Recent advances on neutrophil dysregulation in the pathogenesis of rheumatic diseases.

PURPOSE OF REVIEW: The exact pathogenic mechanisms of rheumatic diseases (RMD) remain largely unknown. Increasing evidence highlights a pathogenic role of neutrophil dysregulation in the development of RMD. RECENT FINDINGS: The purpose of this review is to present a current overview of recent advancements in understanding the role of neutrophil dysfunction in the development of RMD. Additionally, this review will discuss strategies for targeting pathways associated with neutrophil dysregulation as potential treatments for RMD. One specific aspect of neutrophil dysregulation, known as neutrophil extracellular traps (NETs), will be explored. NETs have been found to contribute to chronic pulmonary inflammation and fibrosis, as well as serve as DNA scaffolds for binding autoantigens, including both citrullinated and carbamylated autoantigens. Putative therapies, such as 6-gingerol or defibrotide, have demonstrated beneficial effects in the treatment of RMD by suppressing NETs formation. SUMMARY: Recent advances have significantly reinforced the crucial role of neutrophil dysregulation in the pathogenesis of RMD. A deeper understanding of the potential mechanisms underlying this pathogenic process would aid in the development of more precise and effective targeting strategies, thus ultimately improving the outcomes of RMD.

MicroRNAs-mediated regulation pathways in rheumatic diseases.

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are two common rheumatic disorders marked by persistent inflammatory joint disease. Patients with RA have osteodestructive symptoms, but those with AS have osteoproliferative manifestations. Ligaments, joints, tendons, bones, and muscles are all affected by rheumatic disorders. In recent years, many epigenetic factors contributing to the pathogenesis of rheumatoid disorders have been studied. MicroRNAs (miRNAs) are small, non-coding RNA molecules implicated as potential therapeutic targets or biomarkers in rheumatic diseases. MiRNAs play a critical role in the modulation of bone homeostasis and joint remodeling by controlling fibroblast-like synoviocytes (FLSs), chondrocytes, and osteocytes. Several miRNAs have been shown to be dysregulated in rheumatic diseases, including miR-10a, 16, 17, 18a, 19, 20a, 21, 27a, 29a, 34a, 103a, 125b, 132, 137, 143, 145, 146a, 155, 192, 203, 221, 222, 301a, 346, and 548a.The major molecular pathways governed by miRNAs in these cells are Wnt, bone-morphogenic protein (BMP), nuclear factor (NF)-κB, receptor activator of NF-κB (RANK)-RANK ligand (RANKL), and macrophage colony-stimulating factor (M-CSF) receptor pathway. This review aimed to provide an overview of the most important signaling pathways controlled by miRNAs in rheumatic diseases.

Impact of Adipose-Derived Mesenchymal Stem Cells (ASCs) of Rheumatic Disease Patients on T Helper Cell Differentiation.

Complex pathogenesis of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) is associated with an imbalance of various Th-cell subpopulations. Mesenchymal stem cells (MSCs) have the ability to restore this balance. However, bone marrow-derived MSCs of SLE and SSc patients exhibit many abnormalities, whereas the properties of adipose derived mesenchymal stem cells (ASCS) are much less known. Therefore, we examined the effect of ASCs obtained from SLE (SLE/ASCs) and SSc (SSc/ASCs) patients on Th subset differentiation, using cells from healthy donors (HD/ASCs) as controls. ASCs were co-cultured with activated CD4+ T cells or peripheral blood mononuclear cells. Expression of transcription factors defining Th1, Th2, Th17, and regulatory T cell (Tregs) subsets, i.e., T-bet, GATA3, RORc, and FoxP3, were analysed by quantitative RT-PCR, the concentrations of subset-specific cytokines were measured by ELISA, and Tregs formation by flow cytometry. Compared with HD/ASCs, SLE/ASCs and especially SSc/ASCs triggered Th differentiation which was disturbed at the transcription levels of genes encoding Th1- and Tregs-related transcription factors. However, we failed to find functional consequences of this abnormality, because all tested ASCs similarly switched differentiation from Th1 to Th2 direction with accompanying IFNγ/IL-4 ratio decrease, up-regulated Th17 formation and IL-17 secretion, and up-regulated classical Tregs generation.

The Role of HMGB1 in Rheumatic Diseases.

