T regulatory cells in xenotransplantation.

The role of T regulatory cells (Treg) in the induction and maintenance of allograft tolerance is being studied to a great extent. In contrast, little is known on their potential to prevent graft rejection in the field of xenotransplantation, where acute vascular rejection mediated by cellular and humoral mechanisms and thrombotic microangiopathy still prevents long-term graft survival. In this regard, the induction of donor-specific tolerance through isolation and expansion of xenoantigen-specific recipient Treg is currently becoming a focus of interest. This review will summarize the present knowledge concerning Treg and their potential use in xenotransplantation describing in particular CD4(+)CD25(+)Foxp3(+) T cells, CD8(+)CD28(-) Treg, double negative CD4(-)CD8(-) T cells, and natural killer Treg. Although only studied in vitro so far, human CD4(+)CD25(+)Foxp3(+) Treg is currently the best characterized subpopulation of regulatory cells in xenotransplantation. CD8(+)CD28(-) Treg and double negative CD4(-)CD8(-) Treg also seem to be implicated in tolerance maintenance of xenografts. Finally, one study revealing a role for natural killer CD4(+)Valpha14(+) Treg in the prolongation of xenograft survival needs further confirmation. To our opinion, CD4(+)CD25(+)Foxp3(+) Treg are a promising candidate to protect xenografts. In contrast to cadaveric allotransplantation, the donor is known prior to xenotransplantation. This advantage allows the expansion of recipient Treg in a xenoantigen specific manner before transplantation.

Pharmacological inhibition of interleukin-15 prevents colitis and associated bone loss in IL-10 knockout mice

Bone loss secondary to inflammatory bowel diseases (IBD) is largely explained by activated T cells producing cytokines that trigger osteoclastogenesis and accelerate bone resorptionwhile inhibiting bone formation. In IBD, elevated expression of interleukin (IL)-15, a T cell growth factor, plays a central role in T cell activation, pro-inflammatory cytokine production and the development of colitis. We previously reported that IL-15 enhances RANKL-induced osteoclastogenesis and that an IL-15 antagonist, CRB-15, prevents weight and bone loss in a mousemodel of dextran sulfate sodium-induced colitis.We hypothesized that inhibition of IL-15 signalingmight prevent bone loss in IL-10 deficient (IL10−/−) mice, that develop spontaneous bowel inflammation associatedwith osteopeniawhen they are no longer raised under germ-free conditions.Mice received anIL-15 antagonist (CRB-15, 5 μg/day, n=5) or IgG2a (5 μg/day, n=4) fromweek 10 to 14 of age. The severity of colitis was assessed by histology and bowel cytokine gene expression by real time PCR. Bone mass and architecturewere evaluated by ex vivo DXA on femur and micro-computed tomography on femur and vertebra. Bodyweight gainwas similar in the two groups. After 4 weeks, colonwas 29% shorter in CRB-15 treatedmice (p<0.006), a sign of reduced inflammation. Histological analysis indicated a transmural infiltration of inflammatory cells, lymphoepithelial lesions and increased size of villi (histological score=4/6) in IgG2a treated mice, whereas colon from CRB-15 treated mice exhibited mild infiltration of inflammatory cells of the lamina propria, no mucosal damages and a minimal increased size of villi (histological score=1.6/6). Levels of TNFα, IL-17 and IL-6 mRNA in the colon were significantly reduced in CRB-15 treated mice (p<0.04 vs IgG2), indicating a decrease in colon inflammation. CRB-15 improved femur BMD (+10.6% vs IgG2a, p<0.002), vertebral trabecular bone volume fraction (BV/TV, +19.7% vs IgG2a, p<0.05) and thickness (+11.6% vs IgG2a, p<0.02). A modest but not significant increase in trabecular BV/TV was observed at the distal femur. Cortical thicknesswas also higher at themidshaft femur in CRB-15 treatedmice (+8.3% vs IgG2a, p<0.02). In conclusion, we confirm and extend our results about the effects of CRB-15 in colitis. Antagonizing IL-15 may exert favorable effects on intestinal inflammation and prevent bone loss and microarchitecture alterations induced by colitis. This article is part of a Special Issue entitled ECTS 2011. Disclosure of interest: B. Brounais-Le Royer Grant / Research Support from Novartis Consumer Health Foundation, S. Ferrari-Lacraz: none declared, D. Velin: none declared, X. Zheng: none declared, S. Ferrari: none declared, D. Pierroz: none declared.

