Treating myasthenia gravis beyond the eye clinic

Myasthenia gravis (MG) is one of the most well characterised autoimmune disorders affecting the neuromuscular junction with autoantibodies targeting the acetylcholine receptor (AChR) complex. The vast majority of patients present with ocular symptoms including double vision and ptosis, but may progress on to develop generalised fatiguable muscle weakness. Severe involvement of the bulbar muscles can lead to dysphagia, dysarthria and breathing difficulties which can progress to myasthenic crisis needing ventilatory support. Given the predominant ocular onset of the disease, it is important that ophthalmologists are aware of the differential diagnosis, investigations and management including evolving therapies. When the disease remains localised to the extraocular muscles (ocular MG) IgG1 and IgG3 antibodies against the AChR (including clustered AChR) are present in nearly 50% of patients. In generalised MG this is seen in nearly 90% patients. Other antibodies include those against muscle specific tyrosine kinase (MuSK) and lipoprotein receptor related protein 4 (LRP4). Even though decremental response on repetitive nerve stimulation is the most well recognised neurophysiological abnormality, single fibre electromyogram (SFEMG) in experienced hands is the most sensitive test which helps in the diagnosis. Initial treatment should be using cholinesterase inhibitors and then proceeding to immunosuppression using corticosteroids and steroid sparing drugs. Patients requiring bulbar muscle support may need rescue therapies including plasma exchange and intravenous immunoglobulin (IVIg). Newer therapeutic targets include those against the B lymphocytes, complement system, neonatal Fc receptors (FcRn) and various other elements of the immune system.

Defective autophagy and autophagy activators in myasthenia gravis: a rare entity and unusual scenario

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ) that results from autoantibodies against nicotinic acetylcholine receptors (nAchRs) at NMJs. These autoantibodies are mainly originated from autoreactive B cells that bind and destroy nAchRs at NMJs preventing nerve impulses from activating the end-plates of skeletal muscle. Indeed, immune dysregulation plays a crucial role in the pathogenesis of MG. Autoreactive B cells are increased in MG due to the defect in the central and peripheral tolerance mechanisms. As well, autoreactive T cells are augmented in MG due to the diversion of regulatory T (Treg) cells or a defect in thymic anergy leading to T cell-mediated autoimmunity. Furthermore, macroautophagy/autophagy, which is a conserved cellular catabolic process, plays a critical role in autoimmune diseases by regulating antigen presentation, survival of immune cells and cytokine-mediated inflammation. Abnormal autophagic flux is associated with different autoimmune disorders. Autophagy regulates the connection between innate and adaptive immune responses by controlling the production of cytokines and survival of Tregs. As autophagy is involved in autoimmune disorders, it may play a major role in the pathogenesis of MG. Therefore, this mini-review demonstrates the potential role of autophagy and autophagy activators in MG.Abbreviations: Ach, acetylcholine; Breg, regulatory B; IgG, immunoglobulin G; MG, myasthenia gravis; NMJ, neuromuscular junction; ROS, reactive oxygen species; Treg, regulatory T; Ubl, ubiquitin-like.

Nanodrug Delivery Systems for Myasthenia Gravis: Advances and Perspectives

Myasthenia gravis (MG) is a rare chronic autoimmune disease caused by the production of autoantibodies against the postsynaptic membrane receptors present at the neuromuscular junction. This condition is characterized by fatigue and muscle weakness, including diplopia, ptosis, and systemic impairment. Emerging evidence suggests that in addition to immune dysregulation, the pathogenesis of MG may involve mitochondrial damage and ferroptosis. Mitochondria are the primary site of energy production, and the reactive oxygen species (ROS) generated due to mitochondrial dysfunction can induce ferroptosis. Nanomedicines have been extensively employed to treat various disorders due to their modifiability and good biocompatibility, but their application in MG management has been rather limited. Nevertheless, nanodrug delivery systems that carry immunomodulatory agents, anti-oxidants, or ferroptosis inhibitors could be effective for the treatment of MG. Therefore, this review focuses on various nanoplatforms aimed at attenuating immune dysregulation, restoring mitochondrial function, and inhibiting ferroptosis that could potentially serve as promising agents for targeted MG therapy.

