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G.P.5.10 Role of regulatory T cells in a new mouse model of experimental autoimmune myositis
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Abstracts / Neuromuscular Disorders 18 (2008) 724–833
tising myopathy especially with cardiomyopathy. Recognition of these antibodies as a cause of necrotising myopathy with cardiac involvement should direct aggressive immunotherapy although the optimum treatment of such cases is not established. doi:10.1016/j.nmd.2008.06.165
G.P.5.10 Role of regulatory T cells in a new mouse model of experimental autoimmune myositis S. Solly 1; Y. Allenbach 1; S. Gre´goire 1; O. Dubourg 2; B. Salomon 3; G. Butler-Browne 4; L. Musset 5; S. Herson 6; D. Klatzmann 3; O. Benveniste 6 1 CNRS, Universite´ Pierre et Marie Curie, Hoˆpital de la Pitie´ Salpe´trie`re, UMR 7087 Biothe´rapie Pr Klatzmann, Paris, France; 2 Hoˆpital Pitie´ Salpe´trie`re APHP Universite´ Pierre et Marie Curie, Neuroanatomopathologie, Paris, France; 3 CNRS Universite´ Pierre et Marie Curie, UMR 7087, Paris, France; 4 INSERM Universite´ Pierre et Marie Curie, UMR 787, Paris, France; 5 Hoˆpital Pitie´ Salpe´trie`re APHP Universite´ Pierre et Marie Curie, Immunochimie, Paris, France; 6 Hoˆpital Pitie´ Salpe´trie`re APHP Universite´ Pierre et Marie Curie, Me´decine Interne, Paris, France Polymyositis (PM) is a rare and severe inflammatory muscle disorder due to autoreactive CD8+ cell invasion of muscular fibers, which may result in life-threatening complications. Corticosteroids and other immunosuppressive drugs are partially efficacious and have many side effects. New therapeutic approaches have to be first tested in a relevant animal model. Regulatory CD4+CD25+ T cells (Treg) have been rediscovered as a pivotal cell population in the control of autoimmunity, but sparse data are known between PM and Treg. To develop in BALB/c mice, a reproducible experimental autoimmune myositis (EAM) model of PM, mice were immunized once a week, three times, with 1 mg partially purified myosin emulsified in Complet Freund Adjuvant (CFA). Pertussis toxin was injected at the first immunization. Two weeks after the last immunization, muscle blocks are taken for immunohistology analyses. All mice injected with myosin and CFA developed a myositis with necrotic/regenerative fibers and endomysial inflammatory cells. Some fibers were also invaded. The infiltrates were composed of CD4+, CD8+ cells and macrophages, but no B lymphocytes. In mice which were depleted of Treg (by using anti-CD25 antibodies), the myositis was more severe, as determined by quantitative scoring of the muscle inflammation (2.36 ± 0.9 vs. 1.64 ± 0.8, p = 0.019). In contrast, injection of in vitro expanded polyclonal Treg at the time of immunization significantly improved the disease (quantitative score of inflammation 0.87 ± 1.06 vs. 2.4 ± 0.67, p = 0.047). Transfer of sensitized or CD4+ sorted cells from the lymph nodes of EAM mice induced myositis in irradiated recipient mice. Then EAM is a reproducible and transferable disease in mouse, aggravated by Treg depletion. The beneficial effect of in vitro polyclonal Treg injection is the first encouraging result regarding the therapeutic application of Treg for controlling myositis. doi:10.1016/j.nmd.2008.06.166
G.P.5.11 Calf myositis or focal polyarteritis nodosa: A single entity? T. Lebouvier 1; A. Magot 1; A. Masseau 1; P. Marcorelles 2; Y. Pe´re´on 1; J.M. Mussini 1 1 Centre de Re´fe´rence Maladies Rares Neuromusculaires Nantes-Angers, NANTES, France; 2 Service d’anatomie pathologique, BREST, France Introduction. Triceps surae muscle can be affected by two distinct and focalised primitive inflammatory processes. On one hand, focal myositis
corresponds to the circumscribed lesion of a muscle or a group of adjacent muscles. It is characterized by both endo- and perimysial mononuclear infiltrates, with a necrosis/regeneration pattern. Triceps surae is by far the preferential localization of focal myositis. On the other hand, calf vasculitis displays mainly perivascular inflammatory lesions with secondary necrosis of muscle fibres. When small and middle-sized arteries are involved, polyarteritis nodosa of the calf is considered. Material and methods. In the last 5 years, eight patients were diagnosed with circumscribed vasculitis or myositis of the calf in our neuromuscular center, based upon clinical history and radiological or pathological findings. Biopsy of the involved muscle was performed in six patients. Magnetic resonance imagery (MRI) was performed in seven patients. Results. Clinical findings were homogenous: patients presented with a painful, warm, sometimes indurated calf. Six recovered within a few months, one developed a systemic disease (sarcoidosis) and 1 relapsed. Serum C-reactive protein or CK were slightly elevated in 3 patients. In most cases, MRI revealed a segmental increased signal in the involved muscle on T2 weighted images. Biopsy specimens were characterized by a variable pattern of inflammation involving T cells and macrophages. The infiltrate predominated either in endo/perimysium or in perivascular spaces, allowing the diagnosis of focal myositis or vasculitis, respectively. However, most cases showed both types of alteration. These features were associated with myopathic variations of diameter of muscle fibre diameters, necrosis, and marked fibrosis. Discussion–Conclusion. Our biopsies were in favour of coexistence of myositis and vasculitis processes in all patients. We hypothesize that our cases are representative of a unique pathological entity, characterized by focalized vascular and muscular inflammatory lesions of the triceps surae muscle. doi:10.1016/j.nmd.2008.06.167