Early white matter alterations in men predisposed to FXTAS revealed by MT imaging.

Introduction: The Fragile X - associated Tremor Ataxia Syndrome (FXTAS) is a recently described, and under-diagnosed, late onset (≈ 60y) neurodegenerative disorder affecting male carriers of a premutation in the Fragile X Mental Retardation 1 (FMR1) gene. The premutation is an CGG (Cytosine-Guanine-Guanine) expansion (55 to 200 CGG repeats) in the proximal region of the FMR1 gene. Patients with FXTAS primarily present with cerebellar ataxia and intention tremor. Neuroradiological features of FXTAS include prominent white matter disease in the periventricular, subcortical, middle cerebellar peduncles and deep white matter of the cerebellum on T2-weighted or FLAIR MR imaging (Jacquemmont 2007, Loesch 2007, Brunberg 2002, Cohen 2006). We hypothesize that a significant white matter alteration is present in younger individuals many years prior to clinical symptoms and/or the presence of visible lesions on conventional MR sequences and might be detectable by magnetization transfer (MT) imaging. Methods: Eleven asymptomatic premutation carriers (mean age = 55 years) and seven intra-familial controls participated to the study. A standardized neurological examination was performed on all participants and a neuropsychological evaluation was carried out before MR scanning performed on a 3T Siemens Trio. The protocol included a sagittal T1-weighted 3D gradient-echo sequence (MPRAGE, 160 slices, 1 mm^3 isotropic voxels) and a gradient-echo MTI (FA 30, TE 15, matrix size 256*256, pixel size 1*1 mm, 36 slices (thickness 2mm), MT pulse duration 7.68 ms, FA 500, frequency offset 1.5 kHz). MTI was performed by acquiring consecutively two set of images; first with and then without the MT saturation pulse. MT images were coregistered to the T1 acquisition. The MTR for every intracranial voxel was calculated as follows: MTR = (M0 - MS)/M0*100%, creating a MTR map for each subject. As first analysis, the whole white matter (WM) was used to mask the MTR image in order to create an histogram of the MTR distribution in the whole tissue class over the two groups examined. Then, for each subject, we performed a segmentation and parcellation of the brain by means of Freesurfer software, starting from the high resolution T1-weighted anatomical acquisition. Cortical parcellations was used to assign a label to the underlying white matter by the construction of a Voronoi diagram in the WM voxels of the MR volume based on distance to the nearest cortical parcellation label. This procedure allowed us to subdivide the cerebral WM in 78 ROIs according to the cortical parcellation (see example in Fig 1). The cerebellum, by the same procedure, was subdivided in 5 ROIs (2 per each hemisphere and one corresponding to the brainstem). For each subject, we calculated the mean value of MTR within each ROI and averaged over controls and patients. Significant differences between the two groups were tested using a two sample T-test (p<0.01). Results: Neurological examination showed that no patient met the clinical criteria of Fragile X Tremor and Ataxia Syndrome yet. Nonetheless, premutation carriers showed some subtle neurological signs of the disorder. In fact, premutation carriers showed a significant increase of tremor (CRST, T-test p=0.007) and increase of ataxia (ICARS, p=0.004) when compared to controls. The neuropsychological evaluation was normal in both groups. To obtain general characterizations of myelination for each subject and premutation carriers, we first computed the distribution of MTR values across the total white matter volume and averaged for each group. We tested the equality of the two distributions with the non parametric Kolmogorov-Smirnov test and we rejected the null-hypothesis at a p=0.03 (fig. 2). As expected, when comparing the asymptomatic permutation carriers with control subjects, the peak value and peak position of the MTR values within the whole WM were decreased and the width of the distribution curve was increased (p<0.01). These three changes point to an alteration of the global myelin status of the premutation carriers. Subsequently, to analyze the regional myelination and white matter integrity of the same group, we performed a ROI analysis of MTR data. The ROI-based analysis showed a decrease of mean MTR value in premutation carriers compared to controls in bilateral orbito-frontal and inferior frontal WM, entorhinal and cingulum regions and cerebellum (Fig 3). The detection of these differences in these regions failed with other conventional MR techniques. Conclusions: These preliminary data confirm that in premutation carriers, there are indeed alterations in "normal appearing white matter" (NAWM) and these alterations are visible with the MT technique. These results indicate that MT imaging may be a relevant approach to detect both global and local alterations within NAWM in "asymptomatic" carriers of premutations in the Fragile X Mental Retardation 1 (FMR1) gene. The sensitivity of MT in the detection of these alterations might point towards a specific physiopathological mechanism linked to an underlying myelin disorder. ROI-based analyses show that the frontal, parahippocampal and cerebellar regions are already significantly affected before the onset of symptoms. A larger sample will allow us to determine the minimum CGG expansion and age associated with these subclinical white matter alterations.

