Classification and Antigen Molecules of Autoimmune Bullous Diseases.

Autoimmune bullous diseases (AIBDs), which are a group of tissue-specific autoimmune diseases of the skin, present with various blistering lesions on the skin and mucous membranes, and show autoantibodies of IgG, IgA and IgM against epidermal cell surfaces and basement membrane zone. To date, AIBDs have been classified into a number of distinct subtypes by clinical and histopathological findings, and immunological characteristics. In addition, various biochemical and molecular biological studies have identified various novel autoantigens in AIBDs, which has resulted in proposals of new subtypes of AIBDs. In this article, we summarized various distinct AIBDs, and proposed the latest and most comprehensive classification of AIBDs with their autoantigen molecules.

Miopatía necrotizante autoinmune: Presentación de un caso clínico / Autoimmune necrotizing myositis: Presentation of a clinical case

Las miopatías inflamatorias (MI) son un grupo heterogéneo de enfermedades musculares de rara ocurrencia, caracterizadas por inflamación de los distintos componentes del tejido muscular, ya sea de forma aislada o, más comúnmente, en el contexto de una afección sistémica. Las miopatías necrotizantes inmunomediadas (MNIM) constituyen un subtipo de miopatía inflamatoria caracterizada por debilidad muscular proximal, necrosis de miofibrillas con mínimo infiltrado celular inflamatorio en la biopsia muscular e infrecuente compromiso extramuscular asociado1. Si bien existen similitudes clínicas e histopatológicas, el espectro de las miopatías inflamatorias es considerablemente variable. Por este motivo, es fundamental realizar estudios complementarios para la identificación correcta del subtipo de MI a fin de determinar su pronóstico e implementar un adecuado tratamiento. Se presenta el caso de una paciente de 29 años, sin antecedentes personales y heredofamiliares de enfermedad autoinmune ni antecedentes patológicos relevantes, que consulta a la Guardia Médica de nuestra Institución por un cuadro de dolor e impotencia funcional en los cuatro miembros, con debilidad muscular a predominio de cintura escapular y en menor medida pelviana, acompañado de astenia, tendencia al sueño e hiporreactividad.

Inflammatory myopathies (IM) or myositis are a heterogeneous group of muscle diseases of rare occurrence. Such diseases are characterized by inflammation of the different components of muscle tissue, which can occur either in isolation or, more commonly, as part of a systemic disorder. Immune-mediated necrotizing myopathies (IMNM) are a type of autoimmune myopathy characterized by proximal muscle weakness, myofiber necrosis with minimal inflammatory cell infiltrate on muscle biopsy and infrequent extramuscular involvement1. Even though there are clinical and histopathological similarities. The spectrum of inflammatory myopathies is considerably variable. Therefore, the performance of complementary studies is essential for the proper identification of the IM subtype to contribute accurately on treatment so determine the better prognosis. The present article shows the case of a young 29 years old, with no personal and family history background of autoimmune disease and no relevant pathological background. The patient consulted the medical ward of the Institution with pain, functional impairment of upper and lower extremities, muscle weakness mainly located in the pectoral girdle area and, although to a lesser degree, in the pelvic girdle area. It was also associated with asthenia, tendency to drowsiness and hyporeactivity.

Recognition of seizure semiology and semiquantitative FDG-PET analysis of anti-LGI1 encephalitis.

