Pseudoexon activation by deep intronic variation in GNE myopathy with thrombocytopenia.

INTRODUCTION/AIMS: GNE myopathy is a rare autosomal recessive disorder caused by pathogenic variants in the GNE gene, which is essential for the sialic acid biosynthesis pathway. Although over 300 GNE variants have been reported, some patients remain undiagnosed with monoallelic pathogenic variants. This study aims to analyze the entire GNE genomic region to identify novel pathogenic variants. METHODS: Patients with clinically compatible GNE myopathy and monoallelic pathogenic variants in the GNE gene were enrolled. The other GNE pathogenic variant was verified using comprehensive methods including exon 2 quantitative polymerase chain reaction and nanopore long-read single-molecule sequencing (LRS). RESULTS: A deep intronic GNE variant, c.862+870C>T, was identified in nine patients from eight unrelated families. This variant generates a cryptic splice site, resulting in the activation of a novel pseudoexon between exons 5 and 6. It results in the insertion of an extra 146 nucleotides into the messengerRNA (mRNA), which is predicted to result in a truncated humanGNE1(hGNE1) protein. Peanut agglutinin（PNA） lectin staining of muscle tissues showed reduced sialylation of mucin O-glycans on sarcolemmal glycoproteins. Notably, a third of patients with the c.862+870C>T variant exhibited thrombocytopenia. A common core haplotype harboring the deep intronic GNE variant was found in all these patients. DISCUSSION: The transcript with pseudoexon activation potentially affects sialic acid biosynthesis via nonsense-mediated mRNA decay, or resulting in a truncated hGNE1 protein, which interferes with normal enzyme function. LRS is expected to be more frequently incorporated in genetic analysis given its efficacy in detecting hard-to-find pathogenic variants.

Serum cytokines profile changes in amyotrophic lateral sclerosis.

Background: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder, characterized by progressive limb weakness, dysphagia, dysphonia, and respiratory failure due to degeneration of upper and lower motor neurons. The pathogenesis of ALS is still unclear. Neuroinflammation has been found to be involved in its development and progression. Cytokines play a significant role in the inflammatory process. This study aims to identify novel biomarkers that may assist in the diagnosis of ALS. Methods: In Fujian Medical University Union Hospital and Huashan Hospital Fudan University, two independent centers, we prospectively recruited 50 ALS patients, and 41 healthy controls (25 ALS and 26 controls in the first stage and 25 ALS and 15 controls in the validation stage). An 18-plex Luminex kit was used to screen the serum cytokines levels in the first stage. Commercial ELISA kits were used to measure the levels of target cytokines in the validation stage. A single-molecule array HD-X platform was applied to assess the levels of serum neurofilament light chain (NFL). Results: The levels of serum IL-18 were markedly increased in patients with ALS in the first stage (p = 0.016). The ROC curve showed an area under the curve at 0.695 (95% CI 0.50-0.84) in distinguishing ALS patients from healthy controls. The IL-21 was decreased in elderly patients when grouped by 55 years old (the medium age). Furthermore, the IL-5, IL-13, IL-18, and NFL had a positive relationship with the disease progression of ALS. We also found that serum IL-18 was markedly increased in ALS patients in the validation stage (167.67 [148.25-175.59] vs 116.44 [102.43-122.19]pg/ml, p < 0.0015). Conclusion: In this study, we identified systemic cytokine profile changes in the serum of ALS patients, especially the elevated IL-18, as well as the decreased IL-21 in elder patients. These changes in serum cytokine profiles may shed new light on an in-depth understanding of the immunopathogenic characteristics of ALS.

Clinical features and genetic spectrum of a multicenter Chinese cohort with myotonic dystrophy type 1.

