EuroMyasthenia Newsletter 18 Final

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NEWSLETTER N18, September 2012

EuroMyasthenia(www.euromyasthenia.org)

Report on the12th International Conference on MG and Related

DisordersNew York, NY, 21-23 May, 2012

(underl)The 12thInternational Conference on Myasthenia gravis and related disorders, which was organizedby the New York Academy of Sciences and the Myasthenia Gravis Foundation of America, washeld between the 21stand 23rdof May 2012, in New York. The aim of the conference was to dis-seminate recent advances made in the field and to underline the main issues with respect to thepathophysiology of the disease, diagnosis, treatment and patient care. The programme included 58oral and 101 poster presentations. Continue...

Summary

Welcome

Report on the12th

International Con-ference on MG andRelated Disorders

Interview with a

pioneer of modernMG research, Da-niel Drachman

New findings in MG

research (LRP4,MuSK and so on)

MG community

(EuMGA Assembly,training in Bergenand drawing inPatras)

Forthcoming Mee-

tings

Dear colleagues and friends,

You will find in this newsletter a complete report of the international meeting on MG thatwas held in New-York in May 2012, and an interview with Pr Drachman, a very experiencedclinician and researcher in MG. You will also learn more about anti-LRP4 antibodies, theEuropean association of MG patients, and the clinical team headed by N. Gilhus in Norway.

As you may know, our proposal to the Public Health European Community program was notfunded by the EU. The main reason is that the EU that has previously supported the EuroMGnetwork does not wish to support an existing network. So we have to find other sources offinancial support, maybe via the rare disease associations. I want to thank you all for yourcontribution and involvement. The dynamism of MG research could also be appreciated bythe recent funding of a clinical research project by two French clinician teams (Pr T. Shar-shar and B. Eymard) with the efficient help of M. Cuvelier on the effect of exercise on MG

symptoms. The aim of this project is to answer a question that many patients ask: is exer-cise beneficial or detrimental to MG? This project will start soon and will last 3 years.

Another important event occurred recently in Paris, it is the creation of a biotherapy centerInstitut des biotherapies (Genethon, I-Stem, Atlantic Gene Therapies, Myology Institute)that aims to use cell and gene therapies for rare diseases. Among the cell therapies, the useof stem cells, either from adults, newborn, fetal or embryonic stem cells are diverse possi-bilities to treat not degenerative diseases but also autoimmune diseases since many ofthese stem cells have also immunoregulatory properties. The importance of pluripotentstem cells (iPS) that are adult cells reprogrammed to become embryonic cells usable for anydifferentiation program deserves to be mentioned since Pr J.B Gurdon (UK) and S. Yamanaka(Japan) have very recently obtained the Nobel Price for this major discovery.

The regular meeting of the FIGHT-MG consortium was held on 9thand 10thJuly in Paris and

two members of organizations of patients participated. A brief report dedicated to patientshas been published. For those of you, who are interested to get it, please contact DahliaFasquel ([email protected]). An international meeting on MG similar to theone organized in Paris in 2009 is under discussion, and will be probably organized at theend of 2013. You will get more details soon.

Thanks again to Socrates and his team for this exciting newsletter. Socrates mentioned thathe retired officially from the University of Patras, but he is far from giving up the world ofMG since he is still working at Hellenic Pasteur institute and has just created a company forMG diagnosis. Thank you so much Socrates for your dynamism and continuous involvementand we wish you many more years in the Institute and in this new company!With my best wishesSonia Berrih-Aknin, Coordinator

To get info on the project please contact: Mline Cuvelier ([email protected])


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Newsletter EuroMyasthenia, September 2012

12th International Conference on MG and Related Disorders- continued

The conference kicked-off with a session on the structure andfunction of the neuromuscular junction (NMJ). The session in-cluded talks from leaders in the field such as M. Takamori, H. Ni-shimune and Y. Yamanashi, who analysed key molecular mecha-

nisms for NMJ function, and its organization both at the presynap-tic and muscle membrane with emphasis on the role of Dok7 as acentral player in NMJ development. Additionally, the importanceof the main immunogenic region (MIR) of the AChR 1 subunit as apotent immunogen and possible disease implications were dis-cussed by J. Lindstrom.

