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BackgroundAutoantibodies targeting the acetylcholine receptor (AChR), found in patients with myasthenia gravis (MG), mediate pathology through three mechanisms: complement-directed tissue damage, blocking of the acetylcholine binding site, and internalization of the AChR. Clinical assays, used to diagnose and monitor patients, measure only autoantibody binding. Consequently, they are limited in providing association with disease burden, understanding of mechanistic heterogeneity, and monitoring therapeutic response.ObjectiveDevelop a cell-based assay that measures AChR autoantibody-mediated complement membrane attack complex (MAC) formation.MethodsAn HEK293T cell line—modified using CRISPR/Cas9 genome editing to disrupt expression of the complement regulator genes (CD46, CD55 and CD59)—was used to measure AChR autoantibody-mediated MAC formation via flow cytometry.ResultsSerum samples (n=155) from 96 clinically confirmed AChR MG patients, representing a wide range of disease burden and autoantibody titer, were tested along with 32 healthy donor (HD) samples. AChR autoantibodies were detected in 139 of the 155 (89.7%) MG samples via a cell-based assay. Of the 139 AChR positive samples, autoantibody-mediated MAC formation was detected in 83 (59.7%), while MAC formation was undetectable in the HD group or AChR positive samples with low autoantibody levels. MAC formation was positively associated with autoantibody binding in most patient samples; ratios (MFI) of MAC formation to AChR autoantibody binding ranged between 0.27–48, with a median of 0.79 and interquartile range of 0.43 (0.58–1.1). However, the distribution of ratios was asymmetric and included extreme values; 16 samples were beyond the 10–90 percentile, with high-MAC to low-AChR autoantibody binding ratio or the reverse. Correlation between MAC formation and clinical disease scores suggested a modest positive association (rho=0.34, p=0.0023), which included a subset of outliers that did not follow this pattern. MAC formation did not associate with exposure to immunotherapy, thymectomy, or MG subtypes defined by age-of-onset.ConclusionsA novel assay for evaluating AChR autoantibody-mediated complement activity was developed. A subset of patients that lack association between MAC formation and autoantibody binding or disease burden was identified. The assay may provide a better understanding of the heterogeneous autoantibody molecular pathology and identify patients expected to benefit from complement inhibitor therapy.

Elevated N-linked glycosylation of immunoglobulin G variable regions (IgG-V(N-Glyc)) is an emerging molecular phenotype associated with autoimmune disorders. To test the broader specificity of elevated IgG-V(N-Glyc), we studied patients with distinct subtypes of myasthenia gravis (MG), a B cell-mediated autoimmune disease. Our experimental design focused on examining the B cell repertoire and total IgG. It specifically included adaptive immune receptor repertoire sequencing to quantify and characterize N-linked glycosylation sites in the circulating B cell receptor repertoire, proteomics to examine glycosylation patterns of the total circulating IgG, and an exploration of human-derived recombinant autoantibodies, which were studied with mass spectrometry and antigen binding assays to respectively confirm occupation of glycosylation sites and determine whether they alter binding. We found that the frequency of IgG-V(N-Glyc) motifs was increased in the total B cell receptor repertoire of MG patients when compared to healthy donors. The elevated frequency was attributed to both biased V gene segment usage and somatic hypermutation. IgG-V(N-Glyc) could be observed in the total circulating IgG in a subset of MG patients. Autoantigen binding, by four patient-derived MG autoantigen-specific monoclonal antibodies with experimentally confirmed presence of IgG-V(N-Glyc), was not altered by the glycosylation. Our findings extend prior work on patterns of immunoglobulin variable region N-linked glycosylation in autoimmunity to MG subtypes.

Background: The current global pandemic has created unprecedented challenges in the blood supply network. Given the recent shortages, there must be a civilian plan for massively bleeding patients when there are no blood products on the shelf. Recognizing that the time to death in bleeding patients is less than 2 h, timely resupply from unaffected locations is not possible. One solution is to transfuse emergency untested whole blood (EUWB), similar to the extensive military experience fine-tuned over the last 19 years. While this concept is anathema in current civilian transfusion practice, it seems prudent to have a vetted plan in place. Methods and Materials: During the early stages of the 2020 global pandemic, a multidisciplinary and international group of clinicians with broad experience in transfusion medicine communicated routinely. The result is a planning document that provides both background information and a high-level guide on how to emergently deliver EUWB for patients who would otherwise die of hemorrhage. Results and Conclusions: Similar plans have been utilized in remote locations, both on the battlefield and in civilian practice. The proposed recommendations are designed to provide high-level guidance for experienced blood bankers, transfusion experts, clinicians, and health authorities. Like with all emergency preparedness, it is always better to have a well-thought-out and trained plan in place, rather than trying to develop a hasty plan in the midst of a disaster. We need to prevent the potential for empty shelves and bleeding patients dying for lack of blood.

Background Autoimmune disease prevention requires tools to assess an individual's risk of developing a specific disease. One tool is disease-associated autoantibodies, which accumulate in an asymptomatic preclinical period. However, patients sometimes exhibit autoantibodies associated with a different disease classification. When and how these alternative autoantibodies first appear remain unknown. This cross-sectional study characterizes alternative autoimmunity, and associated genetic and environmental factors, in unaffected first-degree relatives (FDRs) of patients, who exhibit increased future risk for the same disease. Methods Samples (n = 1321) from disease-specific autoantibody-positive (aAb+) systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and type 1 diabetes (T1D) patients; and unaffected aAb+ and autoantibody-negative (aAb–) SLE and RA FDRs were tested for SLE, RA, and T1D aAbs, as well as anti-tissue transglutaminase, anti-cardiolipin and anti-thyroperoxidase. FDR SLE and RA genetic risk scores (GRS) were calculated. Findings Alternative autoimmunity occurred in SLE patients (56%) and FDRs (57·4%), RA patients (32·6%) and FDRs (34·8%), and T1D patients (43%). Expanded autoimmunity, defined as autoantibodies spanning at least two other diseases, occurred in 18·5% of SLE patients, 16·4% of SLE FDRs, 7·8% of RA patients, 5·3% of RA FDRs, and 10·8% of T1D patients. SLE FDRs were more likely to have alternative (odds ratio [OR] 2·44) and expanded (OR 3·27) autoimmunity than RA FDRs. Alternative and expanded autoimmunity were associated with several environmental exposures. Alternative autoimmunity was associated with a higher RA GRS in RA FDRs (OR 1·41), and a higher SLE GRS in aAb+ RA FDRs (OR 1·87), but not in SLE FDRs. Interpretation Autoimmunity commonly crosses disease-specific boundaries in systemic (RA, SLE) and organ-specific (T1D) autoimmune diseases. Alternative autoimmunity is more common in SLE FDRs than RA FDRs, and is influenced by genetic and environmental factors. These findings have substantial implications for preclinical disease pathogenesis and autoimmune disease prevention studies. Fund NIH U01AI101981, R01AR051394, U19AI082714, P30AR053483, P30GM103510, U54GM104938, U01AI101934, R01AI024717, U01AI130830, I01BX001834, & U01HG008666.