BACKGROUND: As the most common subtype of adult muscular dystrophy worldwide, large cohort reports on myotonic dystrophy type I (DM1) in China are still lacking. This study aims to analyze the genetic and clinical characteristics of Chinese Han DM1 patients. METHODS: Based on the multicenter collaborating effort of the Pan-Yangtze River Delta Alliance for Neuromuscular Disorders, patients with suspected clinical diagnoses of DM1 were genetically confirmed from January 2020 to April 2023. Peak CTG repeats in the DMPK gene were analyzed using triplet repeat-primed PCR (TP-PCR) and flanking PCR. Time-to-event analysis of onset age in females and males was performed. Additionally, detailed clinical features and longitudinal changes from the disease onset in 64 DM1 patients were retrospectively collected and analyzed. The Epworth Sleepiness Scale and Fatigue Severity Scale were used to quantify the severity of daytime sleepiness and fatigue. RESULTS: Among the 211 genetically confirmed DM1 patients, the mean age at diagnosis was 40.9 ± 12.2 (range: 12-74) with a male-to-female ratio of 124:87. The average size of CTG repeats was 511.3 (range: 92-1945). Among the DM1 patients with comprehensive clinical data (n = 64, mean age 41.0 ± 12.0), the age at onset was significantly earlier in males than in females (4.8 years earlier, p = 0.026). Muscle weakness (92.2%), myotonia (85.9%), and fatigue (73.4%) were the most prevalent clinical features. The predominant involved muscles at onset are hands (weakness or myotonia) (52.6%) and legs (walking disability) (42.1%). Of them, 70.3% of patients had daytime sleepiness, 14.1% had cataract surgery, 7.8% used wheelchairs, 4.7% required ventilatory support, and 1.6% required gastric tubes. Regarding the comorbidities, 4.7% of patients had tumors, 17.2% had diabetes, 23.4% had dyspnea, 28.1% had intermittent insomnia, 43.8% experienced dysphagia, and 25% exhibited cognitive impairment. Chinese patients exhibited smaller size of CTG repeats (468 ± 139) than those reported in Italy (613 ± 623), the US (629 ± 386), and Japan (625 [302, 1047]), and milder phenotypes with less multisystem involvement. CONCLUSION: The Chinese Han DM1 patients presented milder phenotypes compared to their Caucasian and Japanese counterparts. A male predominance and an early age of onset were identified in male Chinese Han DM1 patients.

Independent risk factors for in-hospital outcome of myasthenic crisis: a prospective cohort study.

Background: Myasthenic crisis (MC) is a life-threatening condition for myasthenia gravis (MG). Therapeutic plasma exchange (TPE) and intravenous immunoglobulin (IVIg) efficaciously treat patients with MC. However, not every MC responds well to rescue therapies, and the determinants for outcome with the evidence from prospective cohorts are still lacking. Objectives: To explore the risk factors for in-hospital outcomes in patients with MC. Methods: Using a national neuromuscular center-based cohort of MG with prospective follow-ups from the crisis to the post-crisis phase, we finally included 90 MC episodes from 76 independent patients who received a standard regimen of rescue therapies. Results: The mean admission age was 52.89 ± 15.72 years. With a female predominance of 63.16% (48/76) and a high proportion of thymoma-associated MG (TMG) of 63.16% (48/76), the overall in-hospital mortality was 2.63% (2/76) and the average duration for mechanical ventilation (MV) use was 17.09 ± 13.36 days (0-53 days). In contrast to the patients with anti-acetylcholine receptor (AChR) antibodies, muscle-specific tyrosine kinase (MuSK)-associated MC exhibited a shorter MV support (5.20 ± 5.07 versus 17.40 ± 13.24 days, p = 0.023), length of intensive care units (ICU) stay (6.00 ± 4.64 versus 19.16 ± 17.54 days, p = 0.046), and hospital stay (16.00 ± 4.12 versus 34.43 ± 20.48 days, p = 0.011). Thymoma [odds ratio (OR): 0.200, 95% confidence interval (CI): 0.058-0.687, p = 0.011], partial pressure of carbon dioxide (PCO2) in blood gas before MV (OR: 1.238, 95% CI: 1.015-1.510, p = 0.035), and pneumonia (OR: 0.204, 95% CI: 0.049-0.841, p = 0.028) were identified as independent risk factors for prolonged MV use. TMG patients with thymoma burden exhibited a notable longer MV use (22.08 ± 17.54 versus 8.88 ± 6.79 days, p = 0.001), a prolonged hospital stay (40.40 ± 26.13 versus 23.67 ± 13.83 days, p = 0.009) compared with non-TMG. Even with complete thymoma resection (R0), TMG exhibited an unfavorable outcome versus non-TMG. Conclusion: With timely rescue therapies and prospective follow-ups, the in-hospital outcome of MCs was substantially improved. Thymoma, PCO2 in blood gas before MV, and pneumonia were identified as independent risk factors for prolonged MV use.

