Individual myasthenia gravis autoantibody clones can efficiently mediate multiple mechanisms of pathology.

Serum autoantibodies targeting the nicotinic acetylcholine receptor (AChR) in patients with autoimmune myasthenia gravis (MG) can mediate pathology via three distinct molecular mechanisms: complement activation, receptor blockade, and antigenic modulation. However, it is unclear whether multi-pathogenicity is mediated by individual or multiple autoantibody clones. Using an unbiased B cell culture screening approach, we generated a library of 11 human-derived AChR-specific recombinant monoclonal autoantibodies (mAb) and assessed their binding properties and pathogenic profiles using specialized cell-based assays. Five mAbs activated complement, three blocked α-bungarotoxin binding to the receptor, and seven induced antigenic modulation. Furthermore, two clonally related mAbs derived from one patient were each highly efficient at more than one of these mechanisms, demonstrating that pathogenic mechanisms are not mutually exclusive at the monoclonal level. Using novel Jurkat cell lines that individually express each monomeric AChR subunit (α2ßδε), these two mAbs with multi-pathogenic capacity were determined to exclusively bind the α-subunit of AChR, demonstrating an association between mAb specificity and pathogenic capacity. These findings provide new insight into the immunopathology of MG, demonstrating that single autoreactive clones can efficiently mediate multiple modes of pathology. Current therapeutic approaches targeting only one autoantibody-mediated pathogenic mechanism may be evaded by autoantibodies with multifaceted capacity.

Effects of virtual reality-based planar motion exercises on upper extremity function, range of motion, and health-related quality of life: a multicenter, single-blinded, randomized, controlled pilot study.

BACKGROUND: Virtual reality (VR)-based rehabilitation is considered a beneficial therapeutic option for stroke rehabilitation. This pilot study assessed the clinical feasibility of a newly developed VR-based planar motion exercise apparatus (Rapael Smart Board™ [SB]; Neofect Inc., Yong-in, Korea) for the upper extremities as an intervention and assessment tool. METHODS: This single-blinded, randomized, controlled trial included 26 stroke survivors. Patients were randomized to the intervention group (SB group) or control (CON) group. During one session, patients in the SB group completed 30 min of intervention using the SB and an additional 30 min of standard occupational therapy; however, those in the CON group completed the same amount of conventional occupational therapy. The primary outcome was the change in the Fugl-Meyer assessment (FMA) score, and the secondary outcomes were changes in the Wolf motor function test (WMFT) score, active range of motion (AROM) of the proximal upper extremities, modified Barthel index (MBI), and Stroke Impact Scale (SIS) score. A within-group analysis was performed using the Wilcoxon signed-rank test, and a between-group analysis was performed using a repeated measures analysis of covariance. Additionally, correlations between SB assessment data and clinical scale scores were analyzed by repeated measures correlation. Assessments were performed three times (baseline, immediately after intervention, and 1 month after intervention). RESULTS: All functional outcome measures (FMA, WMFT, and MBI) showed significant improvements (p < 0.05) in the SB and CON groups. AROM showed greater improvements in the SB group, especially regarding shoulder abduction and internal rotation. There was a significant effect of time × group interactions for the SIS overall score (p = 0.038). Some parameters of the SB assessment, such as the explored area ratio, mean reaching distance, and smoothness, were significantly associated with clinical upper limb functional measurements with moderate correlation coefficients. CONCLUSIONS: The SB was available for improving upper limb function and health-related quality of life and useful for assessing upper limb ability in stroke survivors. TRIAL REGISTRATION: The study was registered with the clinical research information service (CRIS) ( KCT0003783 , registered 15 April 2019; retrospectively registered).

Clinicoserological insights into patients with immune checkpoint inhibitor-induced myasthenia gravis.

