of the anti-ribosomal P (anti-P) antibodies in childhood-onset systemic lupus erythematosus patients (cSLE), healthy controls and first degree relatives. To elucidate the association between anti-P and disease activity, laboratory and treatment features in cSLE patients. Methods: We included consecutive SLE patients with disease onset before 16 years. Controls were age- and sex-matched. SLE patients were assessed for clinical and laboratory SLE manifestations, disease activity (SLE Disease Activity Index (SLEDAI)), damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI)) and current drug exposures. Mood disorders were determined through Becks Depression and Becks Anxiety Inventory. Anti-P measured by enzyme-linked immunosorbent assay. Results: We included 50 consecutive cSLE patients (mean age of 16.82 ± 3.46 years), 35 first degree relatives (mean age of 38.73 ± 3.89 years) and 20 health control (mean age of 18.3 ± 4.97 years). Anti-P was observed in 13 (26%) cSLE patients and in no first-degree relative ( p < 0.01) or control ( p < 0.01). Anti-P was more frequently observed in patients with anxiety ( p < 0.002). No other clinical, laboratory or treatment features, including SLEDAI and SDI scores were associated with the presence of anti-P in cSLE patients. Conclusion: Anti-P is frequently observed in cSLE patients and was associated with the presence of anxiety in this cohort of cSLE.

Placental transmission of human parvovirus 4 in newborns with hydrops, Taiwan

In studying the epidemiology of parvovirus 4 (PARV4) in Taiwan, we detected DNA in plasma of 3 mothers and their newborns with hydrops. In 1 additional case, only the mother had PARV4 DNA. Our findings demonstrate that PARV4 can be transmitted through the placenta.