A retrospective multicenter study on clinical and serological parameters in patients with MuSK myasthenia gravis with and without general immunosuppression.

Introduction: Muscle-specific kinase (MuSK)- myasthenia gravis (MG) is caused by pathogenic autoantibodies against MuSK that correlate with disease severity and are predominantly of the IgG4 subclass. The first-line treatment for MuSK-MG is general immunosuppression with corticosteroids, but the effect of treatment on IgG4 and MuSK IgG4 levels has not been studied. Methods: We analyzed the clinical data and sera from 52 MuSK-MG patients (45 female, 7 male, median age 49 (range 17-79) years) from Italy, the Netherlands, Greece and Belgium, and 43 AChR-MG patients (22 female, 21 male, median age 63 (range 2-82) years) from Italy, receiving different types of immunosuppression, and sera from 46 age- and sex-matched non-disease controls (with no diagnosed diseases, 38 female, 8 male, median age 51.5 (range 20-68) years) from the Netherlands. We analyzed the disease severity (assessed by MGFA or QMG score), and measured concentrations of MuSK IgG4, MuSK IgG, total IgG4 and total IgG in the sera by ELISA, RIA and nephelometry. Results: We observed that MuSK-MG patients showed a robust clinical improvement and reduction of MuSK IgG after therapy, and that MuSK IgG4 concentrations, but not total IgG4 concentrations, correlated with clinical severity. MuSK IgG and MuSK IgG4 concentrations were reduced after immunosuppression in 4/5 individuals with before-after data, but data from non-linked patient samples showed no difference. Total serum IgG4 levels were within the normal range, with IgG4 levels above threshold (1.35g/L) in 1/52 MuSK-MG, 2/43 AChR-MG patients and 1/45 non-disease controls. MuSK-MG patients improved within the first four years after disease onset, but no further clinical improvement or reduction of MuSK IgG4 were observed four years later, and only 14/52 (26.92%) patients in total, of which 13 (93.3%) received general immunosuppression, reached clinical remission. Discussion: We conclude that MuSK-MG patients improve clinically with general immunosuppression but may require further treatment to reach remission. Longitudinal testing of individual patients may be clinically more useful than single measurements of MuSK IgG4. No significant differences in the serum IgG4 concentrations and IgG4/IgG ratio between AChR- and MuSK-MG patients were found during follow-up. Further studies with larger patient and control cohorts are necessary to validate the findings.

Development of a clinical calculator to aid the identification of MODY in pediatric patients at the time of diabetes diagnosis.

Maturity Onset Diabetes of the Young (MODY) is a young-onset, monogenic form of diabetes without needing insulin treatment. Diagnostic testing is expensive. To aid decisions on who to test, we aimed to develop a MODY probability calculator for paediatric cases at the time of diabetes diagnosis, when the existing "MODY calculator" cannot be used. Firth logistic regression models were developed on data from 3541 paediatric patients from the Swedish 'Better Diabetes Diagnosis' (BDD) population study (n = 46 (1.3%) MODY (HNF1A, HNF4A, GCK)). Model performance was compared to using islet autoantibody testing. HbA1c, parent with diabetes, and absence of polyuria were significant independent predictors of MODY. The model showed excellent discrimination (c-statistic = 0.963) and calibrated well (Brier score = 0.01). MODY probability > 1.3% (ie. above background prevalence) had similar performance to being negative for all 3 antibodies (positive predictive value (PPV) = 10% v 11% respectively i.e. ~ 1 in 10 positive test rate). Probability > 1.3% and negative for 3 islet autoantibodies narrowed down to 4% of the cohort, and detected 96% of MODY cases (PPV = 31%). This MODY calculator for paediatric patients at time of diabetes diagnosis will help target genetic testing to those most likely to benefit, to get the right diagnosis.

Distinct cellular immune responses in children en route to type 1 diabetes with different first-appearing autoantibodies.