To compare the immunopathology of immune checkpoint inhibitor-induced myasthenia gravis (ICI-MG) and idiopathic MG, we profiled the respective AChR autoantibody pathogenic properties. Of three ICI-MG patients with AChR autoantibodies, only one showed complement activation and modulation/blocking potency, resembling idiopathic MG. In contrast, AChR autoantibody-mediated effector functions were not detected in the other two patients, questioning the role of their AChR autoantibodies as key mediators of pathology. The contrasting properties of AChR autoantibodies in these cases challenge the accuracy of serological testing in establishing definite ICI-MG diagnoses and underscore the importance of a thorough clinical assessment when evaluating ICI-related adverse events.

Precision targeting of autoantigen-specific B cells in muscle-specific tyrosine kinase myasthenia gravis with chimeric autoantibody receptor T cells.

Muscle-specific tyrosine kinase myasthenia gravis (MuSK MG) is an autoimmune disease that causes life-threatening muscle weakness due to anti-MuSK autoantibodies that disrupt neuromuscular junction signaling. To avoid chronic immunosuppression from current therapies, we engineered T cells to express a MuSK chimeric autoantibody receptor with CD137-CD3ζ signaling domains (MuSK-CAART) for precision targeting of B cells expressing anti-MuSK autoantibodies. MuSK-CAART demonstrated similar efficacy as anti-CD19 chimeric antigen receptor T cells for depletion of anti-MuSK B cells and retained cytolytic activity in the presence of soluble anti-MuSK antibodies. In an experimental autoimmune MG mouse model, MuSK-CAART reduced anti-MuSK IgG without decreasing B cells or total IgG levels, reflecting MuSK-specific B cell depletion. Specific off-target interactions of MuSK-CAART were not identified in vivo, in primary human cell screens or by high-throughput human membrane proteome array. These data contributed to an investigational new drug application and phase 1 clinical study design for MuSK-CAART for the treatment of MuSK autoantibody-positive MG.

Engineering Cell Therapies for Autoimmune Diseases: From Preclinical to Clinical Proof of Concept.

Autoimmune diseases are caused by a dysfunction of the acquired immune system. In a subset of autoimmune diseases, B cells escaping immune tolerance present autoantigen and produce cytokines and/or autoantibodies, resulting in systemic or organ-specific autoimmunity. Therefore, B cell depletion with monoclonal Abs targeting B cell lineage markers is standard care therapy for several B cell-mediated autoimmune disorders. In the last 5 years, genetically-engineered cellular immunotherapies targeting B cells have shown superior efficacy and long-term remission of B cell malignancies compared to historical clinical outcomes using B cell depletion with monoclonal Ab therapies. This has raised interest in understanding whether similar durable remission could be achieved with use of genetically-engineered cell therapies for autoimmunity. This review will focus on current human clinical trials using engineered cell therapies for B cell-associated autoimmune diseases.

Reemergence of pathogenic, autoantibody-producing B cell clones in myasthenia gravis following B cell depletion therapy.

Myasthenia gravis (MG) is an autoantibody-mediated autoimmune disorder of the neuromuscular junction. A small subset of patients (<10%) with MG, have autoantibodies targeting muscle-specific tyrosine kinase (MuSK). MuSK MG patients respond well to CD20-mediated B cell depletion therapy (BCDT); most achieve complete stable remission. However, relapse often occurs. To further understand the immunomechanisms underlying relapse, we studied autoantibody-producing B cells over the course of BCDT. We developed a fluorescently labeled antigen to enrich for MuSK-specific B cells, which was validated with a novel Nalm6 cell line engineered to express a human MuSK-specific B cell receptor. B cells (≅ 2.6 million) from 12 different samples collected from nine MuSK MG patients were screened for MuSK specificity. We successfully isolated two MuSK-specific IgG4 subclass-expressing plasmablasts from two of these patients, who were experiencing a relapse after a BCDT-induced remission. Human recombinant MuSK mAbs were then generated to validate binding specificity and characterize their molecular properties. Both mAbs were strong MuSK binders, they recognized the Ig1-like domain of MuSK, and showed pathogenic capacity when tested in an acetylcholine receptor (AChR) clustering assay. The presence of persistent clonal relatives of these MuSK-specific B cell clones was investigated through B cell receptor repertoire tracing of 63,977 unique clones derived from longitudinal samples collected from these two patients. Clonal variants were detected at multiple timepoints spanning more than five years and reemerged after BCDT-mediated remission, predating disease relapse by several months. These findings demonstrate that a reservoir of rare pathogenic MuSK autoantibody-expressing B cell clones survive BCDT and reemerge into circulation prior to manifestation of clinical relapse. Overall, this study provides both a mechanistic understanding of MuSK MG relapse and a valuable candidate biomarker for relapse prediction.