G.P.5.12 Decorin and lumican are differentially expressed in canine masticatory muscle myositis O. Paciello; F. Trapani; S. Papparella University of Naples Federico II, Pathology and Animal Health, Naples, Italy Fibrosis is a pathological feature often observed as a consequence of inflammatory myopathies (IMs). Canine Masticatory Muscle Myositis (CMMM), a focal IM affecting exclusively the muscles of mastication, is the most common and thoroughly studied IM in dogs. Canine IMs are spontaneously occurring diseases and have been proposed as animal models of human IMs. The presentations of the disease include an acute painful form with swelling of the masticatory muscles, jaw pain, trismus, and ocular signs (such as exophthalmus, conjunctivitis, and blindness), and a chronic form with progressive muscle atrophy and fibrosis. The leucinerich proteoglycans (also known as ‘‘small, leucine-rich proteoglycans,” or SLRPs) decorin and lumican are thought to be involved in the regulation of collagen fibril assembly. Previous studies have shown that decorin gene family was increased in CMMM and that low levels of decorin were identified in human muscular dystrophy patients in association with increased TGFb1 levels, suggesting a therapeutic role for decorin in muscular dystrophy. Decorin and Lumican expression has now been examined in 12 CMMM, and 3 normal muscle by confocal laser scanning microscopy (CLSM) in parallel with conventional immunohistology and immunoblots to begin to determine its role in muscle fibrosis. Decorin and Lumican were located prominently in the perimysium and endomysium; they were also expressed in association with fibre surfaces. Decorin apparently increased in muscle biopsies with high amount of inflammatory cells and less fibrosis, inversely Lumican was less expressed in the same biopsies. These results were confirmed by immunoblots. CLSM analysis revealed co-localization of both Decorin and Lumican with MHC class II and laminin on muscle membrane. It is concluded that decorin is the most abundant of these proteoglycans in CMMM and that decorin and
Abstracts / Neuromuscular Disorders 18 (2008) 724–833
tising myopathy especially with cardiomyopathy. Recognition of these antibodies as a cause of necrotising myopathy with cardiac involvement should direct aggressive immunotherapy although the optimum treatment of such cases is not established. doi:10.1016/j.nmd.2008.06.165
G.P.5.10 Role of regulatory T cells in a new mouse model of experimental autoimmune myositis S. Solly 1; Y. Allenbach 1; S. Gre´goire 1; O. Dubourg 2; B. Salomon 3; G. Butler-Browne 4; L. Musset 5; S. Herson 6; D. Klatzmann 3; O. Benveniste 6 1 CNRS, Universite´ Pierre et Marie Curie, Hoˆpital de la Pitie´ Salpe´trie`re, UMR 7087 Biothe´rapie Pr Klatzmann, Paris, France; 2 Hoˆpital Pitie´ Salpe´trie`re APHP Universite´ Pierre et Marie Curie, Neuroanatomopathologie, Paris, France; 3 CNRS Universite´ Pierre et Marie Curie, UMR 7087, Paris, France; 4 INSERM Universite´ Pierre et Marie Curie, UMR 787, Paris, France; 5 Hoˆpital Pitie´ Salpe´trie`re APHP Universite´ Pierre et Marie Curie, Immunochimie, Paris, France; 6 Hoˆpital Pitie´ Salpe´trie`re APHP Universite´ Pierre et Marie Curie, Me´decine Interne, Paris, France Polymyositis (PM) is a rare and severe inflammatory muscle disorder due to autoreactive CD8+ cell invasion of muscular fibers, which may result in life-threatening complications. Corticosteroids and other immunosuppressive drugs are partially efficacious and have many side effects. New therapeutic approaches have to be first tested in a relevant animal model. Regulatory CD4+CD25+ T cells (Treg) have been rediscovered as a pivotal cell population in the control of autoimmunity, but sparse data are known between PM and Treg. To develop in BALB/c mice, a reproducible experimental autoimmune myositis (EAM) model of PM, mice were immunized once a week, three times, with 1 mg partially purified myosin emulsified in Complet Freund Adjuvant (CFA). Pertussis toxin was injected at the first immunization. Two weeks after the last immunization, muscle blocks are taken for immunohistology analyses. All mice injected with myosin and CFA developed a myositis with necrotic/regenerative fibers and endomysial inflammatory cells. Some fibers were also invaded. The infiltrates were composed of CD4+, CD8+ cells and macrophages, but no B lymphocytes. In mice which were depleted of Treg (by using anti-CD25 antibodies), the myositis was more severe, as determined by quantitative scoring of the muscle inflammation (2.36 ± 0.9 vs. 1.64 ± 0.8, p = 0.019). In contrast, injection of in vitro expanded polyclonal Treg at the time of immunization significantly improved the disease (quantitative score of inflammation 0.87 ± 1.06 vs. 2.4 ± 0.67, p = 0.047). Transfer of sensitized or CD4+ sorted cells from the lymph nodes of EAM mice induced myositis in irradiated recipient mice. Then EAM is a reproducible and transferable disease in mouse, aggravated by Treg depletion. The beneficial effect of in vitro polyclonal Treg injection is the first encouraging result regarding the therapeutic application of Treg for controlling myositis. doi:10.1016/j.nmd.2008.06.166
