Cytokines and the pathogenesis of myasthenia gravis

Expression of lymphocyte activation gene-3 on CD4+T cells is regulated by cytokine interleukin-18 in myasthenia gravis

Myasthenia gravis (MG) is a T cell-dependent, B cell-mediated, and complement-dependent autoimmune disease. Lymphocyte activation gene-3 (LAG-3; CD223) is an immune checkpoint protein that plays an important role in maintaining autoimmune tolerance and homeostasis. To investigate the cytokine-regulated expression pattern of LAG-3, CD4+T cells were sorted from the peripheral blood of healthy volunteers by density gradient centrifugation and stimulated with various cytokines in vitro. The expression of membrane LAG-3 (mLAG-3), membrane a disintegrin and metallopeptidase domain10 (mADAM10) and membrane ADAM17 (mADAM17) on CD4+T cells was detected by flow cytometry; the concentration of soluble LAG-3 (sLAG-3) was detected by ELISA; and the relative expression of genes at the transcriptional level was detected by fluorescence quantitative RT-PCR (qRT-PCR). sLAG-3 levels were significantly increased in the peripheral plasma of AChR Ab-positive patients with MG compared to healthy volunteers, while the percentage of mLAG-3 expression on CD4+T lymphocytes in the peripheral blood of patients with MG was significantly reduced. IL-18 inhibited mLAG-3 levels on CD4+T cells in a concentration-dependent manner. Additionally, the concentration of sLAG-3 in the supernatant increased. After PHA and IL-18 stimulation, ADAM10 and ADAM17 also increased compared to those in the PHA-active group. Moreover, there were significant differences in the expression of mADAM10 and mADAM17 in CD4+T lymphocytes between patients with MG and healthy volunteers. These results suggest that IL-18 may regulate the expression pattern of mLAG-3 in CD4+T cells and sLAG-3 via ADAM10- and ADAM17-mediated pathways, thus affecting the immune effects of CD4+T cells. This study provides a preliminary exploration of the upstream regulatory molecules of the LAG-3 and IL-18/LAG-3 signalling pathways for potential targeted therapy of autoimmune diseases in the future.

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.

Microbiota-mediated shaping of mouse spleen structure and immune function characterized by scRNA-seq and Stereo-seq

Gut microbes exhibit complex interactions with their hosts and shape an organism's immune system throughout its lifespan. As the largest secondary lymphoid organ, the spleen has a wide range of immunological functions. To explore the role of microbiota in regulating and shaping the spleen, we employ scRNA-seq and Stereo-seq technologies based on germ-free (GF) mice to detect differences in tissue size, anatomical structure, cell types, functions, and spatial molecular characteristics. We identify 18 cell types, 9 subtypes of T cells, and 7 subtypes of B cells. Gene differential expression analysis reveals that the absence of microorganisms results in alterations in erythropoiesis within the red pulp region and congenital immune deficiency in the white pulp region. Stereo-seq results demonstrate a clear hierarchy of immune cells in the spleen, including marginal zone (MZ) macrophages, MZ B cells, follicular B cells and T cells, distributed in a well-defined pattern from outside to inside. However, this hierarchical structure is disturbed in GF mice. Ccr7 and Cxcl13 chemokines are specifically expressed in the spatial locations of T cells and B cells, respectively. We speculate that the microbiota may mediate the structural composition or partitioning of spleen immune cells by modulating the expression levels of chemokines.

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.

Factors Affecting Generalization of Ocular Myasthenia Gravis in Patients With Positive Acetylcholine Receptor Antibody

PURPOSE

To evaluate the associated factors of conversion of ocular myasthenia gravis (OMG) to generalized myasthenia gravis (GMG) among patients with seropositive acetylcholine receptor antibody (AchR Ab).

DESIGN

Retrospective cohort study.

METHODS

Setting: Retrospective chart review.

PATIENT

Seventy-one OMG patients with seropositive AchR Ab presented during July 2009 and December 2016. The exclusion criteria were patients who (1) first presented with GMG, (2) were unable to identify the time of onset of OMG or GMG, (3) were unable to provide information about previous treatments before the onset of GMG, and (4) had incomplete or lost medical records.

OBSERVATION PROCEDURE

We collected demographic and clinical characteristics, including onset of OMG and GMG, presence of other autoimmune disorders, history of smoking, presence of thymic abnormalities, and medications received.

MAIN OUTCOME MEASURES

Conversion to GMG and time to conversion.

RESULTS

Thirty-six patients experienced conversion to GMG. Overall incidence of GMG was 14 (95% confidence interval [CI] 10.09-19.4) per 100 patient-years. Probability of conversion at 2 years was .37 (95% CI .27-.49). Overall median conversion time was 4.97 years. Cox proportional hazard model showed that risk factors were female sex (HR 2.52, 95% CI 1.04-6.10), history of smoking (HR 3.42, 95% CI 1.40-8.45), and thymic abnormalities (HR 1.82, 95% CI 0.91-3.67). Protective factors against conversion to GMG were receiving immunosuppressive agents (HR 0.42, 95% CI 0.19-0.97) and pyridostigmine (HR 0.37, 95% CI 0.14-0.93).

CONCLUSIONS

OMG patients with seropositive AchR Ab should be informed that taking pyridostigmine and/or immunosuppressive agents as well as smoking cessation might prevent conversion to GMG.

Whole-exome sequencing reveals a rare interferon gamma receptor 1 mutation associated with myasthenia gravis

Our study is aimed to explore the underlying genetic basis of myasthenia gravis. We collected a Chinese pedigree with myasthenia gravis, and whole-exome sequencing was performed on the two affected siblings and their parents. The candidate pathogenic gene was identified by bioinformatics filtering, which was further verified by Sanger sequencing. The homozygous mutation c.G40A (p.V14M) in interferon gamma receptor 1was identified. Moreover, the mutation was also detected in 3 cases of 44 sporadic myasthenia gravis patients. The p.V14M substitution in interferon gamma receptor 1 may affect the signal peptide function and the translocation on cell membrane, which could disrupt the binding of the ligand of interferon gamma and antibody production, contributing to myasthenia gravis susceptibility. We discovered that a rare variant c.G40A in interferon gamma receptor 1 potentially contributes to the myasthenia gravis pathogenesis. Further functional studies are needed to confirm the effect of the interferon gamma receptor 1 on the myasthenia gravis phenotype.