Neuropathologie et pathologie moléculaire des gliomes [Neuropathology and molecular pathology of gliomas]

Gliomas are the most frequent primary brain tumours. The WHO classification is essentially based on histological and immunohistochemical criteria. More recently multiple cytogenetic and molecular alterations associated with initiation and progression have been shown and the genetic profiles of tumour entities have been incorporated in the WHO classifiacation. Molecular testing of the MGMT promotor methylation in glioblastoma, predictive for the response to combined radio-/chimiothérapie, and the LOH 1p/19q in oligodendroglial tumours, as prognostic factor supplements the histopathological diagnosis. In the near futur array-based profiling techniques will contribute to a refinement of glioma classification and identify targets for more individualized glioma therapies.

Correlation between plasma concentration of cilazapril and haemodynamic and hormonal effects in healthy man.

1. The haemodynamic and humoral effects of cilazapril, a new angiotensin converting enzyme (ACE) inhibitor, were evaluated in normotensive healthy volunteers. 2. Single oral doses of 1.25, 2.5, 5 and 10 mg of cilazapril inhibited ACE by greater than or equal to 90% and induced the expected pattern of changes of the renin-angiotensin-aldosterone-system. 3. Cilazapril had a long duration of action, since some ACE inhibition was still present 72 h after drug intake. 4. Cilazapril administered intravenously at doses of 5 and 20 micrograms kg-1 for 24 h did not produce any significant effects. 5. During repeated administration of cilazapril for 8 days, no accumulation of cilazaprilat was observed and the clinical tolerance was excellent. 6. In normal volunteers, cilazapril administered orally acts as a potent inhibitor of converting enzyme.

Alloimmunity and nonimmunologic risk factors in cardiac allograft vasculopathy.

Graft vasculopathy is an accelerated form of coronary artery disease that occurs in transplanted hearts. Despite major advances in immunosuppression, the prevalence of the disease has remained substantially unchanged during the last two decades. According to the 'response to injury' paradigm, graft vasculopathy is the result of a continuous inflammatory response to tissue injury initiated by both alloantigen-dependent and independent stress responses. Experimental evidence suggests that these responses may become self-sustaining, as allograft re-transplantation into the donor strain at a later stage fails to prevent disease progression. Histological evidence of endothelitis and arteritis, in association with intima fibrosis and atherosclerosis, reflects the central role of alloimmunity and inflammation in the development of arterial lesions. Experimental results in gene-targeted mouse models indicate that cellular and humoral immune responses are both involved in the pathogenesis of graft vasculopathy. Circulating antibodies against donor endothelium are found in a significant number of patients, but their pathogenic role is still controversial. Alloantigen-independent factors include donor-transmitted coronary artery disease, surgical trauma, ischaemia-reperfusion injury, viral infections, hyperlipidaemia, hypertension, and glucose intolerance. Recent therapeutic advances include the use of novel immunosuppressive agents such as sirolimus (rapamycin), HMG-CoA reductase inhibitors, calcium channel blockers, and angiotensin converting enzyme inhibitors. Optimal treatment of cardiovascular risk factors remains of paramount importance.

