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Objective Primary biliary cholangitis (PBC) is an autoimmune disease of liver that may be associated with other conditions, including autoimmune thyroid diseases. We aimed to investigate the frequency of anti-thyroperoxidase antibodies (TPO-Ab), antithyroglobulin antibodies (TG-Ab), and anti–thyrotropin receptor antibodies (TSHR-Ab) in Tunisian patients with PBC. Methods Sera of 80 patients with PBC were collected over a 9-year period. A total of 189 healthy blood donors (HBD) were included in the control group. Measurements of TPO-Ab and TG-Ab were performed using indirect enzyme-linked immunosorbent assay (ELISA). Competitive ELISA was used to assess TSHR-Ab. Results Antithyroid antibodies (ATA) were significantly more frequent in PBC patients than in the control group (13.7% vs 1.6%; P < 10−3). Out of 11 patients with ATA, 10 (90.9%) were female. Nine patients and 2 HBD had TPO-Ab (11.2% vs 1%; P < 10−3). TG-Ab were more frequent in patients than in healthy subjects but the difference was not statistically significant (6.2% vs 1.6%; P =.1). TPO-Ab and TG-Ab were present together in 3 patients (3.7%). TSHR-Ab were absent in patients and controls. Conclusion This study shows that PBC is associated with a high frequency of ATA but not TG-Ab or TSHR-Ab. [ABSTRACT FROM AUTHOR]

Little is known about the association between coronavirus disease 2019 (COVID-19) and autoimmune diseases, especially in the case of systemic lupus erythematosus (SLE). SLE patients met with many questions during the pandemic in COVID-19, such as how to minimize risk of infection, the complex pathological features and cytokine profiles, diagnosis and treatment, rational choice of drugs and vaccine, good nursing, psychological supervision, and so on. In this study, we review and discuss the multifaceted effects of the COVID-19 pandemic on patients living with SLE using the available literature. Cross-talk in implicated inflammatory pathways/mechanisms exists between SLE and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and SARS-CoV-2 displays similar clinical characteristics and immuno-inflammatory responses to SLE. Current epidemiological data inadequately assess the risk and severity of COVID-19 infection in patients with SLE. More evidence has shown that hydroxychloroquine and chloroquine cannot prevent COVID-19. During the pandemic, patients with SLE had a higher rate of hospitalization. Vaccination helps to reduce the risk of infection. Several therapies for patients with SLE infected with COVID-19 are discussed. The cases in the study can provide meaningful information for clinical diagnosis and management. Our main aim is to help preventing infection and highlight treatment options for patients with SLE infected with COVID-19. [ABSTRACT FROM AUTHOR]

Autoimmune diseases are multifactorial and include environmental as well as genetic drivers. Although much progress has been made in understanding the nature of genetic underpinnings of autoimmune disease, by comparison much less is understood regarding how environmental factors interact with genetics in the development of autoimmunity and autoimmune disease. In this report, we utilize the (New Zealand black × New Zealand white [NZB × NZW]) F1 mouse model of systemic lupus erythematosus (SLE). Mercury is a xenobiotic that is environmentally ubiquitous and is epidemiologically linked with the development of autoimmunity. Among other attributes of human SLE, (NZB × NZW) F1 mice spontaneously develop autoimmune-mediated kidney disease. It has been previously shown that if (NZB × NZW) F1 mice are exposed to inorganic mercury (Hg2+), the development of autoimmunity, including autoimmune kidney pathology, is accelerated. We now show that in these mice, the development of kidney disease is correlated with a decreased percentage of marginal zone (MZ) B-cells in the spleen. In Hg2+-intoxicated mice, kidney disease is significantly augmented, and matched by a greater decrease in MZ B-cell splenic percentages than found in control mice. In Hg2+- intoxicated mice, the decrease in MZ B-cells appears to be linked to aberrant B-cell receptor signal strength in transitory 2 (T2) B-cells, developmental precursors of MZ B-cells. [ABSTRACT FROM AUTHOR]