The association between scabies and myasthenia gravis: A nationwide population-based cohort study

Scabies is an infectious inflammatory pruritic skin disease. Cytokine-mediated inflammatory processes contribute to the pathologic mechanism in scabies. Myasthenia gravis (MG) is also an autoimmune disease that is mediated by cytokines. The study aimed to investigate the association between scabies and myasthenia gravis. We conducted a nationwide population-based cohort study utilized data from the National Health Insurance Research Database (NHIRD) of Taiwan. Patients with scabies (n=5429) and control subjects without scabies (n=20,176) were enrolled. We tracked the subjects in both groups for a 7-year period to identify new onset MG. Cox regression analysis was performed to calculate the hazard ratio (HR) for MG. A total of 25,605 patients were enrolled in the study, including 5429 patients in the scabies group and 20,176 in the control group. There were 40 (0.7%) patients from the scabies group and 84 (0.4%) subjects from the control group who were newly diagnosed with MG during the 7-year follow-up period. The scabies patients had a significantly increased risk of MG, with an adjusted HR of 1.27 (95% confidence interval [CI] 1.01-1.89). As such, prompt diagnosis and treatment of scabies may decrease the risk of subsequent MG.

Incidence of autoimmune diseases in patients with scabies: a nationwide population-based study in Taiwan

Scabies is a commonly occurring infectious immune-mediated inflammatory skin disease. Immune-mediated inflammatory processes are also observed in autoimmune diseases. There have been very few previous studies; however, that have investigated the possible association between scabies and autoimmune diseases. To address this research gap, we conducted a nationwide population-based cohort study that included a total of 4481 scabies patients and 16,559 control subjects matched by gender, age, insured region, urbanization and income. We tracked both cohorts for a 7-year period to identify the incidence of autoimmune diseases in both groups during that follow-up period. Relatedly, a Cox regression analysis was performed to calculate and compare the hazard ratio (HR) for autoimmune diseases of both groups. An overall increased risk for 19 autoimmune diseases was observed in the scabies patients, with an adjusted HR (aHR) of 1.14 (95% CI 1.04-1.25). Compared with the control group, the scabies patients exhibited increased risks of hypersensitivity vasculitis (aHR 5.44, 95% CI 1.64-18.07), dermatomyositis (aHR 4.91, 95% CI 1.80-13.38), polyarteritis nodosa (aHR 2.89, 95% CI 1.46-5.73), systemic lupus erythematosus (aHR 2.73, 95% CI 1.33-5.64), psoriasis (aHR 2.31, 95% CI 1.85-2.88), myasthenia gravis (aHR 2.01, 95% CI 1.31-3.12), type 1 diabetes mellitus (aHR 1.93, 95% CI 1.53-2.44), pernicious anemia (aHR 1.92, 95% CI 1.42-2.61), and rheumatoid arthritis (aHR 1.43, 95% CI 1.12-1.83). In conclusion, the associations between scabies and a variety of autoimmune diseases may exist. Further studies are needed to clarify the shared etiologies and relationships between scabies and autoimmune diseases.

B cells produce less IL-10, IL-6 and TNF-α in myasthenia gravis

B cells from myasthenia gravis (MG) patients with autoantibodies (Aab) against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or with no detectable Aab were investigated as cytokine producing cells in this study. B cells were evaluated for memory phenotypes and expressions of IL-10, IL-6 and IL-12A. Induced productions of IL-10, IL-6, IL-12p40, TNF-α and LT from isolated B cells in vitro were measured by immunoassays. MG patients receiving immunosuppressive treatment had higher proportions of memory B cells compared with healthy controls and untreated patients. With CD40 stimulation MG patients produced significantly lower levels of IL-10, IL-6. With CD40 and B cell receptor stimulation of B cells, TNF-α production also decreased in addition to these cytokines. The lower levels of these cytokine productions were not related to treatment. Our results confirm a disturbance of B cell subpopulations in MG subgroups on immunosuppressive treatment. B cell derived IL-10, IL-6 and TNF-α are down-regulated in MG, irrespective of different antibody productions. Ineffective cytokine production by B cells may be a susceptibility factor in dysregulation of autoimmune Aab production.

Recombinant IgG2a Fc (M045) multimers effectively suppress experimental autoimmune myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disorder caused by target-specific pathogenic antibodies directed toward postsynaptic neuromuscular junction (NMJ) proteins, most commonly the skeletal muscle nicotinic acetylcholine receptor (AChR). In MG, high-affinity anti-AChR Abs binding to the NMJ lead to loss of functional AChRs, culminating in neuromuscular transmission failure and myasthenic symptoms. Intravenous immune globulin (IVIg) has broad therapeutic application in the treatment of a range of autoimmune diseases, including MG, although its mechanism of action is not clear. Recently, the anti-inflammatory and anti-autoimmune activities of IVIg have been attributed to the IgG Fc domains. Soluble immune aggregates bearing intact Fc fragments have been shown to be effective treatment for a number of autoimmune disorders in mice, and fully recombinant multimeric Fc molecules have been shown to be effective in treating collagen-induced arthritis, murine immune thrombocytopenic purpura, and experimental inflammatory neuritis. In this study, a murine model of MG (EAMG) was used to study the effectiveness of this novel recombinant polyvalent IgG2a Fc (M045) in treating established myasthenia, with a direct comparison to treatment with IVIg. M045 treatment had profound effects on the clinical course of EAMG, accompanied by down-modulation of pathogenic antibody responses. These effects were associated with reduced B cell activation and T cell proliferative responses to AChR, an expansion in the population of FoxP3(+) regulatory T cells, and enhanced production of suppressive cytokines, such as IL-10. Treatment was at least as effective as IVIg in suppressing EAMG, even at doses 25-30 fold lower. Multimeric Fc molecules offer the advantages of being recombinant, homogenous, available in unlimited quantity, free of risk from infection and effective at significantly reduced protein loads, and may represent a viable therapeutic alternative to polyclonal IVIg.