Developmental, metabolic and immunological costs of flea infestation in the common vole

Parasites use resources from their hosts, which can indirectly affect a number of host functions because of trade-offs in resource allocation. In order to get a comprehensive view of the costs imposed by blood sucking parasites to their hosts, it is important to monitor multiple components of the development and physiology of parasitized hosts over long time periods. The effect of infestation by fleas on body mass, body length growth, haematocrit, resistance to oxidative stress, resting metabolic rate and humoral immune response were experimentally evaluated. During a 3-month period, male common voles, Microtus arvalis, were either parasitized by rat fleas (Nosopsyllus fasciatus), which are naturally occurring generalist ectoparasites of voles, or reared without fleas. Then voles were challenged twice by injecting Keyhole Limpet Haemocyanin (KLH) to assess whether the presence of fleas affects the ability of voles to produce antibodies against a novel antigen. During the immune challenge we measured the evolution of body mass, haematocrit, resistance to oxidative stress and antibody production. Flea infestation negatively influenced the growth of voles. Moreover, parasitized voles had reduced haematocrit, higher resting metabolic rate and lower production of antibodies against the KLH. Resistance to oxidative stress was not influenced by the presence of fleas. During the immune challenge with KLH, body mass decreased in both groups, while the resistance to oxidative stress remained stable. In contrast, the haematocrit decreased only in parasitized voles. Our experiment shows that infestation by a haematophageous parasite negatively affects multiple traits like growth, energy consumption and immune response. Fleas may severely reduce the survival probability and reproductive success of their host in natural conditions.

Morphologic and electroretinographic phenotype of SR-BI knockout mice after a long-term atherogenic diet.

PURPOSE: To evaluate functional and ultrastructural changes in the retina of scavenger receptor B1 (SR-BI) knockout (KO) mice consuming a high fat cholate (HFC) diet. METHODS: Three-month-old male KO and wild-type (WT) mice were fed an HFC diet for 30 weeks. After diet supplementation, plasma cholesterol levels and electroretinograms were analyzed. Neutral lipids were detected with oil red O, and immunohistochemistry was performed on cryostat ocular tissue sections. The retina, Bruch's membrane (BM), retinal pigment epithelium (RPE), and choriocapillaris (CC) were analyzed by transmission electron microscopy. RESULTS: Using the WT for reference, ultrastructural changes were recorded in HFC-fed SR-BI KO mice, including lipid inclusions, a patchy disorganization of the photoreceptor outer segment (POS) and the outer nuclear layer (ONL), and BM thickening with sparse sub-RPE deposits. Within the CC, there was abnormal disorganization of collagen fibers localized in ectopic sites with sparse and large vacuolization associated with infiltration of macrophages in the subretinal space, reflecting local inflammation. These lesions were associated with electroretinographic abnormalities, particularly increasing implicit time in a- and b-wave scotopic responses. Abnormal vascular endothelial growth factor (VEGF) staining was detected in the outer nuclear layer. CONCLUSIONS: HFC-fed SR-BI KO mice thus presented sub-RPE lipid-rich deposits and functional and morphologic alterations similar to some features observed in dry AMD. The findings lend further support to the hypothesis that atherosclerosis causes retinal and subretinal damage that increases susceptibility to some forms of AMD.

Redox dysregulation in the pathophysiology of schizophrenia and bipolar disorder: insights from animal models.

