Die Myasthenia Gravis (MG) ist ein Prototyp einer Antikörper-vermittelte Autoimmunerkrankung. Die Autoantikörper richten sich hauptsächlich gegen den Acetylcholinrezeptor (AChR). Welche Bedeutung TH17-Zellen für die Pathogenese der MG haben, konnte bisher noch nie direkt gezeigt werden. Mithilfe des Tiermodells Experimentelle Autoimmune Myasthenia Gravis (EAMG) sollte die Rolle der TH17-Zellen im Rahmen dieser Arbeit analysiert werden. Eine signifikante Anzahl tAChR-spezifischer CD4+ T-Zellen, die IL17 exprimieren, konnte nach der Immunisierung mit torpedo AChR in CFA in Wildtyp-Mäusen (WT) beobachtet werden. Die IL17ko Mäuse entwickelten weniger oder keine EAMG Symptome, obwohl weder die Frequenz tAChR-spezifischer CD4+ T-Zellen, die IL2, IFNgamma oder IL21 sezernierten noch der prozentuale Anteil der FoxP3+ Treg-Zellen einen Unterschied aufwiesen. Im Gegensatz dazu waren die Level pathogener anti-muriner AChR Antikörper statistisch geringer in IL17ko Mäusen, während bei anti-tAChR Antikörpertitern kein Unterschied festzustellen war. Ähnliche Resultate erbrachten TCRbeta/delta ko Mäuse rekonstituiert mit entweder WT oder IL17ko CD4+ T-Zellen. Die Depletion von Treg-Zellen mithilfe von DEREG Mäusen in der frühen Erkrankungsphase zeigte keine signifikanten Unterschiede bezüglich der analysierten Parameter. Zusammenfassend lässt sich hier festhalten, dass die Frequenz und Differenzierung Antigen-spezifischer CD4+ T-Zellen sowie der Antikörpertiter gegen den tAChR nicht durch die IL17-Defizienz im EAMG Modell beeinflusst wird. Auch hat eine frühe Treg-Zell-Depletion keinen Einfluß auf die Erkrankungsstärke. Allerdings scheint das Durchbrechen der B-Zell Toleranz, das zur Produktion von pathogenen Anti-mAChR-spezifischen Antikörpern und somit zu einer Induktion der Erkrankung führt, abhängig von IL17-produzierenden CD4+ T-Zellen zu sein. Der Einsatz von Anti-IL17-Antikörpern könnte insofern auch für die MG eine Therapieoption darstellen. / Myasthenia gravis (MG) is an antibody-mediated autoimmune disease. The autoantibodies are directed against the acetylcholine receptor (AChR). The importance TH17 cells have for MG pathogenesis has never been directly demonstrated. Therefore, the analysis of TH17 cells in the Experimental Autoimmune Myasthenia Gravis (EAMG) animal model was the aim of this work. Here, it is shown that in wildtype mice (WT) significant numbers of IL17-producing tAChR-specific CD4+ T cells could be observed after immunization with torpedo AChR in CFA. IL17ko mice developed less or no EAMG symptoms, although frequencies of tAChR-specific CD4+T cells secreting IL2, IFNgamma or IL21 as well as percentage of FoxP3+ Treg cells were similar. In contrast, pathogenic anti-murine AChR antibody levels were significantly lower in IL17ko mice, while anti-tAChR antibody levels were equal. Similar results were obtained by the reconstitution of TCR beta/delta ko mice with CD4+ T cells of either WT or IL17ko origin. For the depletion of Treg cells using DEREG mice in the initial phase of the disease no significant differences could be detected in terms of the analyzed parameters. In summary, this thesis demonstrates, that frequencies and differentiation of antigen specific CD4+ T cells as well as the level of anti-tAChR specific antibody titers are not affected by IL17-deficiency in the EAMG model. Likewise, an early Treg cell depletion seems to have no impact on disease severity. However, breaking of B cell tolerance resulting in pathogenic anti-murine AChR specific antibodies and subsequent disease induction, seems to be dependent on IL17 producing CD4+ T cells. In this respect, the application of anti-IL17 antibodies could also become a MG therapy option.

Die vorliegende Arbeit dient der Entwicklung und Evaluierung eines neuen operativen Zugangsweges zur Durchführung einer kompletten Thymektomie (Thx). Die erste klinische Umsetzung erfolgte 1994. Der thorakoskopische Zugang für die Thx wurde an der Chirurgischen Klinik der Charité nach den Prinzipien der "Good clinical practice" zur Einführung eines neuen operativen Verfahrens entwickelt. Eine retrospektive Kohortenstudie bestimmte den internen Standard der erreichbaren Ergebnisse einer Thx in konventioneller Operationstechnik bei MG. Die Daten des eigenen Krankengutes an der Charité waren mit den Literaturangaben übereinstimmend und somit repräsentativ für die Zielstellung eines neuen Operationsverfahrens. Die komplexe Evaluation des neuen operativen Zuganges der thorakoskopischen Thx (tThx) umfaßte neben dem Nachweis der Durchführbarkeit der tThx eine experimentelle anatomische Demonstration der adäquaten Radikalität. Es konnte gezeigt werden, daß eine unilaterale linksseitige thorakoskopische Operationstechnik mit 3 Trokaren im Vergleich zu einer rechtsseitigen 3-Trokar-Technik besser eine komplette Thx realisieren kann. Es folgte die Ausarbeitung einer detaillierten operativen Technik der tThx für den klinischen Einsatz, die den individuell verschiedenen anatomischen Gegebenheiten Rechnung trägt und beschrieben wird. Nach ermutigenden ersten klinischen Ergebnissen wurden dann die Resultate der prospektiven klinischen Untersuchung des Verfahrens an 60 konsekutiven Patienten erstmals nach den Empfehlungen für klinische Forschung der Task Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America standardisiert dargestellt. Die Hypothese der geringeren Beeinträchtigung und schnelleren Erholung der Atemfunktion nach tThx wurde in einem prospektiven Vergleich der tThx mit der am meisten akzeptierten und weitesten verbreiteten Operationstechnik der Thx untersucht und bewiesen. Schließlich wurden die Ergebnisse der funktionellen Besserung der MG nach tThx, Thx durch mediane Sternotomie oder Thx durch anterolaterale Thorakotomie in einer Matched-pair-Studie verglichen. Obwohl technisch anspruchsvoll, ließen sich vergleichsweise adäquate Resultate bei objektiven und subjektiven