Activation of the adenosine A2A receptor attenuates experimental autoimmune myasthenia gravis severity

The adenosine A2A receptor (A2AR) is the major cellular adenosine receptor commonly associated with immunosuppression. Here, we investigated whether A2AR activation holds the potential for impacting the severity of experimental autoimmune myasthenia gravis (EAMG) induced following immunization of Lewis rats with the acetylcholine receptor (AChR) R97-116 peptide. This report demonstrates reduced A2AR expression by both T cells and B cells residing in spleen and lymph nodes following EAMG induction. A2AR stimulation inhibited anti-AChR antibody production and proliferation of AChR-specific lymphocytes in vitro. Inhibition was blocked with the A2AR antagonists or protein kinase A inhibitor. We also determined that the development of EAMG was accompanied by a T-helper cell imbalance that could be restored following A2AR stimulation that resulted in increased Treg cell levels and a reduction in Th1-, Th2-, and Th17-cell subtypes. An EAMG-preventive treatment regimen was established that consisted of (2-(p-(2-carbonylethyl)phenylethylamino)-5-N-ethylcarboxamidoadenosine) (CGS21680; A2AR agonist) administration 1 day prior to EAMG induction. Administration of CGS21680 29 days post EAMG induction (therapeutic treatment) also ameliorated disease severity. We conclude that A2AR agonists may represent a new class of compounds that can be developed for use in the treatment of myasthenia gravis or other T-cell- and B-cell-mediated autoimmune diseases.

Clinical efficacy and immunological impact of tacrolimus in Chinese patients with generalized myasthenia gravis

In this multicenter, open-label pilot study, the efficacy, safety, and immunological impact of tacrolimus in Chinese patients with generalized myasthenia gravis are assessed. Forty-seven generalized myasthenia gravis (MG) patients were enrolled into this study and given 3mg/day tacrolimus for 24 weeks. The primary efficacy measurements used to monitor response to tacrolimus in MG patients were the Osserman grade, the quantitative MG score (QMGS) recommended by the MGFA, the MG-specific manual muscle testing (MMT) score, and the MG-related activities of daily living (MG-ADL) scale. Also, reduction in steroid doses was used to monitor the effect of tacrolimus. Clinical evaluations were conducted at weeks 4, 8, 12, 16, 20, and 24, while immunological parameters were measured at weeks 4, 12, and 24. Measurements of the Osserman grade, QMGS, MMT, and MG-ADL all suggested improvement in patient health by the fourth week of treatment. Steroid dosage was reduced during the course of the study in 74.2% of the forty-three patients who completed the study. There were thirty-one reported adverse events in the study. Only one was considered serious. We found that tacrolimus reduced levels of the IFN-γ, IL-2, IL-10, and IL-13 cytokines and induced the proliferation of tolerogenic plasmacytoid dendritic cells after treatment. Tacrolimus did not change the population of T cell subtypes but did steadily reduce the population of BAFF-R(+) CD19(+) B cells over the course of the study. Our results show that tacrolimus improves the clinical condition of MG patients and is well tolerated. The decrease in IL-13 and reduction of BAFF-R(+) CD19(+) B cells may be related to the therapeutic effect of tacrolimus.

Etanercept treatment in myasthenia gravis

Etanercept is a tumor necrosis factor (TNF) blocking agent that has been shown to suppress ongoing experimental autoimmune myasthenia gravis (EAMG). This subcutaneously administered TNF blocking agent has also been shown to be safe and effective in several rheumatological diseases including rheumatoid arthritis, psoriasis, and ankylosing spondylitis. A prospective clinical pilot trial of etanercept in corticosteroid-dependent autoimmune myasthenia gravis (MG) patients supports further study into etanercept as a treatment for MG.

Haptoglobin study in myasthenia gravis

OBJECTIVE: A cross-sectional study of haptoglobin (Hp) in myasthenia gravis (MG) was designed, with the objective to identify its values and correlate them with different disease status. METHOD: 46 patients were enrolled in the study, all having disease severity established according to the quantitative myasthenia gravis strength scores (QMGSS). Based on the functional scale determined by Myasthenia Gravis Foundation of America (MGFA) recommendations, patients were classified as having: complete stable remission (CSR; n=10); minimal manifestations-0 (MM0; n=6), minimal manifestations-1 (MM1; n=4); pharmacological remission (PR; n=6). Two other groups participated: thymomatous patients (T; n=10) and patients without imunosuppression or thymectomy, until the assessment for Hp (WIT; n=10). Hp dosage was done by immunonephelometry, blindly to clinical data. Student's t-test, Anova test and linear regression were employed for statistical analyses. RESULTS: Statistically significant differences occurred between CSR+MM0xWIT groups (86.62x157.57, p<0.001) and PR+MM1xWIT groups (73.93x157.57, p<0.001). Linear regression showed correlation between Hp levels and QMGSS (r=0.759, p<0.001). CONCLUSION: Our results suggest that Hp may be useful in clinical practice as a disease severity marker in MG.

Clinical efficacy and cytokine network-modulating effects of tacrolimus in myasthenia gravis

To clarify the long-term efficacy, safety and the cytokine network-modulating effects of tacrolimus in myasthenia gravis, medical records of 86 newly diagnosed consecutive patients and nine steroid-dependent patients were retrospectively reviewed, and peripheral blood mononuclear cells (PBMC) were cultured for the cytokine profile. Steroid reduction effects were observed by using tacrolimus, and no serious adverse effects were observed. The culture study showed reduced IL-12, IL-17, IFN-gamma, GM-CSF, TNF-alpha and MIP-1beta, and elevated IL-10 in the PBMC from patients who received tacrolimus, which suggests inhibition of T cells and macrophages, and enhancement of type 1 regulatory T cells.

Polymorphisms of interferon-γ, interleukin-10, and interleukin-12 genes in myasthenia gravis

To assess the involvement of polymorphisms in genetic susceptibility to myasthenia gravis (MG), this study analyzed four polymorphisms of interferon (IFN)-gamma, interleukin (IL)-10, and IL-12 genes in 115 patients and 204 healthy controls (HC). IFNG +874T carriers were less frequent in MG, in patients with anti-acetylcholine receptor (AChR) (63%) and anti-titin (56.2%) antibodies compared with HC (p = 0.01 for all, OR: 0.5, 0.5, and 0.4, respectively). The presence of thymoma was also associated with lower frequency of IFNG +874T allele (p = 0.018, OR = 0.34). At IL10, -2763A allele was found to be slightly more frequent in MG and in patients with anti-AChR than in HC group (p = 0.05, OR = 1.7, p = 0.036, OR = 1.83). However, these associations did not remain significant after correction for multiple comparisons. IL12B allele distribution was not different among groups. These data suggest that some cytokine gene polymorphisms may contribute to susceptibility to or antibody production in MG. These findings need to be replicated in further studies.