Abstract Significance: Schizophrenia (SZ) and bipolar disorder (BD) are classified as two distinct diseases. However, accumulating evidence shows that both disorders share genetic, pathological, and epidemiological characteristics. Based on genetic and functional findings, redox dysregulation due to an imbalance between pro-oxidants and antioxidant defense mechanisms has been proposed as a risk factor contributing to their pathophysiology. Recent Advances: Altered antioxidant systems and signs of increased oxidative stress are observed in peripheral tissues and brains of SZ and BD patients, including abnormal prefrontal levels of glutathione (GSH), the major cellular redox regulator and antioxidant. Here we review experimental data from rodent models demonstrating that permanent as well as transient GSH deficit results in behavioral, morphological, electrophysiological, and neurochemical alterations analogous to pathologies observed in patients. Mice with GSH deficit display increased stress reactivity, altered social behavior, impaired prepulse inhibition, and exaggerated locomotor responses to psychostimulant injection. These behavioral changes are accompanied by N-methyl-D-aspartate receptor hypofunction, elevated glutamate levels, impairment of parvalbumin GABA interneurons, abnormal neuronal synchronization, altered dopamine neurotransmission, and deficient myelination. Critical Issues: Treatment with the GSH precursor and antioxidant N-acetylcysteine normalizes some of those deficits in mice, but also improves SZ and BD symptoms when given as adjunct to antipsychotic medication. Future Directions: These data demonstrate the usefulness of GSH-deficient rodent models to identify the mechanisms by which a redox imbalance could contribute to the development of SZ and BD pathophysiologies, and to develop novel therapeutic approaches based on antioxidant and redox regulator compounds. Antioxid. Redox Signal. 18, 1428-1443.

Increased EBV Reactivation in the Cerebrospinal Fluid of Patients with Early Multiple Sclerosis

Epstein-Barr virus (EBV) has been consistently associated with multiple sclerosis (MS), but whether this virus is a trigger of MS remains undetermined. Recently, EBV-infected B cells recognized by activated CD8_ T cells have been detected in the meninges of autopsied MS patients. In addition, a strong EBV-specific CD8_ T cell response in the blood of patients with MS of recent onset was reported. Here, to further explore the putative relationship between MS and EBV, we assessed the EBV-specific cellular and humoral immune responses in the blood and the cerebrospinal fluid (CSF) of patients with early MS or other neurological diseases, separated into inflammatory (IOND) and non-inflammatory (NIOND) groups. The MS non-associated neurotropic herpesvirus cytomegalovirus (CMV) served as a control. Fifty-eight study subjects were enrolled, including 44 patients (13 with early MS (onset of MS less than one year prior to the assay), 15 with IOND and 16 with NIOND) in the immunological arm of the study. The cellular immune response was investigated using a functional CFSE cytotoxic T lymphocyte (CTL) assay performed with short-term cultured EBV- or CMVspecific effector T cells from the CSF and the blood. The humoral immune response specific for these two viruses was also examined in both the blood and the CSF. The recruitment of a given virusspecific antibody in the CSF as compared to the blood was expressed as antibody indexes (AI). We found that, in the CSF of early MS patients, there was an enrichment in EBV-, but not CMV-specific, CD8_ CTL as compared to the CSF of IOND (P_ 0.003) and NIOND patients (P_0.0009), as well as compared to paired blood samples (P_0.005). Additionally, relative viral capsid antigen (VCA)-, but not EBV encoded nuclear antigen 1 (EBNA1)- or CMV-specific, AI were increased in the CSF of early MS as compared to IOND (P_0.002) or NIOND patients (P_0.008) and correlated with the EBVspecific CD8_ CTL responses in the CSF (rs_0.54, P_0.001). Fourteen additional patients were enrolled in the virological arm of the study: using semi-nested PCR, EBV-encoded nuclear RNA1 (EBER1)-a transcript expressed during all stages of EBV infection-was detected in the CSF of 2/4 early MS, but only 1/6 IOND and 0/4 NIOND patients. Altogether, our data suggest that a reactivation of EBV, but not CMV, is taking place in the central nervous system of patients with MS of recent onset. These data significantly strengthen the link between EBV and MS and may indicate a triggering role of EBV in this disease. This work was supported by grants from the Swiss National Foundation and from the Swiss Society for Multiple Sclerosis.

Do Mice Habituate to "Gentle Handling?" A Comparison of Resting Behavior, Corticosterone Levels and Synaptic Function in Handled and Undisturbed C57BL/6J Mice.