Novel Immunotherapies for Myasthenia Gravis

Myasthenia gravis (MG), a prototype autoimmune neurological disease, had its therapy centred on corticosteroids, non-steroidal broad-spectrum immunotherapy and cholinesterase inhibitors for several decades. Treatment-refractory MG and long-term toxicities of the medications have been major concerns with the conventional therapies. Advances in the immunology and pathogenesis of MG have ushered in an era of newer therapies which are more specific and efficacious. Complement inhibitors and neonatal Fc receptor blockers target disease-specific pathogenic mechanisms linked to myasthenia and have proven their efficacy in pivotal clinical studies. B cell-depleting agents, specifically rituximab, have also emerged as useful for the treatment of severe MG. Many more biologicals are in the pipeline and in diverse stages of development. This review discusses the evidence for the novel therapies and the specific issues related to their clinical use.

The Role of Human Microbiota in Myasthenia Gravis: A Narrative Review

Myasthenia gravis (MG) is an autoimmune neuromuscular disease characterized by fluctuating weakness of the skeletal muscles. Although antibodies against the neuromuscular junction components are recognized, the MG pathogenesis remains unclear, even if with a well-known multifactorial character. However, the perturbations of human microbiota have been recently suggested to contribute to MG pathogenesis and clinical course. Accordingly, some products derived from commensal flora have been demonstrated to have anti-inflammatory effects, while other have been shown to possess pro-inflammatory properties. In addition, patients with MG when compared with age-matched controls showed a distinctive composition in the oral and gut microbiota, with a typical increase in Streptococcus and Bacteroides and a reduction in Clostridia as well as short-chain fatty acid reduction. Moreover, restoring the gut microbiota perturbation has been evidenced after the administration of probiotics followed by an improvement of symptoms in MG cases. To highlight the role of the oral and gut microbiota in MG pathogenesis and clinical course, here, the current evidence has been summarized and reviewed.

Aberrant Dendritic Cell Subsets in Patients with Myasthenia Gravis and Related Clinical Features

INTRODUCTION

Dendritic cells (DCs) play critical roles in the pathogenesis of myasthenia gravis (MG), and a series of DC-based experimental strategies for MG have recently been developed. However, the definite roles of different DC subsets in the mechanism of MG have scarcely been covered by previous studies. The present study aimed to investigate the levels of three main DC subsets, plasmacytoid DCs (pDCs) (CD303 positive) and two distinct subsets of conventional DCs (cDCs), namely CD1c+ cDCs and CD141+ cDCs, in MG patients and analyze related clinical features.

METHODS

From January 2016 to December 2020, 160 newly diagnosed MG patients and matched healthy controls (n = 160) were included in the study, and their clinical data were collected. The blood samples from MG patients before treatment and controls were collected for flow cytometry analysis. A total of 14 MG thymoma, 24 control thymoma, and 3 thymic cysts were used to immunostain the DC subsets.

RESULTS

The flow cytometry analysis showed a significantly higher frequency of circulating pDCs, CD1c+ cDCs, and CD141+ cDCs in MG patients than in healthy controls (p < 0.001 for all). Patients with early-onset MG (<50 years old) had a lower frequency of circulating pDCs but a higher frequency of circulating CD1c+ cDCs than those with late-onset MG (≥50 years old) (p = 0.014 and p = 0.025, respectively). The frequency of circulating pDCs was positively associated with the clinical severity of late-onset MG patients (r = 0.613, p < 0.001). 64.3% (9/14) of MG thymoma is of type B2 under the World Health Organization classification, which is higher than that in control thymoma (33.3%, 8/24) (p = 0.019). For type B2 thymoma, there were significantly more pDCs but fewer CD1c+ cDCs in MG thymoma than in the controls.

CONCLUSION

The distribution of aberrant pDCs, CD1c+ cDCs, and CD141+ cDCs in MG patients displayed age- and thymoma-related differences, which may contribute to the impaired immune tolerance and lead to the onset of MG.

Epidemiology of myasthenia gravis in the province of Ourense (Galicia, Spain)

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease affecting nerve transmission at the level of the neuromuscular junction, and typically causes fluctuating muscle weakness. Epidemiological studies show an increase in MG prevalence, particularly among the older population.

OBJECTIVE

We performed a retrospective epidemiological study to determine the incidence and prevalence of MG in the province of Ourense (Galicia, Spain), characterised by population ageing.