HMGB1, a highly conserved non-histone nuclear protein, is widely expressed in mammalian cells. HMGB1 in the nucleus binds to the deoxyribonucleic acid (DNA) to regulate the structure of chromosomes and maintain the transcription, replication, DNA repair, and nucleosome assembly. HMGB1 is actively or passively released into the extracellular region during cells activation or necrosis. Extracellular HMGB1 as an alarmin can initiate immune response alone or combined with other substances such as nucleic acid to participate in multiple biological processes. It has been reported that HMGB1 is involved in various inflammatory responses and autoimmunity. This review article summarizes the physiological function of HMGB1, the post-translational modification of HMGB1, its interaction with different receptors, and its recent advances in rheumatic diseases and strategies for targeted therapy.

Coordination of retrotransposons and type I interferon with distinct interferon pathways in dermatomyositis, systemic lupus erythematosus and autoimmune blistering disease.

Type I interferon (IFN) plays a crucial role in innate and adaptive immunity, and aberrant IFN responses are involved in systemic autoimmune diseases, such as systemic lupus erythematosus (SLE) and dermatomyositis (DM). Type I IFNs can be induced by transcribed retrotransposons. The regulation of retrotransposons and type I IFN and the downstream IFN pathways in SLE, DM, and autoimmune blistering disease (AIBD) were investigated. The gene expression levels of retrotransposons, including LINE-1, type I-III IFNs, and IFN-stimulated genes (ISGs) in peripheral blood cells from patients with DM (n = 24), SLE (n = 19), AIBD (n = 14) and healthy controls (HCs, n = 10) were assessed by quantitative polymerase chain reaction. Upregulation of retrotransposons and IFNs was detected in DM patient samples, as is characteristic, compared to HCs; however, ISGs were not uniformly upregulated. In contrast, retrotransposons and IFNs, except for type II IFN, such as IFN-γ, were not upregulated in SLE. In AIBD, only some retrotransposons and type I interferons were upregulated. The DM, SLE, and AIBD samples showed coordinated expression of retrotransposons and type I IFNs and distinct spectra of IFN signaling. A positive correlation between LINE-1 and IFN-ß1 was also detected in human cell lines. These factors may participate in the development of these autoimmune diseases.

Conversión de prueba cutánea de derivado proteico purificado durante el tratamiento con anti-TNF / Skin test conversion of purified protein derivative during treatment with anti-TNF

Introducción: los anti-TNF-α se asocian con mayor riesgo de desarrollar tuberculosis (TB). La prueba del derivado proteico purificado (purified protein derivative, PPD) se emplea para diagnosticar infección de tuberculosis latente (ITL). Se recomienda el cribado para TB previo al inicio de terapia anti-TNF-α y el seguimiento para evaluar la posible conversión de la PPD durante el tratamiento. El tratamiento de la ITL puede reducir el riesgo de desarrollar enfermedad activa en un 90%. Objetivos: actualmente los resultados de conversión de la PPD y su interpretación durante el tratamiento anti-TNF-α son variables, por tal motivo nos propusimos conocer la frecuencia de conversión de la PPD en este grupo de pacientes de nuestro medio. Materiales y métodos: realizamos un estudio descriptivo, observacional y retrospectivo que incluyó pacientes >18 años, diagnosticados con enfermedad reumática, tratados con anti-TNF-α. Resultados: se incluyeron 54 pacientes (46,7 ± a 12 años), de los cuales 36, presentaron diagnóstico de artritis reumatoidea, seis de artritis idiopática juvenil, cinco de espondilitis anquilosante, tres de artritis psoriásica, tres de uveítis y uno de queratitis intersticial. Los tratamientos fueron: 30 adalimumab, 17 certolizumab, siete etanercept, 44 metotrexato, 19 leflunomida, nueve hidroxicloroquina, dos sulfasalazina, dos azatioprina, uno mofetil micofenolato y glucocorticoides (28 de 54); la conversión de la PPD ocurrió en un solo paciente. Conclusiones: en el presente trabajo la seroconversión fue baja en contraste con otras series. La prueba de PPD es un método accesible, ampliamente disponible, adecuado y sensible para diagnosticar ITL.

