Immunoadsorption in Myasthenia Gravis Based on Specific Ligands Mimicking the Immunogenic Sites of the Acetylcholine Receptor

Abstract: A specific system for antibody removal from blood circulation in myasthenia gravis (MG) patients was devised by use of the immunoadsorbent bound to an acetylcholine receptor (AChR) peptide that was synthesized corresponding to the sequence of residues 183‐200 of the AChR alpha‐subunit (alpha 183‐200), antibodies which prevent the binding of ACh to AChR. The alpha 183‐200 peptide was confirmed to be immunogenic for induction of an animal model of the disease and for reactivity with MG autoantibodies. We then made use of these results for immunoadsorption therapy through the antigen‐antibody reaction on the molecular level, having given patients relief from myasthenic weakness. The greatest care was taken for the selection of an antigenic region in the molecular structure among various myasthenogenic domains of AChR and for the antigenic conformation of synthetic peptide as the adsorbent to react with antibodies raised against the native protein.     

Development of a Specific Immunoadsorbent Containing Immobilized Synthetic Peptide of Acetylcholine Receptor for Treatment of Myasthenia Gravis

INTRODUCTION Guest Editor's Introduction: The most specific adsorption of antibody can be achieved by the application of antigen‐antibody binding. The antibody is specific for a particular part of antigen called epitope rather than for the whole antigen molecules. Therefore, the immobilized epitope for target antibody could be used as the ligand of the adsorbent. Kuraray Co. developed a specific adsorbent for the anti‐acetylcholine receptor antibody. The adsorbent consists of microporous cellulose beads for the base material which immobilized a synthetic peptide as the epitope ligand. This paper describes the basic design and in vitro characteristics of the adsorbent. This paper was printed in Therapeutic Plasmapheresis, vol 12, page 573–576 (1993), and reprinted here with permission.     

Plasma Exchange for Treatment of Myasthenia Gravis: Pathophysiologic Basis and Clinical Experience

Abstract: Myasthenia gravis is an autoimmune disease characterized by production of antibodies to acetylcholine receptors located at the motor end plate in skeletal muscles. The antibodies bind and subsequently induce degeneration of these receptors. Loss of acetylcholine receptors results in inadequate contraction of muscle fibers in response to acetylcholine released from nerve terminals and clinically apparent muscle weakness. Plasma exchange removes the circulating antibodies in myasthenic patients with short‐term clinical improvement. Plasma exchange may be indicated in patients with acute exacerbation of neuromuscular weakness with bulbar or respiratory compromise, preoperative optimization prior to thymectomy, and postoperative deterioration following thymectomy or other surgical procedures. Long‐term, intermittent plasma exchange for patients who do not adequately respond to standard treatment is another evolving indication.     

Removal Characteristics of Immunoadsorption with the Tryptophan‐Immobilized Column Using Conventional and Selective Plasma Separators in the Treatment of Myasthenia Gravis

Autoimmune neurological diseases are often treated by immunoadsorption using a conventional plasma separator and tryptophan‐immobilized column (IA). However, there is only one case report on treatment with immunoadsorption using a selective plasma separator and tryptophan‐immobilized column (SeIA) in clinical practice. This study aimed to investigate the removal characteristics of antibodies against acetylcholine receptors (AChRAb), immunoglobulin G, fibrinogen, and factor XIII (FXIII) in IA and SeIA in four patients with myasthenia gravis. A total of 19 sessions of immunoadsorption were performed (five sessions of IA and 14 sessions of SeIA) when the processed plasma volume was 2 L. The corresponding reductions were 52.5% ± 6.2% for AChRAb, 58.8% ± 4.2% for fibrinogen, and 36.9% ± 5.5% for FXIII after one session of IA. The corresponding reductions were 45.2% ± 9.9% for AChRAb, 3.5% ± 6.9% for fibrinogen, and ?4.6% ± 11.1% for FXIII after one session of SeIA. The removal rates for AChRAb, fibrinogen, and FXIII in IA were significantly higher than those in SeIA. IA could effectively remove AChRAb, and SeIA could retain fibrinogen and FXIII. IA can be combined with SeIA, resulting in both IgG autoantibodies removal by IA and retention of coagulation factors by SeIA.     