Background In the United States, anal squamous cell carcinoma rates have increased rapidly, particularly among women 50 or older than 66 years of age. As immunosuppression is associated with increased risk, autoimmune conditions may be associated with greater risk of anal squamous cell carcinoma. Methods We conducted a population-based, case-control study using Surveillance, Epidemiology, and End Results–Medicare data (2000-2017). Anal squamous cell carcinoma cases (n = 4505) were matched to 200 000 cancer-free controls. Using multivariable logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between 47 autoimmune conditions diagnosed before selection, identified using Medicare claims, and anal squamous cell carcinoma. The Bonferroni threshold was used to correct for multiple comparisons. Population attributable fractions were calculated for conditions nominally associated with anal squamous cell carcinoma. Results In total, 18% of anal squamous cell carcinoma cases and 15% of cancer-free controls had a diagnosed autoimmune condition. Any autoimmune condition was associated with an increased risk of anal squamous cell carcinoma (OR = 1.11, 95% CI = 1.02 to 1.21; population attributable fraction = 1.8%). Anal squamous cell carcinoma was associated with systemic lupus erythematosus (OR = 1.79, 95% CI = 1.32 to 2.42; population attributable fraction = 0.4%) and nominally associated (P  < .05) with sarcoidosis (OR = 2.09, 95% CI = 1.30 to 3.37; population-attributable fraction = 0.2%) and psoriasis (OR = 1.28, 95% CI = 1.06 to 1.56; population attributable fraction = 0.5%). Stratified by sex, only women showed statistically significant associations for systemic lupus erythematosus (OR = 1.97, 95% CI = 1.46 to 2.68). Statistically significant interaction was observed by sex for psoriasis (men vs women: OR = 1.68 [95% CI = 1.03 to 4.28] vs OR = 1.12 [95% CI = 0.88 to 1.43]) and polymyalgia rheumatica (OR = 0.33 [95% CI = 0.12 to 0.89] vs OR = 0.99 [95% CI = 0.75 to 1.30]). Conclusion Systemic lupus erythematosus, sarcoidosis, and psoriasis were associated with a moderately increased risk of anal squamous cell carcinoma. Given these conditions' rarity and moderate associations with anal squamous cell carcinoma, autoimmune diseases cannot explain the rising trend in this disease. [ABSTRACT FROM AUTHOR]

Objective Flares of autoimmune rheumatic diseases (AIRDs) following COVID-19 vaccination are a particular concern in vaccine-hesitant individuals. Therefore, we investigated the incidence, predictors and patterns of flares following vaccination in individuals living with AIRDs, using global COVID-19 Vaccination in Autoimmune Diseases (COVAD) surveys. Methods The COVAD surveys were used to extract data on flare demographics, comorbidities, COVID-19 history, and vaccination details for patients with AIRDs. Flares following vaccination were identified as patient-reported (a), increased immunosuppression (b), clinical exacerbations (c) and worsening of PROMIS scores (d). We studied flare characteristics and used regression models to differentiate flares among various AIRDs. Results Of 15 165 total responses, the incidence of flares in 3453 patients with AIRDs was 11.3%, 14.8%, 9.5% and 26.7% by definitions a–d, respectively. There was moderate agreement between patient-reported and immunosuppression-defined flares (K  = 0.403, P  = 0.022). Arthritis (61.6%) and fatigue (58.8%) were the most commonly reported symptoms. Self-reported flares were associated with higher comorbidities (P  = 0.013), mental health disorders (MHDs) (P  < 0.001) and autoimmune disease multimorbidity (AIDm) (P  < 0.001). In regression analysis, the presence of AIDm [odds ratio (OR) = 1.4; 95% CI: 1.1, 1.7; P  = 0.003), or a MHD (OR = 1.7; 95% CI: 1.1, 2.6; P  = 0.007), or being a Moderna vaccine recipient (OR = 1.5; 95% CI: 1.09, 2.2; P  = 0.014) were predictors of flares. Use of MMF (OR = 0.5; 95% CI: 0.3, 0.8; P  = 0.009) and glucocorticoids (OR = 0.6; 95% CI: 0.5, 0.8; P  = 0.003) were protective. A higher frequency of patients with AIRDs reported overall active disease post-vaccination compared with before vaccination (OR = 1.3; 95% CI: 1.1, 1.5; P  < 0.001). Conclusion Flares occur in nearly 1 in 10 individuals with AIRDs after COVID vaccination; people with comorbidities (especially AIDm), MHDs and those receiving the Moderna vaccine are particularly vulnerable. Future avenues include exploring flare profiles and optimizing vaccine strategies for this group. [ABSTRACT FROM AUTHOR]

Summary: Interleukin-11 is a cytokine from the IL-6 family of cytokines that includes IL-6 and oncostatin-M. Initially described for its role in platelet generation, it is now appreciated that this cytokine has multiple functions. Recently it has been found that IL-11 is critical in fibrosis in multiple different organ systems and systemically as in the autoimmune disease systemic sclerosis. Animal models of fibrosis have determined that animals with IL-11 receptor deletions have retarded fibrosis and that in wild-type animals IL-11 is found at the organ of fibrosis. Recent evidence suggests that IL-11 may be a master regulator of fibrosis regardless of end target organ. With the development of neutralizing antibodies targeting the cytokine in pre-clinical models this could be a possible therapeutic, in a disease in which no specific therapies exist. This review appraises the evidence of the role of IL-11 in tissue fibrosis, its signalling properties, and therapeutic targeting. The review ends with an appraisal of indications for which IL-11 modulation is targeted. IL-11 is a key IL-6 family cytokine that has recently been associated with tissue fibrosis. [ABSTRACT FROM AUTHOR]

