Myasthenia gravis with tongue muscle atrophy: A case series.

Here, we presented 6 patients who were admitted to our institution and diagnosed as myasthenia gravis (MG) with tongue muscle atrophy. All these 6 patients developed symptoms of bulbar muscle weakness in acetylcholine receptor antibodies positive MG (AChR-MG) (3/6), muscle-specific receptor tyrosine kinase antibodies positive MG (MuSK-MG) (1/6), and sero-negative MG (2/6). Most of patients had "triple-furrowed" tongue except for patient 2 with irregular atrophy of tongue muscle. Tongue muscle atrophy occurs in patients with MuSK-MG, AChR-MG, and sero-negative MG. Atrophied tongue muscles of five patients with MG were reversible after immunotherapy.

Causal relationship between the immune phenotype of monocytes and myasthenia gravis: A Mendelian randomization study.

Background: Monocytes play an essential role in developing autoimmune diseases; however, their association with myasthenia gravis (MG) development is unclear. Methods: We performed a two-sample Mendelian randomization analysis to assess the causal relationship between monocyte-associated traits and MG, reviewing summary statistics of genome-wide association studies (GWAS). Results: Using the inverse variance weighted method, the following were found to be causally associated with MG: HLA-DR on monocytes (OR, 1.363; 95% CI, 1.158-1.605; P = 2E-04), HLA-DR on CD14+ monocytes (OR, 1.324; 95% CI, 1.183-1.482; P = 1.08E-06), HLA-DR on CD14+CD16- monocytes (OR, 1.313; 95% CI, 1.177-1.465; P = 1.07E-06), CD40 on monocytes (OR, 1.135; 95% CI, 1.012-1.272; P < 0.05), CD40 on CD14+CD16- monocytes (OR, 1.142; 95% CI, 1.015-1.285; P < 0.05), CD40 on CD14+CD16+ monocytes (OR, 1.142; 95% CI, 1.021-1.278; P < 0.05), CD64 on CD14+CD16+ monocytes (OR, 1.286; 95% CI, 1.019-1.623; P < 0.05). Conclusions: The present study suggests a causal relationship between the upregulation of CD40, HLA-DR, and CD64 on monocytes and the development of MG. Altered monocyte function may potentially be a risk factor for MG and a therapeutic target.

Altered serum levels of cytokines in patients with myasthenia gravis.

Background: Myasthenia gravis (MG) is an autoimmune disease characterized by generalized skeletal muscle contraction weakness due to autoantibodies targeting neural-muscular junctions. Here, we investigated the relationship between key cytokines and MG type, disease course, antibodies, and comorbidities. Method: Cytokine levels in serum samples collected from MG (n = 45) and healthy control (HC, n = 38) patients from January 2020 to June 2022 were quantified via flow cytometry. Results: Levels of IL-6 were higher in the MG group versus healthy individuals (p = 0.026) and in patients with generalized versus ocular MG (p = 0.019). IL-6 levels were positively correlated with QMG score. In patients with MG with both AChR and Titin antibodies, serum levels of sFas and granulysin were higher than in those with AChR alone (p = 0.036, and p = 0.028, respectively). LOMG had a reduction in serum levels of IL-2 compared to EOMG (p = 0.036). LOMG patients with diabetes had lower serum levels of IL-2, IL-4, and IFN-γ (p = 0.044, p = 0.038, and p = 0.047, respectively) versus those without diabetes. sFas in the MG with Abnormal thymus were reduced compared to those in MG with Normal thymus (p = 0.008). Conclusions: This study revealed a positive correlation between IL-6 level and MG status. Serum cytokine levels of the AChR + Titin MG group differed from those of the AChR group. LOMG had a lower IL-2 level. Comorbidities affect some cytokines in peripheral blood in MG serum.

U-shaped association between serum Klotho and accelerated aging among the middle-aged and elderly US population: a cross-sectional study.

