[Show abstract][Hide abstract] ABSTRACT: To assess the value of major histocompatibility complex (MHC) class II antigen (HLA-DR) expression to distinguish anti-synthetase myopathy (ASM) from dermatomyositis (DM).
[Show abstract][Hide abstract] ABSTRACT: Congenital poikiloderma is characterized by a combination of mottled pigmentation, telangiectasia, and epidermal atrophy in the first few months of life. We have previously described a South African European-descent family affected by a rare autosomal-dominant form of hereditary fibrosing poikiloderma accompanied by tendon contracture, myopathy, and pulmonary fibrosis. Here, we report the identification of causative mutations in FAM111B by whole-exome sequencing. In total, three FAM111B missense mutations were identified in five kindreds of different ethnic backgrounds. The mutation segregated with the disease in one large pedigree, and mutations were de novo in two other pedigrees. All three mutations were absent from public databases and were not observed on Sanger sequencing of 388 ethnically matched control subjects. The three single-nucleotide mutations code for amino acid changes that are clustered within a putative trypsin-like cysteine/serine peptidase domain of FAM111B. These findings provide evidence of the involvement of FAM111B in congenital poikiloderma and multisystem fibrosis.
The American Journal of Human Genetics 11/2013; · 11.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Several medical conditions sharing similar signs and symptoms may be related to immune adjuvants. These conditions described as ASIA (Autoimmune/inflammatory Syndrome Induced by Adjuvants), include a condition characterized by macrophagic myofasciitis (MMF) assessing long-term persistence of vaccine derived-alum adjuvants into macrophages at sites of previous immunization. Despite increasing data describing clinical manifestations of ASIA have been reported, biological markers are particularly lacking for their characterization and follow up. We report an extensive cytokine screening performed in serum from 44 MMF patients compared both to sex and age matched healthy controls and to patients with various types of inflammatory neuromuscular diseases. Thirty cytokines were quantified using combination of Luminex® technology and ELISA. There was significant mean increase of serum levels of the monocyte-chemoattractant protein 1 (CCL2/MCP-1) in MMF patients compared to healthy subjects. MMF patients showed no elevation of other cytokines. This contrasted with inflammatory patients in whom CCL2/MCP-1 serum levels were unchanged, whereas several other inflammatory cytokines were elevated (IL1β, IL5 and CCL3/MIP1α). These results suggest that CCL2 may represent a biological marker relevant to the pathophysiology of MMF rather than a non specific inflammatory marker and that it should be checked in the other syndromes constitutive of ASIA.
Current Medicinal Chemistry 09/2013; · 3.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Macrophagic myofasciitis (MMF) is a specific histological lesion assessing the persistence of vaccine-derived aluminum oxyhydroxide in muscle tissue, at a site of previous immunization. Long-lasting MMF is usually detected in patients with arthromyalgias, chronic fatigue, and stereotyped cognitive dysfunction. MMF diagnosis requires muscle biopsy, an invasive procedure not suitable for the routine investigation of all patients with musculoskeletal pain. To help decision making in routine practice, we designed a retrospective analysis of 130 consecutive arthro-myalgic patients, previously immunized with aluminum-containing vaccines, in whom deltoid muscle biopsy was performed for diagnostic purposes. According to biopsy results, the patients were ascribed to either the MMF or the non-MMF group. MMF was diagnosed in 32.3% of the patients. MMF and non-MMF groups were similar according to both the injected vaccines and the delay between vaccination and biopsy. MMF patients had less frequent fibromyalgia than non-MMF patients (≥11 fibromyalgic tender points in 16.6 vs 55.5%, p<0.04), and more often abnormal evoked potentials suggestive of CNS demyelination (38.5 vs 5.7%, p<0.01). Predictive bioclinical scores based on simple variables such as the number of fibromyalgic tender points, arthralgias, and spinal pain, had sensitivity ranging from 50 to 88.1% and specificity from 36.4 to 76.1%. In conclusion: (i) most aluminum-containing vaccine receivers do not have long-lasting MMF in their muscle, but the prevalence of MMF among patients with arthromyalgia following immunization is substantial; (ii) patients with MMF have more CNS dysfunction and less fibromyalgic tender points than non-MMF patients; (iii) predictive scores may help to identify patients at high vs low risk of MMF.