T cells are critical effectors of cancer immunotherapies, but little is known about their gene expression programs in diffuse gliomas. Here, we leverage single-cell RNA-seq to chart the gene expression and clonal landscape of tumor-infiltrating T cells across 31 patients with IDH-wildtype glioblastoma and IDH-mutant glioma. We identify potential effectors of anti-tumor immunity in subsets of T cells that co-express cytotoxic programs and several NK cell genes. Analysis of clonally expanded tumor-infiltrating T cells further identifies the NK gene KLRB1 (encoding CD161) as a candidate inhibitory receptor. Accordingly, genetic inactivation of KLRB1 or antibody-mediated CD161 blockade enhances T cell-mediated killing of glioma cells in vitro and their anti-tumor function in vivo. KLRB1 and its associated transcriptional program are also expressed by substantial T cell populations in other human cancers. Our work provides an atlas of T cells in gliomas and highlights CD161 and other NK cell receptors as immunotherapy targets.

Elevated N-linked glycosylation of immunoglobulin G variable regions (IgG-VN-Glyc) is an emerging molecular phenotype associated with autoimmune disorders. To test the broader specificity of elevated IgG-VN-Glyc, we studied patients with distinct subtypes of myasthenia gravis (MG), a B cell-mediated autoimmune disease. Our experimental design included adaptive immune receptor repertoire sequencing to quantify and characterize N-glycosylation sites in the global B cell receptor repertoire, proteomics to examine glycosylation patterns of the circulating IgG, and production of human-derived recombinant autoantibodies, which were studied with mass spectrometry and antigen binding assays to confirm occupation of glycosylation sites and determine whether they alter binding. We found that the frequency of IgG-VN-Glyc motifs was increased in the B cell repertoire of MG patients when compared to healthy donors. Motifs were introduced by both biased V gene segment usage and somatic hypermutation. IgG-VN-Glyc could be observed in the circulating IgG in a subset of MG patients. Autoantigen binding, by patient-derived MG autoantigen-specific monoclonal antibodies with experimentally confirmed presence of IgG-VN-Glyc, was not altered by the glycosylation. Our findings extend prior work on patterns of variable region N-linked glycosylation in autoimmunity to MG subtypes. Although occupied IgG-VN-Glyc motifs are found on MG autoantigen-specific monoclonal antibodies, they are not required for binding to the autoantigen in this disease.

Acetylcholine receptor (AChR) autoantibodies, found in patients with autoimmune myasthenia gravis (MG), can directly contribute to disease pathology through activation of the classical complement pathway. Accordingly, complement inhibitors are used as a therapeutic strategy, but the response can be heterogeneous even though AChR autoantibodies are present. The mechanisms underlying the variable response are not defined. Yet there is a need for further understanding so that responses can be better predicted. There is a broad spectrum of circulating complement activity levels activity among MG patients. It is not clear whether this activity associates with disease burden or the circulating levels of autoantibodies. We measured complement activity and investigated these associations in MG patients as a means to explore candidate biomarkers. Most study subjects had complement activity within the range defined by healthy controls and no association between this activity and disease burden or AChR autoantibody titer was observed. Assays measuring the complement activating properties of AChR autoantibodies are needed to identifying patients expected to respond to complement inhibitor-based treatments.

IgG4 autoantibodies in autoimmune myasthenia gravis are functionally monovalent, requiring a high-affinity threshold to reach pathogenic capacity. This capacity is dependent on self-antigen driven maturation, which includes the accumulation of indispensable somatic mutations that may alter electrostatic interactions with the antigen., Pathogenic muscle-specific tyrosine kinase (MuSK)–specific IgG4 autoantibodies in autoimmune myasthenia gravis (MG) are functionally monovalent as a result of Fab-arm exchange. The development of these unique autoantibodies is not well understood. We examined MG patient–derived monoclonal autoantibodies (mAbs), their corresponding germline-encoded unmutated common ancestors (UCAs), and monovalent antigen-binding fragments (Fabs) to investigate how affinity maturation contributes to binding and immunopathology. Mature mAbs, UCA mAbs, and mature monovalent Fabs bound to MuSK and demonstrated pathogenic capacity. However, monovalent UCA Fabs bound to MuSK but did not have measurable pathogenic capacity. Affinity of the UCA Fabs for MuSK was 100-fold lower than the subnanomolar affinity of the mature Fabs. Crystal structures of two Fabs revealed how mutations acquired during affinity maturation may contribute to increased MuSK-binding affinity. These findings indicate that the autoantigen drives autoimmunity in MuSK MG through the accumulation of somatic mutations such that monovalent IgG4 Fab-arm–exchanged autoantibodies reach a high-affinity threshold required for pathogenic capacity., Graphical Abstract

ObjectiveTo identify candidate biomarkers associated with neuromyelitis optica spectrum disorder (NMOSD) using high-throughput technologies that broadly assay the concentrations of serum analytes and frequencies of immune cell subsets.MethodsSera, peripheral blood mononuclear cells (PBMCs), and matched clinical data from participants with NMOSD and healthy controls (HCs) were obtained from the Collaborative International Research in Clinical and Longitudinal Experience Study NMOSD biorepository. Flow cytometry panels were used to measure the frequencies of 39 T-cell, B-cell, regulatory T-cell, monocyte, natural killer (NK) cell, and dendritic cell subsets in unstimulated PBMCs. In parallel, multiplex proteomics assays were used to measure 46 serum cytokines and chemokines in 2 independent NMOSD and HC cohorts. Multivariable regression models were used to assess molecular and cellular profiles in NMOSD compared with HC.ResultsNMOSD samples had a lower frequency of CD16+CD56+ NK cells. Both serum cohorts and multivariable logistic regression revealed increased levels of B-cell activating factor associated with NMOSD. Interleukin 6, CCL22, and CCL3 were also elevated in 1 NMOSD cohort of the 2 analyzed. Multivariable linear regression of serum analyte levels revealed a correlation between CX3CL1 (fractalkine) levels and the number of days since most recent disease relapse.ConclusionsIntegrative analyses of cytokines, chemokines, and immune cells in participants with NMOSD and HCs provide congruence with previously identified biomarkers of NMOSD and highlight CD16+CD56+ NK cells and CX3CL1 as potential novel biomarker candidates.

Pathogenic autoantibodies causing encephalopathy modify the expression of the glucose transporter in oligodendrocytes.

Myasthenia gravis (MG) is a prototypical autoantibody mediated disease. The autoantibodies in MG target structures within the neuromuscular junction (NMJ), thus affecting neuromuscular transmission. The major disease subtypes of autoimmune MG are defined by their antigenic target. The most common target of pathogenic autoantibodies in MG is the nicotinic acetylcholine receptor (AChR), followed by muscle-specific kinase (MuSK) and lipoprotein receptor-related protein 4 (LRP4). MG patients present with similar symptoms independent of the underlying subtype of disease, while the immunopathology is remarkably distinct. Here we highlight these distinct immune mechanisms that describe both the B cell- and autoantibody-mediated pathogenesis by comparing AChR and MuSK MG subtypes. In our discussion of the AChR subtype, we focus on the role of long-lived plasma cells in the production of pathogenic autoantibodies, the IgG1 subclass mediated pathology, and contributions of complement. The similarities underlying the immunopathology of AChR MG and neuromyelitis optica (NMO) are highlighted. In contrast, MuSK MG is caused by autoantibody production by short-lived plasmablasts. MuSK MG autoantibodies are mainly of the IgG4 subclass which can undergo Fab-arm exchange (FAE), a process unique to this subclass. In FAE IgG4, molecules can dissociate into two halves and recombine with other half IgG4 molecules resulting in bispecific antibodies. Similarities between MuSK MG and other IgG4-mediated autoimmune diseases, including pemphigus vulgaris (PV) and chronic inflammatory demyelinating polyneuropathy (CIDP), are highlighted. Finally, the immunological distinctions are emphasized through presentation of biological therapeutics that provide clinical benefit depending on the MG disease subtype.

