Cells In Myasthenia Gravis Patients Research Articles

In vitro modulation of T cells in myasthenia gravis by low-dose IL-2.

Follicular helper (Tfh), peripheral helper (Tph), and regulatory (Treg) T cells are involved in myasthenia gravis (MG) pathogenesis, an autoimmune disorder arising from autoantibodies targeting neuromuscular junction proteins. This study explores the impact of low-dose IL-2 on Tfh, Tph, and Treg cells in vitro in MG. Acetylcholine-receptor antibody-positive MG (AChR-MG), muscle-specific kinase antibody-positive MG (MuSK-MG) patients, and healthy controls (HC) were studied. Blood cells were cultured with/without IL-2 and compared by the ratios of IL-2 stimulated/unstimulated cultures. In both AChR-MG and MuSK-MG patients, CD25+FoxP3+Tregs were lower, while CXCR5+PD-1+ or ICOS+Tfh and CXCR5-PD-1+ or ICOS+Tph cells were higher compared with HC. Among the MG group, the FoxP3+ Treg cells in AChR-MG patients were even lower compared with MuSK-MG patients. In vitro IL-2 stimulation increased Tregs in all groups while decreasing PD-1+/ICOS+Tfh and PD-1+/ICOS+Tph populations. The fold-increase ratio of Tregs and the fold-decrease ratio of PD-1+ or ICOS+Tfh and ICOS+Tph cells in AChR-MG and MuSK-MG patients were greater than in HCs. Low-dose IL-2 treatment may balance Tfh, Tph, and Treg cells in MG patients, offering a potential opportunity for disease modulation.

Effect of thymectomy on the frequencies of peripheral regulatory B and T lymphocytes in patients with Myasthenia gravis-a pilot study

Aim We aimed to investigate the relationship between the peripheral lymphocyte subset frequency and thymectomy in patients with myasthenia gravis (MG). Materials and Methods The frequencies of regulatory B (Breg) and regulatory T (Treg) cells in peripheral blood samples obtained from 69 patients with MG and 10 healthy controls were analyzed using flow cytometry. Serum acetylcholine receptor antibodies (AchR-Ab) were measured. Patients with MG were subdivided into pre-thymectomy, post-thymectomy, and normal thymus control group. Results The percentage of Breg cells was significantly decreased in both the pre-thymectomy (7.92 ± 1.30%) and post-thymectomy (8.14 ± 1.34%) groups compared to healthy controls (16.02 ± 2.78%) and reduced in the exacerbation and relapse phase compared to the stable maintenance stage. The proportion of cluster of differentiation (CD) 4 + CD25 + T cells and CD4 + CD25 + CD127low/- Treg cells in MG patients were not significantly different than healthy controls. AchR-Ab titers in aggravating or recurrence patients after thymectomy were significantly higher than that of the stable remission patients (11.13 ± 0.70 and 6.03 ± 0.85 nmol/L, respectively; p < 0.001). Conclusion The frequency of Breg cells may serve as a potential indicator of MG prognosis, while Treg cell frequency did not demonstrate the same prognostic ability. The concentration of AchR-Ab can be used as a dynamic monitoring index of disease severity in patients with MG.

Single-cell mass cytometry on peripheral cells in Myasthenia Gravis identifies dysregulation of innate immune cells.

Myasthenia Gravis (MG) is a neurological autoimmune disease characterized by disabling muscle weaknesses due to anti-acetylcholine receptor (AChR) autoantibodies. To gain insight into immune dysregulation underlying early-onset AChR+ MG, we performed an in-depth analysis of peripheral mononuclear blood cells (PBMCs) using mass cytometry. PBMCs from 24 AChR+ MG patients without thymoma and 16 controls were stained with a panel of 37 antibodies. Using both unsupervised and supervised approaches, we observed a decrease in monocytes, for all subpopulations: classical, intermediate, and non-classical monocytes. In contrast, an increase in innate lymphoid cells 2 (ILC2s) and CD27- γδ T cells was observed. We further investigated the dysregulations affecting monocytes and γδ T cells in MG. We analyzed CD27- γδ T cells in PBMCs and thymic cells from AChR+ MG patients. We detected the increase in CD27- γδ T cells in thymic cells of MG patients suggesting that the inflammatory thymic environment might affect γδ T cell differentiation. To better understand changes that might affect monocytes, we analyzed RNA sequencing data from CD14+ PBMCs and showed a global decrease activity of monocytes in MG patients. Next, by flow cytometry, we especially confirmed the decrease affecting non-classical monocytes. In MG, as for other B-cell mediated autoimmune diseases, dysregulations are well known for adaptive immune cells, such as B and T cells. Here, using single-cell mass cytometry, we unraveled unexpected dysregulations for innate immune cells. If these cells are known to be crucial for host defense, our results demonstrated that they could also be involved in autoimmunity.