The next session included talks dealing with recent advances inthe field of autoimmunity. J-F. Bach gave an overview of the aeti-ology of autoimmune diseases, explaining their dependence onboth genetic and environmental factors (such as viral and otherinfections, urbanisation, etc), both of which are often difficult toidentify. Following, S. Berrih-Aknin and M. Meriggioli elaborated

on the deregulation of certain populations of T cells in MG patients, resulting in the defective im-munoregulation observed in MG. Furthermore, M. De Baets presented evidence supporting thepathogenic role of the IgG4 population of anti-MuSK autoantibodies, as well as recent findings onbortezomib, a proteosome inhibitor shown to target patient derived plasma cells, indicating itmight be beneficial in the treatment of MG (bortezomib is already approved for the treatment ofmultiple myeloma and in transplantation).

The third session dealt with issues concerning methods of diag-nosis and clinical developments. An overview of the incidence,prevalent features and differences in treatments responses of thevarious types of MG was presented by J. Massey. Then, A. Vincentdiscussed the application of cell based assays for the diagnosis of

MG, especially for patients not detected by other methods, whileA. Evoli presented the results from her extensive experience in themanagement of MG patients, highlighting rituximab as a poten-tially beneficial agent for MG treatment in refractory MuSK-MGcases. Furthermore, data presented by D. Drachman underlinedthe importance of genetic factors in the pathogenesis of MG andintroduced the attempts of his team to identify such factors usingstate-of-the-art DNA analysis techniques.

The last session of the day involved a number of talks discussingthe different scales for quantitative measurement of MG symp-toms, such as the MG composite, or the MG Activities of Daily Liv-ing scale (MG-ADL) which was developed to integrate the status of

symptoms and patient activities (S. Muppidi, M. Rose and T. Burns). Measuring the Quality of Life(QoL) is also very important as it measures the diseaseimpact from the patients point of view, a vital aspectfor every clinical trial. Overall, it became clear that thechoice of the scales and methods to be used dependshighly on the purpose and aims of the particular study.In addition, F. Baggi presented current efforts to de-velop patient registries and explained their importancein understanding the pathology and responses to treat-ment of the disease. At the end of the first day, a seriesof short talks was given, presenting recent data on anovel gene identified responsible for causing congenital

myasthenic syndrome (K. Belaya), on the mechanism ofaction of the drug bortezomib (A. Gomez) and on thenewly identified MG autoantigen, LRP4 (A. Melms).

and aims to the top(view from the venue)

Top Conference!!

Science in NYAS starts from thefloor...


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The second day started with the plenary talk of M.Dalakas, presenting some of the agents that are cur-rently tried against other autoimmune diseases (e.g.psoriasis),which could be proved useful in the man-

agement of MG, such as immunoregulatory agentsand therapeutic monoclonal antibodies. This wasfollowed by a session on recent advances madebased on animal models of the disease. The patho-genic mechanisms in MuSK-MG, the role of comple-ment regulatory proteins in the destruction of theNMJ, and the possibility of using siRNA to silence theC2 complement component as a therapeutic ap-proach, were explored (L. Kusner, D. Richman and P.Christadoss). Furthermore, the central role of theTreg cells and possibly the autoimmune regulator(AIRE) protein in MG pathogenesis was investigated

in EAMG models by M. Souroujon.

The following session included presentations on updates of our knowledge for currentlyavailable agents for MG treatment as well as promising future therapeutic strategies. Astudy by the team of V. Bril comparing plasma exchange to intravenous Ig (IVIG) in patients withmoderate to severe MG showed that there is no significant difference in the efficiency and toler-ance of the two treatments. A clinical trial on mycophenolate mofetil indicated that it might in-

deed be more promising in MG treatment than initialtrials had suggested (Z. Siddiqi). Furthermore, an ongo-ing trial called EPITOME focussing on the efficacy ofprednisone for the treatment of ocular MG was pre-sented by M. Benatar. The next talk by J. Howard Jr.showed the results from a phase II trial of Eculizumab,

a monoclonal antibody directed against the C5 comple-ment component and aiming at preventing C5 comple-ment activation; it appears that treatment caused aclinically meaningful improvement, while being welltolerated by the patients. S. Tzartos presented the re-cent advances made by his team in Athens in the effortto develop an antigen-specific therapy for MG, involv-ing the extracorporeal removal of the autoantibodies.The rest of the evenings talks involved clinical studieson Methotrexate, the antisense AChRE inhibitor EN101

(also known as BL-7040), and rituximab, some of which are still ongoing (J. Sussman, R. Barohnand R. Tandan). Finally, D. Sanders talk covered the issues that need to be addressed while de-signing clinical trials for MG, which have to overcome a number of difficulties mainly due to theheterogeneity of MG patients, the rarityof the disease and the duration of treat-ment/observation required to arrive atmeaningful conclusions.