Post-acute cardiac sequelae, following SARS-CoV-2 infection, are well recognized as complications of COVID-19. We have previously shown the persistence of autoantibodies against antigens in skin, muscle, and heart in individuals following severe COVID-19; the most common staining on skin tissue displayed an inter-cellular cement pattern consistent with antibodies against desmosomal proteins. Desmosomes play a critical role in maintaining the structural integrity of tissues. For this reason, we analyzed desmosomal protein levels and the presence of anti-desmoglein (DSG) 1, 2, and 3 antibodies in acute and convalescent sera from patients with COVID-19 of differing clinical severity. We find increased levels of DSG2 protein in sera from acute COVID-19 patients. Furthermore, we find that DSG2 autoantibody levels are increased significantly in convalescent sera following severe COVID-19 but not in hospitalized patients recovering from influenza infection or healthy controls. Levels of autoantibody in sera from patients with severe COVID-19 were comparable to levels in patients with non-COVID-19-associated cardiac disease, potentially identifying DSG2 autoantibodies as a novel biomarker for cardiac damage. To determine if there was any association between severe COVID-19 and DSG2, we stained post-mortem cardiac tissue from patients who died from COVID-19 infection. This confirmed DSG2 protein within the intercalated discs and disruption of the intercalated disc between cardiomyocytes in patients who died from COVID-19. Our results reveal the potential for DSG2 protein and autoimmunity to DSG2 to contribute to unexpected pathologies associated with COVID-19 infection. We find raised levels of anti-DSG2 autoantibodies in sera from individuals following severe COVID-19. Staining of post-mortem cardiac tissue from individuals that died from COVID-19 with an anti-DSG2 antibody revealed disruption of the intercalated disc between cardiomyocytes that was consistent with separation of the DSG2 protein homodimer. Our results reveal the potential for DSG2 protein and autoimmunity to DSG2 to contribute to unexpected pathologies associated with COVID-19 infection. [ABSTRACT FROM AUTHOR]

For decades, infections have been recognized as strong stimulators of the immune system and subsequently serve as a trigger for autoimmunity and autoimmune diseases. In regard to SARS-CoV-2 and COVID-19 and the kidneys, glomerular diseases - those related to infections - are a classic example of infectious-related autoimmune kidney disorder. [Extracted from the article]

The RNA-binding proteins Roquin-1/2 and Regnase-1 exert essential regulation by controlling pro-inflammatory mRNA expression to prevent autoimmune disease. More recently, inhibition of this post-transcriptional gene regulatory program has been demonstrated to enable enhanced anti-tumor responses by tumor antigen-specific CD8+ T cells. In this review, we describe the functions of these RNA-binding proteins and the phenotypes that arise in association with genetic inhibition or inactivation. We discuss how inducible inactivation of the system reprograms CD4+ and CD8+ T cell fates by changing cell metabolism, activation, differentiation or effector/memory decisions. We furthermore outline what we need to know to precisely modulate this system in order to dampen autoimmune reactions or boost the efficacy of adoptively transferred T cells or chimeric antigen receptor (CAR) T cells in cancer immunotherapies. [ABSTRACT FROM AUTHOR]

The HLA region is the major genetic risk determinant of Type 1 diabetes. How non-HLA loci contribute to the genetic risk is incompletely understood, but there are indications that at least some impact progression of asymptomatic autoimmunity. We examined whether SNPs in 7 susceptibility loci (INS , SH2B3 , PTPN2 , PTPN22 , CTLA4 , CLEC16A, and IL2RA) could improve prediction of the progression from single to multiple autoantibody positivity, and from there on to diagnosis. SNPs were genotyped in persistently autoantibody positive relatives by allelic discrimination qPCR and disease progression was studied by multivariate Cox regression analysis. In our cohort, only the CTLA4 GA genotype (rs3087243, P = 0.002) and the CLEC16A AA genotype (rs12708716, P = 0.021) were associated with accelerated progression from single to multiple autoantibody positivity, but their effects were restricted to presence of HLA-DQ2/DQ8, and IAA as first autoantibody, respectively. The interaction of CTLA4 and HLA-DQ2/DQ8 overruled the effect of DQ2/DQ8 alone. The HLA-DQ2/DQ8-mediated risk of progression to multiple autoantibodies nearly entirely depended on heterozygosity for CTLA4. The SH2B3 TT genotype (rs3184504) was protective for HLA-DQ8 positive subjects (P = 0.003). At the stage of multiple autoantibodies, only the CTLA4 GA genotype was a minor independent risk factor for progression towards clinical diabetes (P = 0.034). Our study shows that non-HLA polymorphisms impact progression of islet autoimmunity in a subgroup-, stage- and SNP-specific way, suggesting distinct mechanisms. If confirmed, these findings may help refine risk assessment, follow-up, and prevention trials in risk groups. [ABSTRACT FROM AUTHOR]

