Search

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. [ABSTRACT FROM AUTHOR]

(1) Background: Macrophagic myofasciitis (MMF) is an inflammatory histopathological lesion demonstrating long-term biopersistence of vaccine-derived aluminum adjuvants within muscular phagocytic cells. Affected patients suffer from widespread myalgia and severe fatigue consistent with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), a poorly understood disorder suspected to result from chronic immune stimulation by infectious and inorganic particles. (2) Methods: In this study we determined the immuno-metabolic properties of MMF phagocytic cells compared to controls, at rest and upon exposure to aluminum oxyhydroxide adjuvant, with or without adsorbed antigens, using protein quantification and an oxygen consumption assay. (3) Results: MMF and control cells similarly internalized the adjuvant and vaccine but MMF cells specifically expressed Rubicon and Nox2, two molecules unique to the LC3-associated phagocytosis (LAP) machinery, a non-canonical autophagic pathway able to downregulate canonical autophagy. MMF cells exhibited an altered inflammatory secretome, producing more pain-inducing CXC chemokines and less TNF-α than controls, consistent with chronic myalgia and exhaustion of the immune system previously documented in ME/CFS. MMF cells exhibited mitochondrial metabolism dysfunction, with exacerbated reaction to adjuvanted vaccine, contrasting with limited spare respiratory capacity and marked proton leak weakening energy production. (4) Conclusions: MMF phagocytes seemingly use LAP to handle aluminum oxyhydroxide vaccine particles, secrete pain-inducing molecules, and exhibit exacerbated metabolic reaction to the vaccine with limited capacity to respond to ongoing energetic requests.

Aluminum compounds are the most widely used adjuvants in veterinary and human vaccines. Despite almost a century of use and substantial advances made in recent decades about their fate and biological effects, the exact mechanism of their action has been continuously debated, from the initial "depot-theory" to the direct immune system stimulation, and remains elusive. Here we investigated the early in vitro response of primary human PBMCs obtained from healthy individuals to aluminum oxyhydroxide (the most commonly used adjuvant) and a whole vaccine, in terms of internalization, conventional and non-conventional autophagy pathways, inflammation, ROS production, and mitochondrial metabolism. During the first four hours of contact, aluminum oxyhydroxide particles, with or without adsorbed vaccine antigen, (1) were quickly recognized and internalized by immune cells; (2) increased and balanced two cellular clearance mechanisms, i.e. canonical autophagy and LC3-associated phagocytosis; (3) induced an inflammatory response with TNF-α production as an early event; (4) and altered mitochondrial metabolism as assessed by both decreased maximal oxygen consumption and reduced mitochondrial reserve, thus potentially limiting further adaptation to other energetic requests. Further studies should consider a multisystemic approach of the cellular adjuvant mechanism involving interconnections between clearance mechanism, inflammatory response and mitochondrial respiration., (© 2023. The Author(s).)

At a time when complex diseases affect globally 280 million people and claim 14 million lives every year, there is an urgent need to rapidly increase our knowledge into their underlying etiologies. Though critical in identifying the people at risk, the causal environmental factors (microbiome and/or pollutants) and the affected pathophysiological mechanisms are not well understood. Herein, we consider the variations of autophagy-related ( ATG ) genes at the heart of mechanisms of increased susceptibility to environmental stress. A comprehensive autophagy genomic resource is presented with 263 single nucleotide polymorphisms (SNPs) for 69 autophagy-related genes associated with 117 autoimmune, inflammatory, infectious, cardiovascular, neurological, respiratory, and endocrine diseases. We thus propose the term 'autophagopathies' to group together a class of complex human diseases the etiology of which lies in a genetic defect of the autophagy machinery, whether directly related or not to an abnormal flux in autophagy, LC3-associated phagocytosis, or any associated trafficking. The future of precision medicine for common diseases will lie in our ability to exploit these ATG SNP x environment relationships to develop new polygenetic risk scores, new management guidelines, and optimal therapies for afflicted patients. Abbreviations: ATG, autophagy-related; ALS-FTD, amyotrophic lateral sclerosis-frontotemporal dementia; ccRCC, clear cell renal cell carcinoma; CD, Crohn disease; COPD, chronic obstructive pulmonary disease; eQTL, expression quantitative trait loci; HCC, hepatocellular carcinoma; HNSCC, head and neck squamous cell carcinoma; GTEx, genotype-tissue expression; GWAS, genome-wide association studies; LAP, LC3-associated phagocytosis; LC3-II, phosphatidylethanolamine conjugated form of LC3; LD, linkage disequilibrium; LUAD, lung adenocarcinoma; MAF, minor allele frequency; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NSCLC, non-small cell lung cancer; OS, overall survival; PtdIns3K CIII, class III phosphatidylinositol 3 kinase; PtdIns3P, phosphatidylinositol-3-phosphate; SLE, systemic lupus erythematosus; SNPs, single-nucleotide polymorphisms; mQTL, methylation quantitative trait loci; ULK, unc-51 like autophagy activating kinase; UTRs, untranslated regions; WHO, World Health Organization.

Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved catabolic process whose loss-of-function has been linked to a growing list of pathologies. Knockout mouse models of key autophagy genes have been instrumental in the demonstration of the critical functions of autophagy, but they display early lethality, neurotoxicity and unwanted autophagy-independent phenotypes, limiting their applications for in vivo studies. To avoid problems encountered with autophagy-null transgenic mice, we investigated the possibility of disturbing autophagy pharmacologically in the long term. Hydroxychloroquine (HCQ) ip injections were done in juvenile and adult C57bl/6j mice, at range doses adapted from the human malaria prophylactic treatment. The impact on autophagy was assessed by western-blotting, and juvenile neurodevelopment and adult behaviours were evaluated for four months. Quite surprisingly, our results showed that HCQ treatment in conditions used in this study neither impacted autophagy in the long term in several tissues and organs nor altered neurodevelopment, adult behaviour and motor capabilities. Therefore, we recommend for future long-term in vivo studies of autophagy, to use genetic mouse models allowing conditional inhibition of selected Atg genes in appropriate lineage cells instead of HCQ treatment, until it could be successfully revisited using higher HCQ doses and/or frequencies with acceptable toxicity.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multifactorial and poorly undersood disabling disease. We present epidemiological, clinical and experimental evidence that ME/CFS constitutes a major type of adverse effect of vaccines, especially those containing poorly degradable particulate aluminum adjuvants. Evidence has emerged very slowly due to the multiplicity, lack of specificity, delayed onset, and frequent medical underestimation of ME/CFS symptoms. It was supported by an epidemiological study comparing vaccinated vs unvaccinated militaries that remained undeployed during Gulf War II. Affected patients suffer from cognitive dysfunction affecting attention, memory and inter-hemispheric connexions, well correlated to brain perfusion defects and associated with a stereotyped and distinctive pattern of cerebral glucose hypometabolism. Deltoid muscle biopsy performed to investigate myalgia typically yields macrophagic myofasciitis (MMF), a histological biomarker assessing longstanding persistency of aluminum agglomerates within innate immune cells at site of previous immunization. MMF is seemingly linked to altered mineral particle detoxification by the xeno/autophagy machinery. Comparing toxicology of different forms of aluminum and different types of exposure is misleading and inadequate and small animal experiments have turned old dogma upside down. Instead of being rapidly solubilized in the extracellular space, injected aluminum particles are quickly captured by immune cells and transported to distant organs and the brain where they elicit an inflammatory response and exert selective low dose long-term neurotoxicity. Clinical observations and experiments in sheep, a large animal like humans, confirmed both systemic diffusion and neurotoxic effects of aluminum adjuvants. Post-immunization ME/CFS represents the core manifestation of "autoimmune/inflammatory syndrome induced by adjuvants" (ASIA)., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: The role of interferons (IFN) in the pathophysiology of primary inflammatory and dysimmune myopathies (IDM) is increasingly investigated, notably because specific neutralisation approaches may constitute promising therapeutic tracks. In present work we analysed the muscular expression of specific IFNα/β and IFNγ-stimulated genes in patients with various types of IDM., Methods: 39 patients with IDM with inclusion body myositis (IBM, n=9), dermatomyositis (DM, n=10), necrotising autoimmune myopathies (NAM, n=10) and antisynthetase myositis (ASM, n=10), and 10 controls were included. Quantification of expression levels of IFNγ, ISG15, an IFNα/β-inducible gene and of six IFNγ-inducible genes (GBP2, HLA-DOB, HLA-DPB, CIITA, HLA-DRB and HLA-DMB) was performed on muscle biopsy samples., Results: DM usually associated with strong type I IFNα/β signature, IBM and ASM with prominent type II IFNγ signature and NAM with neither type I nor type II IFN signature. Immunofluorescence study in ASM and IBM showed myofibre expression of major histocompatibility class 2 (MHC-2) and CIITA, confirming the induction of the IFNγ pathway. Furthermore, MHC-2-positive myofibres were observed in close proximity to CD8+ T cells which produce high levels of IFNγ., Conclusion: Distinct IFN signatures allow a more distinct segregation of IDMs and myofibre MHC-2 expression is a reliable biomarker of type II IFN signature., Competing Interests: Competing interests: None declared.