Beneficial Effect of Tacrolimus on Myasthenia Gravis With Thymoma

We examined the effect of tacrolimus on myasthenia gravis (MG). Five patients with thymoma and 5 patients without thymoma underwent prior thymectomy but showed persistent myasthenic symptoms. Oral administration with tacrolimus significantly improved MG scores 1, 3, and 6 months following the beginning of treatment in all patients (P < 0.05), and the improvement was significantly higher in the thymoma group compared with the nonthymoma group (P < 0.05). However, there was no significant change in antiacetylcholine receptor titers in either group. This indicates a particular application of immunosuppressive therapy for thymomatous MG following thymectomy.

Low-level laser therapy can reduce lipopolysaccharide-induced contractile force dysfunction and TNF-alpha levels in rat diaphragm muscle

Our objective was to investigate if low-level laser therapy (LLLT) could improve respiratory function and inhibit tumor necrosis factor (TNF-alpha) release into the diaphragm muscle of rats after an intravenous injection of lipopolysaccharide (LPS) (5 mg/kg). We randomly divided Wistar rats in a control group without LPS injection, and LPS groups receiving either (a) no therapy, (b) four sessions in 24 h with diode Ga-AsI-Al laser of 650 nm and a total dose of 5.2 J/cm2, or (c) an intravenous injection (1.25 mg/kg) of the TNF-alpha inhibitor chlorpromazine (CPZ). LPS injection reduced maximal force by electrical stimulation of diaphragm muscle from 24.15+/-0.87 N in controls, but the addition of LLLT partly inhibited this reduction (LPS only: 15.01+/-1.1 N vs LPS+LLLT: 18.84+/-0.73 N, P<0.05). In addition, this dose of LLLT and CPZ significantly (P<0.05 and P<0.01, respectively) reduced TNF-alpha concentrations in diaphragm muscle when compared to the untreated control group.

The limitation of IL-10-exposed dendritic cells in the treatment of experimental autoimmune myasthenia gravis and myasthenia gravis

Dendritic cells (DC) are highly specialized antigen presenting cells that play critical roles as instigators and regulators of immune responses including B cell function, antibody synthesis and isotype switch. In this study, we compared immunotherapeutic effect of IL-10-treated DC (IL-10-DC) via both intraperitoneal (i.p.) and subcutaneous (s.c.) delivery in rats with incipient experimental autoimmune myasthenia gravis (EAMG). Spleen DC were isolated from onset of EAMG on day 39 post-immunization, exposed in vitro to IL-10, and then injected into incipient EAMG at dose of 1 x 10(6) cells/rat on day 5 after immunization. Intraperitoneal administration of IL-10-DC suppressed clinical scores, anti-acetylcholine receptors (AChR) antibody secreting cells, antigen-specific IL-10/IFN-gamma production and T cell proliferation compared to control EAMG rats. Importantly, IL-10-DC, if given by s.c. route, failed to ameliorate clinical sign of EAMG. Simultaneously, T cell proliferation, anti-AChR antibody secreting cells and IL-10/IFN-gamma production had no alteration, as compared to control EAMG rats. Both in vitro and in vivo experiments showed that treatment of IL-10 inhibited the migration of DC toward MIP-3beta and lymph node, indicating that in vitro manipulation of DC with IL-10 alters the migration of DC that influences the therapeutic effect in the treatment of autoimmune diseases. In MG patients, neither the improvement of clinical symptom nor the alteration of immunological parameter was observed through s.c. delivery of IL-10-DC, suggesting the limitation of IL-10-DC in the treatment of MG patients.

Construction, purification, and characterization of a chimeric TH1 antagonist

Background

TH1 immune response antagonism is a desirable approach to mitigate some autoimmune and inflammatory reactions during the course of several diseases where IL-2 and IFN-γ are two central players. Therefore, the neutralization of both cytokines could provide beneficial effects in patients suffering from autoimmune or inflammatory illnesses.

Results

A chimeric antagonist that can antagonize the action of TH1 immunity mediators, IFN-γ and IL-2, was designed, engineered, expressed in E. coli, purified and evaluated for its in vitro biological activities. The TH1 antagonist molecule consists of the extracellular region for the human IFNγ receptor chain 1 fused by a four-aminoacid linker peptide to human 60 N-terminal aminoacid residues of IL-2. The corresponding gene fragments were isolated by RT-PCR and cloned in the pTPV-1 vector. E. coli (W3110 strain) was transformed with this vector. The chimeric protein was expressed at high level as inclusion bodies. The protein was partially purified by pelleting and washing. It was then solubilized with strong denaturant and finally refolded by gel filtration. In vitro biological activity of chimera was demonstrated by inhibition of IFN-γ-dependent HLA-DR expression in Colo 205 cells, inhibition of IFN-γ antiproliferative effect on HEp-2 cells, and by a bidirectional effect in assays for IL-2 T-cell dependent proliferation: agonism in the absence versus inhibition in the presence of IL-2.

Conclusion

TH1 antagonist is a chimeric protein that inhibits the in vitro biological activities of human IFN-γ, and is a partial agonist/antagonist of human IL-2. With these attributes, the chimera has the potential to offer a new opportunity for the treatment of autoimmune and inflammatory diseases.

IL-1 receptor antagonist-mediated therapeutic effect in murine myasthenia gravis is associated with suppressed serum proinflammatory cytokines, C3, and anti-acetylcholine receptor IgG1

In myasthenia gravis (MG), TNF and IL-1beta polymorphisms and high serum levels of these proinflammatory cytokines have been observed. Likewise, TNF and IL-1beta are critical for the activation of acetylcholine receptor (AChR)-specific T and B cells and for the development of experimental autoimmune myasthenia gravis (EAMG) induced by AChR immunization. We tested the therapeutic effect of human recombinant IL-1 receptor antagonist (IL-1ra) in C57BL/6 mice with EAMG. Multiple daily injections of 0.01 mg of IL-1ra administered for 2 wk following two AChR immunizations decreased the incidence and severity of clinical EAMG. Furthermore, IL-1ra treatment of mice with ongoing clinical EAMG reduced the clinical symptoms of disease. The IL-1ra-mediated suppression of clinical disease was associated with suppressed serum IFN-gamma, TNF-alpha, IL-1beta, IL-2, IL-6, C3, and anti-AChR IgG1 without influencing total serum IgG. Therefore, IL-1ra could be used as a nonsteroidal drug for the treatment of MG.