糖皮质激素对重症肌无力患者细胞和体液免疫功能影响的研究

目的　探讨糖皮质激素对重症肌无力 (MG )患者细胞和体液免疫功能的影响。方法　ELISA法检测 3 2例MG患者在糖皮质激素治疗前和治疗 3个月后的血清白细胞介素 (IL) 6和乙酰胆碱受体抗体 (AChRab)水平。结果　MG患者血清IL 6和AChRab均显著高于对照组(P <0 .0 1) ,而糖皮质激素治疗后均明显降低 (P <0 .0 5或P <0 .0 1)。血清IL 6在AChRab阳性MG患者高于AChRab阴性患者 (P <0 .0 5 ) ,且与AChRab滴度呈正相关 (r =0 .710 ,P <0 .0 1)。结论　糖皮质激素可通过抑制MG患者体内IL 6和AChRab的产生 ,有效调节机体细胞和体液免疫功能。     

Sequential Plasmapheresis and Intravenous Immunoglobulin Therapy for Refractory Myasthenia Gravis: Case Report

Immunotherapy is currently the standard therapy for myasthenia gravis (MG) although some patients may be refractory to treatment. We describe the use of sequential plasmapheresis and intravenous immunoglobulin (IVIG) therapy for treatment of advanced MG in a patient refractory to all forms of medical treatment including corticosteroids, immunosuppressants, and intermittent plasmapheresis. The patient, a 37-year-old woman with systemic lupus erythematosus (SLE), had initially responded well to treatment with high dose corticosteroids and intermittent plasmapheresis, with the duration of response ranging from 3 to 4 months. However, after 18 months of therapy, the duration of response had gradually decreased to 1 month. She responded well to a 5 day trial of plasmapheresis followed by high dose IVIG, and the duration of response increased to 6 months. The SLE activity was relatively silent during each relapse. This report indicates the potential usefulness of sequential plasmapheresis and IVIG in the treatment of patients with refractory MG and SLE.     

Comparing the Autoantibody Levels and Clinical Efficacy of Double Filtration Plasmapheresis,Immunoadsorption, and Intravenous Immunoglobulin for the Treatment of Late-onset Myasthenia Gravis

The aim of this study was to investigate the effects of double-filtration plasmapheresis (DFPP), immunoadsorption (IA) and intravenous immunoglobulin (IVIg) in the treatment of late-onset myasthenia gravis (MG). A total of 40 late-onset MG patients were randomly divided into three groups: 15 patients were treated with DFPP; 10 patients were treated with IA; and 15 patients received IVIg. The titers of titin antibodies (Titin-ab), acetylcholine receptor antibodies (AChR-ab), presynaptic membrane antibody (Prsm-ab) were detected before and after the treatment, and the quantitative MG score (QMG score) was assessed by blinded examiners before and immediately after the entire course of treatment. The clinical efficacy, duration of respiratory support, hospital stay, and the correlation between the three antibodies and the QMG score were also analyzed. Compared to pre-treatment, the values of Titin-ab, AChR-ab, and PrsmR-ab were all dramatically decreased (P < 0.05); meanwhile the value of Titin-ab in the DFPP and IA groups decreased much more than in the IVIg group (P < 0.01); however, no statistical difference was found between the DFPP and IA groups (P > 0.05). Although the QMG score significantly improved in all three groups, it decreased much more in both the DFPP and IA groups than that in the IVIg group (P < 0.01). Symptoms were also effectively ameliorated by all treatments, but the clinical efficacy of the DFPP and IA groups was higher than the IVIg group (P < 0.05), as was the remission time (P < 0.01), the duration of hospital stay (P < 0.05), and the number of respiratory supports required (P < 0.05). Using Pearson's correlation, the decrease of Titin-ab showed a longitudinal correlation with the decrease of QMG score (r = 0.6107, P < 0.01). Both DFPP and IA showed better short-term clinical effectiveness than immunoglobulin transfusion, rapidly and effectively clearing the pathogenic antibodies in late-onset MG patients, especially for Titin-ab.     