The day was brought to a close witha series of short talks presenting datafrom epitope mapping studies in MuSK-MG (M. Huijbers), studies on AIREknockout mice highlighting the under-lying link with the Treg cells in autoim-mune diseases (R. Aricha), and a novel

calcium channel agonist (GV-359-58)that could be useful in the managementof the Lambert-Eaton myasthenic syn-drome (LEMS) (S. Meriney).


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During the final day of the meeting, the first ses-sion was dedicated to the congenital myasthenicsyndromes (CMS). A number of mutations have

been identified so far responsible for the develop-ment of CMS, especially in the AChR subunit genes(in ~50% of cases), the collagen Q gene (in ~15%)which is involved in AChE function, and DOK-7 (in10-20%), a protein required for MuSK activation. Forthe latter, J. Palace presented evidence suggestingthe majority of patients can benefit from treatmentwith ephedrine or salbutamol for several months,with the effects being more pronounced when treat-ment is initiated at a younger age, while the teamof D. Beeson is pursuing the identification of thepathogenic mutations in the DOK7 gene.

LEMS (Lambert-Eaton myasthenic syndrome), an autoimmune disorder where the presynap-tic component of the NMJ is targeted, was the focus of the next session. The talk by P. Maddisonhighlighted the benefits from treatment with 3,4-diaminopyridine (3,4-DAP), although additionaltreatment in the form of immunosuppressants may be required in case of severe symptoms. Ad-ditionally, M. Titulaer analysed the relationship between LEMS and small cell lung carcinoma(SCLC), since 50% of LEMS patients also have SCLC, and introduced the DELTA-P score (Dutch-English LEMS Tumour Association Prediction), which can be proved useful in the validation ofSCLC in LEMS patients, as detection of SCLC itself can be difficult.

The final session of the conference was dedicated to the long standing issue of thymectomyas a treatment option for MG. The well known clinical trial for thymectomy in non-thymomatous patients (MGTX trial) was presented (G. Wolfe, G. Cutter, H. Kaminski, A. Marx andG. Minisman). The inclusion criteria and difficulties encountered while recruiting patients wereanalysed; so far 120 patients have been enrolled the initial goal being 150 and it is antici-pated that in the remaining months (the trial ends in November 2012) enough patients will havebeen enrolled to provide with an answer. During the MGTX trial, thymectomy specimens as wellas serum are collected for analysis. This is being used for the examination of both thymic tissuepathology and the discovery of MG biomarkers, which are very useful especially for clinical trials.D. Meyer and P. Giulianotti gave an update on current surgical practises with special emphasison the robotic approach using the da Vinci system, which allows for minimal invasion thus re-ducing complications and patient recovery.

The meetings final scientific presentations were a seriesof selected short talks discussing the search for novelantigenic targets for MG autoantibodies (J. Cossins), the

pathogenic role of the IgG4 anti-MuSK autoantibodies (J.Plomp), insights on structural determinants for receptorrecognition by agonists (S. Sine), the details of the de-cline in the safety factor and susceptibility of the ex-traocular muscles to MG (A. Serra), and the immuno-modulatory role of the mesenchymal stem cells, whichcould be exploited in the development of therapeuticapproaches in MG (E. Ben-Ami).

This brought the three day conference to an end. Overall, it was a very interesting and stimulat-ing meeting covering most aspects of myasthenia gravis and related disorders, with talks on allthe latest discoveries.

Kostas Lazaridis


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Interviews with specialists and patients

Continuing from the previous issues, we are presenting one more interview from a person involvedwith Myasthenia Gravis. In this issue, we are very pleased to host Professor Daniel Drachman fromBaltimore, MD, USA.

ProfessorDaniel Drachman

Q. 1973 marked the new era in our understanding of MG and you played a major role in this.Can you give us in short the story of your 1973 findings and your view of the consequencesof those findings?In order to understand how synapses are maintained, I had long been interested in the "trophic"interactions between motor nerves and skeletal muscles. My research focused on the key role ofneurotransmission, and I had shown that interference with cholinergic transmission by a wide vari-ety of pharmacologic methods (curare, the depolarizing blocking agents succinylcholine and de-