MATERIAL AND METHODS

Patients were selected from our clinical neuromuscular diseases database by searching for patients with an active prescription for pyridostigmine bromide. Incidence was estimated for the period 2009-2018. We calculated prevalence at 31/12/2018. According to census data for the province of Ourense, the population on 1/1/2019 was 307 651, of whom 96 544 (31.4%) were aged ≥ 65 years.

RESULTS

We identified 80 cases of MG, with a prevalence rate of 260 cases/1 000 000 population (95% CI, 202.7-316.4), rising to 517.9/1 000 000 population in those aged ≥ 65 (95% CI, 363.2-672.9). Cumulative incidence in the study period was 15.4 cases per 1 000 000 person-years. Early onset (≤ 50 years) was recorded in 29.1% of cases.

CONCLUSION

The prevalence of MG in our health district is one of the highest published figures, and the disease is highly prevalent in the older population.

Suppression of the CD28/B7 pathway reduces the occurrence and development of myasthenia gravis and cytokine levels

BACKGROUND

Myasthenia gravis (MG) is an antibody-mediated, autoimmune neuromuscular disease. Reports have indicated that the CD28/B7 ligand interactions play a crucial role during primary immune responses. Hence, the aim of the present study was to investigate the possible effects of the CD28/B7 pathway on the occurrence and development of MG and its associated cytokine factors.

METHODS

An experimental autoimmune myasthenia gravis (EAMG) was initially established by immunization of Lewis rats with acetylcholine receptor (AChR) α97-116 peptide. Then the rats were treated with dexamethasone and CTLA4-Ig (used for inhibiting the CD28/B7 pathway). Serum levels of AChR IgG and AChR IgG2b were then detected using ELISA. The clinical features, muscle contraction function, AChR content, expression of CD28, CTLA4, B7.1 and B7.2 in mononuclear cells of peripheral blood and the secretion of cytokines (INF-γ, IL-2, IL-10 and IL-12) in serum of rats were measured. Finally, lymphocyte proliferation upon CTLA4 IgG treatment was examined in vitro.

RESULTS

Inhibition of the CD28/B7 pathway and dexamethasone were found to significantly improve clinical symptoms of EAMG rats, reduce serum levels of AChR IgG, AChR IgG2b, INF-γ, IL-2, IL-10 and IL-12, the expression of CD28, CTLA4, B7.1 and B7.2 in mononuclear cells of peripheral blood, and enhance muscle contraction function and AChR content in the muscle in vivo. Meanwhile, CTLA4 IgG could abolish the increased lymphocyte proliferation following AChR stimulation in vitro.

CONCLUSION

Overall, the suppression of the CD28/B7 pathway by CTLA4-Ig can have the potential to retard the occurrence and development of MG.

Imbalance of Th17 and Tregs in thymoma may be a pathological mechanism of myasthenia gravis

An imbalance in Th17 cells and Tregs may be an important cause of the pathogenesis of thymoma with myasthenia gravis (MG). In this study, 30 patients with simple thymoma and 30 patients with thymoma with MG were analyzed. Flow cytometry analysis of Th17 and Tregs in peripheral blood revealed that the percentages of Th17 in thymoma were lower than those in thymoma with MG, while the percentages of Tregs were higher than those in simple thymoma. Serum cytokine ELISA assays showed that IL-6 levels in simple thymoma were lower than those in MG patients. Further, Th17 and Tregs levels were detected by immunohistochemical double staining of thymoma tissue; the number of positive Th17 cells in thymoma with MG was higher than that in simple thymoma, while positive Tregs showed the opposite results. RORγt protein and mRNA expression in thymoma with MG were both higher than those in simple thymoma. FOXP3 protein and mRNA expression in the thymoma with MG group were lower than those in simple thymoma. The results of coculture of thymoma cells and CD4 + T cells showed that thymoma cells could promote the differentiation of Th17 cells and inhibit the Tregs. Overall, Th17 cells and related transcription factors and cytokines in thymoma with MG patients were higher than those in thymoma patients, whereas, Tregs showed the opposite results, the mechanism may be that thymoma can secrete IL6 and IL21. These findings indicated that imbalances in Th17/Tregs may account for the pathogeny of thymoma with MG.

Epidemiology of myasthenia gravis in the province of Ourense (Galicia, Spain)

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease affecting nerve transmission at the level of the neuromuscular junction, and typically causes fluctuating muscle weakness. Epidemiological studies show an increase in MG prevalence, particularly among the older population.