An Immunomodulatory Molecule of Symbiotic Bacteria Directs Maturation of the Host Immune System

The mammalian gastrointestinal tract harbors a complex ecosystem consisting of countless bacteria in homeostasis with the host immune system. Shaped by evolution, this partnership has potential for symbiotic benefit. However, the identities of bacterial molecules mediating symbiosis remain undefined. Here we show that, during colonization of animals with the ubiquitous gut microorganism Bacteroides fragilis, a bacterial polysaccharide (PSA) directs the cellular and physical maturation of the developing immune system. Comparison with germ-free animals reveals that the immunomodulatory activities of PSA during B. fragilis colonization include correcting systemic T cell deficiencies and T(H)1/T(H)2 imbalances and directing lymphoid organogenesis. A PSA mutant of B. fragilis does not restore these immunologic functions. PSA presented by intestinal dendritic cells activates CD4+ T cells and elicits appropriate cytokine production. These findings provide a molecular basis for host-bacterial symbiosis and reveal the archetypal molecule of commensal bacteria that mediates development of the host immune system.

Efficacy of Low-Dose FK506 in the Treatment of Myasthenia gravis – A Randomized Pilot Study

To determine the efficacy of low-dose FK506 in the treatment of myasthenia gravis (MG), untreated de novo patients were randomly selected to receive treatment with (n = 18) or without (n = 16) FK506, and were evaluated for 1 year after treatment with limitation of daily dose of prednisolone. Low-dose FK506 reduced the duration of early-phase therapy in hospital (p < 0.05) and the need for combined therapy with plasmapheresis and high-dose intravenous methylprednisolone or high-dose intravenous methylprednisolone alone (p < 0.05). It also reduced the daily dose of prednisolone (p < 0.05) required to maintain minimal manifestations of MGFA postintervention status. None of the patients exhibited significant side effects up to 1 year after treatment. These findings suggest that low-dose FK506 is safe and efficacious for the treatment of de novo MG patients.

Immunomodulation by a dual altered peptide ligand of autoreactive responses to the acetylcholine receptor of peripheral blood lymphocytes of patients with myasthenia gravis

Myasthenia gravis (MG) is a T cell-dependent, antibody-mediated autoimmune disease. A dual altered peptide ligand (APL) that is composed of the tandemly arranged two single amino acid analogs of two myasthenogenic peptides was demonstrated to downregulate in vitro and in vivo murine MG associated autoreactive responses. Furthermore, treatment with the dual APL ameliorated the clinical manifestations of an established experimental autoimmune MG in mice. This study was undertaken in order to investigate the ability of the dual APL to immunomodulate MG-associated responses of peripheral blood lymphocytes (PBL) of patients with MG to the native autoantigen acetylcholine receptor (AChR). PBL of 22 of 27 patients with MG tested responded by proliferation to torpedo AChR. The proliferative responses of PBL of 21 of 22 responders were significantly inhibited by the dual APL. The inhibition was specific because a control peptide did not inhibit these proliferative responses. The dual APL also downregulated the levels of the secreted pathogenic cytokine IFN-gamma in supernatants of stimulated PBL of 80% of the tested patients. The latter inhibitions correlated with an upregulated production of the immunosuppressive cytokine, tumor growth factor beta. Thus, the results of our study demonstrate that the dual APL is capable of downregulating in vitro autoreactive responses of patients with MG and suggest that this peptide is a potential candidate for a novel specific treatment of patients with MG.

Dendritic cells activate autologous T cells and induce IL-4 and IL-10 production in myasthenia gravis

Dendritic cells (DC), as initiators and orchestrators of immune responses, control both naive and primed T cell responses. Depending on their maturation stage, DC promote immunity or tolerance. Here we investigated (1) the phenotype and cytokine secretion patterns of IL-10-modulated immature DC (IL-10-DC) and lipopolysaccharide (LPS)-driven mature DC (LPS-DC) in comparison with unmodulated immature DC (imDC) and (2) the effects of IL-10-DC, and of LPS-DC, vs. imDC on autologous T cell responses in patients with myasthenia gravis (MG) compared with healthy controls (HC). All three types of DC derived from MG significantly increased the levels of CD4+CD25+ T cells and of their subfraction expressing CD69, when compared to DC derived from HC. IL-10-DC induced production of IL-10 and IL-4 by T cells from MG patients, but only IL-10 production from HC. LPS-DC activated autologous T cells as reflected by augmented CD25, CD69 and CTLA-4 expression on CD4+ T cells, without differences between MG and HC. This was associated with increased production of both Th1 (IFN-gamma) and Th2 (IL-10 and IL-4) cytokines by T cells. These results indicate that DC-induced activation of autologous T cells is more pronounced in MG than in HC. In addition, DC-induced T cell responses in MG vs. HC are more Th2-prone.

Therapeutic vaccines in autoimmunity

Similarly to prophylactic vaccines whose purpose is to prevent infectious diseases, therapeutic vaccines against autoimmune diseases are based on their similarity to the putative causes of the disease. We shall describe here two such examples: a copolymer of amino acids related to myelin basic protein, in the case of multiple sclerosis, and a peptide derived from the nicotinic acetylcholine receptor (AChR), in the case of myasthenia gravis (MG). Copolymer 1 (Cop 1, glatiramer acetate, Copaxone) is a synthetic amino acid random copolymer, immunologically cross-reactive with myelin basic protein and suppresses experimental allergic encephalomyelitis in several animal species. Cop 1 slows the progression of disability and reduces relapse rate in exacerbating-remitting multiple sclerosis patients. It was approved by the Food and Drug Administration in 1996, and today is used by tens of thousands of patients. Cop 1 is a potent inducer of T helper 2 (Th2) regulatory cells in mice and humans, and Th2 cells are found both in the brains and spinal cords of Cop 1-treated mice. MG and experimental autoimmune MG are T cell-regulated, antibody-mediated autoimmune diseases. Two peptides, representing sequences of the human AChR alpha-subunit, p195-212 and p259-271, are immunodominant T cell epitopes in MG patients and in two strains of mice. Altered peptide ligand, composed of the tandemly arranged two single amino acid analogs, inhibits in vitro and in vivo MG-associated autoimmune responses. The active suppression is mediated by the CD4(+)CD25(+) immunoregulatory cells and is associated with the down-regulation of Th1-type cytokines and the up-regulation of the secretion of IL-10 and the immunosuppressive cytokine, transforming growth factor beta.