Macrophagic myofasciitis (MMF) syndrome is a subtype of autoimmune/inflammatory syndrome induced by adjuvants (ASIA) or Shoenfeld's syndrome, characterized by the presence of stereotyped inflammatory lesions at muscle biopsy attesting the long-term persistence of aluminum hydroxide particles at the site of previous immunization. Most frequently reported symptoms are chronic arthromyalgias and fatigue and cognitive complaint. MMF-associated cognitive disorder (MACD) is characterized by the dysfunctioning of attention, executive functions, short-term term and long-term memory, and, in some instances, left ear extinction. MACD is expressed in a chronic, nonevolving, well-defined syndromic framework within which the expression in terms of severity differs from one patient to another. While brain MRI is usually noncontributive, functional imaging using SPECT and PET has revealed the existence of a suggestive pathological pattern with involvement of posterior associative areas, temporal lobes, limbic system, and cerebellum. Put together, neuropsychological and functional neuroimaging investigations support the view that MACD relates to organic central nervous system involvement., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objectives: Myositis-specific autoantibodies (MSAs) are increasingly used to delineate distinct subgroups of JDM. The aim of our study was to explore without a priori hypotheses whether MSAs are associated with distinct clinical-pathological changes and severity in a monocentric JDM cohort., Methods: Clinical, biological and histological findings from 23 JDM patients were assessed. Twenty-six histopathological parameters were subjected to multivariate analysis., Results: Autoantibodies included anti-NXP2 (9/23), anti-TIF1γ (4/23), anti-MDA5 (2/23), no MSAs (8/23). Multivariate analysis yielded two histopathological clusters. Cluster 1 (n = 11) showed a more severe and ischaemic pattern than cluster 2 (n = 12) assessed by: total score severity ⩾ 20 (100.0% vs 25.0%); visual analogic score ⩾6 (100.0% vs 25.0%); the vascular domain score >1 (100.0% vs 41.7%); microinfarcts (100% vs 58.3%); ischaemic myofibrillary loss (focal punched-out vacuoles) (90.9 vs 25%); and obvious capillary loss (81.8% vs 16.7). Compared with cluster 2, patients in cluster 1 had strikingly more often anti-NXP2 antibodies (7/11 vs 2/12), more pronounced muscle weakness, more gastrointestinal involvement and required more aggressive treatment. Furthermore, patients with anti-NXP2 antibodies, mostly assigned in the first cluster, also displayed more severe muscular disease, requiring more aggressive treatment and having a lower remission rate during the follow-up period., Conclusion: Marked muscle ischaemic involvement and the presence of anti-NXP2 autoantibodies are associated with more severe forms of JDM.

Patients with macrophagic myofasciitis (MMF) present with diffuse arthromyalgias, chronic fatigue, and cognitive disorder. Representative features of MMF-associated cognitive dysfunction include attentional dysfunction, dysexecutive syndrome, visual memory deficit and left ear extinction. Our study aims to reevaluate the neuropsychological profile of MMF. 105 unselected consecutive MMF patients were subjected to a neuropsychological battery of screen short term and long-term memory, executive functions, attentional abilities, instrumental functions and dichotic listening. From these results, patients were classified in four different groups: Subsymptomatic patients (n=41) with performance above pathological threshold (-1.65 SD) in all tests; Fronto-subcortical patients (n=31) who showed pathological results at executive functions and selective attention tests; Papezian patients (n=24) who showed pathological results in storage, recognition and consolidation functions for episodic verbal memory, in addition to fronto-subcortical dysfunction; and Extinction patients (n=9) who had a left ear extinction at dichotic listening test in association to fronto-subcortical and papezian dysfunction. In addition, inter-test analysis showed that patients with apparently normal cognitive functions (Subsymptomatic group) performed significantly worse to attention tests compared to others. In conclusion, our study shows that (i) most patients have specific cognitive deficits; (ii) all patients with cognitive deficit have impairment of executive functions and selective attention; (iii) patients without measurable cognitive deficits display significant weakness in attention; (iv) episodic memory impairment affects verbal, but not visual, memory; (v) none of the patients show an instrumental dysfunction., (Copyright © 2017 Elsevier Inc. All rights reserved.)

We reviewed the three toxicokinetic reference studies commonly used to suggest that aluminum (Al)-based adjuvants are innocuous. A single experimental study was carried out using isotopic 26Al (Flarend et al., Vaccine, 1997). This study used aluminum salts resembling those used in vaccines but ignored adjuvant uptake by cells that was not fully documented at the time. It was conducted over a short period of time (28days) and used only two rabbits per adjuvant. At the endpoint, Al elimination in the urine accounted for 6% for Al hydroxide and 22% for Al phosphate, both results being incompatible with rapid elimination of vaccine-derived Al in urine. Two theoretical studies have evaluated the potential risk of vaccine Al in infants, by reference to an oral "minimal risk level" (MRL) extrapolated from animal studies. Keith et al. (Vaccine, 2002) used a high MRL (2mg/kg/d), an erroneous model of 100% immediate absorption of vaccine Al, and did not consider renal and blood-brain barrier immaturity. Mitkus et al. (Vaccine, 2011) only considered solubilized Al, with erroneous calculations of absorption duration. Systemic Al particle diffusion and neuro-inflammatory potential were omitted. The MRL they used was both inappropriate (oral Al vs. injected adjuvant) and still too high (1mg/kg/d) regarding recent animal studies. Both paucity and serious weaknesses of reference studies strongly suggest that novel experimental studies of Al adjuvants toxicokinetics should be performed on the long-term, including both neonatal and adult exposures, to ensure their safety and restore population confidence in Al-containing vaccines., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Rationale: Although several functional studies have demonstrated that positron emission tomography/computed tomography with F-fluorodeoxyglucose (F-FDG PET/CT) appears to be efficient to identify a cerebral substrate in patients with known macrophagic myofasciitis (MMF), the predictive value of this imaging technique for MMF remains unclear., Patient Concerns: We presented data and images of a 46-year-old woman., Diagnoses: The patient was referred to our center for suspected MMF due to diffuse arthromyalgias and cognitive disorder (involving an impairment of visual selective attention and a weakness in executive functions revealed by neuropsychological assessment) which occurred few years after last vaccine injections., Interventions: After a first negative deltoid muscle biopsy, a brain F-FDG PET/CT was performed and revealed the known spatial pattern of a cerebral glucose hypometabolism involving occipital cortex, medial temporal areas, and cerebellum., Outcomes: Given the clinical suspicion of MMF and brain F-FDG PET/CT findings, a 2nd deltoid muscle biopsy was performed and confirmed the diagnosis of MMF with typical histopathological features., Lessons: This case highlights the predictive value of brain F-FDG PET/CT as a noninvasive imaging tool for MMF diagnosis, even when muscle biopsy result comes back negative.