Study Objectives: "Gentle handling" has become a method of choice for 4-6 h sleep deprivation in mice, with repeated brief handling applied before sleep deprivation to induce habituation. To verify whether mice do indeed habituate was assess how 6 days of repeated brief handling impact on resting behavior, on stress, and on the subunit content of N-methyl-D-aspartate receptors (NMDARs) at hippocampal synapases, which is altered by sleep loss. We discuss whether repeated handling biases the outcome of subsequent sleep deprivation.Design: Adult C5BL/6J mice, maintained on a 12 h-12 h light-dark cycle, were left undistrubed for 3 days, then handled during 3 min daily for 6 days in the middle of the light phase. Mice were continuously monitored for their resting time serum conticosterona levels and synaptic NMDAR subunit composition were quantified.Results: Handling caused a similar to 25% reduction of resting time throughtout all handling days, After six, but not after one day of handling, mice had elevated serum corticosterone levels. Six-day handling augmented the presence of the NR2A subunit of NMDARs at hippocampal synapses.Conclusion: Repeated handling induces behavoir and neurochemical alterations that are absent in undisturbed animals. The presistently reduced resting time and the delayed increase in conticosterone levels indicate that mice do not habituate to handling over a 1-week period. Handling-induced modifications bias effects of gentle handling-induced sleep deprivation on sleep homeostasis, stress, glutamate receptor composition and signaling. A standardization of sleep deprivation procedures involving gengle handling will be important for unequivocally specifying how acute sleep loss affects brain function.

Characterization of Epstein-Barr virus-specific immune responses and of the novel cytokine interleukin-26 in patients with multiple sclerosis