Previous studies have revealed heterogeneity in the progression to clinical type 1 diabetes in children who develop islet-specific antibodies either to insulin (IAA) or glutamic acid decarboxylase (GADA) as the first autoantibodies. Here, we test the hypothesis that children who later develop clinical disease have different early immune responses, depending on the type of the first autoantibody to appear (GADA-first or IAA-first). We use mass cytometry for deep immune profiling of peripheral blood mononuclear cell samples longitudinally collected from children who later progressed to clinical disease (IAA-first, GADA-first, ≥2 autoantibodies first groups) and matched for age, sex, and HLA controls who did not, as part of the Type 1 Diabetes Prediction and Prevention study. We identify differences in immune cell composition of children who later develop disease depending on the type of autoantibodies that appear first. Notably, we observe an increase in CD161 expression in natural killer cells of children with ≥2 autoantibodies and validate this in an independent cohort. The results highlight the importance of endotype-specific analyses and are likely to contribute to our understanding of pathogenic mechanisms underlying type 1 diabetes development.

Exploring the depths of IgG4: insights into autoimmunity and novel treatments.

IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.

Levels of anti-topoisomerase I antibody correlated with short onset of cardiopulmonary involvement in Thai systemic sclerosis patients.

Anti-topoisomerase-I antibody (ATA) is associated with disease severity and internal organ involvement in patients with systemic sclerosis (SSc). The correlation between ATA levels and the clinical course of SSc is unclear. We aimed to determine the correlation between ATA level and survival time and the onset of internal organ fibrosis in SSc patients. This historical cohort study was conducted in adult SSc patients with quantitative tests of ATA between January 2019 and December 2022. Patients with overlap syndrome and no quantitative ATA test were excluded. According to the sample size calculation, and 10% compensated for missing data, a total of 153 patients were needed. The respective mean age on the study date and median ATA level was 59.9 ± 11.3 years and 370 U/mL (range 195-652). Most cases (107 cases; 69.9%) were the diffuse cutaneous SSc subset. According to a multivariable analysis, the ATA titer had a negative correlation with the onset of cardiac involvement (Rho - 0.47, p = 0.01), and had a positive correlation with skin thickness progression (Rho 0.39, p = 0.04). Eleven cases exhibited ATA levels < 7 U/mL and outlier ATA levels were excluded, 142 cases were included in the sensitivity analysis, and multivariable analysis showed the correlation between early onset of ILD and cardiac involvement (Rho - 0.43, p = 0.03 and Rho - 0.51, p = 0.01, respectively). The ATA level was correlated with neither the survival time nor the onset of renal crisis in both analyses. High ATA levels were correlated with a short onset of ILD and cardiac involvement and the presence of extensive skin tightness. Quantitative tests of ATA could serve as an effective tool for identifying patients at risk of an unfavorable prognosis.

Anti-integrin αvß6 antibody in Takayasu arteritis patients with or without ulcerative colitis.

Background: It has been well documented that Takayasu arteritis (TAK) and ulcerative colitis (UC) coexist in the same patients. HLA-B*52 characterizes the co-occurrence, which is one of the common genetic features between these two diseases, indicating shared underlying pathologic mechanisms. Anti-integrin αvß6 antibody (Ab) is present in sera of UC patients in a highly specific manner. We investigated if there were any associations between anti-integrin αvß6 Ab and TAK, considering the risk HLA alleles. Methods: A total of 227 Japanese TAK patients were recruited in the current study and their serum samples were subjected to measurement of anti-integrin αvß6 Ab by ELISA. The clinical information, including the co-occurrence of UC, was collected. The HLA allele carrier status was determined by Luminex or genotype imputation. Results: The information about the presence of UC was available for 165 patients, among which eight (4.84%) patients had UC. Anti-integrin αvß6 antibody was identified in 7 out of 8 TAK subjects with UC (87.5%) while only 5 out of 157 (3.18%) TAK subjects without UC had the antibody (OR 121, p=7.46×10-8). A total of 99 out of 218 (45.4%) patients were HLA-B*52 carriers. There was no significant association between the presence of anti-integrin αvß6 Ab and HLA-B*52 carrier status in those without UC (OR 2.01, 95% CI 0.33-12.4, p = 0.189). Conclusions: The prevalence of anti-integrin αvß6 Ab was high in TAK patients with UC, but not in the absence of concomitant UC. The effect of HLA-B*52 on anti-integrin αvß6 Ab production would be minimal.

Untangling the relationship between smoking and systemic sclerosis: an analysis of the EUSTAR cohort.