Introduction: Patients with renal failure who are being treated with dialysis frequently develop neuromuscular manifestations. Renal failure-associated calciphylaxis, also termed calcific uremic arteriolopathy (CUA), is a life-threatening condition usually observed in patients with end-stage renal disease on chronic dialysis or after renal transplantation., Methods: We describe a hemodialyzed patient who presented with rapidly progressive unexplained systemic vasculopathy, muscle atrophy, and proximal weakness, that unexpectedly proved to be caused by calciphylaxis., Results: Quadriceps muscle biopsy disclosed diffuse vascular calcific deposits on medium- and small-sized vessels, characteristic of CUA. Other changes included ischemic myopathy, focal intracellular calcium accumulation within myofibers, and calcium deposits in endomysial capillaries associated with marked complement activation and C5b9 formation., Conclusion: There are only a few descriptions of muscle involvement in the context of CUA, a condition with a prognosis that depends on early diagnosis and treatment. This report underscores the usefulness of muscle biopsy in the diagnosis of systemic calciphylaxis. Muscle Nerve 56: 529-533, 2017., (© 2016 Wiley Periodicals, Inc.)

The aim of this study was to characterize brain metabolic abnormalities in patients with macrophagic myofascitis (MMF) and the relationship with cognitive dysfunction through the use of PET with 18 F-FDG. Methods: 18 F-FDG PET brain imaging and a comprehensive battery of neuropsychological tests were performed in 100 consecutive MMF patients (age [mean ± SD], 45.9 ± 12 y; 74% women). Images were analyzed with statistical parametric mapping (SPM12). Through the use of analysis of covariance, all 18 F-FDG PET brain images of MMF patients were compared with those of a reference population of 44 healthy subjects similar in age (45.4 ± 16 y; P = 0.87) and sex (73% women; P = 0.88). The neuropsychological assessment identified 4 categories of patients: those with no significant cognitive impairment ( n = 42), those with frontal subcortical (FSC) dysfunction ( n = 29), those with Papez circuit dysfunction ( n = 22), and those with callosal disconnection ( n = 7). Results: In comparison with healthy subjects, the whole population of patients with MMF exhibited a spatial pattern of cerebral glucose hypometabolism ( P < 0.001) involving the occipital lobes, temporal lobes, limbic system, cerebellum, and frontoparietal cortices, as shown by analysis of covariance. The subgroup of patients with FSC dysfunction exhibited a larger extent of involved areas (35,223 voxels vs. 13,680 voxels in the subgroup with Papez circuit dysfunction and 5,453 voxels in patients without cognitive impairment). Nonsignificant results were obtained for the last subgroup because of its small population size. Conclusion: Our study identified a peculiar spatial pattern of cerebral glucose hypometabolism that was most marked in MMF patients with FSC dysfunction. Further studies are needed to determine whether this pattern could represent a diagnostic biomarker of MMF in patients with chronic fatigue syndrome and cognitive dysfunction., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)