Leflunomide combined with low-dose prednisone inhibits proinflammatory T cells responses in myasthenia gravis patients.

We previously found that leflunomide combined with low-dose prednisone rapidly improved the clinical symptoms of myasthenia gravis (MG), but we had not investigated the mechanism of this phenomenon. This study documents the effect of leflunomide combined with low-dose prednisone on pro-inflammatory T cells in MG patients. We compared 32 treated MG patients with 18 controls. We collected peripheral blood before treatment and 4, 8, and 12 weeks after treatment. We extracted peripheral blood mononuclear cells (PBMCs) and stimulated them with phorbol 12-myristate 13-acetate (PMA) + ionomycin and quantified IFN-γ, IL-4, IL-17, and IL-9 secretion through ELISA. We quantified T helper (Th) cells Th1 (CD3+CD4+IFN-γ+), Th2 (CD3+CD4+IL-4+), Th17 (CD3+CD4+IL-17A+) and Th9 (CD3+CD4+IL-9+) among PBMCs. The treatment significantly reduced IL-17 and IL-9 secretion in peripheral blood but did not affect IFN-γ levels. Significant decreases in IL-17 and IL-9 appeared at week 12, and the trend of change was similar to that of the MG composite score. Flow cytometry indicated that leflunomide combined with low-dose prednisone significantly reduced the frequency of Th1 and Th17 cells. These findings demonstrate the potential of this treatment as an alternative immunosuppressive therapy for MG.

DCAF12 and HSPA1A May Serve as Potential Diagnostic Biomarkers for Myasthenia Gravis.

Background Myasthenia gravis (MG) is an autoimmune disease that severely affects the life quality of patients. This study explores the differences in immune cell types between MG and healthy control and the role of immune-related genes in the diagnosis of MG. Methods The GSE85452 dataset was downloaded from the Gene Expression Omnibus (GEO) database and analyzed using the limma package to determine differentially expressed genes (DEGs) between patients with MG and the control group. Differentially expressed immune cells were analyzed using single-sample gene set enrichment analysis (GSEA), while immune cell-associated modules were identified by weighted gene coexpression network analysis (WGCNA). Then, the expression of the identified hub genes was confirmed by RT-PCR in peripheral blood mononuclear cells (PBMCs) of MG patients. The R package pROC was used to plot the receiver operating characteristics (ROC) curves. Results The modules related to CD56bright natural killer cells were identified by GSEA and WGCNA. The proportion of CD56bright natural killer cells in the peripheral blood of MG patients is low. The results of RT-PCR showed that the levels of DDB1- and CUL4-associated factor 12 (DCAF12) and heat shock protein family A member 1A (HSPA1A) were significantly decreased in peripheral blood mononuclear cells of MG patients compared with healthy controls. The ROC curve results of DCAF12 and HSPA1A mRNA in MG diagnosis were 0.780 and 0.830, respectively. Conclusions CD56bright NK cell is lower in MG patients and may affect MG occurrence. DCAF12 and HSPA1A are lowly expressed in PBMCs of MG patients and may serve as the diagnostic biomarkers of 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.

The treatment effect on peripheral B cell markers in antibody positive myasthenia gravis patients

B cells play a major role in the pathophysiology of myasthenia gravis (MG) with their ability to produce disease specific, pathogenic antibodies. However, their status during disease development and follow-up stages of the disease in the peripheral blood may need further studies to determine useful markers. In this study, we aimed to detect B cell associated factors concerning immunosuppressive treatment in generalized non-thymomatous MG patients. Although CD19+ B cell distribution did not vary among disease subgroups, expressions of both CD38 and BAFFR were altered on B cells in MG patients under immunosuppressive therapy. Serum levels of BAFF were elevated in untreated MG patients as compared to treated MG patients and healthy controls. B cell activation factors may show profound alterations due to immunosuppression.

CD4+ T Cells of Myasthenia Gravis Patients Are Characterized by Increased IL-21, IL-4, and IL-17A Productions and Higher Presence of PD-1 and ICOS.