Protective potential of experimental autoimmune myasthenia gravis in Lewis rats by IL-10-modified dendritic cells

Dendritic cells (DC) are usually regarded as antigen-presenting cells (APC) involved in T cell activation, but DC also directly or indirectly affect B cell function, antibody synthesis and isotype switch. In this study, we explore potential of DC-based immunotherapy in ongoing experimental autoimmune myasthenia gravis (EAMG) in Lewis rats, which is mediated by anti-acetylcholine receptor (AChR) antibodies. Spleen DC were isolated from onset of Lewis rat EAMG on day 39 post immunization (p.i.), exposed in vitro to IL-10 and then injected intraperitoneally into ongoing EAMG Lewis rats at dose of 1 x 10(6) cells/rat on day 5 p.i. with AChR + complete Freund's adjuvant. IL-10-modified DC resulted in lower clinical scores, less body weight loss, lower numbers of anti-AChR IgG antibody-secreting cells and lower affinity of anti-AChR antibodies in rats receiving IL-10-modified DC, accompanied with lower expression of CD80 and CD86 and lower lymphocyte proliferation among lymph node mononuclear cells compared with control EAMG rats. Lower levels of IL-10 and IFN-gamma were also found in the supernatants of AChR-stimulated lymph node MNC culture in rats receiving IL-10-modified DC. These results demonstrate that IL-10-modified DC induced hypo-responsiveness by down-regulating co-stimulatory molecules, and reduced production of anti-AChR antibodies possibly by inhibiting IL-10 production. Importantly, this procedure that autologous DC from EAMG were adopted to treat ongoing EAMG is more close to clinical trial in human, encouraging future evaluation in human myasthenia gravis.

A dual altered peptide ligand down-regulates myasthenogenic T cell responses by up-regulating CD25- and CTLA-4-expressing CD4+ T cells

Immunization of mice with two myasthenogenic peptides, p195-212 and p259-271, which are sequences of the human acetylcholine receptor, resulted in myasthenia gravis (MG)-associated immune responses. A dual altered peptide ligand (APL) composed of the two APLs of the myasthenogenic peptides inhibited, in vitro and in vivo, those responses. The aims of this study were to further elucidate the mechanism/s by which the dual APL down-regulates MG-associated responses in vivo and characterize the cell population/s involved in this immunomodulatory suppressive effect. We have shown here that s.c. administration of the dual APL activates CD4CD25-expressing cells in lymph nodes (LN) of SJL mice. Furthermore, depletion of these cells diminished significantly the inhibitory effect of the APL on p195-212-specific proliferative responses. Depletion of the CD4+CD25+ cells was accompanied with a decrease in the secretion of the immunosuppressive cytokine, transforming growth factor (TGF)-beta. Administration of the dual APL resulted also in the up-regulation of the expression of cytotoxic T lymphocyte antigen (CTLA)-4 and in a down-regulated expression of CD28 on LN cells. Blockade of the CTLA-4 function, in vitro, abrogated the inhibitory effect of the dual APL on the proliferative responses specific to p195-212. Thus, our results suggest that the active suppression exerted by the dual APL is mediated by the CD4+CD25+ immunoregulatory cell population, either directly through the CTLA-4 molecule expressed on these cells, and/or indirectly by causing the differentiation of other regulatory T cell population/s that secrete immunosuppressive cytokines.

Dehydroepiandrosterone therapy ameliorates experimental autoimmune myasthenia gravis in Lewis rats

To detect a possible effect of dehydroepiandrosterone (DHEA) in the pathogenesis of experimental autoimmune myasthenia gravis (EAMG), DHEA (0.5 mg/rat) was administrated intraperitoneally to Lewis rats every other day from day 4 postimmunization (p.i.) to day 35 p.i. with Torpedo acetylcholine receptor (AChR) and Freund's complete adjuvant. Rats treated with DHEA had a lower clinical score (mean clinic score, 2 versus 0.5 on day 37 p.i.) and a lower body weight loss (mean body weight, 169 versus 142 g on day 37 p.i.) compared with control EAMG rats. DHEA treatment decreased serum anti-AChR IgG and IgG2b antibody titers on days 7, 14, and 21 p.i. and inhibited the levels of anti-AChR IgG antibody secreting cells (60%), accompanied by decreased IL-4 (33%) and augmented TGF-beta1-positive cells (41%) among lymph node mononuclear cells. These results obtained from EAMG in Lewis rats further encourage us to study DHEA treatment in human MG.

Effects of FK506 on myasthenia gravis patients with high interleukin-2 productivity in peripheral blood mononuclear cells

We compared the early effects of FK506 on clinical severity, interleukin-2 (IL-2) production by phytohemagglutinin-stimulated peripheral blood mononuclear cells (PBMs), and serum levels of acetylcholine receptor antibodies between myasthenia gravis (MG) patients with elevated (>1250 pg/ml, n = 9) or normal (<1250 pg/mL, n = 10) levels of PBM IL-2 production. Reduction in clinical severity and PBM IL-2 production were significantly greater in the patients with elevated IL-2 production than those with normal PBM IL-2 production in the first month of treatment.

Anti-TNF-alpha antibodies suppress the development of experimental autoimmune myasthenia gravis

To understand the role of TNF-alpha in the induction of experimental autoimmune myasthenia gravis (EAMG) and detect a possible effect of anti-TNF-alpha antibodies in the treatment of EAMG, anti-TNF-alpha antibodies were administrated intraperitoneally to Lewis rats twice per week for 5 weeks from the day of immunization with Torpedo AChR and complete Freund's adjuvant (CFA). Administration of anti-TNF-alpha antibodies resulted in lower incidence of EAMG, and in delayed onset and only mild muscle weakness compared with control EAMG rats. These mild clinical signs were accompanied by lower AChR-specific lymphocyte proliferation, down-regulated IFN-gamma and IL-10, and up-regulated TGF-beta. The lower levels of anti-AChR IgG, Ig2a and IgG2b and decreased anti-AChR IgG affinity were found in rats treated with anti-TNF-alpha antibodies. These results demonstrate that anti-TNF-alpha antibodies can suppress the induction and development of EAMG.