camethonium, hemicholinium, and famously botulinum toxin) closely reproduced the effects ofactual denervation. Myasthenia was a natural human disease in which to evaluate the role of neuro-transmission, and the highly specific reagent -bungarotoxin had just been discovered by Lee andChang in Taiwan. Doug Fambrough, then at the Carnegie Institution in Baltimore, had been work-ing with radiolabeled -BuTx, and was happy to collaborate with me on the study of MG. In thosedays, IRBs were nowhere near as restrictive as they are now, and I easily got permission to do mo-tor point (ie- end plate containing) muscle biopsies on subjects with MG and control subjects. Ourfinding of reduced post-synaptic ACh receptors was immediate and dramatic, and we published theseminal paper describing it in Science. At first, there was a good deal of skepticism, but the dis-covery was so definitive, and demonstrably reproduced the features of MG (as we subsequentlyshowed in experimental rats), that it gave a clear picture of the true nature of the defect in MG. Ina sense, this finding moved the understanding of the site of the defect in MG just about 200 Ang-

strom units, from the pre-synaptic membrane (where the defect was previously thought to occur)to the post-synaptic membrane --- actually a remarkable difference. Knowledge of the specific de-fect of ACh receptors opened up the field to study the pathogenesis of the disease, ie- how AChRsare lost.

Dr. Daniel Drachman received his medical degree from New York University School of Medicine. He thencompleted an internship in internal medicine at Beth Israel Hospital in Boston Harvard Service and a resi-dency in neurology at the Harvard Neurological Unit at Boston City Hospital. He went on to become a clini-cal and research associate at the National Institutes of Health.

He is Professor of Neurology at Johns Hopkins School of Medicine since 1974. He founded the Neuromus-cular Center within the Department of Neurology which is now named after him. Dr. Drachman was namedthe inaugural W.W. Smith Charitable Trust Professor of Neuroimmunology in May 2003.He is well known as an outstanding teacher, mentor, and lecturer, and has trained a large number of resi-dents and fellows in neuromuscular diseases. Many of his former trainees are now among the leaders in thefield throughout the U.S. and the world.

Dr. Drachman's interests include neuromuscular diseases, immunology, and basic aspects of nerve-muscle interactions and development. He is widely considered to be a leading authority on myasthenia gra-vis, and other neuromuscular disease that involve auto-immunity.

In 1973 two papers in Science by two research groups opened the modern era in MG research, diagnosis

and treatment; the one was by Jim Patrick and Jon Lindstrom (left in bottom picture of page 4; his interviewwill follow in the next newsletter), the other was leaded by Daniel Drachman (right in top picture of page 4).Dr. Drachman proposes here a new name for myasthenia gravis, myasthenia "laevis"


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Interview with D. Drachmancontinue

Q. Since then, have you seen satisfactory progress/improvement on the understanding andtreatment of the disease? Did you have different expectations?

Myasthenia is the one neurological disease that virtually all medical students understand, since itis so straightforward and conceptually satisfying. It has served as a model for understanding andtreatment of many other autoimmune diseases. Our development of the "passive transfer" modelproved the role of antibodies in the pathogenesis of MG. Immunotherapeutic strategies havechanged the prognosis of MG from "gravis" in the past to excellent in most cases at present, ifthey are properly treated. A serious problem is the fact that many MG patients are not treatedadequately, since the principles of immunotherapy are not well understood by physicians whodon't see many cases, in spite of articles and lectures on the subject. The discoveries of antibod-ies against different components of the neuromuscular junction (EG- MuSK and LRP4) is not sur-prising, but is an important advance.

Q. What are your labs additional main discoveries related to MG?a) As above, the reduction of AChRs at neuromuscular junctions.

b) The demonstration that pharmacological reduction of available AChRs in experimental rats ac-curately reproduces the typical features of MG.c) The experimental strategy of passive transfer of IgG from MG patients produces MG in mice,with reduced AChRs, reduced miniature endplate potentials, and weakness in recipient mice.These studies also demonstrated the important role of complement in the pathogenesis of MG(which is rarely quoted).d) Mechanisms of reduction of AChRs by IgG from MG patients: (1) Accelerated endocytosis anddegradation of AChRs; We demonstratedaccelerated loss of AChRs both in muscle cultures and invivo. (2) Blockade of AChRs in culture by IgG from some MG patients. Both of these are in currentuse in commercial clinical assays.e) Demonstration that the clinical severity of MG corresponds to the accelerated degradation plusblockade of AChRs in culture. Undoubtedly the effect of complement binding by the antibodiesalso influences the severity of MG.