Myasthenia gravis (MG) is an autoimmune disease mediated by autoantibodies predominantly against the acetylcholine receptor (AChR). Specific T cell subsets are required for long-term antibody responses, and cytokines secreted mainly from CD4+ T cells regulate B cell antibody production. The aim of this study was to assess the differences in the cytokine expressions of CD4+ T cells in MG patients with AChR antibodies (AChR-MG) and the effect of immunosuppressive (IS) therapy on cytokine activity and to test these findings also in MG patients without detectable antibodies (SN-MG). Clinically diagnosed AChR-MG and SN-MG patients were included. The AChR-MG patients were grouped as IS-positive and -negative and compared with age- and sex-matched healthy controls. Peripheral blood mononuclear cells were used for ex vivo intracellular cytokine production, and subsets of CD4+ T cells and circulating follicular helper T (cTfh) cells were detected phenotypically by the expression of the chemokine and the costimulatory receptors. Thymocytes obtained from patients who had thymectomy were also analyzed. IL-21, IL-4, IL-10, and IL-17A productions in CD4+ T cells were increased in AChR-MG compared to those in healthy controls. IS treatment enhanced IL-10 and reduced IFN-γ production in AChR-MG patients compared to those in IS-negative patients. Increased IL-21 and IL-4 productions were also demonstrated in SN-MG patients. Among CD4+ T cells, Th17 cells were increased in both disease subgroups. Treatment induced higher proportions of Th2 cells in AChR-MG patients. Both CXCR5+ and CXCR5− CD4+ T cells expressed higher programmed cell death protein 1 (PD-1) and inducible costimulatory (ICOS) in AChR-MG and SN-MG groups, mostly irrespective of the treatment. Based on chemokine receptors on CXCR5+PD-1+ in CD4+ T (cTfh) cells, in AChR-MG patients without treatment, the proportions of Tfh17 cells were higher than those in the treated group, whereas the Tfh1 cells were decreased compared with those in the controls. The relevance of CXCR5 and PD-1 in the pathogenesis of AChR-MG was also suggested by the increased presence of these molecules on mature CD4 single-positive thymocytes from the thymic samples. The study provides further evidence for the importance of IL-21, IL-17A, IL-4, and IL-10 in AChR-MG. Disease-related CD4+T cells are identified mainly as PD-1+ or ICOS+ with or without CXCR5, resembling cTfh cells in the circulation or probably in the thymus. AChR-MG and SN-MG seem to have some similar characteristics. IS treatment has distinctive effects on cytokine expression.

Quantitative features and clinical significance of two subpopulations of AChR-specific CD4+ T cells in patients with myasthenia gravis

Acetylcholine receptor (AChR)-specific CD4+ T cells play a driving role in myasthenia gravis (MG) by regulating the production of autoantibodies. However, the quantitative features of AChR-specific T cells and their clinical significance in MG are unclear. In this study, we adopted standard and cultured enzyme-linked immunosorbent spot (ELISPOT) assays to quantify subpopulations of AChR-specific CD4+ T cells in MG patients, and evaluate their correlation with clinical characteristics. The results showed that Th1- and Th17-AChR-specific CD4+ T cells were detectable by standard and cultured ELISPOT assay respectively, with higher levels observed in MG patients comparing with healthy controls. The number of Th17-AChR-specific CD4+ T cells was positively correlated with anti-AChR antibody titer and quantitative MG score and may have latent capacity to reflect responses to immunosuppressants. These results highlight the differences in quantitative features of AChR-specific CD4+ T cells and imply Th17-AChR-specific CD4+ T cells can serve as a biomarker in MG.

Glucose metabolism pattern of peripheral blood immune cells in myasthenia gravis patients.