Korean Version of the Stroke Rehabilitation Motivation Scale: Reliability and Validity Evaluation.

OBJECTIVE: To translate the Stroke Rehabilitation Motivation Scale (SRMS), developed to evaluate the motivation level of stroke patients during rehabilitation, into the Korean language and to verify the reliability and validity of the Korean version of SRMS (K-SRMS). METHODS: The K-SRMS was developed following a structured process that included translation, verification, compromise assessment, reverse translation, feedback, and final correction. K-SRMS reliability was evaluated by performing internal consistency and test-retest analyses. The reliability test was conducted in 50 stroke patients. Its validity was assessed by comparing the K-SRMS with the scale and performing exploratory factor analysis. The validity test was conducted in 102 stroke patients. RESULTS: The test-retest analysis showed good reliability, and the internal consistency of the K-SRMS was similar to that of the original version for all, except 4, items. Thus, these 4 items were excluded, and then the validity test was conducted. Pearson correlation analysis demonstrated that the K-SRMS score was significantly correlated with the BAS total score (Pearson r=0.207, p<0.05). In the exploratory factor analysis, K-SRMS items were categorized into 7 groups (factors), and factors 1 and 4 showed mutual concordance with K-SRMS subscales, including intrinsic motivation factors and amotivation, respectively. CONCLUSION: The newly developed K-SRMS showed good reliability and validity. It could also be used as a tool to objectify the degree of motivation for rehabilitation among stroke patients in clinical care and research.

Changes in the Trend in Bladder Emptying Methods in Patients With Spinal Cord Injury: A 20-Year Single-Center Retrospective Study.

OBJECTIVE: To review trends in bladder emptying methods over a 20-year period in patients with spinal cord injury (SCI) by severity according to the American Spinal Injury Association impairment scale (AIS). METHODS: Medical records of patients with SCI from 1994 to 1998 (group 1) and from 2012 to 2016 (group 2) were retrospectively reviewed. We classified bladder emptying methods according to the International Spinal Cord dataset. We grouped patients with normal voiding, bladder reflex triggering, and bladder expression as those using voiding without catheter. RESULTS: A total of 667 patients were included in the analysis. The proportion of patients using voiding without catheter and intermittent catheterization decreased from 67.0% to 30.0% and increased from 26.8% to 54.8%, respectively. In patients with AIS-A and AIS-B, the proportion of patients with intermittent catheterization increased from 32.8% to 73.3%. In patients with AIS-D, the proportion of patients using voiding without catheter and intermittent catheterization decreased from 88.5% to 68.9% and increased from 11.5% to 26.8%, respectively. In group 2, among 111 patients with AIS-D using voiding without catheter at admission, 8 (7.2%) switched to intermittent catheterization at discharge due to decreased bladder volume, increased post-voiding residual urine, or incontinence. CONCLUSION: Over the past 20 years, trends in bladder emptying methods in patients with SCI changed from voiding without catheter to intermittent catheterization in Korea. This was especially prominent in patients with AIS-A, AIS-B, and AIS-C. Even in patients with AIS-D, the use of intermittent catheterization at hospital discharge increased.

Twist2 promotes CD8+ T-cell differentiation by repressing ThPOK expression.