f) The presence of AChRs on myoid (muscle-like) cells in thymus, and its relevance to the role ofthe thymus in the pathogenesis of MG. We searched for, but did not find evidence for a viral trig-ger of autoimmunity in the myasthenic thymus. However, we did find that "granzyme B", a keyenzyme known to trigger autoimmune responses to proteins it attacks, is produced by leukocytesand macrophages in the myasthenic thymus, and likely plays an omportant pathogenic role.g) Demonstration that IgG from "antibody negative" patients binds to muscle cells in culture, indi-cating the presence of clinically relevant antibodies in addition to those directed against AChR.This presaged the discovery of anti-MuSK and possibly anti- Lrp4 antibodies.h) Clinical treatment of MG with (1) gradually increasing doses of prednisone; (2) cyclosporine,studies in rats with EAMG; (3) Use of mycophenolate in patients with MG.i) Treatment of refractory MG with high dose cyclophosphamide (both in experimental animals,and in humans).

j) Current studies on the genetic features that contribute to susceptibility to MG (Genome-wideassociation study).k) An experimental method for specific immunotherapy of MG by genetically engineered dendriticcells (published last month in J. Neuroimmunology).As a Clinical Neurologist, I founded the Neuromuscular Unit at Johns Hopkins School of Medicine(Now called the "Daniel B. Drachman Neuromuscular Unit") which is the largest division of the JHUNeurology Department. I have trained many Neuromuscular Clinicians who have set up their ownunits throughout the country. I run the Neuromuscular Clinic at Johns Hopkins, as well as seeingpatients with other (ie- general) Neurological diseases.

Q. Are you satisfied with the support (financial or other) MG research is getting in yourcountry? Any suggestions?The success of treatment of MG has had a paradoxical negative effect on the funding of research

in this area. MG is widely considered to be "solved", although there is much more yet to belearned. In the US, a major source for MG funding has been the Muscular Dystrophy Association,but their financial problems, and diversion of efforts to genetic therapy for dystrophies, has re-duced their interest in MG. Fortunately, the MGFA now has greatly improved leadership, and iscurrently helping in funding worthwhile projects.


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Interview with D. Drachmancontinue

Q. In what ways do you think we can improve research on MG?

Many different disciplines impinge on the pathogenesis and treatment of MG. Understanding andtreating MG involves electrophysiology, knowledge of synaptic transmission, immunology, immu-notherapy, genetics, and clinical skills. The immune system is incredibly complex, in many wayssimilar to the nervous system. It is comprised of a wide variety of highly complex cells with greatplasticity; it is able to integrate signals in order to respond; it can learn; it can recognize trillionsof different stimuli. The more we learn about the immunology of MG, and about the genetic in-fluences on immunology, the more we will be able to control the disease. Even more important,since MG is an iconic disease, what is learned from MG can be applied to other autoimmune dis-eases.

Q. Where do you see MG research/treatment/understanding 10 years from now?Present treatment of MG is still empirical: Different patients respond to different methods of im-munosuppression. Undoubtedly, there are underlying principles on which treatment can be

based, and they may depend on the genetic makeup of the patient, or other aspects of the indi-vidual's immune responses. When we understand more about the genetics and the immunologyof MG, we should be able to predict which methods to use in each patient. Current treatment ofMG depends on overall suppression of the immune system. We have shown in an experimentalanimal model that it is possible to develop highly specific methods to turn off only the autoim-mune response against AChR. I hope that this and similar methods will be used in the treatmentof human patients with MG within 10 years.

Q. What are the most frequent problem(s) you face in the clinical management of your MGpatients? Can you provide any suggestions for overcoming these problems?Although MG is not really a rare disease, many Neurologists have little experience in its manage-ment, and in treatment of autoimmune diseases in general. Accordingly, we often see patientswho are considered "refractory", but whose problem is the way they have been treated. A com-mon error is to try to "wean" the patients off immunosuppressive medication after they have im-proved, which frequently results in recurrence of the symptoms, often in more severe degree.The cost of some of the medications is another problem. Following patients requires not onlyknowledge and skill, but a lot of time, and is often lifelong. Education of Neurologists is graduallyhelping to improve the outlook of MG patients.

Q. Which diagnostic tools do you use in addition to clinical examination? Do you considerthem to be reliable?Of course the antibody assays are of great importance in the diagnosis and management of MGpatients. In patients without demonstrable autoantibodies electrodiagnostic methods are oftenhelpful (repetitive nerve stimulation and single fiber EMG). Clinical responses to immunosuppres-sive or immunomodulatory agents (for example IVIg) may be helpful. I use a special dynamome-

ter to quantify the patient's responses and follow their responses to therapy over time.