Aluminium (Al) oxyhydroxide (Alhydrogel ® ), the main adjuvant licensed for human and animal vaccines, consists of primary nanoparticles that spontaneously agglomerate. Concerns about its safety emerged following recognition of its unexpectedly long-lasting biopersistence within immune cells in some individuals, and reports of chronic fatigue syndrome, cognitive dysfunction, myalgia, dysautonomia and autoimmune/inflammatory features temporally linked to multiple Al-containing vaccine administrations. Mouse experiments have documented its capture and slow transportation by monocyte-lineage cells from the injected muscle to lymphoid organs and eventually the brain. The present study aimed at evaluating mouse brain function and Al concentration 180days after injection of various doses of Alhydrogel ® (200, 400 and 800μg Al/kg of body weight) in the tibialis anterior muscle in adult female CD1 mice. Cognitive and motor performances were assessed by 8 validated tests, microglial activation by Iba-1 immunohistochemistry, and Al level by graphite furnace atomic absorption spectroscopy. An unusual neuro-toxicological pattern limited to a low dose of Alhydrogel ® was observed. Neurobehavioural changes, including decreased activity levels and altered anxiety-like behaviour, were observed compared to controls in animals exposed to 200μg Al/kg but not at 400 and 800μg Al/kg. Consistently, microglial number appeared increased in the ventral forebrain of the 200μg Al/kg group. Cerebral Al levels were selectively increased in animals exposed to the lowest dose, while muscle granulomas had almost completely disappeared at 6 months in these animals. We conclude that Alhydrogel ® injected at low dose in mouse muscle may selectively induce long-term Al cerebral accumulation and neurotoxic effects. To explain this unexpected result, an avenue that could be explored in the future relates to the adjuvant size since the injected suspensions corresponding to the lowest dose, but not to the highest doses, exclusively contained small agglomerates in the bacteria-size range known to favour capture and, presumably, transportation by monocyte-lineage cells. In any event, the view that Alhydrogel ® neurotoxicity obeys "the dose makes the poison" rule of classical chemical toxicity appears overly simplistic., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Aluminum oxyhydroxide (Alhydrogel(®)) is a nano-crystalline compound forming aggregates that has been introduced in vaccine for its immunologic adjuvant effect in 1926. It is the most commonly used adjuvant in human and veterinary vaccines but mechanisms by which it stimulates immune responses remain ill-defined. Although generally well tolerated on the short term, it has been suspected to occasionally cause delayed neurologic problems in susceptible individuals. In particular, the long-term persistence of aluminic granuloma also termed macrophagic myofasciitis is associated with chronic arthromyalgias and fatigue and cognitive dysfunction. Safety concerns largely depend on the long biopersistence time inherent to this adjuvant, which may be related to its quick withdrawal from the interstitial fluid by avid cellular uptake; and the capacity of adjuvant particles to migrate and slowly accumulate in lymphoid organs and the brain, a phenomenon documented in animal models and resulting from MCP1/CCL2-dependant translocation of adjuvant-loaded monocyte-lineage cells (Trojan horse phenomenon). These novel insights strongly suggest that serious re-evaluation of long-term aluminum adjuvant phamacokinetics and safety should be carried out., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: The course of dermatomyositis (DM) can be chronic with relapses, which are associated with major morbidity., Objective: The aim of this study was to identify presentation features that predict DM relapses., Methods: We retrospectively reviewed data of patients with DM recorded from 1990 to 2011, including muscle biopsy results. Characteristics of patients with and without relapses were compared. Hazard ratios (HRs) were estimated using a Cox model., Results: We identified 34 patients, with a mean age of 46 ± 17 years (range, 18-77) and 24 (71%) women. The muscle and skin abnormalities relapsed in 21 (61%) patients. By univariate analysis, two presentation features were significantly associated with a subsequently relapsing course, namely, dysphonia [HR = 3.2 (1.2-8.5)] and greater skin lesion severity defined as a Cutaneous Disease Area Severity Index [CDASI] > 20 [HR = 3.5 (1.2-7.9)]., Conclusion: Dysphonia and skin lesion severity at disease onset must be recorded, as they significantly predict a relapsing disease course., (© 2015 European Academy of Dermatology and Venereology.)

Objective: Outcome of JDM is highly heterogeneous. Our objective was to determine clinical and muscle biopsy features associated with poor outcome and response to treatment., Methods: Clinical data and muscle biopsy were obtained from a monocentric cohort of 29 patients. Clinical subgroups were defined by latent class model analysis of initial and follow-up parameters. Myopathological features were analysed using validated scores. Capillary loss was determined on reconstructions of transversal sections and assessed in the different age groups to take into account variations of muscle capillarization during post-natal development. Regression models were used to identify initial predictors of therapeutic response., Results: Two distinct homogeneous subgroups of patients were identified according to clinical severity and pathological findings. The smallest group of patients (7/29) presented with severe JDM. Compared with the other group (22/29), patients had more severe muscle weakness at disease onset, low remission rate at 12 months, frequent subcutaneous limb oedema or gastrointestinal (GI) involvement and higher myopathological scores (capillary dropout, perifascicular necrosis/regeneration, fibres with internal myonuclei and fibrosis subscores). Relevance of capillary dropout to JDM severity was substantiated by age-based analysis, confirming its major role in JDM pathophysiology. Most of these manifestations could be related to vasculopathy (limb oedema, GI involvement, capillary dropout). Furthermore, Childhood Myositis Assessment Scale <34 with either GI involvement or muscle endomysial fibrosis at disease onset were the best predictors of poor response to treatment., Conclusion: Vasculopathy is prominent in severe JDM. Simple criteria can be used at initial evaluation to identify patients requiring a more intensive therapy., (© The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Myotonic Dystrophy type 1 (DM1) is one of the most heterogeneous hereditary disease in terms of age of onset, clinical manifestations, and severity, challenging both medical management and clinical trials. The CTG expansion size is the main factor determining the age of onset although no factor can finely predict phenotype and prognosis. Differences between males and females have not been specifically reported. Our aim is to study gender impact on DM1 phenotype and severity., Methods: We first performed cross-sectional analysis of main multiorgan clinical parameters in 1409 adult DM1 patients (>18 y) from the DM-Scope nationwide registry and observed different patterns in males and females. Then, we assessed gender impact on social and economic domains using the AFM-Téléthon DM1 survey (n = 970), and morbidity and mortality using the French National Health Service Database (n = 3301)., Results: Men more frequently had (1) severe muscular disability with marked myotonia, muscle weakness, cardiac, and respiratory involvement; (2) developmental abnormalities with facial dysmorphism and cognitive impairment inferred from low educational levels and work in specialized environments; and (3) lonely life. Alternatively, women more frequently had cataracts, dysphagia, digestive tract dysfunction, incontinence, thyroid disorder and obesity. Most differences were out of proportion to those observed in the general population. Compared to women, males were more affected in their social and economic life. In addition, they were more frequently hospitalized for cardiac problems, and had a higher mortality rate., Conclusion: Gender is a previously unrecognized factor influencing DM1 clinical profile and severity of the disease, with worse socio-economic consequences of the disease and higher morbidity and mortality in males. Gender should be considered in the design of both stratified medical management and clinical trials.