BackgroundWe investigated the correlation between glucose metabolism patterns of different immune cells and the metabolic regulatory signaling pathways in myasthenia gravis (MG) and aimed to identify therapeutic targets for MG.MethodsWe isolated peripheral blood mononuclear cells (PBMCs) and sorted CD19+B cells, dendritic cells (DCs), CD4+ T cells, CD8+ T cells, CD4+CD25+ regulatory T cells (Tregs), CD4+CD25−T cells, and T helper (Th) cells such as Th1, Th2, and Th17 cells. Then, we detected the expression levels of PI3K/AKT/mTOR-HIF-1α, GLUT1, hexokinase (HK), phosphofructokinase (PFK), and pyruvate kinase (PK) by RT-PCR, measured the oxygen consumption rate and extracellular acidification rate of ex vivo freshly sorted cells using the Seahorse XFe96 Analyzer. In addition, we compared the glycolysis levels using these cells from the same MG patients. By performing in vitro experiments, we measured, the mRNA expression levels of mTOR, HIF-1α, B cell activating factor receptor (BAFF-R), GLUT1, HK, PFK, and PK, in addition to ECAR profiles, frequency of CD80 and CD86, and IgG levels from the culture supernatant of B cells (isolated from MG patients) treated with rapamycin and PX-478 (selective mTOR and HIF-1α inhibitor, respectively) from.ResultsExcept PBMCs, Th2 and CD8+ T cells, the expression levels of the key enzymes involved in glycolysis and HIF-1α were significantly higher in B cells, DCs, Tregs, CD4+CD25−T cells, and Th1 and Th17 cells in MG patients, and the measurement of ECAR and OCR confirmed the metabolic status. In MG patients, B cells and DCs showed significantly higher levels of glycolysis and glycolytic capacity than CD8+ T cells, CD4+ T cells and its subsets. In vitro, except IgG levels, the increased glycolysis levels, expression of key glycolytic enzymes, BAFF-R and frequency of CD80 and CD86 of B cells, could be inhibited by rapamycin and PX-478.ConclusionsDifferent subtypes of immune cells in MG exhibit different glucose metabolism patterns. The mTOR-HIF-1α signaling pathway might be the immunometabolism reprogramming checkpoint of glycolysis-dependent activated B cells in MG.

Decreased expression of circulating Aire and increased Tfh/Tfr cells in myasthenia gravis patients.

Myasthenia gravis (MG) is a rare prototypical autoimmune disorder caused by antibodies (Ab) against postsynaptic membrane proteins. Most reports have investigated the role of autoimmune regulator gene (Aire) in thymic tissue in machianism of MG initiation. So far, the expression of Aire in human peripheral blood cells (we call it circulating Aire expression in the following passage) has not been reported. Herein, we explore the expression of Aire in peripharal blood, circulating T-follicular helper (cTfh) and T-follicular regulatory (cTfr) cells in MG patients. In our research, we found that the acetylcholine receptor (AChR) Ab level is higher in generalized MG (GMG) than that in ocular MG (OMG). Compared with the control group (CG), lower expression of Aire was found in MG patients, especially in GMG. The ratio of Tfh/Tfr was higher in GMG patients, and then in the OMG patients, and lowest in CG. All these differences above were statistically significant. Negative relation was discovered between expression of Aire in circulating blood and ratio of Tfh/Tfr, so did it exist between Aire expression and the severity of MG. Meanwhile, positive relation was discovered between ratio of Tfh/Tfr and the severity of MG. However, no significant relation was manifested in our study between the subset age of MG and Aire level. Overall, these findings imply circulating Aire might play a role in the imbalance of cTfh and cTfr cells and participate in the pathogenesis of MG.

Regulatory B cells in myasthenia gravis are differentially affected by therapies.

We analyzed the number and functionality of regulatory B (Breg) cells in well‐defined myasthenia gravis patients. We first showed a decreased number of circulating CD19+ CD24++ CD38++ Breg cells and an altered functionality of Breg cells in untreated myasthenia gravis patients. Next, we demonstrated that the proportion of circulating Breg cells was restored in myasthenia gravis patients after thymectomy, probably as Breg cells could be sequestered in the myasthenia gravis thymus. In contrast, corticosteroid treatments did not restore and decreased even more the proportion of Breg cells in myasthenia gravis patients. These results clearly demonstrated that two distinct immunomodulatory therapies affect differentially Breg cells.

High Frequency of Tc22 and Th22 Cells in Myasthenia Gravis Patients and Their Significant Reduction after Thymectomy

Objectives: Myasthenia gravis (MG) is an autoimmune disease accompanied by a thymic pathology and in most patients thymectomy (TE) is used as the therapeutic approach. Both B and T cells play an important role in MG pathogenesis. Methods: Twelve pre- and post-TE MG patients and 12 healthy controls (HCs) were enrolled. The mean percentages of Th22 and Tc22 cells were evaluated in MG patients (before and 6 months after TE) and HCs. Results: The mean percentage of Tc22 cells in pre-TE patients was significantly higher than in HCs (p < 0.05), and after TE Tc22 cells significantly decreased compared to pre-TE (p < 0.05). The frequency of Th22 cells in pre-TE MG patients was not significantly different from HCs, but after TE Th22 cells were significantly decreased compared to pre-TE (p < 0.05). Conclusion: Our findings suggest a possible role of Th22 and Tc22 in MG pathogenesis.