Pathogenic IgG4 autoantibodies in autoimmune myasthenia gravis (MG) are functionally monovalent as a result of Fab-arm exchange. The origin and development of these unique autoantibodies are not well understood. We examined MG patient-derived monoclonal autoantibodies (mAbs), their corresponding germline-encoded unmutated common ancestors (UCA) and monovalent antigen-binding fragments (Fabs) to investigate how antigen-driven affinity maturation contributes to both binding and immunopathology. Mature mAbs, their UCA counterparts and mature monovalent Fabs bound to the autoantigen and retained their pathogenic capacity. However, monovalent UCA Fabs still bound the autoantigen but lost their pathogenic capacity. The mature Fabs were characterized by very high affinity (sub-nanomolar) driven by a rapid on-rate and slow off-rate. However, the UCA affinity was approximately 100-fold less than that of the mature Fabs, which was driven by a rapid off-rate. Crystal structures of two Fabs shed light on how mutations acquired during affinity maturation may contribute to increased MuSK binding affinity. These collective findings indicate that the autoantigen initiates the autoimmune response in MuSK MG and drives autoimmunity through the accumulation of somatic hypermutation such that monovalent IgG4 Fab-arm exchanged MG autoantibodies reach a high affinity threshold required for pathogenic capacity.SummaryIgG4 autoantibodies in autoimmune myasthenia gravis are functionally monovalent, requiring a high affinity threshold featuring fast on/slow off rates, to reach pathogenic capacity. This capacity is dependent on self-antigen initiated and driven maturation, which includes the accumulation of indispensable somatic hypermutations that may alter electrostatic interactions with the antigen.

Rituximab, a B cell-depleting therapy, is indicated for treating a growing number of autoantibody-mediated autoimmune disorders. However, relapses can occur after treatment, and autoantibody-producing B cell subsets may be found during relapses. It is not understood whether these autoantibody-producing B cell subsets emerge from the failed depletion of preexisting B cells or are generated de novo. To further define the mechanisms that cause postrituximab relapse, we studied patients with autoantibody-mediated muscle-specific kinase (MuSK) myasthenia gravis (MG) who relapsed after treatment. We carried out single-cell transcriptional and B cell receptor profiling on longitudinal B cell samples. We identified clones present before therapy that persisted during relapse. Persistent B cell clones included both antibody-secreting cells and memory B cells characterized by gene expression signatures associated with B cell survival. A subset of persistent antibody-secreting cells and memory B cells were specific for the MuSK autoantigen. These results demonstrate that rituximab is not fully effective at eliminating autoantibody-producing B cells and provide a mechanistic understanding of postrituximab relapse in MuSK MG.

Autoantibodies that recognize the glycine receptor mediate pathology by directly interrupting glycinergic neurotransmission that manifests as a disorder characterized by muscle stiffness and spasms.

PURPOSE. High-level spinal cord injury (SCI) can result in spinal and supraspinal respiratory control deficits leading to insufficient ventilatory responses to exercise and training-related adaptations. We hypothesized a serotonin agonist, known to improve respiratory function in animal models, would improve adaptations to whole-body functional electrical stimulation (FES) exercise training in patients with acute high-level SCI. METHODS: We identified ten patients (0.66, p

Myasthenia gravis (MG) is an archetypal autoimmune disease. The pathology is characterized by autoantibodies to the acetylcholine receptor (AChR) in most patients or to muscle-specific tyrosine kinase (MuSK) in others and to a growing number of other postsynaptic proteins in smaller subsets. A decrease in the number of functional AChRs or functional interruption of the AChR within the muscle end plate of the neuromuscular junction is caused by pathogenic autoantibodies. Although the molecular immunology underpinning the pathology is well understood, much remains to be learned about the cellular immunology contributing to the production of autoantibodies. This Review documents research concerning the immunopathology of MG, bringing together evidence principally from human studies with an emphasis on the role of adaptive immunity and B cells in particular. Proposed mechanisms for autoimmunity, which take into account that different types of MG may incorporate divergent immunopathology, are offered. Muscle Nerve 57: 172-184, 2018.

To describe the population and functional changes observed after an inpatient rehabilitation facility stay in chordoma patients Materials and Methods: We conducted a consecutive series retrospective review of patients with chordoma, admitted to an academic inpatient rehabilitation facility after surgical resection from 2010 to 2015. Information regarding demographic, tumor- and surgery-specific data, lengths of stay, complications, admission and discharge functional independence measure scores was collected.A total of 40 patients with a diagnosis of chordoma were admitted to an inpatient rehabilitation facility postoperatively were included for analysis. Thirty-three patients had initial resection of chordoma, seven patients had resection of recurrent chordoma, and eight patients had metastatic disease on admission to an inpatient rehabilitation facility. The average change in total and motor functional independence measure scores after an inpatient rehabilitation facility stay was 33.7 and 26.1, respectively. The acute hospital transfer rate was 32.5% and the postoperative complication rate was 62.5%.This study is the first to describe the population and functional improvement in the chordoma population who are admitted to an inpatient rehabilitation facility postoperatively. While there is a high rate of acute hospital transfer and postoperative complications, these values are comparable to prior studies in this population. With the increasing prevalence of cancer survivors, improving function during and after cancer treatment is extremely important. Implications for Rehabilitation Chordoma patients who are admitted to inpatient rehabilitation facilities after surgical tumor resection experience improvement in multiple functional domains. Chordoma patients admitted to inpatient rehabilitation facilities experience a high rate of acute hospital transfer, but it is comparable to other cancer rehabilitation populations. Understanding the characteristics of the postoperative chordoma population is essential to direct future studies regarding cancer rehabilitation.

A role for B cells in autoimmune diseases is now clearly established both in mouse models and humans by successful treatment of multiple sclerosis and rheumatoid arthritis with anti-CD20 monoclonal antibodies that eliminate B cells. However, the underlying mechanisms by which B cells promote the development of autoimmune diseases remain poorly understood. Here we review evidence that patients with autoimmune disease suffer from defects in early B cell tolerance checkpoints and therefore fail to counter-select developing autoreactive B cells. These B cell tolerance defects are primary to autoimmune diseases and may result from altered B cell receptor signaling and dysregulated T cell/regulatory T cell compartment. As a consequence, large numbers of autoreactive naïve B cells accumulate in the blood of patients with autoimmune diseases and may promote autoimmunity through the presentation of self-antigen to T cells. In addition, new evidence suggests that this reservoir of autoreactive naïve B cells contains clones that may develop into CD27(-)CD21(-/lo) B cells associated with increased disease severity and plasma cells secreting potentially pathogenic autoantibodies after the acquisition of somatic hypermutations that improve affinity for self-antigens.