patientenbezogenen Vorteilen für die tThx nachweisen. Ein Studiendesign mit höherem Evidenzgrad erscheint unizentrisch aus ethischen und epidemiologischen Gründen sowie bezogen auf die Pathogenese der MG gegenwärtig für diese Fragestellung schwer erreichbar. In der Zusammenfassung kann die tThx das in der Einleitung beschriebene Dilemma der Suche nach dem optimalen operativen Verfahren zur Thx lösen, indem eine minimale Invasivität, die nicht weiter reduziert werden kann, durch einen optimalen Zugang über 3 Trokare erreicht wird. Dies führt zur Möglichkeit einer radikalen Thx durch die weite Exposition des vorderen Mediastinums. Die tThx sollte bevorzugt werden, da sie adäquate Raten der Verbesserung der MG mit einer minimal-invasiven Operationstechnik erreicht. Die umfassende Untersuchung dieser Technik sollte fortgesetzt werden. / The aim of the present work was to develop and evaluate a novel operation technique to perform a complete thymectomy (Thx). This new approach was first used in a clinical setting in 1994. The thoracoscopic approach for Thx was developed at the Humboldt University Medical School (Charité), Clinic of Surgery, Campus Mitte according to the principles of "good clinical practice" for the introduction of a new operation technique. The success of conventional Thx for MG was determined by a retrospective cohort study as an internal standard. The results of our own clinical series at the Charité corresponded with the data of large published series worldwide and, were thus representative for the aim of developing a new operation technique. Apart from the approval of feasibility, the complex evaluation of the new surgical approach comprised an experimental anatomical study to demonstrate adequate radicality. It could be shown that a unilateral left-sided thoracoscopic operation technique with only 3 trocars can better accomplish a complete Thx as compared to a right-sided 3-trocar-technique. The next step was the development of the detailed and standardized operation technique for the clinical application of thoracoscopic Thx (tThx) which considers the individually different anatomical circumstances and is described. After encouraging first results, the findings of the prospective clinical investigation of the procedure in the first 60 patients were presented, standardized according to the suggestions for clinical research of the Task Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America. The hypothesis of smaller impairment and faster recovery of pulmonary function after tThx was investigated and could be proved in a prospective comparison of tThx versus the most accepted and most common approach for Thx.Consequently, the results of functional improvement of MG after tThx, median sternotomy for Thx, and anterolateral thoracotomy for Thx were compared in a matched-pair study. Though technically demanding, tThx showed adequate results combined with objective and subjective patient-related advantages. For ethical and epidemiological reasons and due to the pathogenesis of MG a single-center study design with higher level of evidence seems difficult to achieve. In conclusion, tThx may solve the dilemma of the search for an optimal operation technique for Thx because minimal invasion is obtained by an optimal approach with only 3 trocars. This creates the possibility of radical Thx by wide exposure of the anterior mediastinum. The technique of tThx should be prefered because an adequate rate of improvement of MG is achieved by a minimally-invasive operation technique. The comprehensive investigation of this technique should be continued.

重症肌無力是由自身抗體在神經肌肉接頭特異性的結合乙酰膽鹼受體和肌肉特異性激酶引起的一種獲得性免疫性疾病。疾病的主要症狀是骨骼肌的軟弱無力和易疲勞性。這一症狀在運動後尤為顯著，休息後會有所緩解。重症肌無力在世界範圍的發病率是百萬分之三到三十。由於近年來患者的數量在不斷增加，重症肌無力引起了醫學界的廣泛關注。但是，目前的診斷和治療措施還不能完全滿足臨床病人的需要。在本課題研究中，我們希望運用代謝組學的手段建立一種新的更加有效可靠的方法用於重症肌無力的診斷。同時，我們希望在代謝物的水平上來闡釋強肌健力方（一種中藥復方）對重症肌無力的治療作用。 / 本研究所用樣本來自42個重症肌無力病人和16個健康志願者。樣本由廣州中醫藥大學第一附屬醫院於二零零七年到二零零八年收集所得。診斷後，病人每日口服一定劑量的強肌健力方接受治療，連續服藥兩個月。分別在服藥前和治療後對病人抽血採樣。進一步分離血清後，樣品進行質譜分析。多元統計學方法如主成分分析，正交偏最小二乘和正交偏最小二乘判別分析等用於質譜數據的分析。 / 通過和健康者比較分析，我們在重症肌無力病人的血液中找到142個顯著改變的離子。其中，14個離子得到鑒定，包括：γ-氨基丁酸，2-哌啶酸，鳥氨酸，5,8-十四碳二羧酸，精胺，己酰肉毒鹼，N-油酰基甘氨酸，鞘氨醇-1-磷酸，聯原膽酸，糞甾烷酸，植物鞘氨醇-1-磷酸，鵝去氧膽酸甘氨酸結合物，輔酶Q4和甘氨酸膽。基於以上142個離子建立的數學診斷模型在診斷重症肌無力時表現出很高的靈敏度和特異性，分別高達92.8%和83.3%。強肌健力方能夠逆轉由重症肌無力引起的特異性代謝變化，將病人體內被改變的代謝網絡恢復正常，特別是大部分的代謝標誌物在治療後都恢復到了相對正常水平，包括：γ-氨基丁酸，哌啶酸，鳥氨酸，5,8-十四碳二羧酸，精胺，己酰肉毒鹼，N-油酰甘氨酸，鞘氨醇-1-磷酸，聯原膽酸，輔酶Q4和甘氨酸膽。 / 本研究揭示了基於液質聯用的代謝組學方法適用於探索重症肌無力的代謝標誌物，並提供了一種可用於診斷重症肌無力的新方法。同時，本研究證實強肌健力方適用於重症肌無力的治療，且無明顯副作用。 / Myasthenia gravis (MG) is an acquired autoimmune disease caused by specific autoantibodies against acetylcholine receptors (AChRs) and muscle-specific kinase (MuSK) proteins at the neuromuscular junctions. The disease is characterized by weakness and fatigability of the voluntary muscles that gets worse with exertion and improves with rest. The global incidence rate of MG is about 3-30 cases per million per year. In recent years, the worldwide prevalence rate of MG is increasing as a result of increased awareness. However, current diagnostic measures and treatments are not conclusive and satisfactory for MG. In this study, a mass spectrometry-based metabolomic strategy was applied to develop a novel and reliable diagnostic measure for MG on the basis of metabolic analysis, and to explore the therapeutic effect of Qiangji Jianli Fang (QJF, a newly developed Chinese medicine formula) on MG at the metabolite level. / Total 42 MG patients (13 males and 29 females) and 16 volunteers (5 males and 11 females) were recruited at the First Affiliated Hospital of Guangzhou University of Chinese Medicine between March 2007 and March 2008. The patients took QJF once per day for 2 months. Peripheral blood from patients was collected at diagnosis and after 2-month treatment, respectively. Sera prepared from the blood samples were monitored by the liquid chromatography Fourier transform mass spectrometry (LC-FTMS). Mass spectral data were analyzed by multivariate statistical analyses, including principal component analysis (PCA), orthogonal partial least squares (OPLS), and orthogonal partial least squares discriminant analysis (OPLS-DA). / By comparing analysis with the healthy volunteers, 142 significantly changed ions from serum metabolic profile of MG patients were picked out as the potential biomarkers of MG. Among of them, 14 ions were temporarily identified. They were gamma-aminobutyric acid (GABA), pipecolic acid, ornithine, 5,8-tetradecadienoic acid, spermine, hexanoylcarnitine, N-oleoyl glycine, sphingosine-1-phosphate (S1P), bisnorcholic acid, coprocholic acid, phytosphingosine-1-P, chenodeoxycholylglycine, coenzyme Q4, and cholylglycine. The developed OPLS-DA diagnostic model based on the 142 special ions showed a high sensitivity (92.8%) and specificity (83.3%) in detecting MG. QJF showed a powerful action on MG by recovering the holistic serum metabolic profile from the disease level to the normal level. Especially, the levels of GABA, pipecolic acid, ornithine, 5,8-tetradecadienoic acid, spermine, hexanoylcarnitine, N-oleoyl glycine, S1P, bisnorcholic acid, coenzyme Q4, and cholylglycine in MG patients were regulated to a relatively normal level after QJF treatment. / My results first indicated that the LC-FTMS-based metabolomics was a useful tool in biomarkers exploration of MG, and it was potentially applicable as a new diagnostic approach for MG. Also, my results demonstrated that QJF was a good optional choice for the treatment of MG, with no reported side effects. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Lu, Yonghai. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 113-129). / Abstract also in Chinese. / Thesis committee --- p.i / Declaration --- p.ii / Abstract (in English) --- p.iii / Abstract (in Chinese) --- p.vi / Acknowledgements --- p.viii / Table of contents --- p.ix / Abbreviations --- p.xiv / List of Tables --- p.xviii / List of Figures --- p.xix / Chapter 1: Introduction --- p.1 / Chapter 1.1 --- Myasthenia gravis --- p.1 / Chapter 1.1.1 --- History --- p.1 / Chapter 1.1.2 --- Epidemiology --- p.2 / Chapter 1.1.3 --- Clinical features --- p.2 / Chapter 1.1.4 --- Clinical classification --- p.4 / Chapter 1.1.5 --- Pathophysiology --- p.5 / Chapter 1.1.6 --- Diagnosis --- p.9 / Chapter 1.1.6.1 --- Physical examination --- p.9 / Chapter 1.1.6.2 --- Blood test --- p.10 / Chapter 1.1.6.3 --- Electrodiagnostic test --- p.10 / Chapter 1.1.6.4 --- Edrophonium test --- p.11 / Chapter 1.1.6.5 --- Imaging --- p.11 / Chapter 1.1.6.6 --- Pulmonary function test --- p.11 / Chapter 1.1.7 --- Treatment --- p.12 / Chapter 1.1.7.1 --- Medication --- p.12 / Chapter 1.1.7.2 --- Thymectomy --- p.12 / Chapter 1.1.7.3 --- Plasmapheresis and intravenous immunoglobulin --- p.13 / Chapter 1.2 --- Qiangji Jianli Fang --- p.14 / Chapter 1.2.1 --- Huang qi --- p.15 / Chapter 1.2.2 --- Dang shen --- p.16 / Chapter 1.2.3 --- Bai shu --- p.16 / Chapter 1.2.4 --- Dang gui --- p.17 / Chapter 1.2.5 --- Sheng ma --- p.17 / Chapter 1.2.6 --- Chai hu --- p.18 / Chapter 1.2.7 --- Chen pi --- p.18 / Chapter 1.2.8 --- Gan cao --- p.19 / Chapter 1.3 --- Metabolomics --- p.19 / Chapter 1.3.1 --- What’s metabolomics? --- p.20 / Chapter 1.3.1.1 --- Metabolites --- p.20 / Chapter 1.3.1.2 --- Metabolome --- p.21 / Chapter 1.3.1.3 --- Two terms: metabolomics and metabonomics --- p.21 / Chapter 1.3.2 --- How metabolomics works? --- p.22 / Chapter 1.3.2.1 --- Sample preparation --- p.22 / Chapter 1.3.2.1.1 --- Quenching --- p.23 / Chapter 1.3.2.1.2 --- Separating metabolites --- p.24 / Chapter 1.3.2.1.3 --- Sample concentration --- p.24 / Chapter 1.3.2.2 --- Analytical technologies (Sample analysis) --- p.25 / Chapter 1.3.2.3 --- Data analysis --- p.26 / Chapter 1.3.2.4 --- Database --- p.28 / Chapter 1.3.3 --- Why metabolomics? --- p.29 / Chapter 1.3.4 --- Metabolomics for human diseases --- p.30 / Chapter 1.3.5 --- Metabolomics for Traditional Chinese Medicine --- p.32 / Chapter 1.4 --- Objectives and significances of the present study --- p.34 / Chapter Chapter 2 --- Metabolic biomarkers of myasthenia gravis --- p.36 / Chapter 2.1 --- Introduction --- p.36 / Chapter 2.2 --- Materials and methods --- p.40 / Chapter 2.2.1 --- Chemicals --- p.40 / Chapter 2.2.2 --- Patients --- p.40 / Chapter 2.2.3 --- Volunteers --- p.42 / Chapter 2.2.4 --- Blood collection --- p.43 / Chapter 2.2.5 --- QC samples --- p.43 / Chapter 2.2.6 --- Sample processing --- p.43 / Chapter 2.2.7 --- Liquid chromatography-mass spectrometry --- p.44 / Chapter 2.2.8 --- Data analysis --- p.45 / Chapter 2.2.9 --- Metabolite identification --- p.45 / Chapter 2.3 --- Results --- p.46 / Chapter 2.3.1 --- Method validation --- p.46 / Chapter 2.3.2 --- An overall comparative analysis between 28 patients and 10 volunteers --- p.48 / Chapter 2.3.3 --- Classification of MG --- p.53 / Chapter 2.3.4 --- Comparative analysis of the metabolic changes in early- and late-stage MG patients respectively --- p.54 / Chapter 2.3.5 --- Biomarker identification --- p.56 / Chapter 2.4 --- Discussion --- p.58 / Chapter 2.5 --- Conclusion --- p.63 / Chapter Chapter 3 --- A novel diagnostic approach for myasthenia gravis --- p.64 / Chapter 3.1 --- Introduction --- p.64 / Chapter 3.2 --- Materials and methods --- p.68 / Chapter 3.2.1 --- Chemicals --- p.68 / Chapter 3.2.2 --- Patients and Volunteers --- p.69 / Chapter 3.2.2.1 --- Training set for establishment of diagnostic model --- p.69 / Chapter 3.2.2.2 --- Test set for evaluation of diagnostic model --- p.69 / Chapter 3.2.3 --- QC samples --- p.70 / Chapter 3.2.4 --- Sample processing --- p.71 / Chapter 3.2.5 --- Chromatography --- p.71 / Chapter 3.2.6 --- Mass spectrometry --- p.72 / Chapter 3.2.7 --- Data analysis --- p.72 / Chapter 3.3 --- Results --- p.72 / Chapter 3.3.1 --- Method validation --- p.73 / Chapter 3.3.2 --- Alterations