RÉSUMÉ La sclérose en plaques (SEP) est une maladie démyélinisante du système nerveux central (SNC) qui touche le plus souvent de jeunes femmes. Bien qu'elle ait été décrite pour la première fois il y a plus de 200 ans, son étiologie n'est pas encore complètement comprise. Contrairement à d'autres maladies purement génétiques, l'épidémiologie de la SEP ne peut être que partiellement expliquée par des facteurs génétiques. Ceci suggère que des facteurs environnementaux pourraient être impliqués dans la pathogenèse de la SEP. Parmi ceux-ci, le virus d'Epstein-Barr (EBV) est un excellent candidat, comme cela a été démontré par de larges études séroépidémiologiques ainsi que pax l'évaluation de la réponse cellulaire dans le sang. Bien que le SNC soit en fait la cible des réponses immunitaires anormales dans la SEP, peu d'études ont été accomplies sur les réponses immunitaires spécifiques à EBV dans ce compartiment. Ceci est particulièrement vrai chez des patients vivants chez lesquels des biopsies sont rarement effectuées, ainsi que pour les réponses cellulaires car très peu de cellules immunitaires peuvent être obtenues du SNC. Nous avons donc développé des conditions de cultures et un readout nous permettant d'étudier le nombre réduit de cellules disponibles dans le liquide céphalo-rachidien (LCR), qui représente le seul matériel pouvant être obtenu du SNC de patients SEP vivants. Nous avons trouvé que les réponses cellulaires et humorales spécifiques à EBV étaient augmentées dans le LCR des patients SEP comparé à du sang pairé, ainsi que par rapport à des patients avec d'autres maladies neurologiques inflammatoires et noninflammatoires. Afin de déterminer si les réponses immunitaires augmentées contre EBV étaient spécifiques à ce virus ou si elles reflétaient simplement une hyperactivation immunitaire aspécifique, nous avons comparé les réponses spécifiques à EBV avec celles spécifiques au cytomegalovirus (CNN). En effet, comme EBV, CNN est un herpesvirus neurotropique qui peut établir des infections latentes, mais ce dernier n'est pas considéré comme étant associé à la SEP. De façon intéressante, les réponses immunitaires spécifiques à CNN trouvées dans le LCR étaient plus basses que dans le sang, et ceci dans toutes les catégories de patients. Ces données suggèrent qu'une réactivation d'EBV pourrait avoir lieu dans le SNC des patients SEP à un stade précoce de la maladie et renforcent fortement l'hypothèse qu'EBV pourrait avoir un rôle déclencheur dans cette maladie. Ainsi, il pourrait être intéressant d'explorer si un traitement ou un vaccin efficace contre EBV peut prévenir le développement de la SEP. On ne connaît toujours pas la raison pour laquelle les réponses immunitaires spécifiques à EBV sont augmentées chez les patients SEP. Une hypothèse est que la réponse immunitaire est qualitativement différente chez les patients SEP par rapports aux contrôles. Pour examiner ceci, nous avons évalué le profile cytokinique de lymphocytes T CD4+ et CD8+ stimulés par EBV, mais nous n'avons pas pu mettre en évidence de différence remarquable entre patients SEP et sujets sains. Cette question reste donc ouverte et d'autres études sont justifiées. Il n'existe pas de marqueur fiable de la SEP. Ici, nous avons trouvé que la cytokine IL-26, récemment décrite, était augmentée dans les lymphocytes T CD8+ des patients avec une SEP secondairement progressive comparé à des patients SEP en poussée, des patients avec une SEP primairement progressive, des patients avec d'autres maladies neurologiques inflammatoires, ou des sujets sains. De plus, nous avons identifié des types de cellules dérivées du cerveau (astrocytes, oligodendrocytes et neurones) qui exprimaient le récepteur de l'IL-26. Ceci ouvre la voie à d'autres études afin de mieux comprendre la fonction de l'II.-26 et son interaction avec la. SEP. SUMMARY : Multiple sclerosis (MS) is a demyelinating disease affecting the central nervous system (CNS), mostly in young female adults. Although it was first described 200 years ago, its etiology is still not completely understood. Contrary to other purely genetic diseases, genetics can explain only part of MS epidemiology. Therefore, environmental factors that might be involved in MS pathogenesis were searched for. Among them, Epstein-Barr virus (EBV) is a strong potential candidate, such as shown by large seroepidemiological studies and cellular immune response assessments in the blood. Although the CNS is the actual target of abnormal immune responses in MS, few studies have been performed on EBV-specific immune responses in this compartment. This is particularly true for live patients, from which biopsy material is almost never available, and for cellular immune responses, since very few immune cells are available from the CNS. We therefore developed culture conditions and a readout that were compatible with the study of the reduced number of cells found in the cerebrospinal fluid (CSF), the only readily available material from the CNS of live ' MS patients. We found that EBV-specific cellular and humoral immune responses were increased in the CSF of MS patients as compared with paired blood, as well as compared with the CSF of patients with other inflammatory and non-inflammatory neurological diseases. To determine whether the enhanced immune responses against EBV were specific of this virus or simply reflected an aspecific immune hyperactivation, we compared the EBV- with the cytomegalovirus (CMV)-specific immune responses. Indeed, like EBV, CMV is a neurotrophic herpesvirus that can establish latent infections, but the latter is not considered to be associated with MS. Interestingly, CSF CMV-specific immune responses were lower than blood ones and this, in all patient categories. These findings suggest that EBV reactivation may be taking place in the CNS of patients at the early stages of MS and strengthen the hypothesis that EBV may have a triggering role in this disease. Therefore, it might be interesting to explore whether an efficient anti-EBV drug or vaccine is able to prevent MS development. The reason why EBV-specific immune responses are increased in MS patients is still missing. One hypothesis might be that the immune response against EBV is qualitatively different in MS patients as compared with controls. To examine this, we assessed the cytokine mRNA profile of EBV-stimulated CD4+ and CD8+ T cells, but could not find any remarkable difference between MS patients and healthy controls. Therefore, this question remains open and fiirther studies are warranted. Reliable disease markers are lacking for MS. Here, we found that the recently described cytokine IL-26 was increased in CD8+ T cells of patients with secondary progressive MS as compared with relapsing MS, primary progressive MS, other inflammatory neurological diseases and healthy controls. Moreover, we identified brain cell types (astrocytes, oligodendrocytes and neurons) that expressed the IL-26 receptor, paring the way for further studies to understand IL-26 function and its interaction with MS.