Objective: To optimize sensitivity and disease specificity of a myelin oligodendrocyte glycoprotein (MOG) antibody assay. Methods: Consecutive sera (n 5 1,109) sent for aquaporin-4 (AQP4) antibody testing were screened for MOG antibodies (Abs) by cell-based assays using either full-length human MOG (FL-MOG) or the short-length form (SL-MOG). The Abs were initially detected by Alexa Fluor goat anti-human IgG (H 1 L) and subsequently by Alexa Fluor mouse antibodies to human IgG1. Results: When tested at 1:20 dilution, 40/1,109 sera were positive for AQP4-Abs, 21 for SLMOG, and 180 for FL-MOG. Only one of the 40 AQP4-Ab–positive sera was positive for SLMOG-Abs, but 10 (25%) were positive for FL-MOG-Abs (p 5 0.0069). Of equal concern, 48% (42/88) of sera from controls (patients with epilepsy) were positive by FL-MOG assay. However, using an IgG1-specific secondary antibody, only 65/1,109 (5.8%) sera were positive on FL-MOG, and AQP4-Ab– positive and control sera were negative. IgM reactivity accounted for the remaining anti-human IgG (H 1 L) positivity toward FL-MOG. The clinical diagnoses were obtained in 33 FL-MOG–positive patients, blinded to the antibody data. IgG1-Abs to FL-MOG were associated with optic neuritis (n 5 11), AQP4-seronegative neuromyelitis optica spectrum disorder (n 5 4), and acute disseminated encephalomyelitis (n 5 1). All 7 patients with probable multiple sclerosis (MS) were MOG-IgG1 negative. Conclusions: The limited disease specificity of FL-MOG-Abs identified using Alexa Fluor goat antihuman IgG (H 1 L) is due in part to detection of IgM-Abs. Use of the FL-MOG and restricting to IgG1-Abs substantially improves specificity for non-MS demyelinating diseases. Classification of evidence: This study provides Class II evidence that the presence of serum IgG1- MOG-Abs in AQP4-Ab–negative patients distinguishes non-MS CNS demyelinating disorders from MS (sensitivity 24%, 95% confidence interval [CI] 9%–45%; specificity 100%, 95% CI 88%–100%). Neurol Neuroimmunol Neuroinflamm 2015;2:e89; doi: 10.1212/ NXI.0000000000000089

Pathogenic autoantibodies in neuromyelitis optica require antigen array assembly and a specific epitope to initiate robust complement activation.

ObjectiveWe sought to validate methods for detection and confirmation of GABAA receptor (R)-IgG and clinically characterize seropositive cases.MethodsArchived serum and CSF specimens (185 total) suspected to harbor GABAAR-IgG were evaluated by indirect immunofluorescence assay (IFA). Twenty-six specimens from 19 patients appeared suspicious for GABAAR–IgG positivity by IFA, based on prior reports and comparison with commercial GABAAR antibody staining. Aliquots of those specimens were tested at the University of Oxford, United Kingdom, and Euroimmun, Lubeck, Germany, for GABAAR-IgG by cell-based assays (CBAs) using HEK293-indicator cells transfected with plasmids encoding different GABAAR subunits.ResultsEight specimens (of 26 tested; 4 serums, 4 CSFs) from 5 patients were confirmed by CBA to be GABAAR-IgG positive. Patient IgGs were always reactive with α1β3 GABAAR subunits. One more patient was identified clinically after this validation study. Median age for the 6 patients at serologic diagnosis was 44 years (range, 1–71 years), and 4 of them were male. Among the 4 for whom clinical information was available (2 treated by the authors), all had encephalitis and antiepileptic drug refractory seizures. Three out of 4 patients treated with a combination of immunotherapies had good outcomes. The fourth, recognized to have an autoimmune cause late in the clinical course, had severe permanent neurologic sequelae and brain atrophy.ConclusionsThough not as common as NMDA-R encephalitis, GABAAR encephalitis generally has a characteristic clinical-radiologic presentation and is treatable, making accurate laboratory diagnosis critical.

IgA-expressing antibody secreting cells that are formed in the gut travel to the brain to diminish inflammation during multiple sclerosis exacerbations.

Myasthenia gravis (MG) is a chronic autoimmune disorder characterized by muscle weakness and caused by autoantibodies that bind to functional membrane proteins at the neuromuscular junction. Most patients have autoantibodies to the acetylcholine receptor (AChR), but a subset of patients instead have autoantibodies to muscle specific tyrosine kinase (MuSK). MuSK is an essential component of the Agrin/Lipoprotein receptor-related protein 4(LRP4)/MuSK/downstream of tyrosine kinase 7 (DOK7) pathway that is responsible for synaptic differentiation, including clustering of AChRs at the neuromuscular junction, both during development and in adult muscle. Nerve-released Agrin binds to LRP4 which then binds to MuSK, stimulating autophosphorylation and recruitment of DOK7 to complete the membrane component of the pathway. Serum-derived IgG4 subclass MuSK autoantibodies prevent the binding of LRP4 to MuSK, subsequently impairing autophosphorylation, resulting in the loss of Agrin-induced AChR clustering in the mouse myotube-forming C2C12 line. Although this autoimmune mechanism appears well understood, MuSK autoantibodies from patients are polyclonal. Most are IgG4 but IgG1, 2 and 3 are also present and can achieve similar results on AChR clustering. In addition, most bind the first Ig-like domain in MuSK, however some patients harbor serum autoantibodies that recognize other domains in MuSK. We sought to establish individual MuSK IgG clones so that the disease mechanisms could be better understood. We isolated MuSK autoantibody-expressing B cells from MuSK MG patients with a fluorescent-tagged MuSK antigen multimer and generated a panel of human monoclonal autoantibodies (mAbs) from these cells. We produced 77 mAbs from single B cells collected from six MuSK MG patients. Here we focused on three highly specific mAbs that bound quantitatively to MuSK in solution, to MuSK-expressing HEK cells and at mouse neuromuscular junctions where they co-localized with AChRs. These three IgG isotype mAbs (two IgG4 and one IgG3 subclass) recognized the Ig-like domain 2 of MuSK. The three MuSK mAbs inhibited Agrin induced-AChR clustering in C2C12 myotubes, but intriguingly, they enhanced rather than inhibited MuSK phosphorylation. This approach for ex vivo isolation of MuSK MG autoantibody-producing cells and production of human recombinant mAbs has identified distinct autoantibody specificities and likely divergent effector mechanisms. Collectively, these findings will enable a better understanding of MuSK autoantibody-mediated pathology.