OBJECTIVES: To untangle the association between smoking and systemic sclerosis (SSc). METHODS: In the European Scleroderma Trials and Research cohort, the autoantibody status was compared between ever-smokers and never-smokers. Time until disease progression was assessed using Kaplan-Meier curves. Cox models were built to investigate the influence of smoking over 15 years of follow-up. All analyses were performed for the total cohort and stratified for sex and for positivity of anti-centromere (ACA) and anti-topoisomerase antibodies (ATA). RESULTS: Overall, 12 314 patients were included in the study. Of these, 10 393 were women (84%), 4637 were ACA-positive (38%), 3919 were ATA-positive (32%) and 4271 (35%) were ever-smokers. In men, but not in women, smoking was associated with mortality (HR 1.63, 95% CI 1.23 to 2.16, p=0.001). Ever-smoking women were at higher risk for skin progression (HR 1.10, 95% CI 1.00 to 1.22, p=0.046) and for 'any organ progression' (HR 1.07, 95% CI 1.00 to 1.13, p=0.036). In women, 34% of never-smokers were ATA-positive compared with 21% of ever-smokers (p<0.001). In the group of ever-smokers, higher exposure rates, reflected by the number of pack-years (OR 0.98, 95% CI 0.97 to 0.99, p<0.001) and by smoking duration (OR 0.96, 95% CI 0.95 to 0.97, p<0.001), were associated with lower frequency of ATA. In ACA-positive patients, the risk of mortality (HR 1.29, 95% CI 1.02 to 1.63, p=0.033), cardiac involvement (HR 1.25, 95% CI 1.03 to 1.43, p=0.001), skin progression (HR 1.21, 95% CI 1.03 to 1.42, p=0.018) and 'any organ progression' (HR 1.14, 95% CI 1.05 to 1.24, p=0.002) was increased among smokers. In ATA-positive smoking patients, mortality (HR 1.40, 95% CI 1.10 to 1.78, p=0.006), skin progression (HR 1.19, 95% CI 1.03 to 1.37, p=0.020) digital ulcers (HR 1.17, 95% CI 1.02 to 1.34, p=0.029) and 'any organ progression' (HR 1.11, 95% CI 1.00 to 1.22, p=0.048) occurred more frequently. CONCLUSIONS: Our stratified analysis demonstrates that smoking is associated with an increased risk for mortality in male SSc patients but not in women. Strikingly, smoking is associated with lower prevalence of ATA positivity, in particular in women. In both ATA-positive and ACA-positive patients, smoking is a risk factor for mortality, skin progression and 'any organ progression'.

Retraction Note: Autoantibodies detection in patients affected by autoimmune retinopathies.

The article "Autoantibodies detection in patients affected by autoimmune retinopathies", by M.R. Ceccarini, M.C. Medori, K. Dhuli, S. Tezzele, G. Bonetti, C. Micheletti, P.E. Maltese, S. Cecchin, K. Donato, L. Colombo, L. Rossetti, G. Staurenghi, A.P. Salvetti, M. Oldani, L. Ziccardi, D. Marangoni, G. Iarossi, B. Falsini, G. Placidi, F. D'Esposito, F. Viola, M. Nassisi, G. Leone, L. Cimino, L. De Simone, V. Mastrofilippo, T. Beccari, M. Bertelli, published in Eur Rev Med Pharmacol Sci 2023; 27 (6 Suppl): 57-63-DOI: 10.26355/eurrev_202312_34690-PMID: 38112948 has been retracted by the Editor in Chief for the following reasons. Following some concerns raised on PubPeer, the Editor in Chief has started an investigation to assess the validity of the results. The outcome of the investigation revealed that the manuscript presented major flaws in the following: -       Issues with ethical approval -       Undeclared conflict of interest In light of concerns regarding the potential manipulation of Supplementary Figure 2, the journal's inquiry has been unable to conclusively determine whether the alterations noted on PubPeer constitute figure manipulation. The investigation yielded divergent evaluations. However, given the aforementioned concerns, the Editor in Chief doubts the integrity of the findings presented and thus, has opted to retract the article. The authors disagree with this retraction. This article has been retracted. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/34690.

Mimickers of autoimmune encephalitis: a literature review.