AIMS: Anti-leucine-rich glioma-inactivated 1 (LGI1) autoimmune encephalitis (AE) is characterized by complex manifestations of seizures. Here, we report a new seizure semiology, attempt to classify the disease by semiology type, and explore the metabolic pattern of each group. METHODS: Anti-LGI1 AE patients were retrospectively screened between May 2014 and September 2019 in our tertiary epilepsy center. All enrolled patients had seizures during long-range video electroencephalogram (EEG) recordings, and all patients (except one) underwent [18 F] fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) scans. Voxel-based metabolic analysis and z-distribution analysis were carried out to determine the metabolic pattern. RESULTS: Thirty-three patients were enrolled. According to the patients' seizure semiology, we divided the patients into four groups: focal impaired awareness seizures (FIAS, n = 17), faciobrachial dystonic seizures (FBDS)-only (n = 6), FBDS-plus (n = 8), and focal aware motor seizures (FAMS) (n = 2). No significant differences were found in the clinical manifestations or accessory tests except for the onset age (FIAS < FBDS-plus) and seizure semiology. This was the first study to extensively describe the clinical manifestations and EEG of FAMS in anti-LGI1 AE patients. In addition, we found that the patients with different semiologies all showed a wide range of abnormal metabolism, which is not limited to the temporal regions and basal ganglia, and extends far beyond our previous interpretation of FDG-PET data. CONCLUSION: Our results showed that FAMS can serve as a rare indicative seizure semiology of anti-LGI1 AE and that individuals with this disease exhibited widespread functional network alterations.

Integrative Analysis Reveals a Molecular Stratification of Systemic Autoimmune Diseases.

OBJECTIVE: Clinical heterogeneity, a hallmark of systemic autoimmune diseases, impedes early diagnosis and effective treatment, issues that may be addressed if patients could be classified into groups defined by molecular pattern. This study was undertaken to identify molecular clusters for reclassifying systemic autoimmune diseases independently of clinical diagnosis. METHODS: Unsupervised clustering of integrated whole blood transcriptome and methylome cross-sectional data on 955 patients with 7 systemic autoimmune diseases and 267 healthy controls was undertaken. In addition, an inception cohort was prospectively followed up for 6 or 14 months to validate the results and analyze whether or not cluster assignment changed over time. RESULTS: Four clusters were identified and validated. Three were pathologic, representing "inflammatory," "lymphoid," and "interferon" patterns. Each included all diagnoses and was defined by genetic, clinical, serologic, and cellular features. A fourth cluster with no specific molecular pattern was associated with low disease activity and included healthy controls. A longitudinal and independent inception cohort showed a relapse-remission pattern, where patients remained in their pathologic cluster, moving only to the healthy one, thus showing that the molecular clusters remained stable over time and that single pathogenic molecular signatures characterized each individual patient. CONCLUSION: Patients with systemic autoimmune diseases can be jointly stratified into 3 stable disease clusters with specific molecular patterns differentiating different molecular disease mechanisms. These results have important implications for future clinical trials and the study of nonresponse to therapy, marking a paradigm shift in our view of systemic autoimmune diseases.

Hypothalamitis: A Novel Autoimmune Endocrine Disease. A Literature Review and Case Report.

CONTEXT: The relationship between the endocrine system and autoimmunity has been recognized for a long time and one of the best examples of autoimmune endocrine disease is autoimmune hypophysitis. A better understanding of autoimmune mechanisms and radiological, biochemical, and immunological developments has given rise to the definition of new autoimmune disorders including autoimmunity-related hypothalamic-pituitary disorders. However, whether hypothalamitis may occur as a distinct entity is still a matter of debate. EVIDENCE ACQUISITION: Here we describe a 35-year-old woman with growing suprasellar mass, partial empty sella, central diabetes insipidus, hypopituitarism, and hyperprolactinemia. EVIDENCE SYNTHESIS: Histopathologic examination of surgically removed suprasellar mass revealed lymphocytic infiltrate suggestive of an autoimmune disease with hypothalamic involvement. The presence of antihypothalamus antibodies to arginine vasopressin (AVP)-secreting cells (AVPcAb) at high titers and the absence of antipituitary antibodies suggested the diagnosis of isolated hypothalamitis. Some similar conditions have sometimes been reported in the literature but the simultaneous double finding of lymphocytic infiltrate and the presence of AVPcAb so far has never been reported. CONCLUSIONS: We think that the hypothalamitis can be considered a new isolated autoimmune disease affecting the hypothalamus while the lymphocytic infundibuloneurohypophysitis can be a consequence of hypothalamitis with subsequent autoimmune involvement of the pituitary. To our knowledge this is the first observation of autoimmune hypothalamic involvement with central diabetes insipidus, partial empty sella, antihypothalamic antibodies and hypopituitarism.