in serum metabolic profile under MG --- p.74 / Chapter 3.3.3 --- Prediction of MG based on biomarkers --- p.74 / Chapter 3.3.4 --- Establishment of diagnostic model on the basis of metabolic profile --- p.77 / Chapter 3.3.5 --- Prediction of MG with diagnostic model --- p.79 / Chapter 3.4 --- Discussion --- p.80 / Chapter 3.5 --- Conclusion --- p.83 / Chapter Chapter 4 --- Qiangji Jianli Fang treatment for myasthenia gravis --- p.84 / Chapter 4.1 --- Introduction --- p.84 / Chapter 4.2 --- Materials and methods --- p.88 / Chapter 4.2.1 --- Chemicals --- p.88 / Chapter 4.2.2 --- Herbs --- p.88 / Chapter 4.2.3 --- Participants --- p.88 / Chapter 4.2.4 --- QC samples --- p.90 / Chapter 4.2.5 --- Sample processing --- p.90 / Chapter 4.2.6 --- Liquid chromatography-mass spectrometry --- p.90 / Chapter 4.2.7 --- Data analysis --- p.91 / Chapter 4.3 --- Results --- p.91 / Chapter 4.3.1 --- Method validation --- p.91 / Chapter 4.3.2 --- Symptomatic examination after QJF treatment --- p.92 / Chapter 4.3.3 --- Holistic metabolic responses to QJF treatment --- p.93 / Chapter 4.3.4 --- MG biomarkers changes after QJF treatment --- p.95 / Chapter 4.3.5 --- Drug-related biomarkers of QJF --- p.97 / Chapter 4.4 --- Discussion --- p.100 / Chapter 4.5 --- Conclusion --- p.103 / Chapter Chapter 5 --- Conclusions --- p.104 / Chapter Chapter 6 --- Perspectives --- p.107 / Chapter 6.1 --- Experimental autoimmune myasthenia gravis model --- p.107 / Chapter 6.2 --- Chemical composition of Qiangji Jianli Fang --- p.111 / References --- p.113 / Appendices --- p.130

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-05-24T20:16:20Z No. of bitstreams: 1 Ezequiel Fernandes de Oliveira.pdf: 6004865 bytes, checksum: 1533cb1828601a79b30eb9ae6ce24420 (MD5) / Made available in DSpace on 2016-05-24T20:16:20Z (GMT). No. of bitstreams: 1 Ezequiel Fernandes de Oliveira.pdf: 6004865 bytes, checksum: 1533cb1828601a79b30eb9ae6ce24420 (MD5) Previous issue date: 2014-12-01 / Introduction: Autoimmune myasthenia gravis is an chronic disease inflammatory characterized by progressive weakness of the skeletal muscles due to a change in the synapses between the nerves and muscle fibers. The manifestations of the respiratory system are generally attributed to the weakness of the diaphragm and other accessory muscles of ventilation leading to breathlessness. Among these manifestations, we highlight the onset of sleep-disordered breathing (SDB) due to weakening of the muscles of the oropharynx. Objectives: To verify the lung function, respiratory muscle strength, and physiological variables during sleep in patients with myasthenia gravis clinically stable. Methods: This is a prospective cross-sectional descriptive study, following a study protocol previously published. Patients were recruited consecutively from the Setor de Investigação de Doenças Neuromusculares of the Universidade Federal de São Paulo in accordance with the eligibility criteria, and referred to the Sleep Laboratory of Universidade Nove de Julho, São Paulo (Brazil). Results: The study included 18 patients The mean age of 42,66±10,91 (15 women). Regarding lung function only two patients had a restrictive ventilatory pattern. The maximum ventilatory pressures observed were considerably reduced in most patients when compared to reference values. Regarding sleep, highlight observe a significant decrease in oxyhemoglobin saturation, reduced REM sleep time, increased stage NREM3, considerable increase of apnea and hypopnea per hour and a high risk for obstructive sleep apnea. Discussion: Data on sleep-related disorders in patients with Autoimmune myasthenia gravis in the literature are scarce and inconclusive, with few studies using basal nocturnal polysomnography. Conclusion: Clinically stable patients with autoimmune myasthenia gravis have a high prevalence of sleep respiratory disorders and a significant reduction in maximal inspiratory and expiratory pressures with reduced quality of life. / Introdução: A Miastenia gravis auto imune adquirida é uma doença crônica, inflamatória, caracterizada pela fraqueza progressiva dos músculos esqueléticos, devido a uma alteração na junção sináptica entre os nervos e as fibras musculares. As manifestações no sistema respiratório geralmente são atribuídas à fraqueza do músculo diafragma e demais músculos acessórios da ventilação levando à dispneia. Dentre estas manifestações, destacamos o surgimento dos transtornos respiratórios do sono (DRS) devido ao enfraquecimento da musculatura da região orofaríngea. Objetivos Verificar a função pulmonar, a força muscular ventilatória e as variáveis fisiológicas do sono em pacientes com Miastenia gravis. Métodos: Trata-se de um estudo transversal descritivo prospectivo. Os pacientes foram recrutados de forma consecutiva do Setor de Investigação de Doenças Neuromusculares da Universidade Federal de São Paulo de acordo com os critérios de elegibilidade, seguindo um protocolo padronizado e encaminhados ao Laboratório do Sono da Universidade Nove de Julho, São Paulo (Brasil). Resultados: Participaram deste estudo 18 pacientes com média de idade de 42,66±10,91 (15 mulheres). Em relação a função pulmonar apenas dois pacientes apresentaram um padrão ventilatório restritivo. As pressões ventilatórias máximas observadas foram consideravelmente reduzidas na maioria dos pacientes quando comparados a normalidade. Em relação ao sono, observamos uma queda significativa da saturação da oxihemoglobina, reduzido tempo de sono REM, aumento do estágio NREM3, considerável aumento do índice de apneia e hipopneia. Discussão Os dados sobre transtornos relacionados ao sono e qualidade do sono em Miastenia gravis na literatura são escassos e baseados nos resultados inconclusivos, com poucos estudos realizados por meio de polissonografia basal noturna. Conclusão: Pacientes com MG auto imune adquirida apresentam uma alta prevalência de distúrbios respiratórios sono e uma significativa redução das pressões máximas inspiratórias e expiratórias com consequente comprometimento da qualidade de vida.