Mitochondria are the controllers of cell metabolism and are recognized as decision makers in cell death pathways, organizers of cytoplasmic signaling networks, managers of cellular stress responses, and regulators of nuclear gene expression. Cells of the immune system are particularly dependent on mitochondrial resources, as they must swiftly respond to danger signals with activation, trafficking, migration, and generation of daughter cells. Analogously, faulty immune responses that lead to autoimmunity and tissue inflammation rely on mitochondria to supply energy, cell building blocks and metabolic intermediates. Emerging data endorse the concept that mitochondrial fitness, and the lack of it, is of particular relevance in the autoimmune disease rheumatoid arthritis (RA) where deviations of bioenergetic and biosynthetic flux affect T cells during early and late stages of disease. During early stages of RA, mitochondrial deficiency allows naïve RA T cells to lose self-tolerance, biasing fundamental choices of the immune system toward immune-mediated tissue damage and away from host protection. During late stages of RA, mitochondrial abnormalities shape the response patterns of RA effector T cells engaged in the inflammatory lesions, enabling chronicity of tissue damage and tissue remodeling. In the inflamed joint, autoreactive T cells partner with metabolically reprogrammed tissue macrophages that specialize in antigen-presentation and survive by adapting to the glucose-deplete tissue microenvironment. Here, we summarize recent data on dysfunctional mitochondria and mitochondria-derived signals relevant in the RA disease process that offer novel opportunities to deter autoimmune tissue inflammation by metabolic interference. [ABSTRACT FROM AUTHOR]

Summary: Immune homeostasis is heavily dependent on the action of regulatory T cells (Tregs) which act to suppress the activation of many immune cell types including autoreactive conventional T cells. A body of evidence has shown that Tregs are intrinsically defective in many common autoimmune diseases, and gene polymorphisms which increase the susceptibility of autoimmune disease development have implicated the interleukin-2 (IL-2) signaling pathway as a key dysregulated mechanism. IL-2 is essential for Treg function and survival, and Tregs are highly sensitive to low levels of this cytokine in their environment. This review will revisit the rationale behind using low-dose IL-2 as a therapy to treat autoimmune diseases and evaluate the outcomes of trials to date. Furthermore, novel engineered IL-2 therapies with increased Treg specificity have shown promise in pre-clinical studies and human clinical trials for some agents have begun. Future studies will determine whether low-dose IL-2 or engineered IL-2 therapies can change the course of autoimmune and inflammatory diseases in patients. [ABSTRACT FROM AUTHOR]

Summary: While inflammation may not be the cause of disease, it is well known that it contributes to disease pathogenesis across a multitude of peripheral and central nervous system disorders. Chronic and overactive inflammation due to an effector T-cell-mediated aberrant immune response ultimately leads to tissue damage and neuronal cell death. To counteract peripheral and neuroinflammatory responses, research is being focused on regulatory T cell enhancement as a therapeutic target. Regulatory T cells are an immunosuppressive subpopulation of CD4+ T helper cells essential for maintaining immune homeostasis. The cells play pivotal roles in suppressing immune responses to maintain immune tolerance. In so doing, they control T cell proliferation and pro-inflammatory cytokine production curtailing autoimmunity and inflammation. For nervous system pathologies, Treg are known to affect the onset and tempo of neural injuries. To this end, we review recent findings supporting Treg's role in disease, as well as serving as a therapeutic agent in multiple sclerosis, myasthenia gravis, Guillain–Barre syndrome, Parkinson's and Alzheimer's diseases, and amyotrophic lateral sclerosis. An ever-broader role for Treg in the control of neurologic disease has been shown for traumatic brain injury, stroke, neurotrophic pain, epilepsy, and psychiatric disorders. To such ends, this review serves to examine the role played by Tregs in nervous system diseases with a focus on harnessing their functional therapeutic role(s). Regulatory T cell:T effector cell imbalances resulting from genetic mutation, neurotoxic environmental factors, developmental disorders, and/or tissue injury lead to an aberrant proinflammatory immune response in a multitude of nervous system pathologies. To counteract the peripheral and neuroinflammatory responses, research is being focused on regulatory T cell enhancement as a therapeutic target in both peripheral and central nervous system disease. [ABSTRACT FROM AUTHOR]