BACKGROUND: Phenotypic age acceleration, which reflects the difference between phenotypic age and chronological age, is an assessment to measure accelerated aging. Klotho is a protein related to slower aging, but its association with accelerated aging remains unclear. METHODS: Based on data from the 2007-2010 National Health and Nutrition Examination Survey, phenotypic age was calculated using chronological age and 9 aging-related biomarkers. A total of 4388 participants aged 40 to 79 years with measured serum Klotho and calculated phenotypic age were enrolled. The association between serum Klotho and phenotypic age acceleration was estimated using multivariable linear regression models. The possible nonlinear relationship was examined with smooth curve fitting. We also conducted a segmented regression model to examine the threshold effect. RESULTS: The association between serum Klotho and phenotypic age acceleration followed a U-shaped curve (p for nonlinearity < 0.001), with the inflection point at 870.7 pg/ml. The phenotypic age acceleration significantly decreased with the increment of serum Klotho (per SD increment: ß -1.77; 95% CI, -2.57 ~ -0.98) in participants with serum Klotho < 870.7 pg/ml, and increased with the increment of serum Klotho (per SD increment:ß, 1.03; 95% CI: 0.53 ~ 1.54) in participants with serum Klotho ≥ 870.7 pg/ml. CONCLUSION: There was a U-shaped association between serum Klotho and accelerated aging among the middle-aged and elderly US population.

Extracellular vesicles encapsulated with caspase-1 inhibitor ameliorate experimental autoimmune myasthenia gravis through targeting macrophages.

Cysteinyl aspartate-specific proteinase-1 (caspase-1) is a multifunctional inflammatory mediator in many inflammation-related diseases. Previous studies show that caspase-1 inhibitors produce effective therapeutic outcomes in a rat model of myasthenia gravis. However, tissue toxicity and unwanted off-target effects are the major disadvantages limiting their clinical application as therapeutic agents. This study shows that dendritic cell-derived extracellular vesicles (EVs) loaded with a caspase-1 inhibitor (EVs-VX-765) are phagocytized mainly by macrophages, and caspase-1 is precisely expressed in macrophages. Furthermore, EVs-VX-765 demonstrates excellent therapeutic effects through a macrophage-dependent mechanism, and it notably inhibits the level of interleukin-1ß and subsequently inhibits Th17 response and germinal center (GC) reactions. In addition, EVs-VX-765 demonstrates better therapeutic effects than routine doses of VX-765, although drug loading is much lower than routine doses, consequently reducing tissue toxicity. In conclusion, this study's findings suggest that EV-mediated delivery of caspase-1 inhibitors is effective for treating myasthenia gravis and is promising for clinical applications.

Methylglyoxal suppresses microglia inflammatory response through NRF2-IκBζ pathway.

Methylglyoxal (MGO) is a highly reactive metabolite generated by glycolysis. Although abnormal accumulation of MGO has been reported in several autoimmune diseases such as multiple sclerosis and rheumatoid arthritis, the role of MGO in autoimmune diseases has not yet been fully investigated. In this study, we found that the intracellular MGO levels increased in activated immune cells, such as microglia and lymphocytes. Treatment with MGO inhibited inflammatory cell accumulation in the spinal cord and ameliorated the clinical symptoms in EAE mice. Further analysis indicated that MGO suppressed M1-polarization of microglia cells and diminished their inflammatory cytokine production. MGO also inhibited the ability of microglial cells to recruit and activate lymphocytes by decreasing chemokine secretion and expression of co-stimulatory molecules. Furthermore, MGO negatively regulated glycolysis by suppressing glucose transporter 1 expression. Mechanically, we found that MGO could activate nuclear factor erythroid 2-related factor 2 (NRF2) pathway and NRF2 could bind to the promoter of IκBζ gene and suppressed its transcription and subsequently pro-inflammatory cytokine production. In conclusion, our results showed that MGO acts as an immunosuppressive metabolite by activating the NRF2-IκBζ.