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-05-25T18:25:43Z No. of bitstreams: 1 Sergio Roberto Nacif.pdf: 1795162 bytes, checksum: 7b6d72682614593467c7e6265c34a637 (MD5) / Made available in DSpace on 2016-05-25T18:25:43Z (GMT). No. of bitstreams: 1 Sergio Roberto Nacif.pdf: 1795162 bytes, checksum: 7b6d72682614593467c7e6265c34a637 (MD5) Previous issue date: 2014-12-16 / Introduction: Obstructive sleep apnea (OSA) is a breathing disorder characterized by the collapse of the upper airway and has significant prevalence in the general population and specifically in neuromuscular diseases. Objective: To determine the effectiveness of the negative expiratory pressure (NEP) test as a screening to the OSA in myasthenia gravis patients. Method: The study included 15 patients (12 women) from the Setor de Investigação de Doenças Neuromusculares and Associação Brasileira de Miastenia Grave (ABRAMI), which underwent overnight standard polysomnography (PSG), spirometry, manovacuometer and NEP test. Results: The mean age was 41.46 ± 11.32 years, mean weight of 78.4 ± 15.28 kg and the mean body mass index was 29.34 ± 5,3kg / m2. The physiological variables of sleep observed in PSG draw attention to the oxygen saturation nadir, for the sleep latency and total sleep rapid eyes movement (REM) time, apnea-hypopnea index (AHI) and snoring time. The mean AHI was 17.5 ± 21.7, being most obstructive origin events. Regarding the Berlin Questionnaire, only one of the fifteen patients evaluated presented low risk for OSA. Regarding the Epworth Sleepiness Scale, we observed that six patients (40%) did not presented excessive daytime sleepiness, three (20%) had mild drowsiness, five individuos presented moderate (33.4%) and only one patient (6.6%) was classified with severe excessive daytime sleepiness with a score of 22 to a maximum of 24 points. The statistics analyses verify the existence of correlation between anthropometric variables, physiological PSG variables, Epworth Sleepiness Scale and Berlin questionnaire show higher values for body mass index (BMI), waist circumference and AHI. Conclusion: We can conclude that patients with MG have lower values of ventilatory maximum pressures associated with normal lung function. They also feature a considerable number of sleep disordered breathing associated with fall oxyhemoglobin saturation and reduced REM sleep, with consequent presence of excessive daytime sleepiness and high risk for OSA. Although we did not observe a correlation between the PNE test with AHI, our data show that patients with moderate-severe OSA have greatly reduced V0,2% (<20%). / Introdução: A apneia obstrutiva do sono (AOS) é um distúrbio respiratório caracterizado pelo colapso da via aérea superior com importante prevalência na população em geral e especificamente nas doenças neuromusculares. Objetivo: Verificar a eficácia do teste da pressão negativa expiratória (PNE) como proposta de screening para AOS em pacientes com Miastenia gravis. Método: Participaram deste estudo 15 pacientes (12 mulheres) provenientes do Setor de Investigação de Doenças Neuromusculares e Associação Brasileira de Miastenia Grave, os quais foram submetidos à polissonografia basal noturna (PSG), espirometria, manovacuometria e teste da PNE. Resultados: A média de idade foi de 41,46 ± 11,32 anos, peso médio de 78,4 ± 15,28 kg e o índice de massa corpórea médio foi de 29,34 ± 5,3kg/m2. As variáveis fisiológicas do sono observadas na PSG chamam a atenção para a saturação periférica mínima de oxigênio, para a latência e tempo total de sono REM, IAH e tempo de ronco. O IAH médio foi de 17,5 ± 21,7 sendo a maioria eventos obstrutivos. A análise estatística para verificação da existência de correlação entre as variáveis PNE e IAH mostrou um R de -0,5 com um valor de p= 0,06 e, para PNE/IDO/h um R -0,45 com um valor de p= 0,08. Quando correlacionamos os valores obtidos no teste de PNE com pressões de -6 e -10cm/H2O observamos uma excelente correlação de R = 0,825 com um p = 0,0000. Em relação ao questionário clínico de Berlim, dos quinze pacientes avaliados apenas um apresentou baixo risco para AOS. As análises estatísticas para verificação da existência de correlação entre as variáveis antropométricas, fisiológicas da PSG, escala de Epworth e questionário de Berlim mostram valores significativos apenas para o IMC, circunferência abdominal e IAH. Conclusão: Pacientes com MG apresentam redução das pressões máximas ventilatórias associado a função pulmonar normal. Também apresentam um considerável IAH associado a queda da saturação da oxihemoglobina e redução do sono REM, com consequente presença de sonolência excessiva diurna e alto risco para AOS. Embora não tenha sido observado uma correlação entre o teste do PNE com o IAH, nossos dados mostram que pacientes com Myasthenia gravis com AOS moderada-grave apresentam grande redução do V0,2%.

Myasthenia gravis (MG) is an autoimmune disease whose name means "grave muscular weakness". MG is a rare disease affecting only 200-400 persons per million and the characteristic symptoms include muscle weakness, particularly in highly active voluntary muscles. MG affects the neuromuscular junction in an antibody-mediated manner, resulting in impaired nerve-muscle cell communication in affected individuals. Specifically, two main proteins are targeted: nicotinic acetylcholine receptors (ACh receptors) and a muscle-specific tyrosine kinase (MuSK). Previous studies have discovered the mechanism of MG pathogenesis but the exact mechanisms which cause the failure to maintain self-tolerance have not been discovered. Based on current knowledge of MG, this paper will explore potential causes of the disease and provide numerous hypotheses directed at future research opportunities.