B cells are classically considered solely as antibody-producing cells driving humoral immune responses to foreign antigens in infections and vaccinations as well as self-antigens in pathological settings such as autoimmunity. However, it has now become clear that B cells can also secrete a vast array of cytokines, which influence both pro- and anti-inflammatory immune responses. Indeed, similarly to T cells, there is significant heterogeneity in cytokine-driven responses by B cells, ranging from the production of pro-inflammatory effector cytokines such as IL-6, through to the release of immunosuppressive cytokines such as IL-10. In this review, focusing on human B cells, we summarize the key findings that have revealed that cytokine-producing B cell subsets have critical functions in healthy immune responses and contribute to the pathophysiology of autoimmune diseases. B cells are classically considered solely as antibody-producing cells driving humoral immune responses to foreign antigens in infections and vaccinations as well as self-antigens in pathological settings such as autoimmunity. However, it has now become clear that B cells can also secrete a vast array of cytokines, which influence both pro- and anti-inflammatory immune responses. In this review, focusing on human B cells, we summarise the key findings that have revealed that cytokine-producing B cell subsets have critical functions in healthy immune responses and contribute to the pathophysiology of autoimmune diseases. [ABSTRACT FROM AUTHOR]

Summary: Our understanding of the B-cell subsets found in human blood and their functional significance has advanced greatly in the past decade. This has been aided by the evolution of high dimensional phenotypic tools such as mass cytometry and single-cell RNA sequencing which have revealed heterogeneity in populations that were previously considered homogenous. Despite this, there is still uncertainty and variation between studies as to how B-cell subsets are identified and named. This review will focus on the most commonly encountered subsets of B cells in human blood and will describe gating strategies for their identification by flow and mass cytometry. Important changes to population frequencies and function in common inflammatory and autoimmune diseases will also be described. This review describes gating strategies to identify B-cell subsets in blood and the changes that occur in these subsets with inflammatory and autoimmune diseases. [ABSTRACT FROM AUTHOR]

Summary: Neutrophils were long considered to be a short-lived homogenous cell population, limited to their role as first responders in anti-bacterial and -fungal immunity. While it is true that neutrophils are first to infiltrate the site of infection to eliminate pathogens, growing evidence suggests their functions could extend beyond those of basic innate immune cells. Along with their well-established role in pathogen elimination, utilizing effector functions such as phagocytosis, degranulation, and the deployment of neutrophil extracellular traps (NETs), neutrophils have recently been shown to possess antigen-presenting capabilities. Moreover, the identification of different subtypes of neutrophils points to a multifactorial heterogeneous cell population with great plasticity in which some subsets have enhanced pro-inflammatory characteristics, while others seem to behave as immunosuppressors. Interestingly, the aberrant presence of activated neutrophils with a pro-inflammatory profile in several systemic and organ-specific autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), multiple sclerosis (MS), and type 1 diabetes (T1D) could potentially be exploited in novel therapeutic strategies. The full extent of the involvement of neutrophils, and more specifically that of their various subtypes, in the pathophysiology of autoimmune diseases is yet to be elucidated. At odds with their supportive roles in anti-microbial immunity and tissue regeneration/repair, neutrophils have been shown to play a deleterious role in the pathology of several autoimmune diseases. This is not surprising considering their wide range of functions, their biotoxicity, and their sheer abundance in the circulation. Rapidly deployed to the site of inflammation and ready to unleash their anti-microbial and immunomodulatory functions, neutrophils are capable of inflicting a lot of collateral damage to the surrounding tissue when activated in the context of autoimmunity. [ABSTRACT FROM AUTHOR]

Type 1 diabetes (T1D) is an autoimmune disease resulting in the destruction of the insulin-producing pancreatic beta cells. Disease progression occurs along a trajectory from genetic risk, the development of islet autoantibodies, and autoreactive T cells ultimately progressing to clinical disease. Natural history studies and mechanistic studies linked to clinical trials have provided insight into the role of the immune system in disease pathogenesis. Here, we review our current understanding of the underlying etiology of T1D, focusing on the immune cell types that have been implicated in progression from pre-symptomatic T1D to clinical diagnosis and established disease. This knowledge has been foundational for the development of immunotherapies aimed at the prevention and treatment of T1D. This review summarizes the current understanding of the underlying immunopathology of T1D, focusing on the immune cell types implicated in progression from pre-symptomatic T1D to clinical diagnosis and established disease. It also highlights how this knowledge is driving the development of immunotherapies aimed at the prevention and treatment of T1D. [ABSTRACT FROM AUTHOR]