OBJECTIVE

We performed a retrospective epidemiological study to determine the incidence and prevalence of MG in the province of Ourense (Galicia, Spain), characterised by population ageing.

MATERIAL AND METHODS

Patients were selected from our clinical neuromuscular diseases database by searching for patients with an active prescription for pyridostigmine bromide. Incidence was estimated for the period 2009-2018. We calculated prevalence at 31/12/2018. According to census data for the province of Ourense, the population on 1/1/2019 was 307,651, of whom 96,544 (31.4%) were aged ≥ 65 years.

RESULTS

We identified 80 cases of MG, with a prevalence rate of 260 cases/1 000 000 population (95% CI, 202.7-316.4), rising to 517.9/1 000 000 population in those aged ≥ 65 (95% CI, 363.2-672.9). Cumulative incidence in the study period was 15.4 cases per 1 000 000 person-years. Early onset (≤ 50 years) was recorded in 29.1% of cases.

CONCLUSION

The prevalence of MG in our health district is one of the highest published figures, and the disease is highly prevalent in the older population.

Effects of Mitophagy on Regulatory T Cell Function in Patients With Myasthenia Gravis

Objective: This study was conducted to determine whether regulatory T cells (CD4⁺CD25⁺T, Tregs) show abnormal mitophagy as well as the function of Tregs in patients with myasthenia gravis (MG).

Methods: CD4⁺T cells and CD4⁺CD25⁺Treg cells were obtained from 15 patients with MG (MG group) and 15 controls (N group). Tregs from the MG group were subjected to rapamycin-induced culture for 48 h (Rapa group) and 3-methyladenine-induced culture for 48 h (3-MA group). The levels of mitophagy in Tregs were then observed through electron and confocal microscopy. Expression of the autophagy-related protein LC3-II was detected by western blotting, and mitochondrial function in each group was evaluated by flow cytometry. Inhibition of Treg cell proliferation was detected by flow cytometry.

Results: Mitophagy in the MG group was lower than that in the N group; it was higher in the Rapa group compared to that in the MG group and lowered in the 3-MA group than in the MG group. Expression of the autophagy-related protein LC3-II was lower in the MG group than in the N group, higher in the Rapa group than in the MG group, and lower in the 3-MA group than in the MG group. The mitochondrial membrane potential was lower in the MG group compared to that in the N group; it was higher in the Rapa group than in the MG group and lowered in the 3-MA group than in the MG group. Inhibition of Treg proliferation was lower in the MG group than in the N group; it was higher in the Rapa group than in the MG group and lowered in the 3-MA group than in the MG group.

Conclusion: The decreased mitochondrial membrane potential and mitophagy in Tregs in the MG group may be related to a decreased inhibition of Treg proliferation. The mitochondrial membrane potential was increased after adding the autophagy agent Rapa to enhance mitophagy, and the proliferation inhibition function of Tregs was also enhanced. The autophagy agent 3-MA down-regulated mitophagy, which decreased the mitochondrial membrane potential and inhibitory effect of Tregs. These results reveal the possible cellular immune mechanism of Treg dysfunction in MG.

Myasthenia gravis after etanercept and ustekinumab treatment for psoriatic arthritis: A case report

A 35-year-old man was diagnosed with psoriatic arthritis treated with methotrexate and cyclosporine, the latter was then interrupted. Subsequently, etanercept was introduced, administered for 10 years and then replaced with ustekinumab. Six months after treatment with ustekinumab, patient underwent a chest CT scan for pneumonia, showing an anterior mediastinal mass which turned out to be a thymoma. He was referred to our department with fatigue, difficulty in raising arms and transient episodes of diplopia after exertion. Clinical history revealed that these symptoms had begun about 7 years previously but were ascribed to psoriatic arthritis. A diagnosis of anti-acetylcholine receptor antibodies positive myasthenia gravis was made; a higher dosage of methotrexate and prednisone were started with regression of symptoms. Our case increases the number of clinical reports of myasthenia gravis onset in patients with a history of rheumatic disease treated with anti-TNFα drugs. We speculate that ustekinumab could contribute to clinical worsening.