Epstein-Barr virus: To be a trigger of autoimmune glial fibrillary acidic protein astrocytopathy?

BACKGROUND: Autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy is a novel autoimmune disease of central nervous system (CNS). It is unclear whether Epstein-Barr virus (EBV) is related to autoimmune GFAP astrocytopathy. OBJECTIVE: To describe the clinical, laboratory, and imaging characteristics of patients with autoimmune GFAP astrocytopathy. METHODS: The clinical, laboratory, and imaging findings of patients are presented. The levels of GFAP in CSF were detected by ELISA. T and B cell subsets in CSF were detected by flow cytometry. GFAP-IgG in serum and cerebrospinal fluid (CSF) were tested by cell-based assay (CBA) and tissue-based assay (TBA). RESULTS: All three patients had fever, cognitive dysfunction, limb weakness, and positive GFAP-IgG with EBV infection in CSF. Enteric glia cells may involve in this disease. Typical imaging findings include the gadolinium enhancement of linear perivascular radial perpendicular to the ventricle, meningeal enhancement (especially in midbrain interpeduncal fossa), longitudinally extensive lesions involving spindle cords, and more T2/Flair-hyperintense lesions in the periventricular white matter at late stage. The patients had poor response to antiviral treatment and strong response to steroid pulse therapy. CONCLUSION: EBV could induce CNS autoimmune response in autoimmune GFAP astrocytopathy. The detection of GFAP-IgG and EBV may facilitate the early diagnosis in these patients.

Association and mediating mechanism between remnant cholesterol and first-ever stroke among the Chinese general population.

Background: Remnant cholesterol (RC) has been suggested to be implicated in atherosclerosis. The objective of the study was to evaluate the association between RC and first-ever stroke in the Chinese general population and to investigate whether the association is mediated via hypertension or diabetes. Methods: This study is a retrospective cohort analysis of participants from the China Health and Nutrition Survey. Participants without previous stroke and myocardial infarction in 2009 were enrolled and followed up in 2011 and 2015. Logistic regression analyses were adopted to explore the association of RC with stroke risk. Propensity score methods and doubly robust estimation method were used to ensure the robustness of our findings. Potential mediators were identified by mediation analyses. Results: A total of 7,035 participants were involved, and during 6 years of follow-up, 78 (1.1%) participants experienced a first-ever stroke. Participants with high RC had a significantly higher incidence of stroke (1.4% versus 0.8%; p = 0.007). High RC was associated with 74% higher stroke risk after adjusting for multiple relevant variables (odds ratio [OR], 1.74; 95% CI, 1.06-2.85). The association was consistent in analyses using propensity score methods and doubly robust estimation method. Hypertension showed a significant mediating effect on the association between RC and stroke, while the mediating effect of diabetes was not significant. Conclusion: High RC increased the risk of first-ever stroke in the Chinese general population without previous stroke and myocardial infarction, partially through the pathway of hypertension. RC might be a potential target for the primary prevention of stroke.

Circulating CXCR5+ natural killer cells are expanded in patients with myasthenia gravis.

Objectives: Myasthenia gravis (MG) is a classic autoantibody-mediated disease in which pathogenic antibodies target postsynaptic membrane components, causing fluctuating skeletal muscle weakness and fatigue. Natural killer (NK) cells are heterogeneous lymphocytes that have gained increasing attention owing to their potential roles in autoimmune disorders. This study will investigate the relationship between the distinct NK cell subsets and MG pathogenesis. Methods: A total of 33 MG patients and 19 healthy controls were enrolled in the present study. Circulating NK cells, their subtypes and follicular helper T cells were analysed by flow cytometry. Serum acetylcholine receptor (AChR) antibody levels were determined by ELISA. The role of NK cells in the regulation of B cells was verified using a co-culture assay. Results: Myasthenia gravis patients with acute exacerbations had a reduced number of total NK cells, CD56dim NK cells and IFN-γ-secreting NK cells in the peripheral blood, while CXCR5+ NK cells were significantly elevated. CXCR5+ NK cells expressed a higher level of ICOS and PD-1 and a lower level of IFN-γ than those in CXCR5- NK cells and were positively correlated with Tfh cell and AChR antibody levels. In vitro experiments demonstrated that NK cells suppressed plasmablast differentiation while promoting CD80 and PD-L1 expression on B cells in an IFN-γ-dependent manner. Furthermore, CXCR5- NK cells inhibited plasmablast differentiation, while CXCR5+ NK cells could more efficiently promote B cell proliferation. Conclusion: These results reveal that CXCR5+ NK cells exhibit distinct phenotypes and functions compared with CXCR5- NK cells and might participate in the pathogenesis of MG.