Journal of inorganic biochemistry 07/2013; · 3.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dysferlinopathy refers to a group of autosomal recessive muscular dystrophies due to mutations in the dysferlin gene causing deficiency of a membrane-bound protein crucially involved in plasma membrane repair. The condition is characterized by marked clinical heterogeneity, the different phenotypes/modes of presentation being unrelated to the genotype. For unknown reasons, patients are often remarkably active before the onset of symptoms. Dysferlin deficiency-related persistence of mechanically induced sarcolemma disruptions causes myofiber damage and necrosis. We postulate that limited myodamage may initially remain hidden with well-preserved resistance to physical strains. By subjecting dysferlin-deficient B6.A/J-Dysf(prmd) mice to long-term swimming exercise, we observed that concentric/isometric strain improved muscle strength and alleviated muscular dystrophy by limiting the accumulation of membrane lesions. By contrast, eccentric strain induced by long-term running in a wheel worsened the dystrophic process. Myofiber damage induced by eccentric strain increased with age, reflecting the accumulation of non-necrotic membrane lesions up to a critical threshold. This phenomenon was modulated by daily spontaneous activity. Transposed to humans, our results may suggest that the past activity profile shapes the clinical phenotype of the myopathy and that patients with dysferlinopathy should likely benefit from concentric exercise-based physiotherapy.
American Journal Of Pathology 04/2013; · 4.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The molecular basis underlying the clinical variability in symptomatic Duchenne muscular dystrophy (DMD) carriers are still to be precised. We report 26 cases of early symptomatic DMD carriers followed in the French neuromuscular network. Clinical presentation, muscular histological analysis and type of gene mutation, as well as X-chromosome inactivation (XCI) patterns using DNA extracted from peripheral blood or muscle are detailed. The initial symptoms were significant weakness (88%) or exercise intolerance (27%). Clinical severity varied from a Duchenne-like progression to a very mild Becker-like phenotype. Cardiac dysfunction was present in 19% of the cases. Cognitive impairment was worthy of notice, as 27% of the carriers are concerned. The muscular analysis was always contributive, revealing muscular dystrophy (83%), mosaic in immunostaining (81%) and dystrophin abnormalities in western blot analysis (84%). In all, 73% had exonic deletions or duplications and 27% had point mutations. XCI pattern was biased in 62% of the cases. In conclusion, we report the largest series of manifesting DMD carriers at pediatric age and show that exercise intolerance and cognitive impairment may reveal symptomatic DMD carriers. The complete histological and immunohistological study of the muscle is the key of the diagnosis leading to the dystrophin gene analysis. Our study shows also that cognitive impairment in symptomatic DMD carriers is associated with mutations in the distal part of the DMD gene. XCI study does not fully explain the mechanisms as well as the wide spectrum of clinical phenotype, though a clear correlation between the severity of the phenotype and inactivation bias was observed.European Journal of Human Genetics advance online publication, 9 January 2013; doi:10.1038/ejhg.2012.269.
European journal of human genetics: EJHG 01/2013; · 3.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Long-term biodistribution of nanomaterials used in medicine is largely unknown. This is the case for alum, the most widely used vaccine adjuvant, which is a nanocrystalline compound spontaneously forming micron/submicron-sized agglomerates. Although generally well tolerated, alum is occasionally detected within monocyte-lineage cells long after immunization in presumably susceptible individuals with systemic/neurologic manifestations or autoimmune (inflammatory) syndrome induced by adjuvants (ASIA).