Risk factors for in-hospital outcome of myasthenic crisis Myasthenic crisis (MC) is a life-threatening condition for myasthenia gravis (MG). Therapeutic plasma exchange (TPE) and intravenous immunoglobulin (IVIg) efficaciously treat patients with MC. However, not every MC responds well to rescue therapies, and the determinants for outcome with the evidence from prospective cohorts are still lacking. Using a national neuromuscular center-based cohort of MG with prospective follow-ups from the crisis to the post-crisis phase, we were able to include 90 MC episodes from 76 independent patients who received a standard regimen of rescue therapies. The mean admission age was 52.89±15.72 years. With a female predominance and a high proportion of thymoma-associated MG. The overall in-hospital mortality was 2.63% (2/76) and the average duration for MV use was 17.09±13.36 days (0-53 days). In contrast to the patients with anti-AChR antibodies, MuSK-associated MC exhibited a shorter MV support, length of ICU stay and hospital stay. Thymoma, PCO2 in blood gas before MV, and pneumonia were identified as independent risk factors for prolonged MV use. TMG patients with thymoma burden exhibited a notable longer MV use, a prolonged hospital stay compared with non-TMG. Even with complete thymoma resection (R0), TMG exhibited an unfavorable outcome versus non-TMG. With timely rescue therapies and prospective follow-ups, the in-hospital outcome of MCs was substantially improved. Thymoma, PCO2 in blood gas before MV, and pneumonia.

Insights into refractory chronic inflammatory demyelinating polyneuropathy: a comprehensive real-world study.

Background: Refractory chronic inflammatory demyelinating polyneuropathy (CIDP) is a challenging subset of CIDP. It does not respond well to immune therapy and causes substantial disability. A comprehensive understanding of its clinical profile, electrophysiological characteristics and potential risk factors associated with refractoriness remains to be further elucidated. Methods: Data in this cross-sectional study was collected and reviewed from the Huashan Peripheral Neuropathy Database (HSPN). Included patients were categorized into refractory CIDP and non-refractory CIDP groups based on treatment response. The clinical and electrophysiological characteristics were compared between refractory and non-refractory CIDP groups. Potential risk factors associated with refractory CIDP were explored with a multivariate logistic regression model. Results: Fifty-eight patients with CIDP were included. Four disease course patterns of refractory CIDP are described: a relapsing-remitting form, a stable form, a secondary progressive form and a primary progressive form. Compared to non-refractory CIDP patients, refractory CIDP exhibited a longer disease duration (48.96 ± 33.72 vs. 28.33 ± 13.72 months, p = 0.038) and worse functional impairment (MRC sum score, 46.08 ± 12.69 vs. 52.81 ± 7.34, p = 0.018; mRS, 2.76 ± 0.93 vs. 2.33 ± 0.99, p = 0.082; INCAT, 3.68 ± 1.76 vs. 3.03 ± 2.28, p = 0.056, respectively). Electrophysiological studies further revealed greater axonal impairment (4.15 ± 2.0 vs. 5.94 ± 2.77 mv, p = 0.011, ulnar CMAP) and more severe demyelination (5.56 ± 2.86 vs. 4.18 ± 3.71 ms, p = 0.008, ulnar distal latency, 7.94 ± 5.62 vs. 6.52 ± 6.64 ms, p = 0.035, median distal latency; 30.21 ± 12.59 vs. 37.48 ± 12.44 m/s, p = 0.035, median conduction velocity; 58.66 ± 25.73 vs. 42.30 ± 13.77 ms, p = 0.033, median F-wave latency), compared to non-refractory CIDP. Disease duration was shown to be an independent risk factor for refractory CIDP (p < 0.05, 95%CI [0.007, 0.076]). Conclusion: This study provided a comprehensive description of refractory CIDP, addressing its clinical features, classification of clinical course, electrophysiological characteristics, and prognostic factors, effectively elucidating its various aspects. These findings contribute to a better understanding of this challenging subset of CIDP and might be informative for management and treatment strategies.

Diagnostic delay in late-onset Pompe disease among Chinese patients: A retrospective study.