Concerns regarding vaccine safety have emerged following reports of potential adverse events in both humans and animals. In the present study, alum, alum-containing vaccine and alum adjuvant tagged with fluorescent nanodiamonds were used to evaluate i) the persistence time at the injection site, ii) the translocation of alum from the injection site to lymphoid organs, and iii) the behavior of adult CD1 mice following intramuscular injection of alum (400 μg Al/kg). Results showed for the first time a strikingly delayed systemic translocation of adjuvant particles. Alum-induced granuloma remained for a very long time in the injected muscle despite progressive shrinkage from day 45 to day 270. Concomitantly, a markedly delayed translocation of alum to the draining lymph nodes, major at day 270 endpoint, was observed. Translocation to the spleen was similarly delayed (highest number of particles at day 270). In contrast to C57BL/6J mice, no brain translocation of alum was observed by day 270 in CD1 mice. Consistently neither increase of Al cerebral content, nor behavioral changes were observed. On the basis of previous reports showing alum neurotoxic effects in CD1 mice, an additional experiment was done, and showed early brain translocation at day 45 of alum injected subcutaneously at 200 μg Al/kg. This study confirms the striking biopersistence of alum. It points out an unexpectedly delayed diffusion of the adjuvant in lymph nodes and spleen of CD1 mice, and suggests the importance of mouse strain, route of administration, and doses, for future studies focusing on the potential toxic effects of aluminum-based adjuvants., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Aluminum oxyhydroxide (alum) is a crystalline compound widely used as an immunologic adjuvant of vaccines. Concerns linked to alum particles have emerged following recognition of their causative role in the so-called macrophagic myofasciitis (MMF) lesion in patients with myalgic encephalomyelitis, revealing an unexpectedly long-lasting biopersistence of alum within immune cells and a fundamental misconception of its biodisposition. Evidence that aluminum-coated particles phagocytozed in the injected muscle and its draining lymph nodes can disseminate within phagocytes throughout the body and slowly accumulate in the brain further suggested that alum safety should be evaluated in the long term. However, lack of specific staining makes difficult the assessment of low quantities of bona fide alum adjuvant particles in tissues., Methods: We explored the feasibility of using fluorescent functionalized nanodiamonds (mfNDs) as a permanent label of alum (Alhydrogel(®)). mfNDs have a specific and perfectly photostable fluorescence based on the presence within the diamond lattice of nitrogen-vacancy centers (NV centers). As the NV center does not bleach, it allows the microspectrometric detection of mfNDs at very low levels and in the long-term. We thus developed fluorescent nanodiamonds functionalized by hyperbranched polyglycerol (mfNDs) allowing good coupling and stability of alum:mfNDs (AluDia) complexes. Specificities of AluDia complexes were comparable to the whole reference vaccine (anti-hepatitis B vaccine) in terms of particle size and zeta potential., Results: In vivo, AluDia injection was followed by prompt phagocytosis and AluDia particles remained easily detectable by the specific signal of the fND particles in the injected muscle, draining lymph nodes, spleen, liver and brain. In vitro, mfNDs had low toxicity on THP-1 cells and AluDia showed cell toxicity similar to alum alone. Expectedly, AluDia elicited autophagy, and allowed highly specific detection of small amounts of alum in autophagosomes., Conclusions: The fluorescent nanodiamond technology is able to overcome the limitations of previously used organic fluorophores, thus appearing as a choice methodology for studying distribution, persistence and long-term neurotoxicity of alum adjuvants and beyond of other types of nanoparticles.