On the grounds of preliminary investigations in 252 patients with alum-associated ASIA showing both a selective increase of circulating CCL2, the major monocyte chemoattractant, and a variation in the CCL2 gene, we designed mouse experiments to assess biodistribution of vaccine-derived aluminum and of alum-particle fluorescent surrogates injected in muscle. Aluminum was detected in tissues by Morin stain and particle induced X-ray emission) (PIXE) Both 500 nm fluorescent latex beads and vaccine alum agglomerates-sized nanohybrids (Al-Rho) were used.
Intramuscular injection of alum-containing vaccine was associated with the appearance of aluminum deposits in distant organs, such as spleen and brain where they were still detected one year after injection. Both fluorescent materials injected into muscle translocated to draining lymph nodes (DLNs) and thereafter were detected associated with phagocytes in blood and spleen. Particles linearly accumulated in the brain up to the six-month endpoint; they were first found in perivascular CD11b+ cells and then in microglia and other neural cells. DLN ablation dramatically reduced the biodistribution. Cerebral translocation was not observed after direct intravenous injection, but significantly increased in mice with chronically altered blood-brain-barrier. Loss/gain-of-function experiments consistently implicated CCL2 in systemic diffusion of Al-Rho particles captured by monocyte-lineage cells and in their subsequent neurodelivery. Stereotactic particle injection pointed out brain retention as a factor of progressive particle accumulation.
Nanomaterials can be transported by monocyte-lineage cells to DLNs, blood and spleen, and, similarly to HIV, may use CCL2-dependent mechanisms to penetrate the brain. This occurs at a very low rate in normal conditions explaining good overall tolerance of alum despite its strong neurotoxic potential. However, continuously escalating doses of this poorly biodegradable adjuvant in the population may become insidiously unsafe, especially in the case of overimmunization or immature/altered blood brain barrier or high constitutive CCL-2 production.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVES: The pathophysiology of dermatomyositis (DM) remains unclear, combining immunopathological mechanisms with ischaemic changes regarded as a consequence of membranolytic attack complex (MAC)-induced capillary destruction. The study is a reappraisal of the microvascular involvement in light of the microvascular organisation in normal human muscle. METHODS: Muscle microvasculature organisation was analysed using 3D reconstructions of serial sections immunostained for CD31, and histoenzymatic detection of endogenous alkaline phosphatase activity of microvessels. An unbiased point pattern analysis-based method was used to evaluate focal capillary loss. Double immunostainings identified cell types showing MAC deposits. RESULTS: The normal arterial tree includes perimysial arcade arteries, transverse arteries penetrating perpendicularly into the endomysium and terminal arterioles feeding a microvascular unit (MVU) of six to eight capillaries contacting an average of five myofibres. Amyopathic DM cases (n=3) and non-necrotic fascicles of early DM cases (n=27), showed patchy capillary loss in the form of 6-by-6 capillary drop-out, corresponding to depletion of one or multiple MVUs. MAC deposits were also clustered (5-8 immunostained structures, including endothelial cells, but also pericytes, mesenchymal cells and myosatellite cells). CONCLUSIONS: Capillary loss may not be the primary cause of muscle ischaemia in DM. The primary event rather stands upstream, probably at the level of perimysial arcade arteries around which inflammatory infiltrates predominate and which lumen may show narrowing in chronic DM. Ischaemia-reperfusion injury, which is favoured by autoimmune backgrounds in experimental models and which activates the complement cascade in capillaries, could represent an hitherto unsuspected (and potentially preventable) mechanism of muscle damage in DM.
Annals of the rheumatic diseases 09/2012; · 8.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the influence of myoinjury on antigen presentation to T cells in draining lymph nodes (LNs).