Introduction: anti-TNF-α are associated with an increased risk of developing tuberculosis (TB). Purified protein derivative (PPD) is used to demonstrate a latent TB infection (LTBI). Screening is recommended for TB prior to the onset of anti-TNF-α and monitoring evaluating possible conversion of PPD during treatment. Treatment of LTBI can reduce the risk of active disease development by up to 90%. Objectives: currently the results of PPD conversion and its interpretation during anti-TNF-α treatment are variable and that is why we set out to know the frequency of conversion of PPD in this group of patients in our environment. Materials and methods: a descriptive, analytical, observational, retrospective study was conducted. Including patients >18 years old, diagnosed with rheumatic disease, treated with anti-TNF-α. Results: 54 patients were included (46.7 ± to 12 years), of which 36 presented a diagnosis of rheumatoid arthritis, 6 juvenile idiopathic arthritis, 5 ankylosing spondylitis, 3 psoriatic arthritis, 3 uveitis, 1 interstitial keratitis. The treatments were: 30 adalimumab, 17 certolizumab, 7 etanercept, 44 methotrexate, 19 leflunomide, 9 hydroxychloroquine, 2 sulfasalazine, 2 azathioprine, 1 mycophenolate mofetil and glucocorticoids (28/54). PPD conversion took place in 1 patient. Conclusions: in the present study, seroconversion was low in contrast to other series. The PPD test is an accessible, widely available, adequate and sensitive method for diagnosing LTBI, which the rheumatologist should use in his daily practice.

Vitamin D and Rheumatic Diseases: A Review of Clinical Evidence.

Vitamin D plays an important role in maintaining a healthy mineralized skeleton. It is also considered an immunomodulatory agent that regulates innate and adaptive immune systems. The aim of this narrative review is to provide general concepts of vitamin D for the skeletal and immune health, and to summarize the mechanistic, epidemiological, and clinical evidence on the relationship between vitamin D and rheumatic diseases. Multiple observational studies have demonstrated the association between a low level of serum 25-hydroxyvitamin D [25(OH)D] and the presence and severity of several rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), spondyloarthropathies, and osteoarthritis (OA). Nevertheless, the specific benefits of vitamin D supplements for the treatment and prevention of rheumatic diseases are less accepted as the results from randomized clinical trials are inconsistent, although some conceivable benefits of vitamin D for the improvement of disease activity of RA, SLE, and OA have been demonstrated in meta-analyses. It is also possible that some individuals might benefit from vitamin D differently than others, as inter-individual difference in responsiveness to vitamin D supplementation has been observed in genomic studies. Although the optimal level of serum 25(OH)D is still debatable, it is advisable it is advisable that patients with rheumatic diseases should maintain a serum 25(OH)D level of at least 30 ng/mL (75 nmol/L) to prevent osteomalacia, secondary osteoporosis, and fracture, and possibly 40-60 ng/mL (100-150 nmol/L) to achieve maximal benefit from vitamin D for immune health and overall health.

A bond between rheumatic diseases and cancer in the elderly: The interleukin-6 pathway.

Interleukin (IL)-6 is a soluble factor secreted by T lymphocytes, involved in antibody generation by B lymphocytes. The IL-6 pathway has risen as a pivotal pathway implicated in immune regulation and dysregulation in various rheumatic diseases. Nonetheless, elevated IL-6 levels can also play a role in cancer. Targeting the IL-6 pathway has led to innovative therapeutic approaches for rheumatic diseases and for COVID-19, particularly in the elderly. Indeed, tocilizumab, an agent targeting IL-6, has recently amassed significant attention as a promising univocal agent for different conditions. In this viewpoint, we sought to recall and describe the common pathway among osteoarthritis, rheumatoid arthritis, and cancer, suggesting that anti-IL-6 may be considered a jack-of-all-trades against inflammaging in the elderly.

Adenosine and Inflammation: Here, There and Everywhere.

Adenosine is a ubiquitous endogenous modulator with the main function of maintaining cellular and tissue homeostasis in pathological and stress conditions. It exerts its effect through the interaction with four G protein-coupled receptor (GPCR) subtypes referred as A1, A2A, A2B, and A3 adenosine receptors (ARs), each of which has a unique pharmacological profile and tissue distribution. Adenosine is a potent modulator of inflammation, and for this reason the adenosinergic system represents an excellent pharmacological target for the myriad of diseases in which inflammation represents a cause, a pathogenetic mechanism, a consequence, a manifestation, or a protective factor. The omnipresence of ARs in every cell of the immune system as well as in almost all cells in the body represents both an opportunity and an obstacle to the clinical use of AR ligands. This review offers an overview of the cardinal role of adenosine in the modulation of inflammation, showing how the stimulation or blocking of its receptors or agents capable of regulating its extracellular concentration can represent promising therapeutic strategies for the treatment of chronic inflammatory pathologies, neurodegenerative diseases, and cancer.