Objectives Though much information exists about the diagnosis, treatment, and epidemiology of myasthenia gravis (MG), a comprehensive data registry and biorepository is critical to better understand disease mechanisms, treatment outcomes, and the impact of treatment strategies. We aimed to design and implement the “Exploring Outcomes and Characteristics of Myasthenia Gravis (EXPLORE-MG) Registry” to address these knowledge gaps. Methods A web-based, non-interventional, longitudinal, observational disease and outcomes registry was developed; incorporating NIH recommended common data elements for the study of MG. Individuals diagnosed with MG based on prespecified criteria were eligible to participate. The registry was further strengthened by a complementary biorepository. An interim analysis was completed on registry data collected through data-lock in 2017. Results A total of 232 MG patients, followed at the Yale MG Clinic from 2011 to 2017, were enrolled, which included 2142 total visit entries. Of the 232 MG patients (mean age 60 years, range 17–99; female:male, 1.04:1), 165 were acetylcholine receptor antibody-positive, 20 were muscle-specific kinase antibody-positive, and 47 were seronegative. This cohort consisted of 64 patients with ocular disease, 168 patients with generalized disease, and 65 patients post-thymectomy, including 20 with thymoma-associated MG. Conclusions Identification of key clinical features that may predict treatment responsiveness or provide insight into patient outcomes is essential to improve patient care. As current research focuses on the development of patient-tailored, targeted-treatment regimens, this registry can help provide important clinical and epidemiological data from a large contemporary patient cohort with long-term follow-up. Registration ClinicalTrials.gov Identifier: NCT03792659

Neuromyelitis optica spectrum disorders (NMOSD) constitute rare autoimmune disorders of the CNS that are primarily characterized by severe inflammation of the spinal cord and optic nerve. Approximately 75% of NMOSD patients harbour circulating pathogenic autoantibodies targeting the aquaporin-4 water channel (AQP4). The source of these autoantibodies remains unclear, but parallels between NMOSD and other autoantibody-mediated diseases posit compromised B cell tolerance checkpoints as common underlying and contributing factors. Using a well established assay, we assessed tolerance fidelity by creating recombinant antibodies from B cell populations directly downstream of each checkpoint and testing them for polyreactivity and autoreactivity. We examined a total of 863 recombinant antibodies. Those derived from three anti-AQP4-IgG seropositive NMOSD patients (n = 130) were compared to 733 antibodies from 15 healthy donors. We found significantly higher frequencies of poly- and autoreactive new emigrant/transitional and mature naïve B cells in NMOSD patients compared to healthy donors (P-values < 0.003), thereby identifying defects in both central and peripheral B cell tolerance checkpoints in these patients. We next explored whether pathogenic NMOSD anti-AQP4 autoantibodies can originate from the pool of poly- and autoreactive clones that populate the naïve B cell compartment of NMOSD patients. Six human anti-AQP4 autoantibodies that acquired somatic mutations were reverted back to their unmutated germline precursors, which were tested for both binding to AQP4 and poly- or autoreactivity. While the affinity of mature autoantibodies against AQP4 ranged from modest to strong (K(d) 15.2–559 nM), none of the germline revertants displayed any detectable binding to AQP4, revealing that somatic hypermutation is required for the generation of anti-AQP4 autoantibodies. However, two (33.3%) germline autoantibody revertants were polyreactive and four (66.7%) were autoreactive, suggesting that pathogenic anti-AQP4 autoantibodies can originate from the pool of autoreactive naïve B cells, which develops as a consequence of impaired early B cell tolerance checkpoints in NMOSD patients.

Self-reactive T cells that traffic to the brain tissue of patients with multiple sclerosis are driven by antigen-experienced B cells.

Activated microglia play a key role in inflammatory demyelinating injury in multiple sclerosis (MS). Microglial activation can be measured in vivo using a positron emission tomography (PET) ligand 11C-PBR28. We evaluated the test-retest variability (TRV) and lesion detectability of 11C-PBR28 binding in MS subjects and healthy controls (HCs) with high-resolution PET. Four clinically and radiologically stable relapsing-remitting MS subjects (age 41 ± 7 years, two men/two women) and four HCs (age 42 ± 8 years, 2 two men/two women), matched for translocator protein genotype [two high- and two medium-affinity binders according to DNA polymorphism (rs6971) in each group], were studied for TRV. Another MS subject (age 41 years, male) with clinical and radiological activity was studied for lesion detectability. Dynamic data were acquired over 120 min after injection of 634 ± 101 MBq 11C-PBR28. For the TRV study, subjects were scanned twice, on average 1.4 weeks apart. Volume of distribution (V T) derived from multilinear analysis (MA1) modeling (t* = 30 min, using arterial input data) was the main outcome measure. Mean test V T values (ml cm−3) were 3.9 ± 1.4 in the whole brain gray matter (GM), 3.6 ± 1.2 in the whole brain white matter (WM) or normal-appearing white matter (NAWM), and 3.3 ± 0.6 in MS WM lesions; mean retest V T values were 3.7 ± 1.0 in GM, 3.3 ± 0.9 in WM/NAWM, and 3.3 ± 0.7 in MS lesions. Test-retest results showed a mean absolute TRV ranging from 7 to 9 % across GM, WM/NAWM, and MS lesions. High-affinity binders demonstrated 30 % higher V T than medium-affinity binders in GM. Focal 11C-PBR28 uptake was detected in two enhancing lesions of the active MS patient. High-resolution 11C-PBR28 PET can visualize focal areas where microglial activation is known to be present and has good test-retest reproducibility in the human brain. 11C-PBR28 PET is likely to be valuable for monitoring both MS disease evolution and response to therapeutic strategies that target microglial activation.

Introduction: Few studies of the demographics, natural history, and clinical management of inclusion body myo- sitis (IBM) have been performed in a large patient population. To more accurately define these characteristics, we developed and distributed a questionnaire to patients with IBM. Methods: A cross-sectional, self-reporting survey was conducted. Results: The mean age of the 916 participants was 70.4 years, the male-to-female ratio was 2:1, and the majority reported difficulty with ambulation and activities of daily living. The earliest symp- toms included impaired use and weakness of arms and legs. The mean time from first symptoms to diagnosis was 4.7 years. Half reported that IBM was their initial diagnosis. A composite functional index negatively associated with age and disease duration, and positively associated with participation in exercise. Conclusions: These data are valuable for informing patients how IBM manifestations are expected to impair daily living and indicate that self-reporting could be used to establish outcome measures in clinical trials. Muscle Nerve 52: 527-533, 2015

Myasthenia gravis (MG) is a B cell-mediated autoimmune disorder of neuromuscular transmission. Pathogenic autoantibodies to muscle-specific tyrosine kinase (MuSK) can be found in patients with MG who do not have detectable antibodies to the acetylcholine receptor (AChR). MuSK MG includes immunological and clinical features that are generally distinct from AChR MG, particularly regarding responsiveness to therapy. B cell depletion has been shown to affect a decline in serum autoantibodies and to induce sustained clinical improvement in the majority of MuSK MG patients. However, the duration of this benefit may be limited, as we observed disease relapse in MuSK MG patients who had achieved rituximab-induced remission. We investigated the mechanisms of such relapses by exploring autoantibody production in the reemerging B cell compartment. Autoantibody-expressing CD27+ B cells were observed within the reconstituted repertoire during relapse but not during remission or in controls. Using two complementary approaches, which included production of 108 unique human monoclonal recombinant immunoglobulins, we demonstrated that antibody-secreting CD27hiCD38hi B cells (plasmablasts) contribute to the production of MuSK autoantibodies during relapse. The autoantibodies displayed hallmarks of antigen-driven affinity maturation. These collective findings introduce potential mechanisms for understanding both MuSK autoantibody production and disease relapse following B cell depletion.