Risk of death among people with rare autoimmune diseases compared with the general population in England during the 2020 COVID-19 pandemic.

OBJECTIVES: To quantify the risk of death among people with rare autoimmune rheumatic diseases (RAIRD) during the UK 2020 COVID-19 pandemic compared with the general population, and compared with their pre-COVID risk. METHODS: We conducted a cohort study in Hospital Episode Statistics for England from 2003 onwards, and linked data from the NHS Personal Demographics Service. We used ONS published data for general population mortality rates. RESULTS: We included 168 691 people with a recorded diagnosis of RAIRD alive on 1 March 2020. Their median age was 61.7 (IQR 41.5-75.4) years, and 118 379 (70.2%) were female. Our case ascertainment methods had a positive predictive value of 85%. A total of 1815 (1.1%) participants died during March and April 2020. The age-standardized mortality rate (ASMR) among people with RAIRD (3669.3; 95% CI: 3500.4, 3838.1 per 100 000 person-years) was 1.44 (95% CI: 1.42, 1.45) times higher than the average ASMR during the same months of the previous 5 years, whereas in the general population of England it was 1.38 times higher. Age-specific mortality rates in people with RAIRD compared with the pre-COVID rates were higher from the age of 35 upwards, whereas in the general population the increased risk began from age 55 upwards. Women had a greater increase in mortality rates during COVID-19 compared with men. CONCLUSION: The risk of all-cause death is more prominently raised during COVID-19 among people with RAIRD than among the general population. We urgently need to quantify how much risk is due to COVID-19 infection and how much is due to disruption to health-care services.

Capilaroscopia periungueal en el Grupo Español de Enfermedades Autoinmunes Sistémicas (GEAS). Resultados de una encuesta electrónica / Nailfold capillaroscopy in the Spanish Group of Systemic Autoimmune Diseases (GEAS). Results of an electronic survey

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Estimated cut-off values for pemphigus severity classification according to pemphigus disease area index (PDAI), autoimmune bullous skin disorder intensity score (ABSIS), and anti-desmoglein 1 autoantibodies.

BACKGROUND: Pemphigus is a potentially fatal disease if left untreated. Valid scoring systems and defined cut-off values for classification of patients would help with better management through specified pharmaceutical and non-pharmaceutical treatments. METHODS: In this study, pemphigus patients who were receiving immunosuppressive treatments and had recent disease relapse were recruited for examination of pemphigus disease area index(PDAI), autoimmune bullous skin disorder intensity score (ABSIS), physician global assessment (PGA), autoimmune bullous disease quality of life (ABQoL), anti-desmoglein 1 (anti-Dsg1), and anti-Dsg3 autoantibody titers from December-2017 to February-2018. Cut-off values were estimated using model-based clustering classification and the 25th and 75th percentiles approach, performed separately for the exclusive cutaneous, exclusive mucosal, and mucocutaneous groups. RESULTS: In the 109 included patients, the 25th and 75th percentiles cut-offs were 6.2 and 27 for PDAI score, and 4 and 29.5 for ABSIS score. The model-based analysis resulted in two groups (cut-point:15) for PDAI score, and three groups (cut-points:6.4 and 31.5) for ABSIS score. The groups were significantly different for the PDAI, ABSIS, PGA, and ABQoL values. Based on anti-Dsg1 autoantibody values, the model-based analysis cut-point was 128 and the 25th and 75th percentiles cut-offs were 98 and 182. Anti-Dsg3 autoantibody values did not differentiate between pemphigus severity classes. CONCLUSIONS: Estimated cut-off values based on the anti-Dsg1 level, PDAI, and ABSIS scoring systems could be used to classify patients into different severity grades for better management and prognosis.

[Idiopathic Inflammatory Myopathies]. / Idiopathische inflammatorische Myopathien.

