PReS-FINAL-2232: Long-term follow-up in a national cohort of MKD patients: search for clinical predictors of a spontaneous improvement

No abstract availabl

Osteological peculiarities of Bufo brongersmai (Anura: Bufonidae) and their possible relation to life in an arid environment

Osteological peculiarities of Bufo brongersmai (Anura: Bufonidae) and their possible relation to life in an arid environment. Zoological Studies 48(1): 108-119. The morphology of selected isolated skeletal elements of the northwestern African endemic toad Bufo brongersmai Hoogmoed 1972 is herein described and compared to those of other Bufo species inhabiting the same area and Europe. The osteological morphology of this species clearly differentiates it from others within the genus, and several diagnostic osteological characters are added to the specific diagnosis. In particular, the presence in adult individuals of a rather-large maxillary fontanella, which late in ontogeny is reduced to a few foramina, has not been observed in other species. These fontanellae, as well as the fenestrations on the sphenethmoid, together with other osteological traits, suggest a significant degree of hypo-ossification. This seems likely related to the rapid larval development that allows B. brongersmai to achieve higher reproductive fitness than other species in the highly ephemeral waters of the rocky, arid environment it inhabits. Other peculiar osteological traits could be related to the exploitation of small crevices to protect adults from overheating and desiccation

FRI0421 Toll like receptor-7/8 activation exacerbates murine experimental autoimmune myositis

BackgroundType I interferon (IFN)-regulated proteins are upregulated in muscle and skin tissues of patients with idiopathic inflammatory myopathies (IIM).1 Type I IFN induction might rely upon the activation of toll-like receptors (TLRs).2 Specifically, TLR-7/8 is indeed upregulated in infiltrating leukocytes and muscle tissue of IIM patients.3 ObjectivesTo investigate whether the activation of TLR-7/8 and type I IFN influences the natural history of the IIM.MethodsExperimental autoimmune myositis (EAM) was induced by injection of the amino-terminal portion of the murine Histydil t-RNA synthetase (HisRS). Disease activity was compared in the presence or absence of the TLR-7/8 agonist R848 in wild-type mice and in mice that failed to express the IFNab receptor (IFNabR null).ResultsEAM induced by a single intramuscular immunisation with HisRS spontaneously abated after 7–8 weeks. In contrast, the levels of anti-HisRS autoantibodies, endomysial/perimysial leukocyte infiltration and myofiber regeneration persisted until the end of the follow-up period (22 weeks after immunisation) in mice immunised with HisRS in the presence of R848. Myofiber MHC class I molecules were detectable in HisRS +R848 immunised mice only. Muscle MHC expression occurred in parallel with leukocyte infiltration. Type I IFN was necessary for the prolonged autoantibody response to occur and for the spreading of the autoimmune response, as demonstrated using IFNabR null mice.Abstract FRI0421 – Figure 1Role of TLR7/8 activation in HisRS-induced myositisConclusionsTLR7/8 activation is needed to induce and maintain a systemic autoimmune response against the skeletal muscle. This EAM model reproduces many characteristics of human IIM and may represent a tool for pre-clinical studies.References[1] Wenzel J, Scheler M, Bieber T, Tuting T. Evidence for a role of type I interferons in the pathogenesis of dermatomyositis. Br J Dermatol. 2005;153:462–463. [author reply 463–464][2] Drexlerand SK, Foxwell BM. The role of toll-like receptors in chronic inflammation. Int J Biochem Cell Biol. 2010;42:506–518.[3] A. Tournadre, V. Lenief, A. Eljaafari, and P. Miossec. Immature muscle precursors are a source of interferon-beta in myositis: role of Toll-like receptor 3 activation and contribution to HLA class I up-regulation. Arthritis and rheumatism. 64:533–541 (2012).Disclosure of InterestNone declare