Q. What would you say to an MG patient about the future of their disease?The future and indeed the present is bright for nearly all patients with MG. Treatment in ex-pert hands is so helpful that I have suggested facetiously that the name should be changed frommyasthenia "gravis "( ie- serious or grave) to myasthenia "laevis" ie- not so serious.

Q. Any more comments suggestions?Myasthenia has been an extraordinary subject, and has led us along fascinating pathways ofphysiology, histology, ultrastructure, pharmacology, immunology, clinical science, and now ge-netics. The study of MG is a "gift that keeps on giving".



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MG News for Doctors, Researchers and Patients

Neuromuscular Junction Players and Mechanisms

What is the real function of LRP4 in neuromuscular junction?As described in the previous newsletter, the low density lipoprotein receptor-related protein 4(LRP4) is a novel autoantigen in MG. Several research groups are now trying to study LRP4 func-tions as well as to develop new assays to be used routinely in the diagnosis of LRP4-MG. anygroups of EuroMyasthenia are oriented in this direction, working in order to create a special net-work for the epidemiological and phenotypic analysis of this MG form.

LRP4 is one of the main components of the neuromuscular junction (NMJ). It is a single trans-membrane protein that possesses a large extracellular domain to which various ligands bind, withthe most important probably being agrin. Specifically, the LRP4-Agrin complex activates MuSK, acrucial step in the process of AChR clustering.

To further investigate how LRP4 regulates the formation of the NMJ, Wu et al. (Neuron 75, 94.2012), generated and characterized mutant mice that lacked LRP4 expression specifically in mus-

cle cells and/or motoneurons and showed:Mice lacking only muscle LRP4 survived and formed primitive NMJs. However, their AChR clus-ters had a different distribution on muscle fibers, smaller size and elongated morphology.

Mice lacking only motoneuron LRP4 showed no differences compared to normal mice. This in-dicates that LRP4 in motoneurons is not required for NMJ formation or function when it is avail-able in muscle fibers.

However, mice, lacking both muscle and motoneuron LRP4, could not form AChR clusters anddid not live long after birth.

Taken together these results suggest that muscle LRP4 is necessary and sufficient for the for-mation of mature AChR clusters and NMJ, but in its absence, motoneuron LRP4 is capable of mak-ing primitive NMJ.

But how can LRP4 in motoneurons regulate postsynaptic differentiation in the absence of mus-cle LRP4? It is known that proteins of the LDLR family (in which LRP4 belongs) can undergo prote-

olytic cleavage (by metalloproteases) at their extracellular domain, to release soluble ecto-domains. The authors hypothesized that LRP4 in motoneurons undergoes extracellular cleavageto release ecto-LRP4, which can interact with agrin, to stimulate AChR clustering in the absence ofmuscle LRP4; indeed they provided support to this hypothesis in a series of in vitroexperiments.Another observation, which confirmed their hypothesis, is that inhibition of metalloproteases inmuscle LRP4-deficient mice caused a reduction in AChR clustering. These results shed light ontothe role of LRP4 in the development of the NMJ.

Neuregulin-1 potentiates agrin-induced AChR clustering through MuSK-phosphorylationAnother actor in the interplay Agrin-LRP4-MuSK-AChR seems to be neuregulin-1. Neuregulin-1 is a

growth factor acting through ErbB kinase receptors to increase the transcription of synaptic genessuch as those for some AChR subunits. Ngoet al.(J. Cell Sci. 125, 1531. 2012) using cul-tured myotubes showed that AChR clusterformation is a multi-stage reversible processinvolving several signals includingneuregulin-1. They studied the role ofneuregulin-1 on AChR clustering through theMuSK-LRP4 complex and showed thatneuregulin-1 may act as a regulator of agrin-induced AChR clustering. After injectingneuregulin-1 into mouse embryos they ob-served an increase in the size of the develop-

ing AChR clusters. They showed thatneuregulin-1 acts by potentiating phosphory-lation of MuSK which in turn induces AChRclustering.


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MG Antibodies and their Effects

MuSK MG: IgG4 autoantibodies cause severe neuromuscular junction dys-function in miceOne of the main differences between MuSK- and AChR-MG is on their autoantibody subclass; inMuSK-MG most of the autoantibodies belong to the IgG4 subclass, while in AChR-MG to the IgG1or IgG3. Moreover, in MuSK-MG the anti-MuSK IgG4 titres in patients sera correlate well with dis-ease severity. This was unexpected because IgG1 and IgG3 can bind to and activate complement,whereas IgG4 do not. Therefore, it was not so far clear whether the anti-MuSK IgG4 antibodies arethe pathogenic factor of MuSK-MG.