Periodic Therapeutic Plasma Exchange in Patients With Moderate to Severe Chronic Myasthenia Gravis Non‐Responsive to Immunosuppressive Agents: An Eight Year Follow‐Up

Few patients with moderate or severe myasthenia gravis (MG) do not respond to immunosuppressive treatment. We present our experience with periodic therapeutic plasma exchange (TPE), in 11 patients with MG resistant to intravenous immunoglobulin (IVIg) therapy, who had frequent relapses even whilst on high doses of immunosuppressive drugs, over a period of 8 years. All patients underwent TPE until control of their symptoms was achieved, and afterwards TPE sessions were continued periodically in an attempt to achieve remission of the disease, without immunosuppressant therapy. Two of the patients were progressively weaned off immunosuppressive agents, as well as TPE, and they are now symptom free. The other nine patients are still under a periodic TPE regime. Seven of them were weaned off all medications and required an average of 3.7 TPE sessions per year during the last 5 years. In the other two patients, those with the most severe form of the disease, the immunosuppressant dosage has been decreased and a TPE session every 2–3 weeks is required in order to control their symptoms. Through all these years TPE has been well tolerated and only minor side‐effects were observed in two patients. Finally, during this 8 year follow‐up period, nine of the patients treated with periodic TPE have been in good control of their symptoms over the last 5 years, and the other two patients live a normal life without any treatment in the last 3 years. Our results suggest that periodic TPE is safe and effective in the control of symptoms in patients with moderate to severe MG who do not respond to immunosuppressive therapies.     

合成胸腺肽对血液中若干生化指标的影响

本文观察合成胸腺五肽(TP-5)对SOD活性,O_2~-的清除作用,红细胞免疫功能等,发现TP-5有明显提高SOD活性达2～3倍以上,用药前为59.96±13.88,用药后为164.97±19.67(P<0.001);也有清除O_2~-的作用,用药前0.879±0.099nm,用药后0.691±0.184nm,清除率为20.07±22.47％(P<0.01);有提高红细胞免疫功能作用,红细胞免疫复合物花环率用药前11.40±2.42,用药后14.40±4.77(P<0.025);红细胞C_3(?)受体花环率用药前为18.69±3.88,用药后为23.33±6.77(P<0.01)。这些说明TP-5有明显的抗衰老作用,具有双重性,既可提高SOD活性,清除O_2-作用,又有提高免疫功能作用。所有注射人员既无局部反应,又无任何全身不适,是一种安全有效的免疫增强剂。     

Myasthenia gravis after allogeneic bone marrow transplantation: A case report and literature review

A 52-year-old man with acute myeloid leukemia underwent allogeneic hematopoietic stem cell transplantation and developed extensive chronic graft-versus-host disease and myasthenia gravis (MG), which became involved with oculobulbar and proximal upper and lower limb weakness in 677 days. In the literature, we identified 24 cases where MG developed after allo-SCT. Graft-versus-host disease development and male recipients of female donors might be prone to the development of posttransplant MG (odds ratio, 3.75).     

Binding of Hepatitis B Virus Pre-S1 Domain-Derived Synthetic Myristoylated Peptide to Scavenger Receptor Class B Type 1 with Differential Properties from Sodium Taurocholate Cotransporting Polypeptide