Myositis is a rare and an extremely heterogeneous autoimmune disease, that causes muscle weakness. Currently, "idiopathic inflammatory myopathies (IIM)" is the preferred umbrella-term used to describe the disease complexity within individuals. IIM include dermatomyositis, polymyositis, inclusion body myositis, autoimmune necrotizing myopathy, overlap myositis and antisynthetase syndrome. Research activity concerning myositis was very intense over the past ten years and led to new diagnostic approach as well as to novel therapeutic strategies. Correct classification is the key for successful management. One single treatment regime for every possible organ involvement in all different forms of IIM is still not existing.

How I investigate neutropenia.

Neutropenia is a common laboratory finding in adults and children. Its underlying causes are extremely heterogeneous and include benign conditions, autoimmune disorders, infections, and malignancies. The clinical laboratory plays a central role in the diagnosis of these disorders, including data derived from hematology, microbiology, molecular biology/cytogenetics, and clinical chemistry. The purpose of this review is to (a) highlight the clinical, hematologic, and molecular genetic features of the major entities resulting in neutropenia and (b) outline an algorithm-based approach to permit the classification of neutropenias.

Adult-onset systemic autoinflammatory disorders: a clinical approach.

Autoinflammatory disorders (AIDs) are a subgroup of immune-mediated syndromes that result from a primary dysfunction of the innate immune system. AIDs can be either monogenic or polygenic diseases. Unlike organspecific AIDs, systemic AIDs are characterized by fever and/or elevation of acute-phase reactants. This review aims to describe the most common adult-onset systemic AIDs, focusing mostly on polygenic and mixed-pattern diseases which are expected to be more prevalent in adult patients than monogenic AIDs overall. The literature was searched in Medline database. Organ-specific or childhood-onset systemic AIDs were excluded. AIDs were divided in three distinct groups: mixed-pattern, polygenic and adult-onset monogenic AIDs. Most adult-onset AIDs are polygenic but late-onset disease is not rare among monogenic AIDs such as familial Mediterranean fever (FMF). The diagnosis of systemic AIDs in adults is often delayed due to several factors and sometimes it is only established when amyloidosis or other complications are present. Therefore, it probably makes sense to primarily exclude common AIDs in adult patients with fever of unknown origin (and probably different presentations such as polyserositis) since a high prevalence of adult-onset Still's disease or FMF is usually expected. Colchicine, nonsteroidal anti-inflammatory drugs, steroids, immunosuppressive agents, interleukin-1 inhibitors and tumor necrosis factor antagonists constitute common therapeutic options for systemic AIDs.

Review of autoimmune blistering diseases: the Pemphigoid diseases.

Autoimmune Blistering Diseases of the Pemphigoid type is characterised by sub-epidermal blisters (SEB) with circulating autoantibodies against components of the basement membrane zone (BMZ). The main disorders to date include bullous pemphigoid (BP), pemphigoid gestationis, mucous membrane pemphigoid (MMP), epidermolysis bullosa acquisita (EBA), linear IgA disease (LABD), dermatitis herpetiformis (DH), lichen planus pemphigoides and bullous lupus. This is in contrast to pemphigus and related disorders, which demonstrate intraepidermal acantholysis and a positive Nikolsky sign. The classification and management is based on clinical, histological and direct and indirect immunofluorescence findings. There are, however, overlapping clinical and histological features between the conditions and clinical heterogeneity within each disease.

CRPS: what's in a name? Taxonomy, epidemiology, neurologic, immune and autoimmune considerations.

This account of the condition now termed complex regional pain syndrome (CRPS) spans approximately 462 years since a description embodying similar clinical features was described by Ambroise Paré in 1557. While reviewing its historical origins, the text describes why it became necessary to change the taxonomies of two clinical syndromes with similar pathophysiologies to one which acknowledges this aspect but does not introduce any mechanistic overtones. Discussed at length is the role of the sympathetic component of the autonomic nervous system (ANS) and why its dysfunction has both directly and indirectly influenced our understanding of the inflammatory aspects of CRPS. As the following article will show, our knowledge has expanded in an exponential fashion to include musculoskeletal, immune, autoimmune, central and peripheral nervous system and ANS dysfunction, all of which increase the complexity of its clinical management. A burgeoning literature is beginning to shed light on the mechanistic aspects of these syndromes and the increasing evidence of a genetic influence on such factors as autoimmunity, and its importance is also discussed at length. An important aspect that has been missing from the diagnostic criteria is a measure of disease severity. The recent validation of a CRPS Severity Score is also included.