Autoimmune encephalitis (AIE) is a rapid, progressive neurological disorder characterized by nervous system inflammation. While the Graus criteria are the best known criteria for AIE diagnosis, other differential diagnoses meeting the Graus criteria must be considered before management. This narrative review discusses the most common etiologies that resemble AIE. We suggest routine exclusion of mimickers meeting the Graus criteria before confirming an AIE diagnosis. We reviewed 28 studies including 356 patients. The main initial diagnosis was AIE, then paraneoplastic limbic encephalitis and anti-N-methyl-D-aspartate receptor encephalitis. Only 194 patients met the possible Graus criteria. The most frequent conditions among the total population were dementia, other neurodegenerative diseases, and psychiatric and functional neurological disorders. AIE is often misdiagnosed, leading to unnecessary treatment. Despite publication of the Graus criteria, medical cases mimicking this condition are being published. Many neurological diseases entering the differential diagnosis of AIE could be excluded through a detailed history, neurological examination, laboratory analysis, and other investigations, including cerebrospinal fluid and brain magnetic resonance imaging. However, some differential diagnoses complied with the possible Graus criteria, with some having concurrent antineuronal antibodies, which were considered true mimickers. AIE diagnosis suspicion is primarily clinical, but a definitive diagnosis requires various diagnostic tools.

The development of anticyclic citrullinated peptide (anti-CCP) antibody following severe COVID-19.

OBJECTIVES: The dysregulated immune response is one of the cardinal features of severe coronavirus disease 2019 (COVID-19). This study was conducted to clarify the occurrence of autoantibodies (AABs) associated with systemic autoimmune rheumatic diseases (SARDs) in hospitalized patients with a moderate, severe, and critical form of COVID-19. METHODS: The serum samples obtained from 176 hospitalized COVID-19 patients were investigated in this study, including patients with moderate (N = 90), severe (N = 50), and critical (N = 36) forms of COVID-19. Also, the serum samples collected from healthy subjects before the COVID-19 pandemic were used as controls (N = 176). The antinuclear antibodies (ANAs), antidouble-stranded DNA (anti-dsDNA), cytoplasmic-anti neutrophil cytoplasmic antibody (c-ANCA), perinuclear ANCA (p-ANCA), antiphospholipid antibodies (aPLs), and anticyclic citrullinated peptide (anti-CCP) occurrence was evaluated using a solid-phase enzyme-linked immunosorbent assay (ELISA). RESULTS: The results showed that the occurrence of ANAs, anti-dsDNA, anti-CCP, c-ANCA, and p-ANCA was significantly higher in the COVID-19 patients compared to serum obtained from healthy subjects (p < .0001, p < .0001, p < .0001, p < .05, and p < .001, respectively). The positive number of anti-CCP tests increased significantly in severe COVID-19 compared to the moderate group (p < .01). CONCLUSION: Our study further supports the development of autoantibodies related to systemic autoimmune rheumatologic diseases. To the best of our knowledge, this is the first study with a large sample size that reported the occurrence of anti-CCP in a severe form of COVID-19.

Prevalence of anti-lymphocyte IgM autoantibodies driving complement activation in COVID-19 patients.

Introduction: COVID-19 patients can develop autoantibodies against a variety of secreted and membrane proteins, including some expressed on lymphocytes. However, it is unclear what proportion of patients might develop anti-lymphocyte antibodies (ALAb) and what functional relevance they might have. Methods: We evaluated the presence and lytic function of ALAb in the sera of a cohort of 85 COVID-19 patients (68 unvaccinated and 17 vaccinated) assigned to mild (N=63), or moderate/severe disease (N=22) groups. Thirty-seven patients were followed-up after recovery. We also analyzed in vivo complement deposition on COVID-19 patients' lymphocytes and examined its correlation with lymphocyte numbers during acute disease. Results: Compared with healthy donors (HD), patients had an increased prevalence of IgM ALAb, which was significantly higher in moderate/severe disease patients and persisted after recovery. Sera from IgM ALAb+ patients exhibited complement-dependent cytotoxicity (CDC) against HD lymphocytes. Complement protein C3b deposition on patients' CD4 T cells was inversely correlated with CD4 T cell numbers. This correlation was stronger in moderate/severe disease patients. Discussion: IgM ALAb and complement activation against lymphocytes may contribute to the acute lymphopenia observed in COVID-19 patients.