(1) Background: The myristoylated pre-S1 peptide (Myr47) synthesized to mimic pre-S1 domain (2-48) in large (L) surface protein of hepatitis B virus (HBV) prevents HBV infection to hepatocytes by binding to sodium taurocholate cotransporting polypeptide (NTCP). We previously demonstrated that yeast-derived nanoparticles containing L protein (bio-nanocapsules: BNCs) bind scavenger receptor class B type 1 (SR-B1). In this study, we examined the binding of Mry47 to SR-B1. (2) Methods: The binding and endocytosis of fluorescence-labeled Myr47 to SR-B1 (and its mutants)-green fluorescence protein (GFP) fusion proteins expressed in HEK293T cells were analyzed using flow cytometry and laser scanning microscopy (LSM). Various ligand-binding properties were compared between SR-B1-GFP and NTCP-GFP. Furthermore, the binding of biotinylated Myr47 to SR-B1-GFP expressed on HEK293T cells was analyzed via pull-down assays using a crosslinker and streptavidin-conjugated beads. (3) Conclusions: SR-B1 bound not only Myr47 but also its myristoylated analog and BNCs, but failed to bind a peptide without myristoylation. However, NTCP only bound Myr47 among the ligands tested. Studies using SR-B1 mutants suggested that both BNCs and Myr47 bind to similar sites of SR-B1. Crosslinking studies indicated that Myr47 binds preferentially SR-B1 multimer than monomer in both HEK293T and HepG2 cells.     

Treatment with B-Type Natriuretic Peptide for Chronic Decompensated Heart Failure: Insights Learned from the Follow-Up Serial Infusion of Nesiritide (FUSION) Trial

Several evidence-based treatment regimens are modestly effective in patients with moderately severe to severe heart failure, but truly effective therapies that improve symptoms, reduce hospitalizations, and extend meaningful survival do not exist for these patients. Only ventricular replacement therapy, with either heart transplantation or left ventricular assist devices, has been shown to significantly improve outcomes. Nesiritide, a recombinant B-type natriuretic peptide, is associated with significant reductions in filling pressure, with corresponding relief of symptoms, and diminished neurohormonal levels and has no inotropic effects and no evidence of proarrhythmia when given to patients with decompensated acute heart failure. Results of the Follow-Up Serial Infusion of Nesiritide (FUSION) trial suggest that a regimen incorporating nesiritide can be accomplished with a reasonable assurance of safety and tolerability; pre-study concerns regarding hypotension were not realized. A qualified look at outcomes data within FUSION I suggests that further study of this paradigm is reasonable, especially if the studied patient population includes patients with a low left ventricular ejection fraction and New York Heart Association (NYHA) class III disease with renal insufficiency, or patients with low left ventricular ejection fraction and NYHA class IV heart failure. Therefore, FUSION II, a double-blind, placebo-controlled trial, will randomly assign approximately 900 such patients to treatment with usual care plus nesiritide or usual care plus placebo and will use mortality/cardiorenal hospitalization as a composite end point. If positive data emerge from FUSION II that either confirm or strengthen the data in FUSION I, a new therapeutic option may be available for patients with chronic decompensated heart failure.     

ACEI联用ARB治疗慢性心力衰竭的疗效和安全性Meta分析

目的通过对慢性心力衰竭患者在接受相关治疗后的总体死亡率、住院情况、副反应进行比较,对血管紧张素转换酶抑制剂(ACEI)联用血管紧张素受体拮抗剂(ARB)治疗慢性心力衰竭的疗效和安全性进行评价。方法检索MEDLINE(1966-2008)、Cochrane图书馆(1980-2008)、中国生物医学文献数据库(1980-2008),万方数据库(1980-2008),纳入比较ACEI单用与ACEI和ARB合用治疗慢性心力衰竭的随机对照试验,对纳入研究的方法学进行评价,并应用RevMan5.0软件进行统计分析。结果共有7个随机对照研究入选,病例数总计5 853例,其中治疗组2 945例,对照组2 908例。Meta分析结果显示联合治疗组在全因死亡率和全因住院率方面与对照组相比无统计学意义。而在减少全因死亡与全因住院的联合终点事件、降低心衰住院事件、增加副反应方面有统计学意义,合并效应量分别为(RR:0.94;95%CI:0.90～0.98)、(RR:0.86;95%CI:0.79～0.93)、(RR:1.40;95%CI:1.24～1.58)。结论 ACEI基础上加用ARB与单用ACEI相比,可以使慢性心衰患者受益,但同时副反应的发生率有所增加。因此对于慢性心衰在ACEI基础上加用ARB应采取审慎的策略。合用则需要严密监测,防止副反应发生。     