Only sparse evidence exists regarding the effectiveness of oral alendronate (ALN) in the prevention of heterotopic ossification (HO) in patients with spinal cord injury (SCI). The objective of this study is to investigate the protective effect of oral ALN intake on the appearance of HO in patients with SCI.Retrospective database review.A Spinal Cord Unit at a Rehabilitation Hospital.Two hundred and ninety-nine patients with SCI during acute inpatient rehabilitation.Administration of oral ALN.The incidence of HO during rehabilitation was compared between patients with SCI receiving oral ALN (n = 125) and patients with SCI not receiving oral ALN (n = 174). The association between HO and/or ALN intake with HO risk factors and biochemical markers of bone metabolism were also explored.HO developed in 19 male patients (6.35%), however there was no significant difference in the incidence of HO in patients receiving oral ALN or not. The mean odds ratio of not developing versus developing HO given ALN exposure was 0.8. Significant correlation was found between abnormal serum alkaline phosphatase (ALP) levels and HO appearance (P0.001) as well as normal serum ALP and ALN intake (P0.05).Even though there was no direct prevention of HO in patients with SCI by oral ALN intake, abnormal serum ALP was found more frequently in patients with HO development and without oral ALN intake. This evidence could suggest that ALN may play a role in preventing HO, especially in patients with acute SCI with increasing levels of serum ALP.

Autoimmune disease results from a loss of tolerance to self-antigens in genetically susceptible individuals. Completely understanding this process requires that targeted antigens be identified, and so a number of techniques have been developed to determine immune receptor specificities. We previously reported the construction of a phage-displayed synthetic human peptidome and a proof-of-principle analysis of antibodies from three patients with neurological autoimmunity. Here we present data from a large-scale screen of 298 independent antibody repertoires, including those from 73 healthy sera, using phage immunoprecipitation sequencing. The resulting database of peptide-antibody interactions characterizes each individual’s unique autoantibody fingerprint, and includes specificities found to occur frequently in the general population as well as those associated with disease. Screening type 1 diabetes (T1D) patients revealed a prematurely polyautoreactive phenotype compared with their matched controls. A collection of cerebrospinal fluids and sera from 63 multiple sclerosis patients uncovered novel, as well as previously reported antibody-peptide interactions. Finally, a screen of synovial fluids and sera from 64 rheumatoid arthritis patients revealed novel disease-associated antibody specificities that were independent of seropositivity status. This work demonstrates the utility of performing PhIP-Seq screens on large numbers of individuals and is another step toward defining the full complement of autoimmunoreactivities in health and disease.

Randomized controlled treatment trials of autoimmune neurologic disorders are generally lacking and data pertaining to treatment are mostly derived from expert opinion, large case series, and anecdotal reports. The treatment of autoimmune neurologic disorders comprises oncologic therapy (where appropriate) and immunotherapy. In this chapter, we first describe the standard acute and chronic immunotherapies and provide a practical overview of their use in the clinic (mechanisms of action, dosing, monitoring, and side effects). Novel approaches to treatment of autoimmune neurologic disorders, through new drug discovery or repurposing, are dependent on improved mechanistic understanding of immunopathology. Such approaches, with emphasis on monoclonal antibodies, are discussed using the paradigm of three autoimmune neurologic disorders whose immunopathogenesis is better understood, specifically myasthenia gravis, neuromyelitis optica, and chronic inflammatory demyelinating polyradiculoneuropathy. It is important to realize that the treatment strategy and management plan must be individualized for each patient. In general these are influenced by the following: clinical severity, antibody type, presence or absence of cancer, and prior treatment response, if known.

Central nervous system demyelinating processes such as multiple sclerosis and acute disseminated encephalomyelitis constitute a group of diseases not completely understood in their physiopathology. Environmental and toxic insults are thought to play a role in priming autoimmunity. The aim of the present report is to describe a case of acute demyelinating disease with fatal outcome occurring 15 days after oral exposure to herbal extracts.

We investigated the overlap shared between the immunoglobulin (Ig) proteome of the cerebrospinal fluid (CSF) and the B cell Ig-transcriptome of CSF and the central nervous system (CNS) tissue of three patients with multiple sclerosis. We determined the IgG-proteomes of CSF by mass spectrometry, and compared them to the IgG-transcriptomes from CSF and brain lesions, which were analyzed by cDNA cloning. Characteristic peptides that were identified in the CSF-proteome could also be detected in the transcriptomes of both, brain lesions and CSF, providing evidence for a strong overlap of the IgG repertoires in brain lesions and in the CSF.

In the central nervous system of patients with multiple sclerosis, B cell aggregates populate the meninges, raising the central question as to whether these structures relate to the B cell infiltrates found in parenchymal lesions or instead, represent a separate central nervous system immune compartment. We characterized the repertoires derived from meningeal B cell aggregates and the corresponding parenchymal infiltrates from brain tissue derived primarily from patients with progressive multiple sclerosis. The majority of expanded antigen-experienced B cell clones derived from meningeal aggregates were also present in the parenchyma. We extended this investigation to include 20 grey matter specimens containing meninges, 26 inflammatory plaques, 19 areas of normal appearing white matter and cerebral spinal fluid. Analysis of 1833 B cell receptor heavy chain variable region sequences demonstrated that antigen-experienced clones were consistently shared among these distinct compartments. This study establishes a relationship between extraparenchymal lymphoid tissue and parenchymal infiltrates and defines the arrangement of B cell clones that populate the central nervous system of patients with multiple sclerosis.

Anti-myelin basic protein (MBP) antibodies in pediatric-onset MS and controls were characterized. Serum samples were obtained from 94 children with MS and 106 controls. Paired CSF and serum were obtained from 25 children with MS at time of their initial episode of acute demyelinating syndrome (ADS). Complementary assays were applied across samples to evaluate the presence, and the physical binding properties, of anti-MBP antibodies. While the prevalence and titers of serum anti-MBP antibodies against both immature and mature forms of MBP were similar in children with MS and in controls, binding characteristics and formal Surface Plasmon Resonance (SPR) studies indicated surprisingly high binding affinities of all pediatric anti-MBP antibodies. Serum levels of anti-MBP antibodies correlated significantly with their CSF levels, and their presence in children with MS was associated with significantly increased risk of an acute disseminated encephalomyelitis-like initial clinical presentation. While antibodies to both immature and mature forms of MBP can be present as part of the normal pediatric humoral repertoire, these anti-myelin antibodies are of surprisingly high affinity, can access the CNS during inflammation, and have the capacity to modulate disease expression. Our findings identify an immune mechanism that could contribute to the observed heterogeneity in spectrum of clinical presentations in early-onset MS.

Multiple sclerosis is an inflammatory demyelinating disease of the central nervous system (CNS) that is thought to be caused by a combination of genetic and environmental factors. To date, considerable evidence has associated Epstein-Barr virus (EBV) infection with disease development. However, it remains controversial whether EBV infects multiple sclerosis brain and contributes directly to CNS immunopathology. To assess whether EBV infection is a characteristic feature of multiple sclerosis brain, a large cohort of multiple sclerosis specimens containing white matter lesions (nine adult and three paediatric cases) with a heterogeneous B cell infiltrate and a second cohort of multiple sclerosis specimens (12 cases) that included B cell infiltration within the meninges and parenchymal B cell aggregates, were examined for EBV infection using multiple methodologies including in situ hybridization, immunohistochemistry and two independent real-time polymerase chain reaction (PCR) methodologies that detect genomic EBV or the abundant EBV encoded RNA (EBER) 1, respectively. We report that EBV could not be detected in any of the multiple sclerosis specimens containing white matter lesions by any of the methods employed, yet EBV was readily detectable in multiple Epstein-Barr virus-positive control tissues including several CNS lymphomas. Furthermore, EBV was not detected in our second cohort of multiple sclerosis specimens by in situ hybridization. However, our real-time PCR methodologies, which were capable of detecting very few EBV infected cells, detected EBV at low levels in only 2 of the 12 multiple sclerosis meningeal specimens examined. Our finding that CNS EBV infection was rare in multiple sclerosis brain indicates that EBV infection is unlikely to contribute directly to multiple sclerosis brain pathology in the vast majority of cases.