The clinical usefulness of post-diagnosis islet autoantibody levels is unclear and factors that drive autoantibody persistence are poorly defined in type 1 diabetes (T1D). Our aim was to characterise the longitudinal loss of islet autoantibody responses after diagnosis in a large, prospectively sampled UK cohort. Participants with T1D [n = 577] providing a diagnosis sample [range −1.0 to 2.0 years] and at least one post-diagnosis sample (<32.0 years) were tested for autoantibodies to glutamate decarboxylase 65 (GADA), islet antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A). Select HLA and non-HLA SNPs were considered. Non-genetic and genetic factors were assessed by multivariable logistic regression models for autoantibody positivity at initial sampling and autoantibody loss at final sampling. For GADA, IA-2A, and ZnT8A, 70.8%, 76.8%, and 40.1%, respectively, remained positive at the final sampling. Non-genetic predictors of autoantibody loss were low baseline autoantibody titres (P < 0.0001), longer diabetes duration (P < 0.0001), and age-at-onset under 8 years (P < 0.01–-0.05). Adjusting for non-genetic covariates, GADA loss was associated with low-risk HLA class II genotypes (P = 0.005), and SNPs associated with autoimmunity RELA/11q13 (P = 0.017), LPP/3q28 (P = 0.004), and negatively with IFIH1/2q24 (P = 0.018). IA-2A loss was not associated with genetic factors independent of other covariates, while ZnT8A loss was associated with the presence of HLA A*24 (P = 0.019) and weakly negatively with RELA/11q13 (P = 0.049). The largest longitudinal study of islet autoantibody responses from diagnosis of T1D shows that autoantibody loss is heterogeneous and influenced by low titres at onset, longer duration, earlier age-at-onset, and genetic variants. These data may inform clinical trials where post-diagnosis participants are recruited. Loss of islet autoantibodies after diabetes onset is heterogeneous but influenced by non-genetic and genetic factors. [ABSTRACT FROM AUTHOR]

Summary: Autoimmune diseases have long been known to share a common pathogenesis involving a dysregulated immune system with a failure to recognize self from non-self-antigens. This immune dysregulation is now increasingly understood to be induced by environmental triggers in genetically predisposed individuals. Although several external environmental triggers have been defined in different autoimmune diseases, much attention is being paid to the role of the internal micro-environment occupied by the microbiome, which was once termed "the forgotten organ." In this regard, the gut microbiome, serving as an intermediary between some of those external environmental effectors and the immune system, helps programming of the immune system to be tolerant to innocent external and self-antigens. However, in the presence of perturbed gut microbiota (dysbiosis), the immune system could be erroneously directed in favor of pro-inflammatory pathways to instigate different autoimmune processes. An accumulating body of evidence, including both experimental and human studies (observational and interventional), points to the role of the gut microbiome in different autoimmune diseases. Such evidence could provide a rationale for gut microbiome manipulation with therapeutic and even preventative intent in patients with established or predisposed to autoimmune diseases, respectively. Perturbations of the gut microbiome have been delineated in some immune mediated diseases, IBD in particular. However, such patterns of disturbance (microbiome signatures) and related pathogenetic roles of the gut microbiome are context dependent and cannot be generalized in the same exact way to other autoimmune disorders, and the contribution of the gut microbiome to different disease phenotypes has to be precisely defined. In this review, we revise the evidence for a role of the gut microbiome in various autoimmune diseases and possible mechanisms mediating such a role. Several studies point to a role of gut microbiome in the development and progress of different autoimmune diseases. In this review, we revise the evidence and potential mechanism for such a role. This evidence could provide a strong rationale for instigating future clinical trials of gut microbiome manipulation as a therapeutic intervention in patients with established autoimmune diseases. [ABSTRACT FROM AUTHOR]

Background: Attention-deficit/hyperactivity disorder (ADHD) has been associated with several autoimmune diseases (AD), both within individuals and across relatives, implying common underlying genetic or environmental factors in line with studies indicating that immunological mechanisms are key to brain development. To further elucidate the relationship between ADHD and autoimmunity we performed a population-wide familial co-aggregation study.Methods: We linked Swedish national registries, defined a birth cohort with their biological relatives and identified individuals diagnosed with ADHD and/or 13 ADs. The cohort included 5 178 225 individuals born between 1960 and 2010, of whom 118 927 (2.30%) had been diagnosed with ADHD. We then investigated the associations between ADHD and ADs within individuals and across relatives, with logistic regression and structural equation modelling.Results: Within individuals, ADHD was associated with a diagnosis of any of the 13 investigated ADs (adjusted odds ratio (OR) =1.34, 95% confidence interval (CI) = 1.30-1.38) as well as several specific ADs. Familial co-aggregation was observed. For example, ADHD was associated with any of the 13 ADs in mothers (OR = 1.29, 95% CI = 1.26-1.32), fathers (OR = 1.14, 95% CI = 1.11-1.18), full siblings (OR = 1.19, 95% CI = 1.15-1.22), aunts (OR = 1.12, 95% CI = 1.10-1.15), uncles (OR = 1.07, 95% CI = 1.05-1.10) and cousins (OR = 1.04, 95% CI = 1.03-1.06). Still, the absolute risks of AD among those with ADHD were low. The genetic correlation between ADHD and a diagnosis of any of the investigated ADs was 0.13 (95% CI = 0.09-0.17) and the environmental correlation was 0.02 (95% CI = -0.03-0.06).Conclusions: We found that ADHD and ADs co-aggregate among biological relatives, indicating that the relationship between ADHD and autoimmune diseases may in part be explained by shared genetic risk factors. The patterns of familial co-aggregation of ADHD and ADs do not readily support a role of maternal immune activation in the aetiology of ADHD. The findings have implications for aetiological models of ADHD. However, screening for autoimmunity among individuals with ADHD is not warranted. [ABSTRACT FROM AUTHOR]