Η βαριά μυασθένεια (Myasthenia gravis-MG) είναι μία επίκτητη αυτοάνοση δυσλειτουργία στη νευρομυϊκή σύναψη που προκαλείται από αντισώματα που κατευθύνονται ειδικά έναντι του μυϊκού τύπου νικοτινικού υποδοχέας της ακετυλοχολίνης (AChR) που βρίσκεται στα μυϊκά κύτταρα. Τα αντισώματα μειώνουν τον αριθμό των λειτουργικών υποδοχέων με αποτέλεσμα οι μυς να μην μπορούν να ανταποκριθούν στα μηνύματα που λαμβάνουν από τα νευρικά κύτταρα. Η κλινική εικόνα χαρακτηρίζεται από χρόνια μυϊκή αδυναμία. Η σωστή διάγνωση από τον θεράποντα ιατρό και ο σχεδιασμός της κατάλληλης θεραπείας, αποτελούν τη βάση για την αντιμετώπιση μιας νόσου και την ενίσχυση της ποιότητας ζωής. Η μη συμμόρφωση όμως του ασθενούς, στη θεραπεία που του προτείνεται, αποτελεί αντικείμενο έρευνας τις τελευταίες δεκαετίες. Η μη συμμόρφωση έχει ως αποτέλεσμα την αύξηση του κόστους περίθαλψης, προκαλώντας μεγάλες κοινωνικοοικονομικές συνέπειες. Στην παρούσα έρευνα δημιουργήθηκε ένα ερωτηματολόγιο και διατέθηκε σε δείγμα 30 μυασθενών. Μέσω της συλλογής των απαντήσεων έγινε μια προσπάθεια να προσδιοριστούν οι παράγοντες που οδηγούν σε μη συμμόρφωση. Διερευνάται η στάση ζωής που κρατά ο ασθενής, η εικόνα που έχει ο ίδιος για τον εαυτό του και ο ρόλος που έχουν το στενό περιβάλλον, ο ιατρός και ο φαρμακοποιός του, ούτως ώστε, ο ασθενής να είναι συνεπής στην αγωγή που του έχει προταθεί. / Myasthenia Gravis (MG) is an acquired autoimmune neuromuscular junction disorder caused by antibodies directed specifically toward the skeletal muscle nicotinic acetylcholine receptor (AChR). The antibodies decrease the number of functional AChRs which compromises neuromuscular transmission. The clinical course of MG is characterized by muscular weakness and fatigability. The right diagnosis of the attending physician and the design of appropriate therapy are determinant for the treatment of a disease and enhance quality of life. Non-compliance of the patient (also adherence or capacitance) to the treatment that his doctor suggested, however, is being investigated in the last decades. Non-compliance increase health care costs and evoke considerable socioeconomic consequences. Worldwide, non-compliance is a major obstacle to the effective delivery of health care. In the present dissertation a questionnaire is created and distributed to a sample of 30 MG patients. Through the collection of responses we attempted to analyze the factors that lead to non-compliance. The objective was to identify how the patient sees himself. It was also made an effort to clarify the roles of doctor, pharmacist and family in patient compliance when long term medication is needed.

Οι υποδοχείς της ακετυλοχολίνης (AChRs) είναι διαμεμβρανικές πρωτεΐνες ενεργοποιούμενες με τη δέσμευση της ακετυλοχολίνης (ACh). Με κριτήρια, όπως η χημική συγγένεια που εμφανίζουν για σηματοδότικά μόρια και οι φαρμακολογικές τους ιδιότητες, ταξινομούνται στην ομάδα των νικοτινικών AChRs και στην ομάδα των μουσκαρινικών AChRs. Οι νικοτινικού τύπου υποδοχείς δημιουργούνται από τη συναρμογή πέντε ομόλογων υπομονάδων και υποδιαιρούνται σε μυϊκού τύπου, ευρισκόμενους κυρίως στους σκελετικούς μύες των σπονδυλωτών και σε νευρικού τύπου, απαντώμενους κατά κύριο λόγο στο κεντρικό και περιφερικό νευρικό σύστημα. Οι AChRs σχετίζονται με σειρά παθολογικών καταστάσεων, μεταξύ των οποίων και η βαρειά μυασθένεια (Myasthenia Gravis-MG). Η μυασθένεια χαρακτηρίζεται από χρόνια μυϊκή αδυναμία, προκαλούμενη από τη δράση αντισωμάτων υψηλής συγγένειας έναντι του μυϊκού τύπου AChR. Με απώτερο σκοπό τη διερεύνηση της παθογονικότητας των αυτοαντισωμάτων έναντι μεμονωμένων υπομονάδων του AChR, προχωρήσαμε στην παραγωγή ανασυνδυασμένων πολυπεπτιδικών τμημάτων των υπομονάδων στο ζυμομύκητα Pichia pastoris. Τα πολυπεπτίδια χρησιμοποιήθηκαν στην παρασκευή χρωματογραφικών-ανοσοπροσροφητικών στηλών, που εφαρμόστηκαν ακολούθως για την απομόνωση αυτοαντισωμάτων από επιλεγμένους ορούς μυασθενικών ατόμων. Η παθογόνος δράση των απομονωμένων αυτοαντισωμάτων ελέχθηκε μέσω της προκαλούμενης απώλειας υποδοχέων (αντιγονική τροποποίηση-antigenic modulation) σε κυτταρική σειρά (ΤΕ671) που εκφράζει τον AChR και μέσω της χορήγησή τους σε πειραματόζωα και τον έλεγχο της εμφάνισης χαρακτηριστικών συμπτωμάτων της νόσου. Εκτενής συγκριτική μελέτη μεταξύ τεσσάρων επιλεγμένων ορών και αντισωμάτων έναντι της α1 και της β υπομονάδας του υποδοχέα, που απομονώθηκαν από τους συγκεκριμένους ορούς, έδειξαν πως τα αυτοαντισώματα ευθύνονται για δράση των ορών στους υποδοχείς των κυττάρων. Τόσο οι ολικοί οροί όσο και τα απομονωμένα-καθαρά αυτοαντισώματα έναντι των υπομονάδων α1 και β, προκάλεσαν δοσοεξαρτώμενη απώλεια υποδοχέων στα κύτταρα και μάλιστα τα αντι-α1 αντισώματα εμφανίστηκαν περίπου τέσσερις φορές δραστικότερα από τα αντι-β. Η ικανότητα των μερικώς απαλλαγμένων από αυτοαντισώματα έναντι του υποδοχέα ορών να προκαλούν απώλεια υποδοχέων στα κύτταρα, φάνηκε να ποικίλλει και να συσχετίζεται άμεσα με το είδος των αντισωμάτων που έχουν παραμείνει στον ορό, υποστηρίζοντας μια διαφορετικότητα στην παθογονικότητα των επιμέρους αντισωμικών κλασμάτων. Με σκοπό την επιβεβαίωση και ενίσχυση των αποτελεσμάτων που προκύπτουν από τα in vitro πειράματα, ακολούθησαν προσπάθειες για την πρόκληση πειραματικής μυασθένειας σε πειραματόζωα, με τη χορήγηση ορών μυασθενικών και καθαρών αυτοαντισωμάτων έναντι διαφόρων υπομονάδων του υποδοχέα. Η χορήγηση σε ζώα τόσο του ολικού ορού, όσο και καθαρών αντισωμάτων έναντι της α1-υπομονάδας του υποδοχέα, προκάλεσαν σημαντική απώλεια βάρους και εμφάνιση έντονων συμπτωμάτων μυϊκής αδυναμίας, μέχρι και το θάνατο. Πειραματόζωα που ενέθηκαν με το κλάσμα του ορού από το οποίο έχουν απομακρυνθεί τα συγκεκριμένα αντισώματα εμφάνισαν πολύ ηπιότερα ή και καθόλου συμπτώματα, ενώ απουσία συμπτωμάτων καταγράφηκε και κατά τη χορήγηση ορού που