Objective Intrathecal IgG synthesis, persistence of bands of oligoclonal IgG, and memory B-cell clonal expansion are well-characterized features of the humoral response in multiple sclerosis (MS). Nevertheless, the target antigen of this response remains enigmatic. Methods We produced 53 different human IgG1 monoclonal recombinant antibodies (rAbs) by coexpressing paired heavy- and light-chain variable region sequences of 51 plasma cell clones and 2 B-lymphocyte clones from MS cerebrospinal fluid in human tissue culture cells. Chimeric control rAbs were generated from anti-myelin hybridomas in which murine variable region sequences were fused to human constant region sequences. Purified rAbs were exhaustively assayed for reactivity against myelin basic protein, proteolipid protein, and myelin oligodendrocyte glycoprotein by immunostaining of transfected cells expressing individual myelin proteins, by protein immunoblotting, and by immunostaining of human brain tissue sections. Results Whereas humanized control rAbs derived from anti-myelin hybridomas and anti-myelin monoclonal antibodies readily detected myelin antigens in multiple immunoassays, none of the rAbs derived from MS cerebrospinal fluid displayed immunoreactivity to the three myelin antigens tested. Immunocytochemical analysis of tissue sections from MS and control brain demonstrated only weak staining with a few rAbs against nuclei or cytoplasmic granules in neurons, glia, and inflammatory cells. Interpretation The oligoclonal B-cell response in MS cerebrospinal fluid is not targeted to the well-characterized myelin antigens myelin basic protein, proteolipid protein, or myelin oligodendrocyte glycoprotein.

Objective Neurovascular niches have been proposed as critical components of the neural stem cell (NSC) response to acute central nervous system injury; however, it is unclear whether these potential reparative niches remain functional during chronic injury. Here, we asked how central nervous system inflammatory injury regulates the intrinsic properties of NSCs and their niches. Methods We investigated the sonic hedgehog (Shh)-Gli1 pathway, an important signaling pathway for NSCs, in experimental autoimmune encephalomyelitis (EAE) and multiple sclerosis (MS), and its regulation by inflammatory cytokines. Results We show that Shh is markedly upregulated by reactive and perivascular astroglia in areas of injury in MS lesions and during EAE. Astroglia outside the subventricular zone niche can support NSC differentiation toward neurons and oligodendrocytes, and Shh is a critical mediator of this effect. Shh induces differential upregulation of the transcription factor Gli1, which mediates Shh-induced NSC differentiation. However, despite the increase in Shh and the fact that Gli1 was initially increased during early inflammation of EAE and active lesions of MS, Gli1 was significantly decreased in spinal cord oligodendrocyte precursor cells after onset of EAE, and in chronic active and inactive lesions from MS brain. The Th1 cytokine interferon-γ was unique in inducing Shh expression in astroglia and NSCs, while paradoxically suppressing Gli1 expression in NSCs and inhibiting Shh-mediated NSC differentiation. Interpretation Our data suggest that endogenous repair potential during chronic injury appears to be limited by inflammation-induced alterations in intrinsic NSC molecular pathways such as Gli1. Ann Neurol 2008;64:417–427

More than 92000 Americans are on waiting lists for organ transplants, and an average of 17 of them die each day while waiting. The US Organ Donation Breakthrough Collaborative (ODBC), which began in 2003 at the request of the Secretary of the US Department of Health and Human Services, was a formal, concerted effort of the donation and transplantation community to bring about a major change to improve the organ donation system. The nationwide Collaborative was housed within a Health and Human Services agency, the Health Resources and Services Administration (HRSA) Division of Transplantation, and included participation of the organ procurement organizations (OPOs) throughout the United States and the American hospitals with the largest organ-donor potential. HRSA leaders used the Breakthrough Series Collaborative method, originally developed by the Institute for Healthcare Improvement, as the model for the intervention. Expert practitioners drawn from hospitals and OPOs that had already demonstrated their ability to achieve and sustain high organ donation rates were chosen as faculty for the collaborative and best practices were gleaned from their institutions. The number of organ donors in Collaborative hospitals increased 14.1% in the first year, a 70% greater increase than the 8.3% increase experienced by non-Collaborative hospitals. Moreover, the increased organ recovery continued into the post-Collaborative periods. Between October 2003 and September 2006, the number of total US organ donors increased 22.5%, an increase 4-fold greater than the 5.5% increase measured over the same number of years in the immediate pre-Collaborative period. The study did not involve a randomized design, but time-series analysis using statistical process control charts shows a highly significant discontinuity in the rate of increase in participating hospitals concurrent with the Collaborative program, and strongly suggests that the activities of the Collaborative were a major contributor to this increase. Given the stable nature of the historical increases over many years, the HRSA estimates that more than 4000 annual additional transplants have occurred in association and apparently as a result of these increases in organ donation.

Objective The authors examine the differences in outcome between black and white patients receiving electroconvulsive therapy (ECT) as a part of the Consortium for Research on Electroconvulsive Therapy multisite study. Methods A total of 624 patients were enrolled in an National Institute of Mental Health (NIMH)-funded, randomized, controlled ECT trial comparing the efficacy of continuation ECT versus continuation pharmacotherapy between 1997 and 2004. This analysis focuses on the 32 black and 483 white patients who participated in phase I of the study. The authors compared baseline demographic and clinical variables and acute outcomes of these 2 groups. Results Compared with whites, far fewer blacks participated in the study. Those who did were less likely to have failed adequate medication trials and were more likely to have psychotic features. Their initial 24-item Hamilton Rating Scale for Depression scores were higher than those of the whites, and they showed a greater reduction in these 24-item Hamilton Rating Scale for Depression scores by the end of the treatment period. Although sample size limited the statistical significance of the findings, black patients also showed a higher rate of remission after an acute phase of ECT. Conclusions This study found that black and white patients with major depressive disorder had comparable outcomes. We also found that fewer black patients received ECT than whites, a difference that has been reported in other samples.

Objective To determine the relationship between baseline melancholic features with outcomes in patients with major depressive disorder referred for electroconvulsive therapy (ECT). Method In a multihospital (Consortium for Research in ECT) collaborative ECT study, SCID-1 interviews were obtained at study entry. Ratings of the 24-item Hamilton Rating Scale for Depression were obtained thrice weekly during the course of ECT, once during a subsequent treatment-free week, and periodically during 6-month continuation treatment with either bitemporal ECT or nortriptyline plus lithium (continuation pharmacotherapy). Results The evaluable sample was severely ill with a mean 24-item Hamilton Rating Scale for Depression score of 35.2 (+/-6.9). Of 489 patients, 63.6% (311) met DSM-IV criteria for melancholic features. During acute ECT, 62.1% of those with melancholic features remitted, as compared with 78.7% for those without melancholic features (P = 0.002). During medication continuation treatment (continuation pharmacotherapy), relapse rates were higher for those with melancholic features than for those without these features. Conversely, with continuation ECT, the rate of relapse was lower for those with, compared with those without, melancholic features. Conclusions Ascertaining melancholic features by SCID-1 criteria does not identify depressed patients more likely to respond to ECT as had been anticipated from the literature. Melancholic features were associated with poorer treatment outcomes in acute ECT. Those with melancholic features were less likely to relapse with continuation ECT, but those with melancholic features were more likely to relapse with continuation pharmacotherapy. The limitations of the DSM-IV criteria for melancholia are discussed.