High frequencies of circulating Tfh-Th17 cells in myasthenia gravis patients.

Recent studies show that the frequencies of circulating follicullar helper T (cTfh) cells are significantly higher in myasthenia gravis (MG) patients compared with healthy controls (HC). And, they are positively correlated with levels of serum anti-acetylcholine receptor antibody (anti-AchR Ab). It is unclear whether cTfh cell subset frequencies are altered and what role they play in MG patients. In order to clarify this, we examined the frequencies of cTfh cell counterparts, their subsets, and circulating plasmablasts in MG patients by flow cytometry. We determined the concentrations of serum anti-AChR Ab by enzyme-linked immunosorbent assay (ELISA). We assayed the function of cTfh cell subsets by flow cytometry and real-time polymerase chain reaction (RT-PCR). We found higher frequencies of cTfh cell counterparts, cTfh-Th17 cells, and plasmablasts in MG patients compared with HC. The frequencies of cTfh cell counterparts and cTfh-Th17 cells were positively correlated with the frequencies of plasmablasts and the concentrations of anti-AChR Ab in MG patients. Functional assays showed that activated cTfh-Th17 cells highly expressed key molecular features of Tfh cells including ICOS, PD-1, and IL-21. Results indicate that, just like cTfh cell counterparts, cTfh-Th17 cells may play a role in the immunopathogenesis and the production of anti-AChR Ab of MG.

Increased frequency of thymic T follicular helper cells in myasthenia gravis patients with thymoma.

To investigate the presence of T follicular helper (TFH) cells and their associated molecules in myasthenia gravis (MG) patients with thymoma. TFH cells are detected in thymus around the thymoma region of 50 patients and atrophic thymus in 10 patients as control. The percentage of TFH cells among CD4(+) T cells and the expression level of surface markers CXC chemokine receptor 5 (CXCR5), inducible co-stimulator (ICOS), programmed cell death 1 and the cytoplasmic marker B cell lymphoma 6 (Bcl-6) were analyzed by immunohistochemistry (IHC) staining, immunofluorescence (IF) and western blotting (WB). Higher percentage of thymic TFH cells was found in MG patients with thymoma compared with both thymoma patients without MG and control group. The expression levels of the four markers in thymoma of MG patients were significantly higher than thymoma patients without MG and control group. No significant difference was found in the levels of programmed cell death 1 (PD-1) and Bcl-6 between thymoma patients without MG and the control, while the levels of CXCR5 and ICOS in thymoma patients without MG were higher than control group. These results suggested thymic TFH cells might involve in the pathogenesis of MG with thymoma. However, it needs further study to test if the inhibition of the function of TFH cells could effectively alleviate the severity of MG.

Novel CXCL13 transgenic mouse: inflammation drives pathogenic effect of CXCL13 in experimental myasthenia gravis.

Abnormal overexpression of CXCL13 is observed in many inflamed tissues and in particular in autoimmune diseases. Myasthenia gravis (MG) is a neuromuscular disease mainly mediated by anti-acetylcholine receptor autoantibodies. Thymic hyperplasia characterized by ectopic germinal centers (GCs) is a common feature in MG and is correlated with high levels of anti-AChR antibodies. We previously showed that the B-cell chemoattractant, CXCL13 is overexpressed by thymic epithelial cells in MG patients. We hypothesized that abnormal CXCL13 expression by the thymic epithelium triggered B-cell recruitment in MG. We therefore created a novel transgenic (Tg) mouse with a keratin 5 driven CXCL13 expression.The thymus of Tg mice overexpressed CXCL13 but did not trigger B-cell recruitment. However, in inflammatory conditions, induced by Poly(I:C), B cells strongly migrated to the thymus. Tg mice were also more susceptible to experimental autoimmune MG (EAMG) with stronger clinical signs, higher titers of anti-AChR antibodies, increased thymic B cells, and the development of germinal center-like structures. Consequently, this mouse model finally mimics the thymic pathology observed in human MG.Our data also demonstrated that inflammation is mandatory to reveal CXCL13 ability to recruit B cells and to induce tertiary lymphoid organ development.

Feasibility of up-regulating CD4(+)CD25(+) Tregs by IFN-γ in myasthenia gravis patients.