Surveys and retrospective studies have revealed considerable delays in diagnosing late-onset Pompe disease (LOPD) in China, where the contributing factors remain poorly represented. Our study analyzed the diagnostic journey of 34 LOPD patients seen at our neuromuscular clinic from 2005 to 2022. We defined diagnostic delay as the time from the onset of the first relevant symptoms and laboratory findings suggestive of LOPD to the eventual diagnosis, and we constructed a correlation matrix to assess relationships among these variables. The cohort consisted of 34 patients with an equal male-to-female ratio, and the mean age at diagnosis was 27.68 ± 10.03 years. We found the median diagnostic delay to be 5 years, with a range of 0.3 to 20 years, with 97.1% having been misdiagnosed previously, most commonly with "Type II Respiratory insufficiency" (36.7%). Notably, patients at earlier onset (mean age, 18.19 years vs. 31 years; p < 0.005) tended to have higher creatine kinase (CK) levels. Furthermore, 92.6% reported difficulty in sitting up from a supine position since childhood. Our research emphasizes the role of early indicators like dyspnea and difficulty performing sit-ups in adolescents for timely LOPD diagnosis and treatment initiation. The importance of early high-risk screening using dried blood spot testing cannot be overstated.

Clinical outcome and peripheral immune profile of myasthenic crisis with omicron infections: A prospective cohort study.

The impact of Omicron infections on the clinical outcome and immune responses of myasthenia gravis (MG) remained largely unknown. From a prospective multicenter MG cohort (n = 189) with 197 myasthenic crisis (MC), we finally included 41 independent MG patients to classify into two groups: the Omicron Group (n = 13) and the Control Group (n = 28). In this matched cohort study, all-cause mortality was 7.69% (1/13) in Omicron Group and 14.29% (4/28) in Control Group. A higher proportion of elevated serum IL-6 was identified in the Omicron Group (88.89% vs 52.38%, P = 0.049). In addition, the proportions of CD3+CD8+T in lymphocytes and Tregs in CD3+CD4+ T cells were significantly elevated in the Omicron Group (both P = 0.0101). After treatment, the Omicron Group exhibited a marked improvement in MG-ADL score (P = 0.026) and MG-QoL-15 (P = 0.0357). MCs with Omicron infections were associated with elevated serum IL-6 and CD3+CD8+T response. These patients tended to present a better therapeutic response after fast-acting therapies and anti-IL-6 treatment.

Machine learning-based radiomics to differentiate immune-mediated necrotizing myopathy from limb-girdle muscular dystrophy R2 using MRI.

Objectives: This study aimed to assess the feasibility of a machine learning-based radiomics tools to discriminate between Limb-girdle muscular dystrophy R2 (LGMDR2) and immune-mediated necrotizing myopathy (IMNM) using lower-limb muscle magnetic resonance imaging (MRI) examination. Methods: After institutional review board approval, 30 patients with genetically proven LGMDR2 (12 females; age, 34.0 ± 11.3) and 45 patients with IMNM (28 females; age, 49.2 ± 16.6) who underwent lower-limb MRI examination including T1-weighted and interactive decomposition water and fat with echos asymmetric and least-squares estimation (IDEAL) sequences between July 2014 and August 2022 were included. Radiomics features of muscles were obtained, and four machine learning algorithms were conducted to select the optimal radiomics classifier for differential diagnosis. This selected algorithm was performed to construct the T1-weighted (TM), water-only (WM), or the combined model (CM) for calf-only, thigh-only, or the calf and thigh MR images, respectively. And their diagnostic performance was studied using area under the curve (AUC) and compared to the semi-quantitative model constructed by the modified Mercuri scale of calf and thigh muscles scored by two radiologists specialized in musculoskeletal imaging. Results: The logistic regression (LR) model was the optimal radiomics model. The performance of the WM and CM for thigh-only images (AUC 0.893, 0.913) was better than those for calf-only images (AUC 0.846, 0.880) except the TM. For "calf + thigh" images, the TM, WM, and CM models always performed best (AUC 0.953, 0.907, 0.953) with excellent accuracy (92.0, 84.0, 88.0%). The AUCs of the Mercuri model of the calf, thigh, and "calf + thigh" images were 0.847, 0.900, and 0.953 with accuracy (84.0, 84.0, 88.0%). Conclusion: Machine learning-based radiomics models can differentiate LGMDR2 from IMNM, performing better than visual assessment. The model built by combining calf and thigh images presents excellent diagnostic efficiency.

Eomesodermin expression in CD4+ T-cells associated with disease progression in amyotrophic lateral sclerosis.