Vascular Endothelial Growth Factor Biology and Its Potential as a Therapeutic Target in Rheumatic Diseases.

Rheumatic diseases constitute a diversified group of diseases distinguished by arthritis and often involve other organs. The affected individual has low quality of life, productivity even life-threatening in some severe conditions. Moreover, they impose significant economic and social burdens. In recent years, the patient outcome has been improved significantly due to clearer comprehension of the pathology of rheumatic diseases and the effectiveness of "treat to target" therapies. However, the high cost and the adverse effects are the concerns and full remissions are not often observed. One of the main processes that contributes to the pathogenesis of rheumatic diseases is angiogenesis. Vascular endothelial growth factor (VEGF), a central mediator that regulates angiogenesis, has different isoforms and functions in various physiological processes. Increasing evidence suggests an association between the VEGF system and rheumatic diseases. Anti-VEGF and VEGF receptor (VEGFR) therapies have been used to treat several cancers and eye diseases. This review summarizes the current understanding of VEGF biology and its role in the context of rheumatic diseases, the contribution of VEGF bioavailability in the pathogenesis of rheumatic diseases, and the potential implications of therapeutic approaches targeting VEGF for these diseases.

B cells as target for immunotherapy in rheumatic diseases - current status.

This mini-review is a short overview of different therapeutical strategies targeting B cells in systemic autoimmune rheumatic diseases, mainly: rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and primary Sjogren Syndrome (pSS). Many strategies and their rationale are discussed in this review: B cells' depletion (anti-CD20, anti-CD22), long-lived plasma cells depletion (anti-CD19, anti-CD27, anti-CD38 and anti-CD138), changing activation of B cells (anti-BAFF) and inhibiting proteasomes in plasma cells (bortezomib). The past successful therapies and less successful are shown, and the possible reasons for failures are discussed.

Adiponectin Deregulation in Systemic Autoimmune Rheumatic Diseases.

Deregulation of adiponectin is found in systemic autoimmune rheumatic diseases (SARDs). Its expression is downregulated by various inflammatory mediators, but paradoxically, elevated serum levels are present in SARDs with high inflammatory components, such as rheumatoid arthritis and systemic lupus erythematosus. Circulating adiponectin is positively associated with radiographic progression in rheumatoid arthritis as well as with cardiovascular risks and lupus nephritis in systemic lupus erythematosus. However, in SARDs with less prominent inflammation, such as systemic sclerosis, adiponectin levels are low and correlate negatively with disease activity. Regulators of adiponectin gene expression (PPAR-γ, Id3, ATF3, and SIRT1) and inflammatory cytokines (interleukin 6 and tumor necrosis factor α) are differentially expressed in SARDs and could therefore influence total adiponectin levels. In addition, anti-inflammatory therapy could also have an impact, as tocilizumab treatment is associated with increased serum adiponectin. However, anti-tumor necrosis factor α treatment does not seem to affect its levels. Our review provides an overview of studies on adiponectin levels in the bloodstream and other biological samples from SARD patients and presents some possible explanations why adiponectin is deregulated in the context of therapy and gene regulation.

Interferon lambda in inflammation and autoimmune rheumatic diseases.

Interferons are potent antiviral cytokines that modulate immunity in response to infection or other danger signals. In addition to their antiviral functions, type I interferons (IFNα and IFNß) are important in the pathogenesis of autoimmune diseases. Type III interferons (IFNλs) were initially described as a specialized system that inhibits viral replication at epithelial barrier surfaces while limiting inflammatory damage. However, evidence now suggests that type III interferons have complex effects on both innate and adaptive immune responses and might also be pathogenic in systemic autoimmune diseases. Concentrations of IFNλs are increased in blood and tissues in a number of autoimmune rheumatic diseases, including systemic lupus erythematosus, and are further associated with specific clinical and laboratory parameters. This Review is aimed at providing a critical evaluation of the current literature on IFNλ biology and how type III interferons might contribute to immune dysregulation and tissue damage in autoimmunity. The potential effects of type III interferons on treatment strategies for autoimmune rheumatic diseases, such as interferon blockade, are also considered.

Prealbumin Correlates with C-reactive Protein in Rheumatic Musculoskeletal Diseases.