Type 2 diabetes mellitus as a possible risk factor for myasthenia gravis: a case-control study.

Background: A certain number of myasthenia gravis (MG) patients clinically had type 2 diabetes mellitus (T2DM) prior to MG onset, which suggests that the onset of MG may correlate with the history of T2DM. This study aimed to examine the correlation between MG and T2DM. Methods: In a single-center, retrospective, 1:5 matched case-control study, all 118 hospitalized patients with a diagnosis of MG from 8 August 2014 to 22 January 2019 were enrolled. In total, four datasets with different sources of the control group were retrieved from the electronic medical records (EMRs). Data were collected at the individual level. A conditional logistic regression analysis was used to test the risk of MG associated with T2DM. Findings: The risk of MG was significantly associated with T2DM, and there were notable differences by sex and age. Whether compared to the general population, general hospitalized patients without autoimmune diseases (AIDs), or patients with other AIDs except MG, women aged over 50 years with T2DM had an increased risk of MG. The mean onset age of diabetic MG patients was more than that of the non-diabetic MG patients. Interpretation: This study demonstrates that T2DM is strongly associated with the subsequent risk of MG and varies significantly by sex and age. It reveals that diabetic MG may be a unique subtype that is different from the conventional MG subgroup classification. More clinical and immunological features of diabetic MG patients need to be explored in further studies.

Diabetes mellitus aggravates humoral immune response in myasthenia gravis by promoting differentiation and activation of circulating Tfh cells.

Myasthenia gravis (MG) is a T-cell-dependent, antibody-mediated autoimmune disease. Diabetes mellitus (DM) is a chronic metabolic disease characterized by hyperglycemia and emerging evidence indicates its profound impacts on the immune homeostasis. Previous studies and our data showed DM might serve as an independent risk factor of MG, yet the underlying immune and molecular mechanisms remain to be addressed. Our study observed that circulating Tfh (cTfh) cells were increased in MG patients with DM and expressed a high level of ICOS. Besides, positive correlations between activated cTfh cells and plasmablasts were documented. Further studies demonstrated hyperglycemia promoted the differentiation and activation of Tfh cells which, in turn, caused abnormal plasmablasts differentiation and antibody secretion through the mTOR signaling pathway. These results indicated DM might aggravate the aberrant humoral immunity in MG patients by augmenting Tfh cells differentiation and function and tight glycemic control might be beneficial for MG patients with DM.

Therapeutic Effects of Batoclimab in Chinese Patients with Generalized Myasthenia Gravis: A Double-Blinded, Randomized, Placebo-Controlled Phase II Study.