AIM: To clarify the role of Eomesodermin (EOMES) to serve as a disease-relevant biomarker and the intracellular molecules underlying the immunophenotype shifting of CD4+ T subsets in amyotrophic lateral sclerosis (ALS). METHODS: The derivation and validation cohorts included a total of 148 ALS patients and 101 healthy controls (HCs). Clinical data and peripheral blood were collected. T-cell subsets and the EOMES expression were quantified using multicolor flow cytometry. Serum neurofilament light chain (NFL) was measured. In 1-year longitudinal follow-ups, the ALSFRS-R scores and primary endpoint events were further recorded in the ALS patients of the validation cohort. RESULTS: In the derivation cohort, the CD4+ EOMES+ T-cell subsets were significantly increased (p < 0.001). EOMES+ subset was positively correlated with increased serum NFL levels in patients with onset longer than 12 months. In the validation cohort, the elevated CD4+ EOMES+ T-cell proportions and their association with NFL levels were also identified. The longitudinal study revealed that ALS patients with higher EOMES expression were associated with higher progression rates (p = .010) and worse prognosis (p = .003). CONCLUSIONS: We demonstrated that increased CD4+ EOMES+ T-cell subsets in ALS were associated with disease progression and poor prognosis. Identifying these associations may contribute to a better understanding of the immunopathological mechanism of ALS.

Myasthenic crisis in thymoma-associated myasthenia gravis: a multicenter retrospective cohort study.

Thymoma-associated myasthenia gravis (TMG) had more severe symptoms and worse prognoses in comparison to non-thymoma-associated MG. Thymoma recurrence was frequently associated with transient worsening of MG and even acute respiratory failure, namely myasthenic crisis (MC). However, little is known about the clinical features and outcomes of MC in thymoma-associated MG patients. We performed a retrospective cohort study in MG patients recruited from 9 independent tertiary neuromuscular centers in China from Jan 2015, through Oct 2022. Overall, 156 MC from 149 MG patients with positive anti-acetylcholine receptor (AChR) antibodies were finally analyzed. Next, these patients were divided into two subgroups: the TMG group (n = 60 MCs, 58 patients) and the non-thymoma-associated MG group (n = 96 MCs, 91 patients). Compared with non-thymoma-associated MG, TMG patients had a significantly shorter disease duration from symptom onset to the crisis (17.95±40.9 vs 51.31±60.61 months, P<0.0001), a larger proportion of MGFA IVa as the initial onset clinical classification (6.67% vs 0, P = 0.0205), and a longer hospital stay (39.24±22.09 [6-111] vs. 33.2 ± 23.42 days [7-120]; P = 0.0317) during the crisis. Within the TMG group, the hospital stay was significantly longer in patients with unresected thymoma compared to that in postoperative myasthenic crisis (POMC) (47.68±24.9 [6-111] vs. 34.21±18.87 days [12-82]; P = 0.0257). Early identification of the MG categories may provide some hints in tailoring therapeutic strategies to improve the prognosis.

Peripheral immune landscape for hypercytokinemia in myasthenic crisis utilizing single-cell transcriptomics.

BACKGROUND: Myasthenia gravis (MG) is the most prevalent autoimmune disorder affecting the neuromuscular junction. A rapid deterioration in respiratory muscle can lead to a myasthenic crisis (MC), which represents a life-threatening condition with high mortality in MG. Multiple CD4+ T subsets and hypercytokinemia have been identified in the peripheral pro-inflammatory milieu during the crisis. However, the pathogenesis is complicated due to the many types of cells involved, leaving the underlying mechanism largely unexplored. METHODS: We conducted single-cell transcriptomic and immune repertoire sequencing on 33,577 peripheral blood mononuclear cells (PBMCs) from two acetylcholine receptor antibody-positive (AChR +) MG patients during MC and again three months post-MC. We followed the Scanpy workflow for quality control, dimension reduction, and clustering of the single-cell data. Subsequently, we annotated high-resolution cell types utilizing transfer-learning models derived from publicly available single-cell immune datasets. RNA velocity calculations from unspliced and spliced mRNAs were applied to infer cellular state progression. We analyzed cell communication and MG-relevant cytokines and chemokines to identify potential inflammation initiators. RESULTS: We identified a unique subset of monocytes, termed monocytes 3 (FCGR3B+ monocytes), which exhibited significant differential expression of pro-inflammatory signaling pathways during and after the crisis. In line with the activated innate immune state indicated by MC, a high neutrophil-lymphocyte ratio (NLR) was confirmed in an additional 22 AChR + MC patients in subsequent hemogram analysis and was associated with MG-relevant clinical scores. Furthermore, oligoclonal expansions were identified in age-associated B cells exhibiting high autoimmune activity, and in CD4+ and CD8+ T cells demonstrating persistent T exhaustion. CONCLUSIONS: In summary, our integrated analysis of single-cell transcriptomics and TCR/BCR sequencing has underscored the role of innate immune activation which is associated with hypercytokinemia in MC. The identification of a specific monocyte cluster that dominates the peripheral immune profile may provide some hints into the etiology and pathology of MC. However, future functional studies are required to explore causality.