Defects of CTLA-4 Are Associated with Regulatory T Cells in Myasthenia Gravis Implicated by Intravenous Immunoglobulin Therapy

Myasthenia gravis (MG) is a CD4⁺ T cell-dependent autoimmune disease resulting from aberrant immune response mediated by circulating autoantibodies at the neuromuscular junction. Intravenous immunoglobulin (IVIg) is an expensive and commonly used immunotherapeutic approach to treat patients with MG. The mechanisms of actions involved in IVIg treatment, however, remain to be investigated. In an effort to examine the roles of various subsets of CD4⁺ T cells in the periphery blood of MG and uncover the mechanisms that contribute to the therapeutical effects of IVIg, we first demonstrated that a subset of CD4⁺ T cells, CTLA-4-expressing regulatory T (Treg) cells, were underrepresented and functionally defective in MG patients. The dynamic profiling during the IVIg therapy course further revealed an inverse relationship between the frequency of CTLA-4⁺ Treg and the quantitative MG (QMG) score that represents disease severity. Our mechanistic studies indicated that IVIg expands CTLA-4-Treg cells via modulating antigen-presenting dendritic cells (DCs). To determine the molecular defects of CTLA-4 in abnormities of Treg in MG patients, we demonstrated hypermethylation at -658 and -793 CpGs of CTLA-4 promoter in MG Tregs. Interestingly, IVIg therapy significantly reduced the methylation level at these two sites in MG patients. Overall, our study may suggest a role of CTLA-4 in functionally defected Treg cells in MG and its actions involved in IVIg therapy.

Unbalanced expression of membrane-bound and soluble inducible costimulator and programmed cell death 1 in patients with myasthenia gravis

This study aimed to investigate the possible functions and mechanisms of positive and negative costimulatory molecules in the pathological process of myasthenia gravis (MG). The expression levels of membrane-bound inducible costimulator (ICOS) and programmed cell death 1 (PD-1) in peripheral blood T cells, their corresponding ligands ICOSL and PDL-1 on B cells, and their soluble forms (sICOS, sPD-1, sICOSL, and sPDL-1) in plasma were detected in patients with untreated-stage MG (USMG) and remission-stage MG (RSMG). The results showed that the expression levels of membrane-bound ICOS and PD-1 in the peripheral blood T cells of the USMG group and their corresponding ligands ICOSL and PD-L1 on B cells were significantly increased compared to those in the RSMG group and healthy controls (HCs). The levels of sICOSL and sPD-1 were significantly upregulated in USMG patients compared to those in the RSMG and HC groups, while the levels of sICOS and sPD-L1 were not different. The expression of PD-L1 on CD19⁺ B cells was positively correlated with the concentrations of AchR Ab in the USMG group. The expression of ICOS and PD-1 in CD4⁺ T cells and the expression of ICOSL and PD-L1 on CD19⁺ B cells were positively correlated with the quantitative myasthenia gravis (QMG) scores in the USMG group. Also, in the USMG group, the plasma levels of sICOSL and sPD-1 were positively correlated with the QMG scores. In addition, the percentage of peripheral blood follicular helper T (Tfh) cells in the USMG group was positively correlated with ICOS and PD-1 expression on CD4⁺ T cells and ICOSL and PD-L1 expression on CD19⁺ B cells. There were positive correlations between sICOSL and sPD-1 levels and the percentage of peripheral blood Tfh cells and plasma interleukin-21 (IL-21) levels in the USMG group. The results suggest that the positive ICOS/ICOSL and negative PD-1/PD-L1 costimulatory molecule pairs participate in the pathological process of MG. Abnormal sICOSL and sPD-1 expression might interfere with the normal signal transduction of ICOS and PD-1 on Tfh cells, causing excessive activation of Tfh cells and promotion of disease progression. sICOSL and sPD-1 have potential value in monitoring MG disease states.

Inhibition of ROCK activity regulates the balance of Th1, Th17 and Treg cells in myasthenia gravis

Aberrant ROCK activation has been found in patients with several autoimmune diseases, but the role of ROCK in myasthenia gravis (MG) has not yet been clearly investigated. Here, we demonstrated that ROCK activity was significantly higher in peripheral blood mononuclear cells (PBMCs) from MG patients. ROCK inhibitor Fasudil down-regulated the proportions of Th1 and Th17 cells in PBMCs of MG patients in vitro. Intraperitoneal injection of Fasudil ameliorated the severity of experimental autoimmune myasthenia gravis (EAMG) rats and restored the balance of Th1/Th2/Th17/Treg subsets. Furthermore, Fasudil inhibited the proliferation of antigen-specific Th1 and Th17 cells, and inhibited CD4 + T cells differentiated into Th1 and Th17 through decreasing phosphorylated Stat1 and Stat3, but promoted Treg cell differentiation through increasing phosphorylated Stat5. We conclude that dysregulated ROCK activity may be involved in the pathogenic immune response of MG and inhibition of ROCK activity might serve as a novel treatment strategy for MG.