The inflammatory myopathies are putative autoimmune disorders characterized by muscle weakness and the presence of intramuscular inflammatory infiltrates. Although inclusion body myositis and polymyositis have been characterized as cytotoxic CD8+ T cell-mediated diseases, we recently demonstrated high frequencies of CD138+ plasma cells in the inflamed muscle tissue of patients with these diseases. To gain a deeper understanding of the role these B cell family members play in the disease pathology, we examined the molecular characteristics of the H chain portion of the Ag receptor. Biopsies of muscle tissue were sectioned and tissue regions and individual cells were isolated through laser capture microdissection. Ig H chain gene transcripts isolated from the sections, regions, and cells were used to determine the variable region gene sequences. Analysis of these sequences revealed clear evidence of affinity maturation in that significant somatic mutation, isotype switching, receptor revision, codon insertion/deletion, and oligoclonal expansion had occurred within the B and plasma cell populations. Moreover, analysis of tissue regions isolated by laser capture microdissection revealed both clonal expansion and variation, suggesting that local B cell maturation occurs within muscle. In contrast, sequences from control muscle tissues and peripheral blood revealed none of these characteristics found in inflammatory myopathy muscle tissue. Collectively, these data demonstrate that Ag drives a B cell Ag-specific response in muscle in patients with dermatomyositis, inclusion body myositis, and polymyositis. These findings highlight the need for a revision of the current paradigm of exclusively T cell-mediated intramuscular Ag-specific autoimmunity in inclusion body myositis and polymyositis.

The central nervous system (CNS) of patients with multiple sclerosis (MS) is the site where disease pathology is evident. Damaged CNS tissue is commonly associated with immune cell infiltration. This infiltrate often includes B cells that are found in multiple locations throughout the CNS, including the cerebrospinal fluid (CSF), parenchyma, and the meninges, frequently forming tertiary lymphoid structures in the latter. Several groups, including our own, have shown that B cells from distinct locations within the MS CNS are clonally related and display the characteristics of an antigen-driven response. However, the antigen(s) driving this response have yet to be conclusively defined. To explore the antigen specificity of the MS B cell response, we produced recombinant human immunoglobulin (rIgG) from a series of expanded B cell clones that we isolated from the CNS tissue of six MS brains. The specificity of these MS-derived rIgG and control rIgG derived from non-MS tissues was then examined using multiple methodologies that included testing individual candidate antigens, screening with high-throughput antigen arrays and evaluating binding to CNS-derived cell lines. We report that while several MS-derived rIgG recognized particular antigens, including neurofilament light and a protocadherin isoform, none were unique to MS, as non-MS-derived rIgG used as controls invariably displayed similar binding specificities. We conclude that while MS CNS resident B cells display the characteristics of an antigen-driven B cell response, the antigen(s) driving this response remain at large.

Neuromyelitis optica (NMO) is an inflammatory autoimmune disorder of the CNS that predominantly affects the spinal cord and optic nerves. A majority (approximately 75%) of patients with NMO are seropositive for autoantibodies against the astrocyte water channel aquaporin-4 (AQP4). These autoantibodies are predominantly IgG1, and considerable evidence supports their pathogenicity, presumably by binding to AQP4 on CNS astrocytes, resulting in astrocyte injury and inflammation. Convergent clinical and laboratory-based investigations have indicated that B cells play a fundamental role in NMO immunopathology. Multiple mechanisms have been hypothesized: AQP4 autoantibody production, enhanced proinflammatory B cell and plasmablast activity, aberrant B cell tolerance checkpoints, diminished B cell regulatory function, and loss of B cell anergy. Accordingly, many current off-label therapies for NMO deplete B cells or modulate their activity. Understanding the role and mechanisms whereby B cells contribute to initiation, maintenance, and propagation of disease activity is important to advancing our understanding of NMO pathogenesis and developing effective disease-specific therapies. peerReviewed

Despite the efficacy of standard immunotherapy, a subset of myasthenia gravis (MG) patients remains medically refractory. Muscle-specific kinase autoantibody positive (MuSK+) patients, in particular, do not respond well to treatment, exhibit more bulbar symptoms and have more frequent exacerbations as compared to acetylcholine receptor antibody positive (AChR+) patients.1 ,2 Autoreactive B cells are appropriate candidates for targeted drug therapy as they play an important role in the pathogenesis of MG.2–4 Rituximab, a chimeric monoclonal antibody that targets the CD20 antigen on B lymphocytes, is the only B cell–directed biologic currently approved for clinical use. Several groups, including our own, have observed the benefits of rituximab in both AChR+ and MuSK+ patients.2–7 The durability of this positive response has varied among different reports. One group reported sustained benefit after a mean follow-up of 31 months in the combined AChR+ and MuSK+ cohort and 40 months in the MuSK+ subpopulation.3 Here, we report our experience with the sustained effects of rituximab in nine refractory MuSK+ patients in a follow-up period ranging from 2 to 5.5 years. A retrospective study was performed of generalised MuSK+ MG patients referred to our neuromuscular clinic from 2003 to 2011. Nine MuSK+ patients were identified with refractory disease and treated with rituximab. The group consisted of eight females and one male with a median age of 40. Patients were defined as refractory when they: (1) could not lower …

An enzyme-linked immunosorbent assay of antibodies in the serum of 86 patients with multiple sclerosis and that of 51 healthy controls that used KIR4.1 as the target protein showed no significant between-group difference.

Although accumulating evidence strongly suggests that aplastic anemia (AA) is a T cell-mediated autoimmune disease, no target antigens have yet been described for AA. In autoimmune diseases, target autoantigens frequently induce not only cellular T-cell responses but also humoral B-cell responses. We hypothesized that the presence of antigen-specific autoantibodies could be used as a “surrogate marker” for the identification of target T-cell autoantigens in AA patients. We screened a human fetal liver library for serologic reactivity against hematopoietic stem/progenitor cell antigens and isolated 32 genes. In 7 of 18 AA patients, an immunoglobulin G (IgG) antibody response was detected to one of the genes, kinectin, which is expressed in all hematopoietic cell lineages tested including CD34+ cells. No response to kinectin was detected in healthy volunteers, multiply transfused non-AA patients, or patients with other autoimmune diseases. Epitope mapping of IgG autoantibodies against kinectin revealed that the responses to several of the epitopes were shared by different AA patients. Moreover, CD8+ cytotoxic T cells raised against kinectin-derived peptides suppressed the colony formation of granulocyte macrophage colony-forming units (CFU-GMs) in an HLA class I-restricted fashion. These results suggest that kinectin may be a candidate autoantigen that is involved in the pathophysiology of AA. (Blood. 2003;102:4567-4575)