Analysis of muscle magnetic resonance imaging of a large cohort of patient with VCP-mediated disease reveals characteristic features useful for diagnosis.

BACKGROUND: The diagnosis of patients with mutations in the VCP gene can be complicated due to their broad phenotypic spectrum including myopathy, motor neuron disease and peripheral neuropathy. Muscle MRI guides the diagnosis in neuromuscular diseases (NMDs); however, comprehensive muscle MRI features for VCP patients have not been reported so far. METHODS: We collected muscle MRIs of 80 of the 255 patients who participated in the "VCP International Study" and reviewed the T1-weighted (T1w) and short tau inversion recovery (STIR) sequences. We identified a series of potential diagnostic MRI based characteristics useful for the diagnosis of VCP disease and validated them in 1089 MRIs from patients with other genetically confirmed NMDs. RESULTS: Fat replacement of at least one muscle was identified in all symptomatic patients. The most common finding was the existence of patchy areas of fat replacement. Although there was a wide variability of muscles affected, we observed a common pattern characterized by the involvement of periscapular, paraspinal, gluteal and quadriceps muscles. STIR signal was enhanced in 67% of the patients, either in the muscle itself or in the surrounding fascia. We identified 10 diagnostic characteristics based on the pattern identified that allowed us to distinguish VCP disease from other neuromuscular diseases with high accuracy. CONCLUSIONS: Patients with mutations in the VCP gene had common features on muscle MRI that are helpful for diagnosis purposes, including the presence of patchy fat replacement and a prominent involvement of the periscapular, paraspinal, abdominal and thigh muscles.

The clinical features and TCAP mutation spectrum in a Chinese cohort of patients with limb-girdle muscular dystrophy R7.

Limb-girdle muscular dystrophy R7 (LGMDR7) is an autosomal recessive hereditary muscular dystrophy caused by mutations in titin-cap (TCAP). Here, we summarized the clinical characteristics and TCAP mutations in a Chinese cohort of 30 patients with LGMDR7. The onset age of Chinese patients was 19.89 ± 6.70 years old, which is later than European and South Asian patients (P < 0.05). Clinically speaking, 20.0% of patients presented with predominant distal weakness, and 73.3% of patients presented with predominant pelvic girdle weakness. Radiological study revealed semitendinosus and magnus adductor were severely involved in Chinese LGMDR7 patients. Rectus femoris, vastus lateralis, vastus intermedius, soleus and tibialis anterior were moderately to severely involved. The most prevalent mutation in this cohort is c.26_33dupAGGTGTCG, while c.165dupG and c.110 + 5G > A are unique in Chinese population as two of the common mutations. Besides, variant c.26_33dupAGGGTGTCG might be a founder mutation in Asian patients. Internal nuclei, lobulated fibers, and scattered rimmed vacuoles were typical morphological changes in Chinese LGMDR7 patients. This is the largest LGMDR7 cohort in the Chinese population and in the world. This article also expands the clinical, pathological, mutational and radiological spectrum of patients with LGMDR7 in China and in the world.

Effectiveness and safety of rituximab in autoimmune nodopathy: a single-center cohort study.