A Neurologist's Perspective on Understanding Myasthenia Gravis: Clinical Perspectives of Etiologic Factors, Diagnosis, and Preoperative Treatment

Myasthenia gravis (MG) is a disease of neuromuscular transmission caused by antibodies directed toward proteins concentrated at the neuromuscular junction. Mild to life-threatening weakness varies in severity over time and with level of activity. Therefore, clinical diagnosis is often challenging. MG may be categorized by autoantibody type, thymic pathologic condition, and age of onset. Treatments are tailored for each group. A key management concern is severe exacerbation of weakness resulting from infections or exposure to certain medications, including antibiotics, which may be severe enough to produce respiratory decompensation. The article reviews key diagnostic issues and treatment options.

Decreased regulatory function of CD4+CD25+CD45RA+ T cells and impaired IL-2 signalling pathway in patients with type 2 diabetes mellitus

In this study, the frequency and function of CD4⁺CD25⁺CD45RA⁺ regulatory T cells (Treg) and intracellular IL-2 signalling molecules in patients with type 2 diabetes mellitus (T2DM) were investigated. Tregs and responder T cells (Tresp, CD4⁺CD25^- T cells) were sorted and suppression assays were performed using flow cytometry. Phosphorylation of signal transducer and activator of transcription-5 (pSTAT5) were assessed using flow cytometry. Gene expression of FOXP3 was performed with the SYBR green Real Time PCR method. Production of IL-2 from cultured cells was assessed using ELISA. We observed a functional defect of CD4⁺CD25⁺CD45RA⁺ Tregs in T2DM patients with higher proliferation of Tresp cells, in response to anti-CD3 and anti CD28 stimulation in the presence of Tregs in vitro. The results showed that the proliferation of Tresps in the absence of Treg cells was higher in T2DM patients than in healthy controls. Decreased FOXP3 mRNA expression and pSTAT5 were observed within the Tregs of the patients, whereas the level of secreted IL-2 from PBMCs culture was not statically different between T2DM patients and healthy individuals. Changes in intracellular IL-2 pathways and FOXP3 gene expression may contribute to the defect of Tregs in T2DM patients. These findings indicating that the purified CD4⁺CD25⁺CD45RA⁺ Treg cells have reduced functional capacity together with impaired IL-2 pathway in T2DM, and the Tregs could be used for a potential novel therapeutic target.

Chinese Herbal Medicine for Myasthenia Gravis: A Systematic Review and Meta-Analysis

Myasthenia gravis (MG) is an acquired autoimmune disease with the disorder of the neuromuscular junction transmission caused by autoantibodies. Currently, various Chinese herbal medicines (CHMs) are widely used for MG. This meta-analysis was conducted to assess the effectiveness and safety of CHMs for MG and its possible mechanisms. Fourteen studies with 1039 individuals were identified by searching seven databases from inception to March 2017. The methodological quality was assessed by using 7-item criteria from the Cochrane's Collaboration tool, and which assessed ≥4 "yes" in the domains were selected for detailed assessment and meta-analysis. All the data were analyzed using Rev-Man 5.3 software. Meta-analysis showed a significant effect of CHM as adjuvant therapy for improving the effectiveness compared with WCM alone or placebo in treating MG (p < 0.01). Moreover, there were fewer adverse effects and relapse rate in total when compared with the control group. The possible mechanisms of CHM for MG are associated with immunoregulation by reconstituting the functional ability of Tregs. In conclusion, despite the apparent positive results, the present evidence supports, to an extent, that CHM can be used for MG patients because of the methodological flaws and CHM heterogeneity. Further rigorous RCT for MG is needed.