Cytokine secretion by peripheral blood mononuclear cells in myasthenia gravis

We studied spontaneous secretion of anti-acetylcholine receptor antibody (AChRAb), IgG and cytokines by peripheral blood mononuclear cells (PBMC) from 19 MG patients without therapy and 10 normal controls. IgG secretion was higher in the culture medium of MG than in that of normal controls. AChRAb secretion was correlated with IgG secretion in MG. Interleukin (IL)-2, IL-4, IL-5, IL-6, IL-10, IL-13, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha secreted by PBMC from MG patients were not different from those produced by those from normal controls. IgG secretion was, however, correlated with the secretions of IL-5 and IL-6 in MG. Spontaneous B cell activation was suspected in patients with MG.

IL-1 genes in myasthenia gravis: IL-1A -889 polymorphism associated with sex and age of disease onset

Myasthenia gravis (MG) is a multifactorial autoimmune disease of the neuromuscular junction. We investigated the relation between four polymorphisms of the interleukin (IL)-1 gene cluster on 2q12-22, and MG susceptibility and clinical features in a large cohort of individuals. No polymorphism was associated with MG susceptibility. However, the IL-1A -889 CC genotype was associated with early disease onset (p=0.0044) in the whole MG group and the subgroup of CC males developed MG about 18 years earlier than males carrying other IL-1A -889 genotypes (p=0.022). This finding suggests that IL-1A is a disease modifier in MG, or is in linkage disequilibrium with an unknown locus on chromosome 2.

Acetylcholine receptor-reactive antibody induces nitric oxide production by a rat skeletal muscle cell line: influence of cytokine environment

The monoclonal Lewis rat skeletal muscle cell line, LE1, responded to the acetylcholine receptor (AChR)-reactive antibody mAb35 by up-regulating levels of mRNA for inducible nitric oxide synthase (iNOS/NOS-II), followed by levels of NO. Interferon-gamma (IFN-gamma) and interleukin-1 (IL-1) were also each capable of inducing iNOS message, and synergistically with mAb35. Finally, myocyte-derived NO was implicated as a possible source of immunomodulation in experimental autoimmune myasthenia gravis (EAMG), as shown by the ability of the culture fluids from IFN-gamma-activated LE1 cells to inhibit the proliferation of AChR-reactive T cells.

NKT-associated markers and perforin in hyperplastic thymuses from patients with Myasthenia gravis

Immunohistochemical expression of natural killer T (NKT) cell-associated markers (Valpha24 and CD56) and perforin in relation to CD44-highly positive (CD44(high)) cells was studied in hyperplastic thymuses from patients with myasthenia gravis (MG) whose symptoms dramatically improved after thymectomy and compared with non-MG control thymuses. In the control thymuses, Valpha24-positive (Valpha24(+)) and CD56-positive (CD56(+)) cells were sparsely distributed in the medullary area only. In contrast, in hyperplastic MG thymus, Valpha24(+) and CD56(+) cells were more frequent in connective tissue, appeared to have penetrated the thymic parenchyma, and most coexpressed CD44(high). Perforin-positive cells were not present in the control thymus, but were in the connective tissue and perilobular cortical areas in the hyperplastic MG thymus. Most of these perforin-positive cells were CD44(high) and were located near blood vessels. They appeared to have migrated directly from the vascular system and penetrated the thymic parenchyma. Some perforin-positive cells coexpressed Valpha24, CD56, or both. These findings suggest that in this particular type of MG thymus, NKT-like cells may have increased via a CD44- and perforin-mediated mechanism, leading to an imbalance in the immune system that favored an antibody-mediated autoimmunity against the acetylcholine receptor.

Myasthenia gravis during low-dose IFN-alpha therapy for chronic hepatitis C

We describe the case of a 56-year-old man who had high aminotransferase levels and anti-hepatitis C virus (HCV) antibodies. He underwent liver biopsy and biochemical screening to evaluate whether he would benefit from interferon (IFN) treatment. The patient was discharged with a diagnosis of HCV-related active chronic hepatitis, skin porphyria, and type 2 diabetes. On December 5, 1995, he began therapy with recombinant IFN-alpha at a dose of 3 MIU three times a week. He stopped this therapy in February 1996 because of asthenia, diplopia, headache, and anxiety. During IFN therapy, he had normal aminotransferase levels and no detectable HCV RNA, a condition that persists to the present. Between March and May 1996, the patient was admitted several times to a neurology clinic, where myasthenia gravis was diagnosed and treatment with pyridostigmine and cyclosporine was initiated. This case and others indicate that caution should be exercised in administering IFN because low doses can be correlated with myasthenia gravis in patients without malignancies.

Blockade of CD40 Ligand Suppresses Chronic Experimental Myasthenia Gravis by Down-Regulation of Th1 Differentiation and Up-Regulation of CTLA-4

Myasthenia gravis (MG) and experimental autoimmune MG (EAMG) are T cell-dependent Ab-mediated autoimmune disorders, in which the nicotinic acetylcholine receptor (AChR) is the major autoantigen. Th1-type cells and costimulatory factors such as CD40 ligand (CD40L) contribute to disease pathogenesis by producing proinflammatory cytokines and by activating autoreactive B cells. In this study we demonstrate the capacity of CD40L blockade to modulate EAMG, and analyze the mechanism underlying this disease suppression. Anti-CD40L Abs given to rats at the chronic stage of EAMG suppress the clinical progression of the autoimmune process and lead to a decrease in the AChR-specific humoral response and delayed-type hypersensitivity. The cytokine profile of treated rats suggests that the underlying mechanism involves down-regulation of AChR-specific Th1-regulated responses with no significant effect on Th2- and Th3-regulated AChR-specific responses. EAMG suppression is also accompanied by a significant up-regulation of CTLA-4, whereas a series of costimulatory factors remain unchanged. Adoptive transfer of splenocytes from anti-CD40L-treated rats does not protect recipient rats against subsequently induced EAMG. Thus it seems that the suppressed progression of chronic EAMG by anti-CD40L treatment does not induce a switch from Th1 to Th2/Th3 regulation of the AChR-specific immune response and does not induce generation of regulatory cells. The ability of anti-CD40L treatment to suppress ongoing chronic EAMG suggests that blockade of CD40L may serve as a potential approach for the immunotherapy of MG and other Ab-mediated autoimmune diseases.