In the patients with neurological autoimmune diseases such as anti-IgLON5 disease, insomnia symptoms are very common. Clinical diagnosis of the anti-IgLON5 disease is usually made when neurodegenerative processes have occurred. To find the early signs of anti-IgLON5 disease, we evaluate the presence of IgLON5 autoantibodies in the serum of patients with chronic insomnia disease. Based on video-polysomnography, 22 individuals with isolated chronic insomnia disease were found. A control group of 22 healthy people was chosen using the Pittsburgh Sleep Quality Index (PSQI). An indirect immunofluorescence cell-based test of serum anti-IgLON5 antibodies was used to investigate IgLON5 autoimmunity. Anti-IgLON5 antibodies were detected in the serum of four of these patients with the titer of 1/10. The presence of IgLON5 autoantibodies in some patients with chronic insomnia disease can be considered a causing factor of insomnia which can be effective in more specific treatments of these patients. Moreover, the recognition of anti-IgLON5 disease in the early stages and before the progression of tauopathies can be useful in effective and timely treatment. Clinical diagnosis of anti-IgLON5 disease is usually made when neurodegenerative processes have occurred. Considering the importance of sleep deprivation in predicting of neurodegenerative disorders, the present study aimed to determine the existence of IgLON5 autoantibodies in serum from patients with isolated chronic insomnia disease. The presence of IgLON5 autoantibodies in some patients with chronic insomnia disease can be considered a causing factor of insomnia which can be effective in more specific treatments of these patients. [ABSTRACT FROM AUTHOR]

The major histocompatibility complex (MHC) is a central molecule in the immune system. The MHC is also a highly polymorphic gene that is the most strongly involved in susceptibility to many autoimmune diseases. Therefore, the elucidation of the mechanism by which specific MHC alleles are involved in autoimmune disease susceptibility is important to our understanding of the pathogenesis of autoimmune diseases. Specific autoantibody production is observed in many autoimmune diseases, but the mechanism underlying their production remains unclear. We have found that MHC class II molecules exhibit a chaperone-like function to transport misfolded proteins in the endoplasmic reticulum to the outside of cells. Furthermore, misfolded proteins transported to the cell surface by MHC class II molecules of autoimmune disease risk alleles are major autoantibody targets. In this article, I propose a novel mechanism underlying autoimmune diseases mediated by misfolded proteins complexed with MHC class II molecules. [ABSTRACT FROM AUTHOR]

Current literature regarding systemic autoimmune diseases in X‐chromosome aneuploidies is scarce and limited to case reports. Our aim was to evaluate the frequency of anti‐nuclear (ANAs), extractable nuclear (ENA), anti‐double‐stranded DNA (dsDNAs), anti‐smooth muscle (ASMAs) and anti‐mitochondrial (AMAs) antibodies in a large cohort of adults with Klinefelter's syndrome (KS, 47,XXY) and rare higher‐grade sex chromosome aneuploidies (HGAs) for the first time. Sera from 138 X‐chromosome aneuploid patients [124 adult patients with 47,XXY KS and 14 patients with HGA (six children, eight adults)] and 50 age‐matched 46,XY controls were recruited from the Sapienza University of Rome (2007–17) and tested for ANAs, ENAs, anti‐dsDNAs, ASMAs and AMAs. Non‐organ‐specific immunoreactivity was found to be significantly higher in patients with 47,XXY KS (14%) than in the controls (2%, p = 0.002). Among all the antibodies investigated, only ANAs were observed significantly more frequently in patients with 47,XXY KS (12.1%) than in the controls (2%, p = 0.004). No anti‐dsDNA immunoreactivity was found. Stratifying by testosterone replacement therapy (TRT), non‐organ‐specific autoantibody frequencies were higher in TRT‐naive (p = 0.01) and TRT‐treated groups than in controls. No patients with HGA were found positive for the various autoantibodies. Non‐organ‐specific autoantibodies were significantly present in 47,XXY adult patients. Conversely, HGAs did not appear to be target of non‐organ‐specific immunoreactivity, suggesting that KS and HGAs should be considered as two distinct conditions. The classification and diagnosis of systemic autoimmune diseases is frequently difficult. To support a correct clinical evaluation of KS disease and to prevent eventual secondary irreversible immune‐mediated damages, we highlight the importance of screening for non‐organ‐specific autoimmunity in Klinefelter's syndrome. [ABSTRACT FROM AUTHOR]