H-intensity scale score to estimate CSF GluN1 antibody titers with one-time immunostaining using a commercial assay.

Introduction: Anti-NMDA receptor encephalitis is an autoimmune disorder caused by autoantibodies (abs) against the conformational epitope on GluN1 subunits. GluN1-abs have been determined with cell-based assay (CBA) co-expressing GluN1/GluN2 subunits. However, commercial fixed CBA expressing only GluN1 subunit has increasingly been used in clinical practice. The ab titers can be determined with serial dilutions, but its clinical significance remains unclear. We aimed to develop an H-intensity scale (HIS) score to estimate GluN1-ab titers in cerebrospinal fluid (CSF) with one-time immunostaining using both commercial CBA and immunohistochemistry and report its usefulness. "H" is the initial of a patient with high CSF GluN1-ab titers (1:2,048). Methods: We first determined the reliability of CBA in 370 patients with suspected autoimmune encephalitis by comparing the results between commercial CBA and established assay in Dalmau's Lab. Then, we made positive control panels using the patient H's CSF diluted in a fourfold serial dilution method (1:2, 1:8, 1:32, 1:128, 1:512, and 1:2,048). Based on the panels, we scored the intensity of ab reactivity of 79 GluN1-ab-positive patients' CSF (diluted at 1:2) on a scale from 0 to 6 (with ≥1 considered positive). To assess inter-assay reliability, we performed immunostaining twice in 21 patients' CSF. We investigated an association between the score of CSF obtained at diagnosis and the clinical/paraclinical features. Results: The sensitivity and specificity of CBA were 93.7% (95% CI: 86.0-97.3) and 98.6% (95% CI: 96.5-99.5), respectively. Linear regression analysis showed a good agreement between the scores of the first and second assays. Patients with a typical spectrum, need for mechanical ventilation support, autonomic symptoms/central hypoventilation, dyskinesias, speech dysfunction, decreased level of consciousness, preceding headache, ovarian teratoma, and CSF leukocyte count >20 cells/µL had a higher median HIS score than those without, but HIS score was not associated with sex, age at onset, or seizure. HIS score at diagnosis had a significant effect on 1-year functional status. Discussion: The severity of disease and four of the six core symptoms were associated with higher GluN1-ab titers in CSF at diagnosis, which may play a role in poor 1-year functional status. An incomplete phenotype can be attributed to low CSF GluN1-ab titers.

Successful Treatment of Ultrasound-confirmed Synovitis in Anti-MDA5 Antibody-positive Clinically Amyopathic Dermatomyositis with Corticosteroid Therapy.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive clinically amyopathic dermatomyositis (CADM) is a subtype of dermatomyositis without severe myositis but with characteristic cutaneous manifestations and severe interstitial lung disease. Joint symptoms can occur in patients with anti-MDA5 antibody-positive CADM. However, the treatment strategy and utility of ultrasound for treating joint symptoms remain unknown. We herein report an 85-year-old man with anti-MDA5 antibody-positive CADM who presented with ultrasound-confirmed synovitis that improved with medium-dose corticosteroid therapy.

The ouroboros of autoimmunity.

Human autoimmunity against elements conferring protective immunity can be symbolized by the 'ouroboros', a snake eating its own tail. Underlying infection is autoimmunity against three immunological targets: neutrophils, complement and cytokines. Autoantibodies against neutrophils can cause peripheral neutropenia underlying mild pyogenic bacterial infections. The pathogenic contribution of autoantibodies against molecules of the complement system is often unclear, but autoantibodies specific for C3 convertase can enhance its activity, lowering complement levels and underlying severe bacterial infections. Autoantibodies neutralizing granulocyte-macrophage colony-stimulating factor impair alveolar macrophages, thereby underlying pulmonary proteinosis and airborne infections, type I interferon viral diseases, type II interferon intra-macrophagic infections, interleukin-6 pyogenic bacterial diseases and interleukin-17A/F mucocutaneous candidiasis. Each of these five cytokine autoantibodies underlies a specific range of infectious diseases, phenocopying infections that occur in patients with the corresponding inborn errors. In this Review, we analyze this ouroboros of immunity against immunity and posit that it should be considered as a factor in patients with unexplained infection.