Juvenile polyautoimmunity in a rheumatology setting.

Overt polyautoimmunity (PolyA) corresponds to the presence of more than one well-defined autoimmune disease (AD) manifested clinically in a single patient. The current study aimed to describe the main characteristics of juvenile PolyA in a pediatric rheumatology setting and analyze the chronological aspects, index cases, familial autoimmunity, and clustering pattern. This was a cross-sectional and multicenter study in which 313 children with overt PolyA were included. Patients were systematically interviewed and their medical records reviewed using a questionnaire that sought information about demographic, clinical, immunological, and familial characteristics. A hierarchical cluster analysis was done to determine similarities between autoimmune diseases based on PolyA. PolyA occurred simultaneously in 138 (44%) patients. Multiple autoimmune syndrome was observed in 62 (19.8%) patients. There were 25 index diseases of which, systemic lupus erythematosus (SLE, n = 134, 42.8%), juvenile idiopathic arthritis (JIA, n = 40, 12.7%), Hashimoto's thyroiditis (HT, n = 24, 7.66%), immune thrombocytopenic purpura (ITP n = 20, 6.39%), antiphospholipid syndrome (APS, n = 15, 4.79%), and vitiligo (VIT, n = 15, 4.79%) were the most frequent and represented 79.23% of the total number of patients. Familial autoimmunity influenced PolyA. A high aggregation of autoimmunity was observed (λr = 3.5). Three main clusters were identified, of which SLE and APS were the most similar pair of diseases (based on the Jaccard index) followed by HT and JIA, which were related to ITP and Sjögren's syndrome. The third cluster was composed of localized scleroderma and VIT. Our findings may assist physicians to make an early diagnosis of this frequent condition. Pediatric patients with ADs should be systematically assessed for PolyA.

18F-FDG PET/CT versus conventional investigations for cancer screening in autoimmune inflammatory myopathy in the era of novel myopathy classifications.

BACKGROUND: To compare the performance of fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) and conventional tests for cancer screening in autoimmune inflammatory myopathy (AIM) patients. PATIENTS AND METHODS: We carried out a retrospective cohort study of AIM patients from one academic center in Montreal, Canada, classified using myositis-specific antibodies, who underwent F-FDG PET/CT between April 2005 and February 2018 and were followed up on average 3.5±2.4 years. Patients were excluded if follow-up was insufficient, AIM diagnosis was indeterminate, and/or malignancy was diagnosed before an F-FDG PET/CT scan. Demographic/clinical data, F-FDG PET/CT results, and available conventional screening tests results were retrieved from electronic and paper medical records. RESULTS: 100 F-FDG PET/CT studies in 63 unique patients [31/63 dermatomyositis (DM), 25/63 overlap myositis, 1/63 inclusion body myositis, 1/63 polymyositis, 1/63 orbital myositis and 4/63 unspecified myositis] were evaluated. Three patients, all classified as DM, were diagnosed with cancer during follow-up with conventional cancer screening tests: breast cancer detected by mammography; squamous cell carcinoma of the skin detected by physical examination; and multiple myeloma detected by blood work. F-FDG PET/CT did not detect any malignancy and led to more additional biopsies than conventional screening (8 vs. 5). CONCLUSION: F-FDG PET/CT does not appear to be useful in cancer screening for AIM patients compared with conventional screening and carries potential harms associated with follow-up investigations. The risk of cancer in AIM differs by myositis-specific antibodies-defined subsets and cancer screening is likely to be indicated only in high-risk patients, particularly DM. These results, replicated in larger, multicentered studies, may carry significant consequences for optimal management of AIM and health resource utilization.