INTRODUCTION: We investigated the safety and explore potential efficacy of batoclimab administered subcutaneously in Chinese patients with generalized myasthenia gravis (gMG). METHODS: A randomized, double-blinded, placebo-controlled, parallel phase II study was conducted. First, in the double-blinded treatment period, eligible patients received batoclimab (680 mg), batoclimab (340 mg), or placebo on days 1, 8, 15, 22, 29, and 36. In the open-label treatment period, patients received batoclimab (340 mg) on days 50, 64, and 78. In the follow-up period, patients were examined on days 92, 106, and 120. The primary endpoint was Myasthenia Gravis Activities of Daily Living (MG-ADL) score change on day 43 from baseline. RESULTS: In total, 30 eligible patients were enrolled, with 11, 10, and 9 patients in the batoclimab 680 mg, batoclimab 340 mg, and placebo groups, respectively. MG-ADL score changes from baseline to day 43 were -2.2 ± 0.9, -4.7 ± 0.6, and -4.4 ± 1.0 in the placebo, batoclimab 340 mg, and 680 mg groups, respectively. Similar changes were observed in Quantitative Myasthenia Gravis, Myasthenia Gravis Composite, and 15-item Myasthenia Gravis Quality of Life scores in the placebo, batoclimab 340 mg, and 680 mg groups, respectively. The proportion of patients with clinically significant improvement on day 43 was higher in the batoclimab groups. On day 120, all four scales in the placebo group had more significant improvement compared with the batoclimab groups, with total serum IgG levels reaching a plateau. No death or treatment-emergent adverse events (TEAEs) led to study discontinuation. CONCLUSION: Batoclimab is effective and safe in Chinese patients with gMG. TRIAL REGISTRATION: This study was registered at ClinicalTrials.gov (NCT04346888) on 15 April 2020, with the first patient enrolled on 23 July 2020.

Diabetes mellitus exacerbates experimental autoimmune myasthenia gravis via modulating both adaptive and innate immunity.

BACKGROUND: Diabetes mellitus (DM) is a common concomitant disease of late-onset myasthenia gravis (MG). However, the impacts of DM on the progression of late-onset MG were unclear. METHODS: In this study, we examined the immune response in experimental autoimmune myasthenia gravis (EAMG) rats with DM or not. The phenotype and function of the spleen and lymph nodes were determined by flow cytometry. The serum antibodies, Tfh cells, and germinal center B cells were determined by ELISA and flow cytometry. The roles of advanced glycation end products (AGEs) in regulating Tfh cells were further explored in vitro by co-culture assays. RESULTS: Our results indicated clinical scores of EAMG rats were worse in diabetes rats compared to control, which was due to the increased production of anti-R97-116 antibody and antibody-secreting cells. Furthermore, diabetes induced a significant upregulation of Tfh cells and the subtypes of Tfh1 and Tfh17 cells to provide assistance for antibody production. The total percentages of B cells were increased with an activated statue of improved expression of costimulatory molecules CD80 and CD86. We found CD4+ T-cell differentiation was shifted from Treg cells towards Th1/Th17 in the DM+EAMG group compared to the EAMG group. In addition, in innate immunity, diabetic EAMG rats displayed more CXCR5 expression on NK cells. However, the expression of CXCR5 on NKT cells was down-regulated with the increased percentages of NKT cells in the DM+EAMG group. Ex vivo studies further indicated that Tfh cells were upregulated by AGEs instead of hyperglycemia. The upregulation was mediated by the existence of B cells, the mechanism of which might be attributed the elevated molecule CD40 on B cells. CONCLUSIONS: Diabetes promoted both adaptive and innate immunity and exacerbated clinical symptoms in EAMG rats. Considering the effect of diabetes, therapy in reducing blood glucose levels in MG patients might improve clinical efficacy through suppressing the both innate and adaptive immune responses. Additional studies are needed to confirm the effect of glucose or AGEs reduction to seek treatment for MG.

Natural killer cells promote the differentiation of follicular helper T cells instead of inducing apoptosis in myasthenia gravis.