Background: Patients with aluminum hydroxide adjuvant-induced macrophagic myofasciitis (MMF) complain of arthromyalgias, chronic fatigue and cognitive deficits. This study aimed to characterize brain perfusion in these patients., Methods: Brain perfusion SPECT was performed in 76 consecutive patients (aged 49±10 y) followed in the Garches-Necker-Mondor-Hendaye reference center for rare neuromuscular diseases. Images were acquired 30 min after intravenous injection of 925 MBq 99mTc-ethylcysteinate dimer (ECD) at rest. All patients also underwent a comprehensive battery of neuropsychological tests, within 1.3±5.5 mo from SPECT. Statistical parametric maps (SPM12) were obtained for each test using linear regressions between each performance score and brain perfusion, with adjustment for age, sex, socio-cultural level and time delay between brain SPECT and neuropsychological testing., Results: SPM analysis revealed positive correlation between neuropsychological scores (mostly exploring executive functions) and brain perfusion in the posterior associative cortex, including cuneus/precuneus/occipital lingual areas, the periventricular white matter/corpus callosum, and the cerebellum, while negative correlation was found with amygdalo-hippocampal/entorhinal complexes. A positive correlation was also observed between brain perfusion and the posterior associative cortex when the time elapsed since last vaccine injection was investigated., Conclusions: Brain perfusion SPECT showed a pattern of cortical and subcortical changes in accordance with the MMF-associated cognitive disorder previously described. These results provide a neurobiological substrate for brain dysfunction in aluminum hydroxide adjuvant-induced MMF patients.

The satellite cells, which serve as adult muscle stem cells, are both located beneath myofiber basement membranes and closely associated with capillary endothelial cells. We observed that 90% of capillaries were associated with pericytes in adult mouse and human muscle. During post-natal growth, newly formed vessels with their neuroglial 2 proteoglycan (NG2)-positive pericytes became progressively associated with the post-natal muscle stem cells, as myofibers increased in size and satellite cells entered into quiescence. In vitro, human muscle-derived pericytes promoted myogenic cell differentiation through insulin-like growth factor 1 (IGF1) and myogenic cell quiescence through angiopoietin 1 (ANGPT1). Diphtheria toxin-induced ablation of muscle pericytes in growing mice led both to myofiber hypotrophy and to impaired establishment of stem cells quiescence. Similar effects were observed following conditional in vivo deletion of pericyte Igf1 and Angpt1 genes, respectively. Our data therefore demonstrate that, by promoting post-natal myogenesis and stem cell quiescence, pericytes play a key role in the microvascular niche of satellite cells., (© 2015. Published by The Company of Biologists Ltd.)

Aluminum oxyhydroxide (alum) is a crystalline compound widely used as an immunological adjuvant of vaccines. Concerns linked to the use of alum particles emerged following recognition of their causative role in the so-called macrophagic myofasciitis (MMF) lesion detected in patients with myalgic encephalomyelitis/chronic fatigue/syndrome. MMF revealed an unexpectedly long-lasting biopersistence of alum within immune cells in presumably susceptible individuals, stressing the previous fundamental misconception of its biodisposition. We previously showed that poorly biodegradable aluminum-coated particles injected into muscle are promptly phagocytosed in muscle and the draining lymph nodes, and can disseminate within phagocytic cells throughout the body and slowly accumulate in brain. This strongly suggests that long-term adjuvant biopersistence within phagocytic cells is a prerequisite for slow brain translocation and delayed neurotoxicity. The understanding of basic mechanisms of particle biopersistence and brain translocation represents a major health challenge, since it could help to define susceptibility factors to develop chronic neurotoxic damage. Biopersistence of alum may be linked to its lysosome-destabilizing effect, which is likely due to direct crystal-induced rupture of phagolysosomal membranes. Macrophages that continuously perceive foreign particles in their cytosol will likely reiterate, with variable interindividual efficiency, a dedicated form of autophagy (xenophagy) until they dispose of alien materials. Successful compartmentalization of particles within double membrane autophagosomes and subsequent fusion with repaired and re-acidified lysosomes will expose alum to lysosomal acidic pH, the sole factor that can solubilize alum particles. Brain translocation of alum particles is linked to a Trojan horse mechanism previously described for infectious particles (HIV, HCV), that obeys to CCL2, signaling the major inflammatory monocyte chemoattractant.