Autoimmune nodopathy is a peripheral neuropathy characterized by acquired motor and sensory deficit with autoantibodies against the node of Ranvier or paranodal region in the peripheral nervous system. The clinical and pathological characteristics of the disease are distinct from that of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), and the standard treatment for CIDP is partially effective. Rituximab is a chimeric monoclonal antibody which binds and depletes B cells in peripheral blood. This prospective observational study included 19 patients with autoimmune nodopathy. Participants received intravenous rituximab treatment 100 mg the first day and 500 mg the next day and given every 6 months. The Inflammatory Neuropathy Cause and Treatment (INCAT) disability score, Inflammatory Rasch-Built Overall Disability Scale (I-RODS), Medical Research Council (MRC) sum score, and Neuropathy Impairment Score (NIS) were collected at entry and before the rituximab infusion every 6 months. At the last visit, 94.7% (18/19) of the patients showed clinical improvement on either the INCAT, I-RODS, MRC, or NIS scale. After the first infusion, 9 patients (47.7%) showed improvement on the INCAT score, and 11 patients (57.9%) on cI-RODS. In patients who received more than one rituximab infusion, the improvement of INCAT score and cI-RODS at the last assessment was higher than that after the first infusion. We also observed tapered or withdrawn concomitant oral medications in these patients.

Safety of COVID-19 vaccine in patients with myasthenia gravis: a self-controlled case series study.

Background: The safety of COVID-19 vaccines has been clarified in clinical trials; however, some immunocompromised patients, such as myasthenia gravis (MG) patients, are still hesitant to receive vaccines. Whether COVID-19 vaccination increases the risk of disease worsening in these patients remains unknown. This study aims to evaluate the risk of disease exacerbation in COVID-19-vaccinated MG patients. Methods: The data in this study were collected from the MG database at Tangdu Hospital, the Fourth Military Medical University, and the Tertiary Referral Diagnostic Center at Huashan Hospital, Fudan University, from 1 April 2022 to 31 October 2022. A self-controlled case series method was applied, and the incidence rate ratios were calculated in the prespecified risk period using conditional Poisson regression. Results: Inactivated COVID-19 vaccines did not increase the risk of disease exacerbation in MG patients with stable disease status. A few patients experienced transient disease worsening, but the symptoms were mild. It is noted that more attention should be paid to thymoma-related MG, especially within 1 week after COVID-19 vaccination. Conclusion: COVID-19 vaccination has no long-term impact on MG relapse.

Short-term outcome prediction for myasthenia gravis: an explainable machine learning model.

Background: Myasthenia gravis (MG) is an autoimmune disease characterized by muscle weakness and fatigability. The fluctuating nature of the disease course impedes the clinical management. Objective: The purpose of the study was to establish and validate a machine learning (ML)-based model for predicting the short-term clinical outcome in MG patients with different antibody types. Methods: We studied 890 MG patients who had regular follow-ups at 11 tertiary centers in China from 1 January 2015 to 31 July 2021 (653 patients for derivation and 237 for validation). The short-term outcome was the modified post-intervention status (PIS) at a 6-month visit. A two-step variable screening was used to determine the factors for model construction and 14 ML algorithms were used for model optimisation. Results: The derivation cohort included 653 patients from Huashan hospital [age 44.24 (17.22) years, female 57.6%, generalized MG 73.5%], and the validation cohort included 237 patients from 10 independent centers [age 44.24 (17.22) years, female 55.0%, generalized MG 81.2%]. The ML model identified patients who were improved with an area under the receiver operating characteristic curve (AUC) of 0.91 [0.89-0.93], 'Unchanged' 0.89 [0.87-0.91], and 'Worse' 0.89 [0.85-0.92] in the derivation cohort, whereas identified patients who were improved with an AUC of 0.84 [0.79-0.89], 'Unchanged' 0.74 [0.67-0.82], and 'Worse' 0.79 [0.70-0.88] in the validation cohort. Both datasets presented a good calibration ability by fitting the expectation slopes. The model is finally explained by 25 simple predictors and transferred to a feasible web tool for an initial assessment. Conclusion: The explainable, ML-based predictive model can aid in forecasting the short-term outcome for MG with good accuracy in clinical practice.

Subclinical cardiac involvement present as electrocardiographic abnormalities in various neuromuscular diseases.