Recent evidence has shown that natural killer (NK) cells have an immunoregulatory function in the pathogenesis of myasthenia gravis (MG). In this study, the phenotype and function of NK cell subsets in peripheral blood of new-onset MG (N-MG) and stable MG (S-MG) patients were explored. Circulating CD56dim and CD56bright NK cells were increased and decreased, respectively, in patients with N-MG and S-MG compared with healthy control (HC). Moreover, all circulating NK cell subsets from N-MG patients showed significantly lower expression of activating receptor NKG2D and production of Interferon (IFN) -γ than that from HC. The killing effects of NK cells on CD4+ T cells and Tfh cells were impaired in MG patients, whereas, they promoted the differentiation and activation of Tfh cells. These data indicated that the immune-regulation of NK cells on CD4+ T cells and Tfh cells in MG patients was abnormal, which may contribute to the immune-pathological mechanism of MG.

Prophylactic administration of fingolimod (FTY720) ameliorated experimental autoimmune myasthenia gravis by reducing the number of dendritic cells, follicular T helper cells and antibody-secreting cells.

Fingolimod (FTY720), a sphingosine 1-phosphate (S1P) receptor antagonist, possesses potent immunomodulatory activity via lymphocyte homing. The effects of FTY720 have been widely studied in various T-cell-mediated autoimmune diseases, while the immunomodulatory effects on experimental autoimmune myasthenia gravis (EAMG), a typical disease model for antibody-mediated autoimmunity, remain elusive. In the present study, FTY720 was administered to EAMG rats as prophylaxis. The clinical scores were recorded every other day, and serum antibodies at different time points were measured by enzyme-linked immunosorbent assay (ELISA). The immune cell subsets in the spleen, bone marrow, circulation, and thymus were determined by flow cytometry. The prophylactic administration alleviated EAMG symptoms by reducing the level of serum antibodies IgG and its isotype IgG2b on days 30 and 46 post immunization, as well as IgG and Ig kappa antibody-secreting cells in the spleen and bone marrow. The mitigated humoral immune response can be attributed to the decreased dendritic cells, follicular T help cells (Tfh) and Tfh subsets (Tfh1, Tfh2, and Tfh17), and T helper cell subsets (Th1, Th2, and Th17) in the spleen. The promotion of lymphocyte homing and inhibition of thymocyte egress contribute to the effects of FTY720 on these effector T cell subsets. Overall, the prophylactic administration of FTY720 ameliorated EAMG partially by regulating humoral immune response，suggesting that FTY720 could be part of a pharmacological strategy for managing myasthenia gravis.

Vitamin D Receptor Polymorphism and Myasthenia Gravis in Chinese Han Population.

Myasthenia gravis (MG) is an autoimmune disease in which antibodies bind to acetylcholine receptors (AChR) or other functional molecules in the postsynaptic membrane at the neuromuscular junction. Vitamin D (VD) has a number of pluripotent effects, which include immune-regulation and bone metabolism. The immunomodulatory actions of 1,25(OH)2D3 are mediated by its binding to a vitamin D receptor (VDR). In the study, we undertook a case-control study to explore the association between VDR gene polymorphism and the susceptibility and severity of MG patients. Four hundred and eighty MG patients and 487 healthy controls were included and gene polymorphisms of VDR were determined with improved multiplex ligation detection reaction technique and SNPscanTM technique. MG patients were classified into subgroups by essential clinical features and by a comprehensive classification. The frequencies of alleles and genotypes were compared between the MG group and the control group, between each MG subgroup and the control group, and between each pair of MG subgroups. There were no significant differences in frequencies of alleles and genotypes between MG patients and healthy controls, between MG subgroups and healthy controls, or between each pair of MG subgroups in the analysis of subgroups classified by essential clinical features (onset age, gender, thymoma, AChRAb positivity, onset involvement) and the maximal severity (modified Oosterhuis score). In the analysis of subgroups with a comprehensive classification, the frequencies of alleles and genotypes in rs731236 showed significant differences between adult non-thymoma AChRAb negative MG subgroup and the control group, as well as the adult non-thymoma AChRAb positive MG group. In the Chinese Han population, rs731236 was found to be possibly associated with adult non-thymoma AChRAb negative MG patients, although this needs further confirmation.