Klooster et al. (Brain 135; 1081. 2012) made in vivoand ex vivoexperiments in order to inves-tigate separately the action of the IgG4 and IgG1-3 subclasses in mice. Firstly, they purified theIgG4 and IgG1-3 fractions from plasmapheresis fluid of patients with MuSK-MG and from healthyindividuals. Then, they incubated muscles cells with purified IgGs and -bungarotoxin (which

binds to the AChRs) and they saw that IgG4 co-localized with the AChRs, suggesting that the IgG4selectively bind to the neuromuscular junction; this was not observed with any IgG of the healthyindividuals.

Following, they injected mice with IgG4 and IgG1-3 from MuSK-MG sera and from healthy indi-viduals and observed muscle weakness and body weight loss only in mice injected with the IgG4from MuSK-MG.

MuSK interacts also with acetylcholinesterase and the authors suggested a possible reductionof acetylcholinesterase, which is not observed in AChR-MG. This may contribute to the pathogenicpotential of MuSK-MG IgG4 and could explain why many MuSK-MG patients who are treated withacetylcholinesterase inhibitors are not benefited. Also, they observed severe morphological ab-normalities of the NMJ, showing that anti-MuSK IgG4 induces fragmentation and reduction of thepostsynaptic area.

In conclusion, with their mouse model, the authors showed that the IgG4 autoantibodies might

indeed be the main pathogenic factor in MuSK-MG, since these antibodies can cause MG by them-selves, without the need of additional immune system components like the complement.

Abnormal sympathetic hyper-reactivity in MG patientsThe purpose of this study was to investigate possible anomalies in sympathetic and parasympa-thetic functions in MG patients, potentially useful to know by patients and doctors. Shukla et al.(Clin Neurol Neurosurg. 2012) performed several tests (such as orthostatic test, isometric handgrip test and sympathetic skin response) in 64 MG patients and many healthy individuals andfound evidence of abnormal sympathetic reactivity in patients with MG.

They showed that patients with MG had a higher increase in systolic and diastolic pressurethan controls. This could cause a significant rise in their blood pressure and wide fluctuations in

their heart rate. They suggested that MG patients may suffer from a subtle sympathetic dysfunc-tion. In contrast, parasympathetic function appeared normal, although parasympathetic abnor-malities may have been masked with drugs like pyridostigmine, which are frequently used in pa-tients with MG.

This sympathetic hyper-reactivity may become more intense when patients undergo surgery(e.g. thymectomy) or during a myasthenic crisis, because of the negative impact of stressful con-ditions in the function of the autonomic system. As a result, extra attention may be requiredwhen using drugs like phenylephrine (cholinomimetic drug) in patients with MG, as it could causea rise in their blood pressure.

MG News for Doctors, Researchers and Patients - continue


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MG Community

European Myasthenia Gravis AssociationThird Annual Meeting and General Assembly

May 26th, 2012, Brussels, Belgium

The Third Annual Meeting and General Assembly of the European Myasthenia Gravis Association(EuMGA) took place Saturday, May 26th, 2012 in Brussels, Belgium Under the patronage of EU-RORDIS. The Meeting was hosted at the Management Centre Europe (MCE) Conference Centre theday after the European Conference for Rare Disease (ECRD-May 24-25, 2012). The date and loca-tion of the EuMGA meeting were chosen to offer the members the opportunity to join the EuMGAmeeting with the ECRD.The EuMGA meeting was organized in two sessions: the first session was reserved to EuMGA Gen-eral Assembly, with the Chairmans and Treasurers reports, the Directors' reports, and the elec-tion of the members to the Board of Directors for the coming year. The elected Board is:Fulvio Baggi : Italian Association against Myasthenia Gravis Onlus (AIM) Milan, Italy. ChairpersonPeter Finney: Myasthenia Gravis Association (MGA), Ashtead, UK TreasurerRudolf Janzen: German Myasthenia Gravis Association Germany

Nadia Radulescu: Associata Nationala Miastenia Gravis Romania Bucarest-RomaniaGeorge Makris: Hellenic Myasthenia Gravis Associatin (H-MGA), GreeceAila Weaver: Finish MG Association, Helsinki, Finland.