Alterations of bone microarchitecture in young patients with inflammatory bowel diseases are associated with fracture risk during growth

Aims: Inflammatory bowel diseases (IBD) appearing during childhood and adolescence compromise peak bone mass acquisition and increase fracture risk. The structural determinants of bone fragility in IBD however remain unknown. Methods: We investigated volumetric bone mineral density (vBMD), trabecular and cortical bone microstructure at distal radius and tibia by high-resolution pQCT (XtremeCT, Scanco, Switzerland), aBMD at distal radius, hip and spine and vertebral fracture assessment (VFA) by DXA in 107 young patients (mean age 22.8 yrs, range 12.2-33.7 yrs; 62 females and 45 males) with Crohn's disease (n=75), ulcerative colitis (n=25), undetermined colitis (n=2), and no definitive diagnosis (n=5), and in 389 healthy young individuals. Results: Mean disease duration was 6.1 yrs, 89/107 IBD patients received corticosteroids, 83 other immunomodulators, and 59 vitamin D. Clinical fractures were reported by 38 patients (mean age at 1st fracture, 12.6 yrs), the vast majority of the forearm, arm or hand; 5 had vertebral crush fractures (Grade 1 or 2) and 11 had multiple fractures. As compared to healthy controls (matched 2:1 for age, sex, height and fracture history), the 102 patients with established IBD had similar weight but significantly lower aBMD at all sites, lower trabecular (Tb) BV/TV and number, and greater Tb separation and inhomogeneous Tb distribution (1/SD TbN) at both distal radius and tibia, lower tibia cortical thickness (CTh), but no differences in cortical vBMD nor bone perimeter. Among IBD's, aBMD was not associated with fractures (by logistic regression adjusted for age, age square, sex, height, weight and protein intake). However, radius and tibia Tb BV/TV, thickness and SD 1/TbN, as well as radius Tb separation and perimeter, were significantly associated with fracture risk (fully adjusted as above), whereas cortical vBMD and CTh were not. After adjustment for aBMD at radius, respectively at femur neck, radius SD 1/TbN and tibia BV/TV, TbTh and perimeter remained independently associated with fracture risk. Conclusions: Young subjects with IBD have low bone mass and poor bone microarchitecture compared to healthy controls. Alterations of bone microarchitecture, particularly in the trabecular bone compartment, are specifically associated with increased fracture risk during growth.

Low-replicating viruses and strong anti-viral immune response associated with prolonged disease control in a superinfected HIV-1 LTNP elite controller.

OBJECTIVE: To study the causes for the lack of clinical progression in a superinfected HIV-1 LTNP elite controller patient.¦METHODOLOGY AND PRINCIPAL FINDINGS: We studied host genetic, virological and immunological factors associated with viral control in a SI long term non progressor elite controller (LTNP-EC). The individual contained both viruses and maintained undetectable viral loads for >20 years and he did not express any of the described host genetic polymorphisms associated with viral control. None of four full-length gp160 recombinants derived from the LTNP-EC replicated in heterologous peripheral blood mononuclear cells. CTL responses after SI were maintained in two samples separated by 9 years and they were higher in breadth and magnitude than responses seen in most of 250 treatment naïve patients and also 25 controller subjects. The LTNP-EC showed a neutralization response, against 4 of the 6 viruses analyzed, superior to other ECs.¦CONCLUSIONS: The study demonstrated that a strong and sustained cellular and humoral immune response and low replicating viruses are associated with viral control in the superinfected LTNP-EC.

Tricky and terrible T-cell tumors: these are thrilling times for testing: molecular pathology of peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) encompass a group of rare and usually clinically aggressive diseases. The classification and diagnosis of these diseases are compounded by their marked pathological heterogeneity and complex clinical features. With the exception of ALK-positive anaplastic large cell lymphoma (ALCL), which is defined on the basis of ALK rearrangements, genetic features play little role in the definition of other disease entities. In recent years, hitherto unrecognized chromosomal translocations have been reported in small subsets of PTCLs, and genome-wide array-based profiling investigations have provided novel insights into their molecular characteristics. This article summarizes the current knowledge on the best-characterized genetic and molecular alterations underlying the pathogenesis of PTCLs, with a focus on recent discoveries, their relevance to disease classification, and their management implications from a diagnostical and therapeutical perspective.