OBJECTIVE: Prealbumin is a blood component tested for nutrition monitoring, which could be affected during inflammation. This study aimed to investigate the relationships between prealbumin and C-reactive protein (CRP) in inflammatory rheumatic musculoskeletal diseases (RMDs), including Takayasu arteritis, antineutrophil cytoplasmic antibody-associated vasculitis, systemic lupus erythematosus, Behcet's disease and polymyositis/dermatomyositis. METHODS: A total of 52 healthy controls and 508 RMD patients were included. We collected 3714 clinical and laboratory records from June 2011 to August 2019, and the longest follow-up period was eleven years. The associations between prealbumin and CRP, the globulin gap, the albumin-to-globulin ratio, and IgG were evaluated. RESULTS: Prealbumin had a high correlation coefficient (r=-0.497, P<0.001), consistent changes over time with CRP, and a high area under the curve [AUC=0.777 (95% CI 0.76-0.795)] for CRP. The statistical relationship between the prealbumin and CRP was not affected by sex, ethnicity or age. Among RMDs, prealbumin showed the strongest correlation with CRP in Takayasu arteritis (r=0.607, P<0.001). In addition, a moderate relationship was observed between prealbumin and IgG, the globulin gap and the albumin-to-globulin ratio. CONCLUSION: Prealbumin is closely related to CRP in Chinese patients with five chronic inflammatory RMDs, which may be due to the influence of chronic inflammation during the course of disease.

Role of placental inflammatory mediators and growth factors in patients with rheumatic diseases with a focus on systemic sclerosis.

OBJECTIVES: Pregnancy in SSc is burdened with an increased risk of obstetric complications. Little is known about the underlying placental alterations. This study aimed to better understand pathological changes and the role of inflammation in SSc placentas. Leucocyte infiltration, inflammatory mediators and atypical chemokine receptor 2 (ACKR2) expression in SSc placentas were compared with those in other rheumatic diseases (ORD) and healthy controls (HC). METHODS: A case-control study was conducted on eight pregnant SSc patients compared with 16 patients with ORD and 16 HC matched for gestational age. Clinical data were collected. Placentas were obtained for histopathological analysis and immunohistochemistry (CD3, CD20, CD11c, CD68, ACKR2). Samples from four SSc, eight ORD and eight HC were analysed by qPCR for ACKR2 expression and by multiplex assay for cytokines, chemokines and growth factors involved in angiogenesis and inflammation. RESULTS: The number of placental CD3, CD68 and CD11 cells was significantly higher in patients affected by rheumatic diseases (SSc+ORD) compared with HC. Hepatocyte growth factor was significantly increased in the group of rheumatic diseases patients (SSc+ORD) compared with HC, while chemokine (C-C motif) ligand 5 (CCL5) was significantly higher in SSc patients compared with ORD and HC. CCL5 levels directly correlated with the number of all local inflammatory cells and higher levels were associated with histological villitis. CONCLUSIONS: Inflammatory alterations characterize placentas from rheumatic disease patients and could predispose to obstetric complications in these subjects.

Inflammasomes and Childhood Autoimmune Diseases: A Review of Current Knowledge.

Inflammasomes are multiprotein complexes capable of sensing pathogen-associated molecular patterns (PAMPs), danger-associated molecular patterns (DAMPs), and cellular perturbations. Upon stimulation, the inflammasomes activate the production of the pro-inflammatory cytokines IL-1ß and IL-18 and induce gasdermin D-mediated pyroptosis. Dysregulated inflammasome signaling could lead to hyperinflammation in response to environmental triggers, thus contributing to the pathogenesis of childhood autoimmune/autoinflammatory diseases. In this review, we group childhood rheumatic diseases into the autoinflammation to autoimmunity spectrum and discuss about the involvement of inflammasomes in disease mechanisms. Genetic mutations in inflammasome components cause monogenic autoinflammatory diseases, while inflammasome-related genetic variants have been implicated in polygenic childhood rheumatic diseases. We highlight the reported associations of inflammasome signaling-related genetic polymorphisms/protein levels with pediatric autoimmune disease susceptibility and disease course. Furthermore, we discuss about the use of IL-1 receptor antagonist as an adjunctive therapy in several childhood autoimmune diseases, including macrophage activation syndrome (MAS) and multisystem inflammatory syndrome in children (MIS-C) related to COVID-19. A comprehensive multi-cohort comparison on inflammasome gene expression profile in different pediatric rheumatic diseases is needed to identify patient subsets that might benefit from the adjunctive therapy of IL-1ß inhibitors.