G.P.5.11 Calf myositis or focal polyarteritis nodosa: A single entity? T. Lebouvier 1; A. Magot 1; A. Masseau 1; P. Marcorelles 2; Y. Pe´re´on 1; J.M. Mussini 1 1 Centre de Re´fe´rence Maladies Rares Neuromusculaires Nantes-Angers, NANTES, France; 2 Service d’anatomie pathologique, BREST, France Introduction. Triceps surae muscle can be affected by two distinct and focalised primitive inflammatory processes. On one hand, focal myositis
corresponds to the circumscribed lesion of a muscle or a group of adjacent muscles. It is characterized by both endo- and perimysial mononuclear infiltrates, with a necrosis/regeneration pattern. Triceps surae is by far the preferential localization of focal myositis. On the other hand, calf vasculitis displays mainly perivascular inflammatory lesions with secondary necrosis of muscle fibres. When small and middle-sized arteries are involved, polyarteritis nodosa of the calf is considered. Material and methods. In the last 5 years, eight patients were diagnosed with circumscribed vasculitis or myositis of the calf in our neuromuscular center, based upon clinical history and radiological or pathological findings. Biopsy of the involved muscle was performed in six patients. Magnetic resonance imagery (MRI) was performed in seven patients. Results. Clinical findings were homogenous: patients presented with a painful, warm, sometimes indurated calf. Six recovered within a few months, one developed a systemic disease (sarcoidosis) and 1 relapsed. Serum C-reactive protein or CK were slightly elevated in 3 patients. In most cases, MRI revealed a segmental increased signal in the involved muscle on T2 weighted images. Biopsy specimens were characterized by a variable pattern of inflammation involving T cells and macrophages. The infiltrate predominated either in endo/perimysium or in perivascular spaces, allowing the diagnosis of focal myositis or vasculitis, respectively. However, most cases showed both types of alteration. These features were associated with myopathic variations of diameter of muscle fibre diameters, necrosis, and marked fibrosis. Discussion–Conclusion. Our biopsies were in favour of coexistence of myositis and vasculitis processes in all patients. We hypothesize that our cases are representative of a unique pathological entity, characterized by focalized vascular and muscular inflammatory lesions of the triceps surae muscle. doi:10.1016/j.nmd.2008.06.167
G.P.5.12 Decorin and lumican are differentially expressed in canine masticatory muscle myositis O. Paciello; F. Trapani; S. Papparella University of Naples Federico II, Pathology and Animal Health, Naples, Italy Fibrosis is a pathological feature often observed as a consequence of inflammatory myopathies (IMs). Canine Masticatory Muscle Myositis (CMMM), a focal IM affecting exclusively the muscles of mastication, is the most common and thoroughly studied IM in dogs. Canine IMs are spontaneously occurring diseases and have been proposed as animal models of human IMs. The presentations of the disease include an acute painful form with swelling of the masticatory muscles, jaw pain, trismus, and ocular signs (such as exophthalmus, conjunctivitis, and blindness), and a chronic form with progressive muscle atrophy and fibrosis. The leucinerich proteoglycans (also known as ‘‘small, leucine-rich proteoglycans,” or SLRPs) decorin and lumican are thought to be involved in the regulation of collagen fibril assembly. Previous studies have shown that decorin gene family was increased in CMMM and that low levels of decorin were identified in human muscular dystrophy patients in association with increased TGFb1 levels, suggesting a therapeutic role for decorin in muscular dystrophy. Decorin and Lumican expression has now been examined in 12 CMMM, and 3 normal muscle by confocal laser scanning microscopy (CLSM) in parallel with conventional immunohistology and immunoblots to begin to determine its role in muscle fibrosis. Decorin and Lumican were located prominently in the perimysium and endomysium; they were also expressed in association with fibre surfaces. Decorin apparently increased in muscle biopsies with high amount of inflammatory cells and less fibrosis, inversely Lumican was less expressed in the same biopsies. These results were confirmed by immunoblots. CLSM analysis revealed co-localization of both Decorin and Lumican with MHC class II and laminin on muscle membrane. It is concluded that decorin is the most abundant of these proteoglycans in CMMM and that decorin and