Muscle crush was performed in mice injected with exogenous ovalbumin (OVA) and in transgenic SM-OVA mice expressing OVA as a muscle-specific self antigen. Antigen exposure and the resulting stimulation of T cell proliferation in draining LNs was assessed by transferring carboxyfluorescein succinimidyl ester (CFSE)-labeled OVA-specific CD8+ and CD4+ T cells from OT-I and OT-II mice and by measuring the dilution of CFSE, which directly reflects their proliferation. The role of monocyte-derived dendritic cells (DCs) in T cell priming was assessed using pharmacologic blockade of DC migration. Immunofluorescence was used to detect CD8+ T cells, inflammatory monocyte-derived DCs, and type I major histocompatibility complex (MHC)-expressing myofibers in crushed muscle, and to assess expression of perforin, interferon-γ (IFNγ), interleukin-2 (IL-2), IL-10, and transforming growth factor β1 (TGFβ1).
OVA injection into intact muscle induced strong proliferation of CD4+ and CD8+ T cells, indicating efficient exposure of soluble antigens in draining LNs. OVA-specific CD8+ T cell proliferation in draining LNs of SM-OVA mice required myoinjury and was unaffected by pharmacologic inhibition of monocyte-derived DC migration. On day 7 postinjury, activated CD8+ T cells expressing perforin, IFNγ and IL-2 were transiently detected in crushed muscle, and these cells were in close contact with class I MHC-positive regenerating myofibers. Beginning on day 7, the immunosuppressive cytokines IL-10 and TGFβ1 were conspicuously expressed by CD11b+ cells, and CD8+ T cells rapidly disappeared from the healing muscle.
Myofiber damage induces an episode of muscle antigen-specific CD8+ T cell proliferation in draining LNs. Activated CD8+ T cells transiently infiltrate the injured muscle, with prompt control by immunosuppressive cues. Inadequate control might favor sustained autoimmune myositis.
[Show abstract][Hide abstract] ABSTRACT: Duchenne Muscular Dystrophy (DMD) is characterized by the lack of dystrophin that leads to severe myofiber degeneration. We have shown that endomysial fibrosis is correlated with age at ambulation loss in DMD patients. However, the dystrophin-deficient mdx mouse does not have fibrotic lesions in adult limb muscles. Here, we describe a model of chronic mechanical muscle injury that triggers chronic lesions in mdx hindlimb muscle.
Micromechanical injuries were performed daily in tibialis anterior muscles for 2 weeks.
Endomysial fibrosis appeared beginning 1 week post-injury, remained stable for 3 months and was associated with loss of specific maximal force. Fibrosis was associated with an increased expression of factors involved in fibrogenesis including α-smooth muscle actin, connective tissue growth factor, and lysyl oxidase, which colocalized with collagen deposits.
This induced fibrotic dystrophic model may be useful to study mechanisms of fibrosis in dystrophinopathies and to evaluate antifibrotic treatments.
[Show abstract][Hide abstract] ABSTRACT: Aluminium oxyhydroxide (alum), a nanocrystalline compound forming agglomerates, has been used in vaccines for its immunological adjuvant effect since 1927. Alum is the most commonly used adjuvant in human and veterinary vaccines, but the mechanisms by which it stimulates immune responses remain incompletely understood. Although generally well tolerated, alum may occasionally cause disabling health problems in presumably susceptible individuals. A small proportion of vaccinated people present with delayed onset of diffuse myalgia, chronic fatigue and cognitive dysfunction, and exhibit very long-term persistence of alum-loaded macrophages at the site of previous intramuscular (i.m.) immunization, forming a granulomatous lesion called macrophagic myofasciitis (MMF). Clinical symptoms associated with MMF are paradigmatic of the recently delineated 'autoimmune/inflammatory syndrome induced by adjuvants' (ASIA). The stereotyped cognitive dysfunction is reminiscent of cognitive deficits described in foundry workers exposed to inhaled Al particles. Alum safety concerns will largely depend on whether the compound remains localized at the site of injection or diffuses and accumulates in distant organs. Animal experiments indicate that biopersistent nanomaterials taken up by monocyte-lineage cells in tissues, such as fluorescent alum surrogates, can first translocate to draining lymph nodes, and thereafter circulate in blood within phagocytes and reach the spleen, and, eventually, slowly accumulate in the brain.