The impact of shrunken pore syndrome in patient with rheumatic diseases on bone mineral metabolism.

The study aimed to investigate the influence of shrunken pore syndrome (SPS), defined as a cystatin C (CysC)-based estimated glomerular filtration rate (eGFRCysC) <60% of the creatinine (Cr)-based eGFR (eGFRCr), on bone mineral density (BMD) in patients with rheumatic diseases. A total of 831 patients with rheumatic diseases were enrolled in the study. Patients were classified into the SPS group (G-SPS) and non-SPS group (G-nSPS). The correlation between the presence of SPS and BMD of the lumbar spine (BMD_LS), BMD of the femoral neck (BMD_FN), serum parathyroid hormone (PTH) level, chronic kidney dysfunction (CKD), and parameters were evaluated statistically. The prevalence of SPS was 4.0%. Serum PTH level, tartrate-resistant acid phosphatase-5b (TRACP-5b), and eGFRCr in the G-SPS were significantly higher than in the G-nSPS, whereas BMD_LS and BMD_FN in the G-SPS were significantly lower than in the G-nSPS. Serum PTH level was significantly correlated with CysC. BMD_LS had no significant correlation with BMD_FN. The presence of SPS was the only factor that demonstrated significant negative correlation with both BMD_LS and BMD_FN. Relationship between BMD_LS and the presence of SPS was present regardless of CKD stage; however, the negative relationship between BMD_LS and serum PTH was observed only in CKD stage 1 and 2 patients. BMD_FN demonstrated significant negative correlation with serum PTH in the group with progression of CKD. These results suggest that there is a serious potential risk of osteoporosis in patients with SPS and increased PTH, and BMD_LS poses a higher risk in CKD stage 1 and 2.

Interferon-stimulated GTPases in autoimmune and inflammatory diseases: promising role for the guanylate-binding protein (GBP) family.

Human IFNs are secreted cytokines shown to stimulate the expression of over one thousand genes. These IFN-inducible genes primarily encode four major protein families, known as IFN-stimulated GTPases (ISGs), namely myxovirus-resistance proteins, guanylate-binding proteins (GBPs), p47 immunity-related GTPases and very large inducible guanosine triphosphate hydrolases (GTPases). These families respond specifically to type I or II IFNs and are well reported in coordinating immunity against some well known as well as newly discovered viral, bacterial and parasitic infections. A growing body of evidence highlights the potential contributory and regulatory roles of ISGs in dysregulated inflammation and autoimmune diseases. Our focus was to draw attention to studies that demonstrate increased expression of ISGs in the serum and affected tissues of patients with RA, SS, lupus, IBD and psoriasis. In this review, we analysed emerging literature describing the potential roles of ISGs, particularly the GBP family, in the context of autoimmunity. We also highlighted the promise and implications for therapeutically targeting IFNs and GBPs in the treatment of rheumatic diseases.

How Retroviruses and Retrotransposons in Our Genome May Contribute to Autoimmunity in Rheumatological Conditions.

More than 200 human disorders include various manifestations of autoimmunity. The molecular events that lead to these diseases are still incompletely understood and their causes remain largely unknown. Numerous potential triggers of autoimmunity have been proposed over the years, but very few of them have been conclusively confirmed or firmly refuted. Viruses have topped the lists of suspects for decades, and it seems that many viruses, including those of the Herpesviridae family, indeed can influence disease initiation and/or promote exacerbations by a number of mechanisms that include prolonged anti-viral immunity, immune subverting factors, and mechanisms, and perhaps "molecular mimicry". However, no specific virus has yet been established as being truly causative. Here, we discuss a different, but perhaps mechanistically related possibility, namely that retrotransposons or retroviruses that infected us in the past and left a lasting copy of themselves in our genome still can provoke an escalating immune response that leads to autoimmune disease. Many of these loci still encode for retroviral proteins that have retained some, or all, of their original functions. Importantly, these endogenous proviruses cannot be eliminated by the immune system the way it can eliminate exogenous viruses. Hence, if not properly controlled, they may drive a frustrated and escalating chronic, or episodic, immune response to the point of a frank autoimmune disorder. Here, we discuss the evidence and the proposed mechanisms, and assess the therapeutic options that emerge from the current understanding of this field.