Macrophagic myofasciitis (MMF) is an emerging condition characterized by specific muscle lesions assessing abnormal long-term persistence of aluminum hydroxide within macrophages at the site of previous immunization. Affected patients usually are middle-aged adults, mainly presenting with diffuse arthromyalgias, chronic fatigue, and marked cognitive deficits, not related to pain, fatigue, or depression. Clinical features usually correspond to that observed in chronic fatigue syndrome/myalgic encephalomyelitis. Representative features of MMF-associated cognitive dysfunction include dysexecutive syndrome, visual memory impairment, and left ear extinction at dichotic listening test. Most patients fulfill criteria for non-amnestic/dysexecutive mild cognitive impairment, even if some cognitive deficits appear unusually severe. Cognitive dysfunction seems stable over time despite marked fluctuations. Evoked potentials may show abnormalities in keeping with central nervous system involvement, with a neurophysiological pattern suggestive of demyelination. Brain perfusion SPECT shows a pattern of diffuse cortical and subcortical abnormalities, with hypoperfusions correlating with cognitive deficiencies. The combination of musculoskeletal pain, chronic fatigue, and cognitive disturbance generates chronic disability with possible social exclusion. Classical therapeutic approaches are usually unsatisfactory making patient care difficult.

Objectives: To assess the value of major histocompatibility complex (MHC) class II antigen (HLA-DR) expression to distinguish anti-synthetase myopathy (ASM) from dermatomyositis (DM)., Methods: Muscle biopsies from patients with ASM (n = 33), DM without anti-synthetase antibodies (ASAb) (n = 17), and normal muscle biopsy (n = 10) were first reviewed. ASAb included anti-Jo1 (26/33), anti-PL12 (4/33), anti-PL7 (2/33), and anti-EJ (1/33). Immunohistochemistry was performed for MHC-I/HLA-ABC, MHC-II/HLA-DR, membrane attack complex (C5b-9), neural cell adhesion molecule (NCAM)/CD56 expression, and inflammatory cell subsets. Twenty-four ASM and 12 DM patients from another center were added for HLA-DR evaluation., Results: Ubiquitous myofiber HLA-ABC expression was equally observed in ASM and DM (93.9% vs 100%, NS). In contrast, myofiber HLA-DR expression was found in 27/33 (81.8%) ASM (anti-Jo1: 23/26, 88.5%; others: 5/7, 71.4%) vs 4/17 (23.5%) DM patients (p < 0.001). HLA-DR was perifascicular in ASM, a pattern not observed in DM. In addition, C5b-9 deposition was observed on sarcolemma of non-necrotic perifascicular fibers in ASM, while, in DM, C5b-9was mainly detected in endomysial capillaries. CD8 cells were more abundant in ASM than in DM (p < 0.05), and electively located in perimysium or in perifascular endomysium. HLA-DR expression correlated positively with the CD8+ cells infiltrates. Strictly similar observations were made in the confirmatory study., Conclusion: ASM is characterized by strong myofiber MHC-II/HLA-DR expression with a unique perifascicular pattern, not described so far. HLA-DR detection must be included for routine myopathological diagnosis of inflammatory/dysimmune myopathies. HLA-DR expression in ASM may indicate a specific immune mechanism, possibly involving IFNγ.

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 monocytechemoattractant 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.

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., (Copyright © 2013 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Unlabelled: 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., (© 2013.)

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., (Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

Background: 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)., Methods: 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., Results: 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., Conclusion: 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.

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.

Juvenile dermatomyositis (JDM) is a systemic, inflammatory, idiopathic disease, mainly affecting the skin and the muscles, starting before the age of 16, with an incidence around one case per 1 million children. Some patients display typical features of JDM without skin involvement, or even without muscle involvement; however, both tissues are affected over time in most cases. Diagnosis criteria were established by Bohan and Peter 35 years ago, based on the presence of typical skin rash and proximal muscle involvement. Other conditions have to be ruled out before making a diagnosis of JDM, such as other connective tissue diseases, polymyositis, infectious/postinfectious myositis, genetic diseases, or metabolic or drug-induced myopathies. Unlike adult-onset dermatomyositis, JDM is exceptionally associated with a malignant disease. JDM may also affect several organs, including the lungs and the digestive tract. In a subset of patients, glucose intolerance, lipodystrophia and/or calcinosis develop. Delay in treatment initiation or inadequate treatment may favor diffuse, debilitating calcinosis. JDM patients have to be referred to reference pediatric centers to properly assess disease activity and disease-related damage (including low bone density in most cases), and to define the best treatment. Long-lasting corticosteroid therapy remains the gold standard, together with physiotherapy. Ongoing clinical trials are assessing the effect of several immunosuppressive and immunomodulatory drugs, which may help to control the disease and possibly demonstrate a corticosteroid-sparing effect. Most patients respond to treatment; relapses are frequent but a complete disease remission is achieved in most cases before adulthood., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Objective: To investigate the influence of myoinjury on antigen presentation to T cells in draining lymph nodes (LNs)., Methods: 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)., Results: 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., Conclusion: 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., (Copyright © 2012 by the American College of Rheumatology.)

Introduction: 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., Methods: Micromechanical injuries were performed daily in tibialis anterior muscles for 2 weeks., Results: 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., Conclusions: This induced fibrotic dystrophic model may be useful to study mechanisms of fibrosis in dystrophinopathies and to evaluate antifibrotic treatments., (Copyright © 2012 Wiley Periodicals, Inc.)

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.

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., (Copyright © 2011 Elsevier Inc. All rights reserved.)