[Show abstract][Hide abstract] ABSTRACT: Transplantation of muscle precursor cells is of therapeutic interest for focal skeletal muscular diseases. However, major limitations of cell transplantation are the poor survival, expansion and migration of the injected cells. The massive and early death of transplanted myoblasts is not fully understood although several mechanisms have been suggested. Various attempts have been made to improve their survival or migration. Taking into account that muscle regeneration is associated with the presence of macrophages, which are helpful in repairing the muscle by both cleansing the debris and deliver trophic cues to myoblasts in a sequential way, we attempted in the present work to improve myoblast transplantation by coinjecting macrophages. The present data showed that in the 5 days following the transplantation, macrophages efficiently improved: i) myoblast survival by limiting their massive death, ii) myoblast expansion within the tissue and iii) myoblast migration in the dystrophic muscle. This was confirmed by in vitro analyses showing that macrophages stimulated myoblast adhesion and migration. As a result, myoblast contribution to regenerating host myofibres was increased by macrophages one month after transplantation. Altogether, these data demonstrate that macrophages are beneficial during the early steps of myoblast transplantation into skeletal muscle, showing that coinjecting these stromal cells may be used as a helper to improve the efficiency of parenchymal cell engraftment.
PLoS ONE 01/2012; 7(10):e46698. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Macrophagic myofasciitis (MMF) is characterized by specific muscle lesions assessing long-term persistence of aluminum hydroxide within macrophages at the site of previous immunization. Affected patients are middle-aged adults, mainly presenting with diffuse arthromyalgias, chronic fatigue, and cognitive dysfunction. Representative features of MMF-associated cognitive dysfunction (MACD) include (i) dysexecutive syndrome; (i) visual memory; (iii) left ear extinction at dichotic listening test. In present study we retrospectively evaluated the progression of MACD in 30 MMF patients. Most patients fulfilled criteria for non-amnestic/dysexecutive mild cognitive impairment, even if some cognitive deficits seemed unusually severe. MACD remained stable over time, although dysexecutive syndrome tended to worsen. Long-term follow-up of a subset of patients with 3 or 4 consecutive neuropsychological evaluations confirmed the stability of MACD with time, despite marked fluctuations.
Journal of inorganic biochemistry 11/2011; 105(11):1457-63. · 3.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inflammatory myopathies (IMs) often have distinct histopathologic features suggesting humorally mediated involvement of the microcirculation in dermatomyositis (DM), including early capillary deposition of the complement C5b-9 membranolytic attack complex (MAC) and secondary ischaemic changes; and CD8 T-cell-mediated and MHC1-restricted autoimmune attack of myofibers in polymyositis (PM) and inclusion body myositis. Novel insights in these specific diseases include emerging evidence that capillary loss involves whole microvascular units in DM, and that regulatory T-cells strongly protect myofibers from experimental autotoxic attack in PM. However, all IMs do not exhibit pathophysiology-relevant histopathologic features of DM or PM. Autoimmune necrotizing myopathies (AINM) occur in the absence of endomysial inflammatory cells and may be specifically associated with anti-SRP autoantibodies. Moreover, IM histopathological features may be scarce, unspecific and overlapping. Therefore, increasing attention is paid to features shared by IMs regardless of their type, relevant to the innate immune response and to non-immune mechanisms. Innate immune responses to myodamage (and/or as yet unknown stimuli), involves release of chemokines, activation of specific Toll-like receptors (TLRs) and complex Th-1, Th-17 and other cytokine interplays; it triggers DC recruitment and maturation, and is associated with type 1 IFN signature (especially in DM where type 1 IFN-producing cells called plasmacytoid DCs are mainly detected). Non-immune mechanisms mainly include endoplasmic reticulum (ER) stress induced in myofibers by up-regulation of MHC-class I antigens (as typically observed in PM with a diffuse pattern and in DM with perifascicular predominance). ER stress may favour autoimmune reactions but may also be associated with myofiber damage and dysfunction in the absence of lymphocytes. Overlap myositis (OM) may be associated with other connective tissue diseases and a variety of autoantibodies, such as those directed against tRNA synthetase. Myositis specific autoantibodies are mainly expressed by regenerating myofibers, that may also express MHC-1 and endogenous ligand-binding TLRs, thus drawing a picture in which the regenerating myofiber plays a central pathophysiologic role.