Peptide-Based Technologies to Alter Adenoviral Vector Tropism: Ways and Means for Systemic Treatment of Cancer

Due to the fundamental progress in elucidating the molecular mechanisms of human diseases and the arrival of the post-genomic era, increasing numbers of therapeutic genes and cellular targets are available for gene therapy. Meanwhile, the most important challenge is to develop gene delivery vectors with high efficiency through target cell selectivity, in particular under in situ conditions. The most widely used vector system to transduce cells is based on adenovirus (Ad). Recent endeavors in the development of selective Ad vectors that target cells or tissues of interest and spare the alteration of all others have focused on the modification of the virus broad natural tropism. A popular way of Ad targeting is achieved by directing the vector towards distinct cellular receptors. Redirecting can be accomplished by linking custom-made peptides with specific affinity to cellular surface proteins via genetic integration, chemical coupling or bridging with dual-specific adapter molecules. Ideally, targeted vectors are incapable of entering cells via their native receptors. Such altered vectors offer new opportunities to delineate functional genomics in a natural environment and may enable efficient systemic therapeutic approaches. This review provides a summary of current state-of-the-art techniques to specifically target adenovirus-based gene delivery vectors.     

Tolerability Profiles of Leukotriene Receptor Antagonists and Long-Acting β2-Adrenoceptor Agonists in Combination with Inhaled Corticosteroids for Treatment of Asthma: A Review

Inhaled corticosteroids, long-acting β₂-adrenoceptor agonists, and leukotriene receptor antagonists are widely used for treatment of asthma. Inhaled corticosteroids are recommended as first-line therapy, whereas long-acting β₂-adrenoceptor agonists and leukotriene receptor antagonists are indicated as add-on therapy in patients not adequately controlled with corticosteroids alone. A number of studies have investigated the efficacy of combinations of these drugs in asthma, but several issues concerning the safety of these treatments are highly debated. This review provides a critical appraisal of the tolerability profiles of long-acting β₂-agonists and leukotriene receptor antagonists used in combination with inhaled corticosteroids for the treatment of asthma.     

Antibody Responses to the BNT162b2 mRNA Vaccine in Healthcare Workers in a General Hospital in Japan: A Comparison of Two Assays for Anti-spike Protein Immunoglobulin G

Objective This study assessed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody responses to the BNT162b2 mRNA vaccine in Japanese healthcare workers. Methods In this prospective cohort study, participants received two doses of the BNT162b2 mRNA vaccine on days 0 and 21 and provided blood for anti-SARS-CoV-2 antibody testing before the first vaccine and on days 21 and 35 after vaccination. Anti-spike protein immunoglobulin G (S-IgG) was measured using Abbott and Fujirebio chemiluminescent immunoassays. Patients One hundred healthcare workers (median age: 39 years old, interquartile range: 30-48 years old), including 6 who had been previously infected with SARS-CoV-2 and 3 individuals taking immunosuppressive drugs, participated in the study. Results The S-IgG antibody titers (AU/mL) measured using both the Abbott and Fujirebio assays increased significantly (p＜0.001) over time, both with a prevalence of 100% at 35 days after the first vaccination. The multivariate log-normal linear regression analysis indicated the effect of immunosuppressant medication using both the Abbott (p=0.013) and Fujirebio (p=0.039) assays on S-IgG levels after complete vaccination. Pearson''s correlation coefficient between the Abbott and Fujirebio S-IgG results in all 300 samples collected before and after vaccination and 50 positive controls from patients with coronavirus disease 2019 were 0.963 [95% confidence interval (CI): 0.954-0.970, p＜0.001] and 0.909 (95% CI: 0.845-0.948, p＜0.001), respectively. Conclusion The BNT162b2 mRNA vaccine was effective at increasing S-IgG levels in Japanese immunocompetent healthcare workers. The Fujirebio S-IgG assay showed high diagnostic accuracy, using the Abbott S-IgG assay as the reference test.