Background: Cardiac involvement is commonly present in various neuromuscular diseases which may develop life-threatening consequences. The early manifestation is often asymptomatic which however has been insufficiently studied. Objectives: We aim to characterize electrocardiographic (ECG) changes in neuromuscular diseases without cardiac symptoms. Methods: Adults having genetically and/or pathologically confirmed type 1 myotonic dystrophy (DM1), Becker muscular dystrophy (BMD), limb girdle muscular dystrophies (LGMDs) and mitochondrial diseases (MtDs) but without history of heart diseases and cardiovascular symptoms were enrolled. The 12-lead ECG characteristics and other test results at diagnosis were retrieved and analyzed. Results: 196 patients with neuromuscular diseases (44 DM1, 25 BMD, 82 LGMDs, 45 MtDs) were consecutively enrolled. ECG abnormalities were identified in 107 (54.6%) patients with a prevalence of 59.1% in DM1, 76.0% in BMD, 40.2% in LGMDs and 64.4% in MtDs. Conduction block was more commonly present in DM1 than the other groups (P < 0.01), which had a longest PR interval and QRS duration of 186.1 ± 38.3 ms and 104.2 [90.0-108.0]ms, respectively. QT prolongation was most frequently seen in DM1 (P < 0.001). Left ventricular hypertrophy features were found in BMD, LGMDs and MtDs (P < 0.05) without intergroup difference, while a significantly higher right ventricular amplitude is observed in BMD than in other groups (P < 0.001). Conclusions: Subclinical cardiac involvement is commonly present as ECG abnormalities in multiple adult neuromuscular diseases before associated symptoms occur and show diversity in different groups.

Causal relationships between mood instability and autoimmune diseases: A mendelian randomization analysis.

OBJECTIVES: The interrelationship between mental health and autoimmunity gains more and more attention in recent years. However, the causality between personality traits and autoimmune diseases remained largely unknown. METHODS: We first conducted two-sample mendelian randomization (MR) analysis on the relationships between mood instability, which is a common personality trait in the general population, and 10 autoimmune diseases. The results were further validated in secondary analyses of sensitivity where different MR methods, ethnicities, genders, and ascertainment methods were compared. RESULTS: In the primary analyses, three autoimmune diseases showed genetical predisposition to mood instability: asthma (OR [95%CI] = 3.45 [2.48, 4.78], P = 1.33E- 13), hypothyroidism (OR [95%CI] = 1.02 [1.00, 1.03], P = 1.71E-02), and systemic lupus erythematosus (OR [95%CI] = 5.25 [1.21, 22.76], P = 2.67E-02). The results were consistent in subsequent secondary analyses. Three diseases remained significantly correlated with mood instability by different MR methods with asthma remaining significant in Finnish and mixed populations, and in females from the UK biobank, while hypothyroidism remained significant in both genders from the UK biobank. CONCLUSION: Mood instability is a modifiable risk factor for three autoimmune diseases including asthma, hypothyroidism and systemic lupus erythematosus.

Pneumonia in myasthenia gravis: Microbial etiology and clinical management.

Introduction: Patients with myasthenia gravis (MG) are prone to the development of pneumonia due to the long-term immunotherapies they receive and a tendency for aspiration. Pneumonia remains a risk factor for MG worsening and is the most prevalent cause of mortality in MG patients. Classification of the pathogens involved and exploration of the risk factors for mechanical ventilation (MV) could aid in improving clinical outcomes. Methods: Between January 2013 and October 2022, we performed an inpatient database review for MG patients with pneumonia concurrence in a tertiary research center specializing in neuromuscular disorders. The clinical and microbiological characteristics of 116 MG patients with pneumonia were retrospectively analyzed. Results: In our cohort, 90.32% (112/124) of organisms were bacteria and 42.86% (48/112) of pathogenic bacteria were carbapenem-resistant. A high abundance of Epstein-Barr virus (EBV) was detected using next-generation sequencing (NGS) in 12 patients, while cytomegalovirus (CMV) was detected in 8 patients. Non-fermentative Gram-negative bacilli were the most prevalent microorganisms, in which ampicillin, sulfamethoxazole-trimethoprim (SMZ-TMP), piperacillin, cefoperazone, ceftazidime, and cefepime may have an anti-infectious effect. Moreover, peripheral lymphocyte percentage [odds ratio (OR) 0.88, 95% CI 0.75-0.96, p = 0.02] and serum globulin (OR 1.16, 95% CI 1.02-1.35, p = 0.03) were significantly associated with the risk of MV demand. Discussion: Our identification of the microbial etiology of pneumonia in MG patients may provide future perspectives on accurate antibiotic options and enable early interventions when risk factors are present.