Advances in autoimmune myasthenia gravis management

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune neuromuscular disorder with no cure and conventional treatments limited by significant adverse effects and variable benefit. In the last decade, therapeutic development has expanded based on improved understanding of autoimmunity and financial incentives for drug development in rare disease. Clinical subtypes exist based on age, gender, thymic pathology, autoantibody profile, and other poorly defined factors, such as genetics, complicate development of specific therapies. Areas covered: Clinical presentation and pathology vary considerably among patients with some having weakness limited to the ocular muscles and others having profound generalized weakness leading to respiratory insufficiency. MG is an antibody-mediated disorder dependent on autoreactive B cells which require T-cell support. Treatments focus on elimination of circulating autoantibodies or inhibition of effector mechanisms by a broad spectrum of approaches from plasmapheresis to B-cell elimination to complement inhibition. Expert commentary: Standard therapies and those under development are disease modifying and not curative. As a rare disease, clinical trials are challenged in patient recruitment. The great interest in development of treatments specific for MG is welcome, but decisions will need to be made to focus on those that offer significant benefits to patients.

Myasthenia gravis: new developments in research and treatment

PURPOSE OF REVIEW

Myasthenia gravis, a rare disorder of the neuromuscular transmission, is increasingly acknowledged as a syndrome more than as a single disease. This review summarizes recent advances in pathophysiology which confirm the disease heterogeneity, and may help find disease-targeted and patient-targeted therapies.

RECENT FINDINGS

Antibodies to the acetylcholine receptor, the muscle-specific tyrosine kinase and the lipoprotein receptor protein 4, characterize disease subtypes with distinct clinical traits and immune-pathogenic mechanisms. Genome-wide approaches have identified susceptibility loci within genes that participate in the immune response. Regulatory T and B cells appear to be defective in myasthenia gravis. In patients with acetylcholine receptor antibodies, thymectomy associated with prednisone proved more effective than prednisone alone in a multicenter randomized trial. New therapeutic options target B cells, B-cell growth factors and complement inhibition, and are currently reserved for patients with refractory disease.

SUMMARY

In the recent past, there has been an active search for new antigens in myasthenia gravis, whereas clinical and experimental studies have provided new insights of crucial pathways in immune regulation, which might become the targets of future therapeutic interventions.

A Sensitive Method for Detecting Peptide-specific CD4+ T Cell Responses in Peripheral Blood from Patients with Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune neurological disorder typified by skeletal muscle fatigue and most often production of autoantibodies against the nicotinic acetylcholine receptor (AChR). The present study was undertaken to assess the extent of AChR-peptide recognition in MG patients using co-culturing (DC:TC) of autologous monocyte-derived dendritic cells (moDCs) and highly enriched CD4⁺ T cells from the blood as compared to the traditional whole peripheral blood mononuclear cell (PBMC) cultures. We found that the DC:TC cultures were highly superior to the PBMC cultures for detection of reactivity toward HLA-DQ/DR-restricted AChR-peptides. In fact, whereas DC:TC cultures identified recognition in all MG patients the PBMC cultures failed to detect responsiveness in around 40% of the patients. Furthermore, reactivity to multiple peptides was evident in DC:TC cultures, while PBMC cultures mostly exhibited reactivity to a single peptide. No healthy control (HC) CD4⁺ T cells responded to the peptides in either culture system. Interestingly, whereas spontaneous production of IFNγ and IL-17 was observed in the DC:TC cultures from MG patients, recall responses to peptides enhanced IL-10 production in 9/13 MG patients, while little increase in IFNγ and IL-17 was seen. HCs did not produce cytokines to peptide stimulations. We conclude that the DC: TC culture system is significantly more sensitive and better identifies the extent of responsiveness in MG patients to AChR-peptides than traditional PBMC cultures.

A Novel Approach to Reinstating Tolerance in Experimental Autoimmune Myasthenia Gravis Using a Targeted Fusion Protein, mCTA1-T146

Reinstating tissue-specific tolerance has attracted much attention as a means to treat autoimmune diseases. However, despite promising results in rodent models of autoimmune diseases, no established tolerogenic therapy is clinically available yet. In the experimental autoimmune myasthenia gravis (EAMG) model several protocols have been reported that induce tolerance against the prime disease-associated antigen, the acetylcholine receptor (AChR) at the neuromuscular junction. Using the whole AChR, the extracellular part or peptides derived from the receptor, investigators have reported variable success with their treatments, though, usually relatively large amounts of antigen has been required. Hence, there is a need for better formulations and strategies to improve on the efficacy of the tolerance-inducing therapies. Here, we report on a novel targeted fusion protein carrying the immunodominant peptide from AChR, mCTA1–T146, which given intranasally in repeated microgram doses strongly suppressed induction as well as ongoing EAMG disease in mice. The results corroborate our previous findings, using the same fusion protein approach, in the collagen-induced arthritis model showing dramatic suppressive effects on Th1 and Th17 autoaggressive CD4 T cells and upregulated regulatory T cell activities with enhanced IL10 production. A suppressive gene signature with upregulated expression of mRNA for TGFβ, IL10, IL27, and Foxp3 was clearly detectable in lymph node and spleen following intranasal treatment with mCTA1–T146. Amelioration of EAMG disease was accompanied by reduced loss of muscle AChR and lower levels of anti-AChR serum antibodies. We believe this targeted highly effective fusion protein mCTA1–T146 is a promising candidate for clinical evaluation in myasthenia gravis patients.