CD4/CD8 T-cell lineage differentiation is a key process in immune system development; however, a defined regulator(s) that converts the signal from T-cell receptor and co-receptor complexes into lineage differentiation remains unclear. Here, we show that Twist2 is a critical factor in CD4/CD8 thymocyte differentiation. Twist2 expression is differentially regulated by T-cell receptor signaling, leading to differentiation into the CD4 or CD8 lineage. Forced Twist2 expression perturbed CD4+ thymocyte differentiation while enhancing CD8+ thymocyte differentiation. Furthermore, Twist2 expression produced mature CD8+ thymocytes in B2m-/- mice, while its deficiency significantly impaired CD8+ cells in MHC class-II-/- and TCR transgenic mice, favoring CD8 T-cell differentiation. During CD8 lineage differentiation, Twist2 interacted with Runx3 to bind to the silencer region of the ThPOK locus, thereby blocking ThPOK expression. These findings indicate that Twist2 is a part of the transcription factor network controlling CD8 lineage differentiation.

Antigen-specific B cell depletion for precision therapy of mucosal pemphigus vulgaris.

Desmoglein 3 chimeric autoantibody receptor T cells (DSG3-CAART) expressing the pemphigus vulgaris (PV) autoantigen DSG3 fused to CD137-CD3ζ signaling domains, represent a precision cellular immunotherapy approach for antigen-specific B cell depletion. Here, we present definitive preclinical studies enabling a first-in-human trial of DSG3-CAART for mucosal PV. DSG3-CAART specifically lysed human anti-DSG3 B cells from PV patients and demonstrated activity consistent with a threshold dose in vivo, resulting in decreased target cell burden, decreased serum and tissue-bound autoantibodies, and increased DSG3-CAART engraftment. In a PV active immune model with physiologic anti-DSG3 IgG levels, DSG3-CAART inhibited antibody responses against pathogenic DSG3 epitopes and autoantibody binding to epithelial tissues, leading to clinical and histologic resolution of blisters. DSG3 autoantibodies stimulated DSG3-CAART IFN-γ secretion and homotypic clustering, consistent with an activated phenotype. Toxicology screens using primary human cells and high-throughput membrane proteome arrays did not identify off-target cytotoxic interactions. These preclinical data guided the trial design for DSG3-CAART and may help inform CAART preclinical development for other antibody-mediated diseases.

Validity of the Budapest Criteria For Poststroke Complex Regional Pain Syndrome.

OBJECTIVES: Complex regional pain syndrome-1 is a chronic neuropathic disorder, and poststroke complex regional pain syndrome (PS-CRPS) is not a rare complication. There is a lack of study implementing the Budapest criteria for PS-CRPS diagnosis. Thus, the present study investigated the validity of the Budapest criteria for PS-CRPS diagnosis and assessed the PS-CRPS-related factors in stroke patients with an affected upper extremity. METHODS: The study included 72 patients with first-ever stroke resulting in hemiplegia. The prevalence of PS-CRPS and diagnostic validity were compared among the Budapest clinical criteria, Budapest research criteria, modified Budapest criteria (removal of the motor factor from the motor/trophic category), and International Association for the Study of Pain (IASP) criteria in patients diagnosed with PS-CRPS according to the Budapest clinical criteria. RESULTS: PS-CRPS was diagnosed in 6 (8.3%), 1 (1.4%), 6 (8.3%), and 11 patients (15.3%) according to the Budapest clinical criteria, Budapest research criteria, modified Budapest criteria, and IASP criteria, respectively. The Budapest criteria and IASP criteria had sensitivities of 0.99 and 1.00, respectively, and specificities of 0.68 and 0.41, respectively, for PS-CRPS diagnosis. There were no differences in risk factors between PS-CRPS patients and non-PS-CRPS patients when the diagnosis was based on the Budapest clinical criteria. However, there were differences in muscle strength and Brunnstrom stage between PS-CRPS patients and non-PS-CRPS patients when the diagnosis was based on the IASP criteria. DISCUSSION: Our findings indicate that the diagnostic validity of the current Budapest clinical criteria for PS-CRPS is low. Thus, the current Budapest criteria might not be appropriate for PS-CRPS diagnosis.