Estimating autoantibody signatures to detect autoimmune disease patient subsets.

Autoimmune diseases are characterized by highly specific immune responses against molecules in self-tissues. Different autoimmune diseases are characterized by distinct immune responses, making autoantibodies useful for diagnosis and prediction. In many diseases, the targets of autoantibodies are incompletely defined. Although the technologies for autoantibody discovery have advanced dramatically over the past decade, each of these techniques generates hundreds of possibilities, which are onerous and expensive to validate. We set out to establish a method to greatly simplify autoantibody discovery, using a pre-filtering step to define subgroups with similar specificities based on migration of radiolabeled, immunoprecipitated proteins on sodium dodecyl sulfate (SDS) gels and autoradiography [Gel Electrophoresis and band detection on Autoradiograms (GEA)]. Human recognition of patterns is not optimal when the patterns are complex or scattered across many samples. Multiple sources of errors-including irrelevant intensity differences and warping of gels-have challenged automation of pattern discovery from autoradiograms.In this article, we address these limitations using a Bayesian hierarchical model with shrinkage priors for pattern alignment and spatial dewarping. The Bayesian model combines information from multiple gel sets and corrects spatial warping for coherent estimation of autoantibody signatures defined by presence or absence of a grid of landmark proteins. We show the pre-processing creates more clearly separated clusters and improves the accuracy of autoantibody subset detection via hierarchical clustering. Finally, we demonstrate the utility of the proposed methods with GEA data from scleroderma patients.

Rituximab in systemic autoimmune rheumatic diseases: indications and practical use.

Objectives: To review the therapeutic option of Rituximab, a chimeric anti-CD20 antibody, in systemic autoimmune rheumatic diseases (SARDs) such as systemic lupus erythematosus, systemic sclerosis, primary Sjögren syndrome and idiopathic inflammatory myopathy. Methods: A non-systematic review was conducted. Results: The specific role and indication of rituximab in SARDs has been the subject of multiple trials in recent years. Evidence supports the use of rituximab in moderate-to-severe refractory systemic lupus erythematosus, diffuse skin involvement in systemic sclerosis and systemic involvement in primary Sjögren syndrome. Several guidelines have adopted these indications. In addition, there is a consensus about the use of rituximab in refractory myositis. The role of rituximab in interstitial lung disease associated with these SARDs needs to be further explored. Conclusion: Rituximab is a treatment option in several SARDs. Upcoming trials, use in daily practice and the safety profile are elaborated on.

Neuroanatomical features and its usefulness in classification of patients with PANDAS.

OBJECTIVE: An obsessive-compulsive disorder (OCD) subtype has been associated with streptococcal infections and is called pediatric autoimmune neuropsychiatric disorders associated with streptococci (PANDAS). The neuroanatomical characterization of subjects with this disorder is crucial for the better understanding of its pathophysiology; also, evaluation of these features as classifiers between patients and controls is relevant to determine potential biomarkers and useful in clinical diagnosis. This was the first multivariate pattern analysis (MVPA) study on an early-onset OCD subtype. METHODS: Fourteen pediatric patients with PANDAS were paired with 14 healthy subjects and were scanned to obtain structural magnetic resonance images (MRI). We identified neuroanatomical differences between subjects with PANDAS and healthy controls using voxel-based morphometry, diffusion tensor imaging (DTI), and surface analysis. We investigated the usefulness of these neuroanatomical differences to classify patients with PANDAS using MVPA. RESULTS: The pattern for the gray and white matter was significantly different between subjects with PANDAS and controls. Alterations emerged in the cortex, subcortex, and cerebellum. There were no significant group differences in DTI measures (fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity) or cortical features (thickness, sulci, volume, curvature, and gyrification). The overall accuracy of 75% was achieved using the gray matter features to classify patients with PANDAS and healthy controls. CONCLUSION: The results of this integrative study allow a better understanding of the neural substrates in this OCD subtype, suggesting that the anatomical gray matter characteristics could have an immune origin that might be helpful in patient classification.