[Show abstract][Hide abstract] ABSTRACT: Little is known about systemic sclerosis (SSc)-related myopathy. We aimed to compare the clinical and immunological features of SSc patients with or without associated myopathy.
Forty SSc patients with myopathy, defined by myalgia or muscle weakness associated with creatine kinase (CK) more than five times the upper limit range or myopathic electromyography (EMG) or abnormal myopathology, were identified from the records of four French hospital centres. For each patient, we selected two SSc controls matched for cutaneous SSc form, sex, age at SSc onset, and disease duration. We performed a case-control study testing clinical and immunological SSc-related features for association with myopathy by conditional logistic regression.
Muscle and SSc features of patients with myopathy did not differ significantly among the four centres of origin. Only four (10%) patients with SSc-associated myopathy had anti-polymyositis-scleroderma (PM-Scl) antibodies. Case-control univariate analysis revealed that reduced forced vital capacity (FVC) [odds ratio (OR) 3.0, 95% confidence interval (CI) 1.3-34.9], heart involvement, defined as clinical congestive heart failure, left ventricular ejection fraction (LVEF) < 60%, arrhythmia or conductive abnormalities (OR 2.9, 95% CI 1.3-6.5), and scleroderma renal crisis (OR 3.0, 95% CI 1.3-34.9) were significantly more frequent in patients with myopathy than in controls. Two autoantibodies were more frequent in patients with myopathy: anti-PM-Scl (OR 5.0, 95% CI 1.1-23.9) and anti-RNP (OR 6.9, 95% CI 1.1-64.4). Multivariate analysis retained two variables associated positively with myopathy [reduced FVC (OR 3.1, 95% CI 1.3-9.8) and heart involvement (OR 2.5, 95% CI 1.1-7.1)], while anti-centromere antibodies were associated negatively (OR 0.11, 95% CI 0.03-0.53).
Heart monitoring of SSc patients with myopathy should be undertaken regularly because of the association of myocardial and skeletal myopathies in such patients.
Scandinavian journal of rheumatology 11/2010; 39(6):498-505. · 2.51 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Muscle inflammation can be a prominent feature in several muscular dystrophies. In dysferlin myopathy, it is mainly composed of macrophages. To understand the origin of inflammation in dysferlin-deficient muscle, we analyzed soluble factors involved in monocyte chemotaxis released by myoblasts and myotubes from control and dysferlinopathy patients using a transwell system. Dysferlin-deficient myotubes released more soluble factors involved in monocyte chemotaxis compared with controls (p < 0.001). Messenger RNA microarray analysis showed a 3.2-fold increase of thrombospondin 1 (TSP-1) expression in dysferlin-deficient myotubes. Retrotranscriptasepolymerase chain reaction analysis, ELISA, and immunohistochemistry confirmed these results. Dysferlin mRNA knockdown with short-interfering RNA in normal myogenic cells resulted in TSP-1 mRNA upregulation and increased chemotaxis. Furthermore, monocyte chemotaxis was decreased when TSP-1 was blocked by specific antibodies. In muscle biopsies from dysferlinopathy patients, TSP-1 expression was increased in muscle fibers but not in biopsies of patientswith other myopathies with inflammation; TSP-1 was seen in some macrophages in all samples analyzed. Taken together, the data demonstrate that dysferlin-deficient muscle upregulates TSP-1 in vivoand in vitro and indicate that endogenous chemotactic factors arecrucial to the sustained inflammatory process observed in dysferlinopathies.
Journal of Neuropathology and Experimental Neurology 06/2010; 69(6):643-53. · 4.35 Impact Factor