περιείχε αποκλειστικά αντισώματα έναντι της β υπομονάδας, αλλά και απομονωμένων αντι-β αντισωμάτων. Η παρούσα μελέτη υπέδειξε τα αυτοαντισώματα έναντι του AChR ως τον μοναδικό παθογόνο παράγοντα στον ορό μυασθενικών ατόμων, συμβάλλοντας στην κατανόηση της παθοφυσιολογίας της νόσου. Επιβεβαίωσε την υπεροχή των αντι-α1 αντισωμάτων έναντι των αντι-β, ως πρός την παθογονικότητά τους, τόσο in vitro όσο και in vivo, με την επιφύλαξη βέβαια που επιβάλλει ο μικρός αριθμός δειγμάτων που μελετήθηκαν. Η δυνατότητα λήψης αντισωμάτων που στοχεύουν σε συγκεκριμένη υπομονάδα μπορεί να συμβάλλει στη λεπτομερή μελέτη της δραστικότητας του κλάσματος και να οδηγήσει στη συσχέτισή του με την εμφάνιση συγκεκριμένων συμπτωμάτων της νόσου. / Acetylcholine receptors (AChRs) are integral membrane proteins that respond to the binding of acetylcholine (ACh), which is synthesized, stored and finally released by cholinergic neurons. Like other transmembrane receptors, AChRs have been classified according to either their pharmacological properties or their relative affinities for various molecules, and can therefore be further divided into: i) nicotinic AChRs, which are particularly responsive to nicotine and ii) muscarinic AChRs, which are particularly responsive to muscarine. AChRs are involved in myasthenia gravis (MG) and many other physiological disorders, mainly affecting the central and peripheral nervous system. In MG, autoantibodies are directed against the nicotinic AChR at the neuromuscular junction. The disease is characterized by various symptoms, including muscle weakness and fatigability, due to defective neuromuscular transmission. To obtain an insight into the role of the various anti-AChR antibody specificities in MG, we isolated and studied the in vitro and in vivo activity of autoantibodies targeting individual AChR subunits. Using recombinant proteins corresponding to extracellular domains (ECDs) of individual AChR subunits as immunoadsorbents; we isolated autoantibodies which specifically bind to these subunits. We then used the well established TE671 human muscle cell line to examine the in vitro functions of subunit-specific autoantibody populations through their ability to induce nAChR antigenic modulation. Isolated subunit-specific autoantibodies were also used to determine their capacity to passively transfer experimental MG into lab animals. Our results clearly demonstrated that autoantibodies against the α1 or β subunit can cause AChR loss via antigenic modulation in a dose-dependent manner, the anti-α1 autoantibodies being much more effective than the anti-β autoantibodies. Furthermore, we showed that the autoantibody-depleted sera were much less effective, or were completely inactive, at causing AChR loss. In in vivo experiments, the administration of MG sera derivatives to lab animals showed that sera enriched in anti-α1 autoantibodies, as well as the corresponding pure anti-α1 autoantibodies from two individuals, are efficient in inducing MG like symptoms to the animals. A single serum contained almost 100% anti-β antibodies and the corresponding purified antibodies did not cause any clinical MG symptoms. The depleted fraction of MG sera tested, induced mild symptoms or no symptoms were observed, and this is in agreement with the in vitro results, strongly suggesting that the anti-AChR autoantibodies in MG sera and mainly the anti-α1 specificities are the sole pathogenic factor in anti-AChR antibody-seropositive MG.

Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 4 uppsatser.

Η βαριά μυασθένεια (Myasthenia Gravis, MG) είναι μια αυτοάνοση νόσος η οποία χαρακτηρίζεται από διαταραχή στη νευροδιαβίβαση στο επίπεδο της νευρομυϊκής σύναψης. Η διάγνωση της MG βασίζεται στην κλινική συμπτωματολογία η οποία συνεπικουρείται από φαρμακολογικές, ηλεκτροφυσιολογικές και απεικονιστικές δοκιμασίες και επιβεβαιώνεται συνήθως από την ορολογική ανίχνευση αυτοαντισωμάτων έναντι συστατικών της νευρομυϊκής σύναψης. Οι σύγχρονες διαγνωστικές δοκιμασίες είναι συνήθως ικανές προς ανίχνευση της παρουσίας αντισωμάτων στο 85-90% περίπου των μυασθενών με γενικευμένη MG και στο 50% περίπου των ασθενών με οφθαλμική MG. Το κενό αυτό στη διάγνωση της MG δημιουργεί ένα σημαντικό πρόβλημα στις περισσότερες περιπτώσεις που ελέγχονται επειδή ένα αρνητικό αποτέλεσμα (το οποίο είναι το συχνότερο αποτέλεσμα στη συνήθη εργαστηριακή διάγνωση της MG) αφήνει μία ασάφεια σχετικά με την ύπαρξη MG. Πράγματι, ακόμη και ένας πολύ χαμηλός τίτλος θα μπορούσε να είναι επαρκής για να εξηγήσει την παρουσία της μυασθένειας, δεδομένου ότι δεν έχει διαπιστωθεί σημαντική συσχέτιση μεταξύ του τίτλου των αντισωμάτων και της σοβαρότητας της νόσου στον πληθυσμό των ασθενών. Ως εκ τούτου, υπάρχει αυξανόμενη ανάγκη για την ανάπτυξη ιδιαίτερα ευαίσθητων διαγνωστικών μεθόδων, για την αναμφισβήτητη απόδειξη της νόσου. Η πλέον ευαίσθητη διαγνωστική δοκιμασία είναι η ραδιολογική ανοσοκαθίζηση (Radioimmunoprecipitation assay, RIPA) και ο πλέον σημαντικός περιοριστικός παράγων για την ανίχνευση χαμηλού τίτλου αντισωμάτων, είναι η αδυναμία χρήσης μεγάλου όγκου ορού (μέγιστο είναι ~5-20 μl), η οποία θα καθιστούσε αναγκαία την επακόλουθη χρήση υψηλού όγκου αντί-ορού και η οποία θα οδηγούσε σε υπερβολικά μεγάλα άνοσο-ιζήματα, τα οποία με τη σειρά τους συνδέονται με απαράδεκτα επίπεδα μη ειδικού θορύβου υπόβαθρου. Με την ανάπτυξη στην παρούσα μελέτη της RIPA δύο-σταδίων ξεπεράσθηκαν σε μεγάλο βαθμό τα προβλήματα αυτά. Η δοκιμασία αυτή βασίζεται στην ακινητοποίηση του αντιγόνου-στόχου σε ένα αδιάλυτο υπόστρωμα, ακολουθούμενη από την επώαση με μεγάλους όγκους (π.