The second session was open to all Myasthenia Gravis Patient Organizations in Europe, mem-bers and non members of EuMGA, for presentation of their recent activities, networking and dis-cussions on common projects. Representatives were from the Myasthenia Gravis Association ofthe UK, Asociatia Nationala Miastenia Gravis Romania, Associazione Italiana Miastenia Grave Mi-lano, The Cyprus Myasthenia Gravis Association, Deutsche Myasthenie Gesellschaft e.V. (DMG)engl. GermanMGA, Hellenic Myasthenia Gravis Association-HMGA, Danish Myasthenia Gravis As-sociation, MG Association of Hungary, Netherland VSN, MG Working Group, Association des My-asthniques Isols et Solidaires AMIS.Among other subjects the member of the Board Dr. Rudolf Jansen took the initiative to organize alist of what is valid throughout Europe for off labels drugs (except prescription) in order to pro-

pose an common action in all European countries. For this reason a questionnaire will be sent tothe members of the EuMGA.

The Chairman, Dr. Fulvio Baggi presented a scientific work with comparative demographic datafor MG patients. In this context was discussed the question of recording incidents in detail forMG patients. Finally the Hungarian representative talked on the role of diet in the life of the MGpatient.

Importantly, the General Assembly decided to set up an annual European MG Week, as pro-posed by the Cyprus MGA. EuMGA member associations should organize various activities includ-ing lectures, publication of MG-dedicated newspaper articles, exhibitions, TV interviews, andmany other activities. We hope that this initiative will help to strengthen the solidarity feeling inthe MG community across Europe. The MG week will be held at the same period that the EU-RORDIS events for rare diseases will be in action. Dr. George Makris and Mr. Stamatis Kontaris

from HMGA will undertake the coordination of the European MG week.

G. Makris

The Assembly in

front of its tasks


11/11

11


MG Communitycontinue

Six-months advanced MG-training in Norway

I am a young neurologist and a PhD student at the Department of Neurology, State University ofMedicine and Pharmacy Nicolae Testemitanu, Chisinau, Republic of Moldova. Thanks to a grant

supported by the European Federation of Neurological Societies (EFNS) Fellowship Education Pro-gram I have had the chance to spend a period of six months at the Department of Neurology,Haukeland University Hospital and University of Bergen. This clinic is a great place for a youngdoctor eager to learn and practice neurology, and the EFNS Fellowship programme can help yourealize your dream.

My main field of interest is MG and otherneuromuscular disorders. I am grateful thatduring this fellowship I have been able tocombine clinical practice and research, withfocus on MG. I am learning advanced hands-on clinical neurophysiological examinations(EMG; Repetitive Nerve Stimulation; SingleFiber EMG, EEG), Doppler ultrasound, and

routine immunological laboratory tests likeacetylcholine receptor antibodies. Mean-while I pursue a project on Comorbidity inmyasthenia gravis under the excellentguidance of Professor Gilhus. Also, I amattending the educational program foryoung doctors in the Department, both forthe clinical neurology and research training at the PhD-level.

This experience has given me a valuable insight into the rapidly developing technologicalmedical world, and I have got a better understanding and knowledge of the complex manage-ment of patients with neurological disorders. I am pretty sure this experience will help to improvethe quality of life for patients with MG in Moldova and will improve my future work as a physicianand researcher. I intend to share my knowledge and experiences from Bergen with neurologistsin Moldova, and plan for further cooperation between the departments. Last, but not the least, Ihave had a great chance to know Norwegian culture (Bergen area), touristic attractions, Norwe-gian traditions and people, that made a profound and pleasant impression on me. Thank you verymuch EFNS and Department of Neurology, Haukeland University Hospital for this great experi-ence.

Aliona Nacu, Republic of Moldova

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Style for retirement?

Last August Socrates Tzartos got his retirement from theDepartment of Pharmacy of the University of Patras and

assumed again full time work at the Hellenic Pasteur Insti-

tute. In June his colleagues at the Department organized a

very nice short celebration/meeting in his honor (maybe

with a .relief from their side!). The last talk was by Soc-

rates describing how lucky he indeed was by joining the

Department and serving it for 11 years. He ended his

short talk with the presentation of a cartoon of him (right)

made by a student during the boring lab-examination time

in her examination paper unfortunately the student

failed, despite her obvious talent!

Al iona (2nd from lef t) and the Gilhus group

This newsletter has been prepared by Socrates Tzartos ([email protected]),Veta Tzartos ([email protected]), Dafni Chroni ([email protected]) and other members of the Hellenic Pasteur Institute

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EuroMyasthenia Newsletter 18 Final

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