Much is said about precision medicine, but its real significance and potential are far from certain. Several studies in each of the autoimmune diseases have provided important insights into molecular pathways, but the use of molecular studies, particularly those looking into transcriptome pathways, has seldom approached the possibility of using the data for disease stratification and then for prediction, or for diagnosis. Only the type I IFN signature has been considered for therapeutic purposes, particularly in the case of SLE. This review provides an update on precision medicine, on what can be translated into clinical practice and on what single-cell molecular studies contribute to our knowledge of autoimmune diseases, focusing on a few examples. The main message is that we should try to move from precision medicine of established diseases to preventive medicine in order to predict the development of disease. [ABSTRACT FROM AUTHOR]

Objective: To describe clinical features and long-term prognosis in patients with Good syndrome (GS). Methods: We retrospectively reviewed medical records of GS patients at Peking Union Medical College Hospital from January 2001 to May 2019. Data regarding clinical manifestations and treatments were collected. Patients were routinely followed-up via clinical and telephone interviews, and survival analysis was performed with Kaplan-Meier analysis. Results: Twenty-four patients were identified, including eight males and 16 females, with a median age at diagnosis of 58 years (interquartile range [IQR], 52-62 years). Twelve patients (50%) had autoimmune manifestations. Multi-organ involvements included musculoskeletal (37.5%), respiratory (33.3%), gastrointestinal (29.2%), hematologic (29.2%) systems, et.al. Infections were detected in 23 (95.8%) patients, mostly located in lung (69.6%), blood (26.1%), and gastrointestinal tract (21.7%). Thymectomy was performed in 23 patients, with the most common histology of type AB (10, 47.6%). Twenty-one patients were consecutively followed-up with a median follow-up of 84 (IQR, 48-116) months and 11 (52.4%) died, mainly due to infection (8/11, 72.7%). The 5- and 10-year survival rates were 90% (95% confidence interval [CI], 77.8-100%) and 38.5% (95% CI, 19.6-75.5%), respectively. Conclusion: GS patients tended to present with various infections and autoimmune manifestations. The 10-year survival rate from the Chinese population was poor, mainly due to infections. [ABSTRACT FROM AUTHOR]

Summary: Human B cells could be divided into four classical subsets based on CD27 and immunoglobulin (Ig)D expression. Distinct from the other three well‐studied subsets, CD27−IgD− B cells, also termed as double‐negative (DN) B cells, have long been neglected. However, in recent years emerging evidence shows that DN B cells are unique memory B cells with important functions. They are expanded in a variety of diseases, especially in autoimmune diseases, contributing to the disease pathogenesis. Here, we briefly review the studies on DN B cells, including their origins, characteristics, subsets and roles in diseases, to try to bring new insights into this under‐recognized B cell subset. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a disease of unknown aetiology that causes irreversible joint destruction and has been known to present with not only various extra-articular symptoms, but also various autoimmune disorders. Mucous membrane pemphigoid (MMP) is a chronic autoimmune disease characterised by inflamed and eroded mucosa. The prognosis of MMP can be poor, so early diagnosis and prompt initiation of therapy are necessary for optimal management. Here, we report a rare case of RA complicated with MMP involving a 68-year-old woman admitted to our hospital because of hoarseness and symmetrical narrowing of the eye fissures. She presented with bilateral coxalgia and had been diagnosed with RA 24 years earlier. Oral methotrexate was prescribed, but subsequently discontinued, and this was followed by treatment with tocilizumab 3 years earlier. Tocilizumab was discontinued because of financial distress 5 months earlier, after which her RA disease activity worsened. She presented to our hospital after further worsening of her eye-opening difficulty. Physical and laboratory examinations led to a diagnosis of MMP. Her sputum, cough, throat discomfort, conjunctival congestion, mucous erosion, and blistering promptly disappeared after treatment with rituximab (500 mg per week for 4 weeks). She subsequently recovered her vocalisation ability, and her hoarseness, dysphagia, and eye-opening difficulty gradually improved, but not completely. This case suggests that that RA and MMP share common immunological mechanisms. Therefore, MMP should be considered when encountering patients with RA who present with systemic membrane mucous disorders. [ABSTRACT FROM AUTHOR]