χ. 0,1-1ml) του προς εξέταση ορού και την επακόλουθη απελευθέρωση των προσδεμένων αντισωμάτων με μικρό όγκο διαλύματος χαμηλού pH, τα οποία στη συνέχεια ανιχνεύονται και τιτλοδοτούνται με απλή RIPA με τη χρήση 125I-σημασμένων αντιγόνων. Δηλαδή χρησιμοποιήθηκε η αρχή του καθαρισμού με χρωματογραφία συγγένειας με όχι αυστηρό αλλά με απλό και εύκολο τρόπο, προκειμένου να εμπλουτισθεί ο ορός σε μεγάλο βαθμό στα ειδικά για το αντιγόνο αντισώματα πριν από τον προσδιορισμό και την τιτλοποίηση τους με τις συνήθεις ανοσολογικές δοκιμασίες. Έγινε προσπάθεια ανάπτυξης της προσέγγισης αυτής για την ανίχνευση αντισωμάτων έναντι του AChR και έναντι της MuSK. Έγιναν πολλές προσπάθειες για την εφαρμογή της για την ανίχνευση αντί-AChR αυτοαντισωμάτων. Σημειώθηκε μεγάλη πρόοδος, αλλά απαιτούνται επιπρόσθετες βελτιώσεις για την εφαρμογή της στην διάγνωση ρουτίνας. Για την ανίχνευση των αντί-MuSK αυτοαντισωμάτων με την προσέγγιση αυτή επετεύχθη σημαντικότερη βελτίωση. Η παρούσα συστηματική προσέγγιση απεδείχθη τουλάχιστον 20-50 φορές περισσότερο ευαίσθητη από την κλασική RIPA. Όλοι οι οροί οι οποίοι είχαν χαρακτηρισθεί προηγουμένως ως θετικοί ή αρνητικοί με την κλασική RIPA βρέθηκαν όπως αναμενόταν επίσης θετικοί ή αρνητικοί αντίστοιχα. Επιπλέον όμως μερικοί εκ των ορών οι οποίοι στο παρελθόν είχαν χαρακτηρισθεί ως αμφίβολοι βρέθηκαν σαφώς θετικοί, ή μερικοί άλλοι οι οποίοι είχαν χαρακτηρισθεί ως αρνητικοί αλλά παρουσίαζαν τίτλους ελαφρά υψηλότερους του μηδενός, αλλά όχι στατιστικά σημαντικούς ώστε να αξιολογηθούν ως υψηλότεροι του υπόβαθρου, βρέθηκαν θετικοί, ενώ άλλοι εξακολουθούν να παραμένουν αρνητικοί. Η δοκιμασία που αναπτύξαμε ήταν αρχικά περισσότερο επίπονη από ότι η κλασική RIPA, αλλά με την ανάπτυξη σημαντικών βελτιώσεων, η διαδικασία αυτή έχει απλουστευθεί ώστε να είναι δυνατός ο ταυτόχρονος έλεγχος μεγάλου όγκου (0,1-1 ml) πολλαπλών δειγμάτων ορών και έχει καταστεί δυνατή η χρήση της στην καθημερινή διάγνωση. Η βελτιωμένη αυτή μέθοδος εφαρμόζεται σήμερα για την ανίχνευση αντί-MuSK αντισωμάτων και αποσκοπεί στην ανίχνευση πολύ μικρών ποσοτήτων αυτοαντισωμάτων στον ορό των μυασθενικών οι οποίοι έχουν χαρακτηρισθεί ως οροαρνητικοί ή αμφίβολοι. / Myasthenia Gravis (MG), is an autoimmune disease, characterized by impairment in neurotransmission at the neuromuscular junction level. The diagnosis of MG is based on clinical symptomatology, assisted by pharmacological, electrophysiological and imaging tests and is usually confirmed by serological detection of autoantibodies to components of the neuromuscular junction. The available diagnostic tests are usually able to detect the presence of antibodies in 85-90% of myasthenic patients with generalized MG and 50% of patients with ocular MG. This gap in the diagnosis of MG creates a major problem in most cases during diagnosis because a negative result (which is the most common result in ordinary laboratory diagnosis of MG) leaves an ambiguity regarding the existence of MG. Even a very low titer of specific antibodies, would be sufficient to explain the presence of myasthenia, since there has been no significant correlation between the titer of antibodies and the severity of disease among patients. Therefore, there is increasing need for the development of highly sensitive diagnostic methods for the unambiguous confirmation of the disease. The most sensitive diagnostic test so far, is the radiological immunoprecipitation assay (Radioimmunoprecipitation, RIPA) and the most important limiting factor for detecting low antibody titer, is the inability to use large volumes of serum (maximum is ~ 5- 20 ml), which would require the subsequent use of high-volume of anti-serum, which will result in excessively large immuno-sediments, which in turn are associated with unacceptable levels of nonspecific background values. With the development of two-step RIPA assay in this study we have largely overcome these problems. This test is based on the immobilization of target antigen to an insoluble substrate, followed by incubation with large volume (eg 0,1-1ml) of the test serum and release of bound antibodies with small volume of low pH solution, which are then detected and titrated with simple RIPA using 125I-labeled antigens. We used the principle of enrichment of serum to a large extent in antigen-specific antibodies by affinity purification with no strict but simple and easy way, before the final identification and titration of specific antibodies with standard immunoassays. We attempted the development of this approach in order to detect antibodies against AChR and MuSK. Numerous efforts have been made to implement this method in order to detect AChR autoantibodies, but although there was substantial progress, additional improvements are required for its application in routine diagnosis. With this approach we achieved significant improvement for detection of anti- MuSK autoantibodies. This systematic approach was proved to be at least 20-50 times more sensitive than classical RIPA. All sera which were previously classified as positive or negative with standard RIPA were also positive and negative respectively, as expected. In addition some of the sera which were previously classified as ambiguous were clearly positive and some others who were classified as negative but were slightly higher than zero, but not statistically significant so as to assess them as higher than the background, were positive, while others still remain negative. This newly developed test was originally more laborious than the classical RIPA, but with the development of significant improvements, the process has been simplified and allows the simultaneous testing of large volumes (0,1-1 ml) of multiple serum samples and its use has been made possible in everyday diagnosis. This improved method is currently applied to detect anti-MuSK antibodies and is designed to detect very small amounts of autoantibodies in the serum of myasthenic patients who are classified as seronegative or ambiguous.