BackgroundIn myasthenia gravis (MG) patients, the dysfunction of CD4+CD25+ regulatory T cells (CD4+CD25+ Tregs) may be one of the important pathogenesis of MG. Currently, the role of IFN-γ in autoimmune diseases is still controversial and needs further exploration. In this study, whether IFN-γ can induce CD4+CD25− T cells into CD4+CD25+ Tregs in MG in vitro was investigated systematically.MethodsFlow cytometry was used to analyze the number of CD4+CD25+ Tregs in MG patients and healthy controls (HCs). CD4+CD25− T cells were separated from the peripheral blood mononuclear cells of MG patients and HCs, and the CD4+CD25+ Tregs were separated from HCs by Magnetic cell sorting (MACS). IFN-γ with different concentrations was used to stimulate CD4+CD25− T cells. The percentages of the induced CD4+CD25+ T cells were detected by flow cytometry. The FoxP3 expression of the induced CD4+CD25+ T cells in MG patients was detected by real-time PCR at mRNA level. The induced CD4+CD25+ T cells were co-cultured with autologous CD4+CD25− T cells to estimate the suppressive ability of the induced CD4+CD25+ T cells to CD4+CD25− T cells.ResultsIt shows the percentages of CD4+CD25+ T cells among CD4+ T cells have no significant difference in MG patients compared with those in HCs. There is also merely no difference in the percentages of CD4+CD25+ T cells between thymectomized and non-thymectomized MG patients. CD4+CD25− T cells can be induced to CD4+CD25+ T cells after applying IFN-γ in MG patients and HCs. The proportion and FoxP3 expression of the induced CD4+CD25+ T cells are the highest at the level of 40 ng/ml IFN-γ, and the suppressive function of the CD4+CD25+ T cells induced by 40 ng/ml IFN-γ is the strongest in MG patients.ConclusionsThis subject will further reveal the role of IFN-γ in the pathogenesis of MG from a new perspective. It will also provide the scientific basis for the clinical targeted therapy of MG.

Interleukin‐10 producing‐B cells and their association with responsiveness to rituximab in myasthenia gravis

A subset of regulatory B cells in humans and mice has been defined functionally by their ability to produce interleukin (IL)-10. We characterized IL-10-producing B (B10) cells in myasthenia gravis (MG) patients and correlated them with disease activity and responsiveness to rituximab therapy. Frequencies of B10 cells from MG patients and healthy controls were monitored by fluorescence-activated cell sorting (FACS). MG patients had fewer B10 cells than controls, which was associated with more severe disease status. Moreover, patients who responded well to rituximab therapy exhibited rapid repopulation of B10 cells, whereas in patients who did not respond well to rituximab, B10 cell repopulation was delayed. The kinetics of B10 cells were related to the responsiveness to rituximab in MG. We have characterized a specific subset of B10 cells in MG patients which may serve as a marker for disease activity and responsiveness to immune therapy.

Disturbed B cell subpopulations and increased plasma cells in myasthenia gravis patients

Whether there is a general perturbation of B and plasma cell subsets in myasthenia gravis (MG) has not been investigated so far. Here we performed a detailed flow cytometric analysis of blood and if available thymic tissue in order to detect MG-specific and therapy-induced changes. We observed significant differences in the distribution of B cell subsets in MG patients, yet these were mainly attributable to medical treatment. Furthermore MG is associated with significantly increased frequencies of plasma cells that were especially activated in purely ocular disease manifestation. In contrast to thymoma, B cell subset distribution in hyperplastic thymus could be distinguished from peripheral blood, however both tissues were not significantly enriched with plasma cells. Thus B cell differentiation in general is not defective in MG, but modified by therapy and enhanced frequencies of plasma cells can be detected in MG patients.

Expansion of circulating counterparts of follicular helper T cells in patients with myasthenia gravis

Growing evidence has demonstrated that dysfunction of follicular helper T (TFH) cells results in an abnormal positive selection of autoreactive B cells, which contributes to the development of autoimmune diseases. This study reveals that the frequency of circulating counterparts of TFH cells in myasthenia gravis (MG) patients is significantly higher compared to healthy controls. Interestingly, the frequencies of circulating TFH cells were positively correlated with the levels of serum anti-AChR Ab in MG patients. Our data suggest the presence of overactivation and expansion of circulating counterparts of TFH cells in MG patients, which may contribute to the immunopathogenesis of MG.