IL-10 and IFN-gamma in Guillain-Barré syndrome. Network Members of the Swedish Epidemiological Study Group

Guillain-Barré syndrome (GBS) is an acute inflammatory disease affecting myelin and axons of the peripheral nervous system (PNS). GBS is considered to be caused by breakdown of tolerance to autoantigens of the PNS. The involvement of cytokines in GBS and in relation to treatment with high dose intravenous immunoglobulin (IvIg) is incompletely known. We studied the temporal profiles of IL-10 and IFN-gamma-secreting blood mononuclear cells (MNC) over the course of GBS, using enzyme-linked immunospot (ELISPOT) assays. Pretreatment levels of blood MNC spontaneously secreting IL-10 were higher in the acute phase of GBS than in control patients with aseptic meningitis, other neurological diseases, diabetic neuropathy and healthy subjects. Levels of IFN-gamma-secreting blood MNC were not increased over the course of GBS. Patients treated with IvIg had lower numbers of IL-10-secreting MNC compared to untreated patients. High levels of IL-10-secreting MNC correlated with serum anti-ganglioside IgM antibody levels, and with neurophysiological signs of axonal damage. The present data suggests that IFN-gamma is not involved in GBS pathogenesis, and IL-10 being up-regulated in the early phase of GBS and associated with axonal damage, may have a pathogenetic role in GBS.

Cytokine profile and T cell adhesiveness to endothelial selectins: in vivo induction by a myasthenogenic T cell epitope and immunomodulation by a dual altered peptide ligand

Myasthenia gravis (MG) is a T cell-regulated antibody-mediated autoimmune disease. Immunization with two myasthenogenic peptides, p195-212 and p259-271, that are sequences of the human acetylcholine receptor alpha subunit was shown to induce experimental autoimmune MG (EAMG)-associated immune responses. A peptide composed of the two altered peptide ligands (APL) of the myasthenogenic peptides (designated as dual APL) inhibited, in vitro and in vivo, those responses. The objectives of this study were to examine (i) whether in vivo T cell activation by p259-271 affects the cytokine profile and the T cell migration ability, and (ii) whether the latter are immunomodulated by in vivo administration of the dual APL. Our results showed that immunization of mice with p259-271 enriched the population of lymph node and spleen cells with subsets of T cells with strong adhesiveness towards E- and P-selectins. This enrichment was associated with an acquisition of a T(h)1-type cytokine profile. Treatment of the immunized mice with the dual APL interfered with both the migratory potential of the autoreactive T cells, and the production of the T(h)1-type cytokines IL-2 and IFN-gamma (known to play a pathogenic role in MG and EAMG). T cells derived from APL-treated mice acquired a T(h)3-type cytokine profile, characterized by the secretion of the immunosuppresive cytokine transforming growth factor-ss. Thus, our results suggest that T cell selectin ligands and T cell-derived cytokines are involved in the induction and immunomodulation of EAMG- and MG-associated T cell responses.

Different age-related effects of thymectomy in myasthenia gravis: role of thymoma, zinc, thymulin, IL-2 and IL-6

Different age-related immune pathogenetic mechanisms in myasthenia gravis (MG) have been suggested because of restoration after thymectomy (Tx) of altered zinc, thymulin (TH) and T-cell subsets exclusively in early-onset patients (younger <50 years), not in late-onset patients (older >50 years). In this context interleukin-2 (IL-2), interleukin-6 (IL-6) and thymoma are crucial because both involved in MG pathogenesis and correlated with acetylcholine receptors (AchRs) Ab production. Moreover, IL-2 and IL-6 are zinc-dependent, are altered in aging and related with zinc and TH age-dependent declines. Moreover, zinc is relevant for immune efficiency. In order to confirm these different age-related pathogenetic mechanisms further, the role of thymoma, zinc, TH, IL-2 and IL-6 is studied in MG patients with generalized MG with and without thymoma before and 1 month and 1 year after Tx. The high IL-2, IL-6, zinc, and AChR Ab levels observed before Tx are significantly correlated each other in younger MG patients (<50 years) independently by thymoma and in older MG patients (>50 years) with thymoma. No correlations exist in older MG patients without thymoma. Thymulin is not correlated with other parameters considered to be both in younger and older MG patients independently by the thymoma. Thymectomy restores zinc; immune parameters and AChR Ab are exclusively in the younger group, not in the older one. These findings suggest that IL-2 and IL-6, via zinc, rather than TH, may be involved in different age-related pathogenetic mechanisms mainly in early-onset MG. By contrast, thymoma may be involved in MG etiology in late-onset representing, as such, a useful discriminant tool for MG etiology between early and late-onset MG patients. Because autoimmune phenomena may rise in aging, a parallelism with altered immune functions during aging is discussed.

Presence of interleukin 10 in the serum and blister fluid of patients with pemphigus vulgaris and pemphigoid

Interleukin 10 (IL-10) is an immunoregulatory cytokine produced by T lymphocytes and macrophages. Recently, it has been suggested that IL-10 may be involved in the pathogenesis of various inflammatory and autoimmune diseases. Using an ELISA we investigated the presence of IL-10 in the serum and blister fluid of pemphigus vulgaris (PV) patients with active disease and those in prolonged clinical remission compared with normal controls. Sera from patients with bullous pemphigoid (BP), ocular cicatricial pemphigoid (OCP), oral pemphigoid (OP) and blister fluid from five patients with BP were also studied. Increased levels of IL-10 were detected in the sera of 87.5% of patients with active PV and were statistically significant (P=0.0003) when compared with levels in normal human serum. Lower levels of IL-10 were detected in 12.5% PV patients in remission and were statistically significant (P=0.0001) when compared with levels in patients with active disease. Levels of IL-10 were detected in sera of 4.6% (1 of 24) of the normal controls. The levels of IL-10 were approximately four times higher in blister fluids than levels in the serum in the same PV patients. This difference was highly statistically significant (P=0.0008). A correlation was observed between serum levels of IL-10 and titres of pemphigus autoantibodies and with disease severity. Elevated level of IL-10 was detected in the blister fluid from five BP patients. Levels of IL-10 in the sera of patients with BP, OCP and OP were not significantly increased. These preliminary data suggest that IL-10 in concert with other cytokines may play an important role in the pathogenesis of PV and BP.