The effect of interleukin (IL)-21 and CD4+ CD25++ T cells on cytokine production of CD4+ responder T cells in patients with myasthenia gravis

Impairment of the suppressive function of regulatory T (T_reg ) cells has been reported in myasthenia gravis (MG). In this study, cytokine-related mechanisms that may lead to the defect of T_reg were investigated in patients with anti-acetylcholine receptor antibody-positive MG (AChR + MG). Proliferation and cytokine production of responder T (T_resp ) cells in response to polyclonal activation were measured in a suppression assay. The effect of interleukin (IL)-21 on suppression was evaluated in vitro in co-culture. IL-21 increased the proliferation of T_resp cells in T_resp /T_reg co-cultures. T_resp cells from patients with MG secreted significantly lower levels of IL-2. In patients with MG, IL-2 levels did not change with the addition of T_reg to cultures, whereas it decreased significantly in controls. In T_resp /T_reg co-cultures, IL-4, IL-6 and IL-10 production increased in the presence of T_reg in patients. Interferon (IFN)-γ was decreased, whereas IL-17A was increased in both patient and control groups. IL-21 inhibited the secretion of IL-4 in MG and healthy controls (HC), and IL-17A in HC only. The results demonstrated that IL-21 enhances the proliferation of T_resp cells in the presence of T_reg . An effect of IL-21 mainly on T_resp cells through IL-2 is implicated.

Moderate Exercise Enhances the Production of Interferon-γ and Interleukin-12 in Peripheral Blood Mononuclear Cells

The purpose of this study was to explore the effect of two months moderate exercise on levels of IFN-γ, IL-12, IL-6 and IL-4 in serum and supernatants of in vitro mitogen-activated (PHA for 48 h) whole blood (WB) and peripheral blood mononuclear cells (PBMCs). Sixteen healthy males participated in running program (30 min/day, 5 days/week). Blood samples were collected in three stages; 24 h before to start exercise, 48 h and two months after the last session of the exercise. The samples were analyzed for the cytokines by ELISA. The levels of IFN-γ and IL-12 were increased significantly in activated PBMCs culture after exercise and were back to normal level after two months rest. A significant elevation of IFN-γ/IL-4 ratio was observed in activated PBMCs culture by acting possibly on IFN-γ. The results suggest that short moderate intensity exercise enhances Th1 immune inflammatory and anti-allergic conditions in response to mitogen.

Amyotrophic Lateral Sclerosis and Myasthenia Gravis Overlap Syndrome: A Review of Two Cases and the Associated Literature

Objective

To describe the characteristics of patients with amyotrophic lateral sclerosis (ALS) and myasthenia gravis (MG) overlap syndrome and explore the relationship between the two diseases.

Methods

We conducted a search of medical records at Peking Union Medical University Hospital from 1983 to 2015 for coexistence of ALS and MG and searched the PubMed database for all literature describing ALS and MG overlap syndrome published through December 2016. We analyzed the clinical and neurophysiological characteristics of patients by groups according to strict diagnostic criteria.

Results

We presented 2 patients in our database with combined ALS and MG, and together with 25 cases reported in the literature, the patients were divided into 4 groups: 12 patients with MG followed by ALS, 8 patients with ALS followed by MG, 5 ALS patients with false-positive anti-acetylcholine receptor, and the other 2 ALS patients with only myasthenia symptoms. Most patients had limb onset ALS, and myasthenia symptoms mainly affected ocular and bulbar muscles. Clinical and neurophysiological characteristics were summarized.

Conclusion

These findings support the conclusion that immunological mechanisms and alterations in the neuromuscular junction are related to ALS pathogenesis.