Anti-Hu antibody associated paraneoplastic neurological syndrome in a child with ganglioneuroblastoma: A rare case report and literature review.

RATIONALE: Paraneoplastic neurological syndrome with anti-Hu antibody (Hu-PNS) is a neurological disorder that occur in patients with malignancy. The syndrome has a wide range of presentations and can present before diagnosis of primary malignancy. Familiarity with these paraneoplastic neurological syndromes can help early recognition and take appropriate regimens. PATIENTS CONCERNS: Diagnosis and treatment of Hu-PNS. DIAGNOSES: This is retrospective study that analyzed the clinical data of this case. Through retrospective analysis and targeted antibody screening, serum anti-Hu antibody was detected. Subsequent spinal imaging revealed a mass in the paraspinal region, which was confirmed as ganglioneuroblastoma by pathologic examination. INTERVENTIONS: The child was treated with a course of intravenous immunoglobulin and radical surgical operation without chemotherapy. OUTCOMES: The neurological symptoms were gradually improved and no signs indicate disease progression or tumor recurrence. LESSONS: Hu-PNS has rarely been reported in children with ganglioneuroblastomas. They can mimic non-neoplastic processes, making detection and diagnosis difficult. Serum and/or cerebrospinal fluid onconeural antibody can strongly indicate occult cancers. Early detection of paraneoplastic neurological syndromes can help take appropriate regimens and improve prognosis.

[How to Perform Autoantibody Testing for Autoimmune and Inflammatory Diseases of Peripheral Nerves and Muscles].

Measurement of autoantibodies is essential for the management of several peripheral nerve and muscle diseases. The clinical significance of autoantibody testing differs for each antibody. In addition, clinicians must understand several issues including the accuracy of the test, isotype and subclass distribution, and its relationship to disease activity. Moreover, many autoantibody tests are not covered by health insurance. With limited medical resources, clinicians are required to be up-to-date with the latest information to utilize test results in daily practice without misunderstanding.

[Paraneoplastic Disorders of Peripheral Nervous System].

Paraneoplastic disorders of the peripheral nervous system are immune-mediated neurological syndromes associated with tumors. Several clinical phenotypes have been associated with these disorders. Sensory neuronopathy is the most well-known clinical phenotype, and is caused by neuronal cell injury to the dorsal root ganglia. Symptoms of the peripheral nervous system usually lead to the discovery of tumors. Antineuronal antibodies are occasionally identified in the serum and/or cerebrospinal fluid of these patients. The prevalence of small-cell lung cancer is notable in these patients. Early tumor resection, coupled with the initiation of immunotherapy, may prove effective in improving and stabilizing clinical symptoms.

[Autoimmune Autonomic Ganglionopathy and Acute Autonomic Sensory Neuropathy].

Autoimmune autonomic ganglionopathy (AAG) and acute autonomic sensory neuropathy (AASN) are immune-mediated neuropathies that affect the autonomic and/or dorsal root ganglia. Autoantibodies against the nicotinic ganglionic acetylcholine receptor (gAChR) detected in the sera of patients with AAG play a key role in the pathogenesis of this condition. Notably, gAChR antibodies are not detected in the sera of patients with AASN. Currently, AAG and AASN are not considered to be on the same spectrum with regard to disease concept based on clinical symptoms and laboratory findings. However, extra-autonomic brain symptoms (including psychiatric symptoms and personality changes) and endocrine disorders occur in both diseases, which suggests shared pathophysiology between the two conditions.

[AChR Antibody-Positive Myasthenia Gravis].

Herein, we describe the mechanisms, diagnostic procedures, and treatment options for acetylcholine receptor (AChR) antibody-positive myasthenia gravis (MG). The upstream pathomechanism of this condition involves AChR-sensitized T cell-dependent B cell proliferation and the subsequent production of pathogenic autoantibodies. Downstream molecules include AChR antibodies that activate complement pathways, resulting in the destruction of motor endplates. We further introduce newly-developed molecular targeted drugs for the treatment of MG that aims to secure patients' health-related quality of life.