Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis

Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.

Meningeal B-cell follicles in secondary progressive multiple sclerosis associate with early onset of disease and severe cortical pathology

Intrathecal antibody production is a hallmark of multiple sclerosis and humoral immunity is thought to play an important role in the inflammatory response and development of demyelinated lesions. The presence of lymphoid follicle-like structures in the cerebral meninges of some multiple sclerosis patients indicates that B-cell maturation can be sustained locally within the CNS and contribute to the establishment of a compartmentalized humoral immune response. In this study we examined the distribution of ectopic B-cell follicles in multiple sclerosis cases with primary and secondary progressive clinical courses to determine their association with clinical and neuropathological features. A detailed immunohistochemical and morphometric analysis was performed on post-mortem brain tissue samples from 29 secondary progressive (SP) and 7 primary progressive (PP) multiple sclerosis cases. B-cell follicles were detected in the meninges entering the cerebral sulci of 41.4% of the SPMS cases, but not in PPMS cases. The SPMS cases with follicles significantly differed from those without with respect to a younger age at multiple sclerosis onset, irreversible disability and death and more pronounced demyelination, microglia activation and loss of neurites in the cerebral cortex. Cortical demyelination in these SPMS cases was also more severe than in PPMS cases. Notably, all meningeal B-cell follicles were found adjacent to large subpial cortical lesions, suggesting that soluble factors diffusing from these structures have a pathogenic role. These data support an immunopathogenetic mechanism whereby B-cell follicles developing in the multiple sclerosis meninges exacerbate the detrimental effects of humoral immunity with a subsequent major impact on the integrity of the cortical structures.

Meningeal inflammation is widespread and linked to cortical pathology in multiple sclerosis

Meningeal inflammation in the form of ectopic lymphoid-like structures has been suggested to play a prominent role in the development of cerebral cortical grey matter pathology in multiple sclerosis. The aim of this study was to analyse the incidence and distribution of B cell follicle-like structures in an extensive collection of cases with secondary progressive multiple sclerosis with a wide age range and to determine their relationship to diffuse meningeal inflammation, white matter perivascular infiltrates and microglial activation. One hundred and twenty three cases with secondary progressive multiple sclerosis were examined for the presence of meningeal and perivascular immune cell infiltrates in tissue blocks and/or whole coronal macrosections encompassing a wide array of brain areas. Large, dense, B cell-rich lymphocytic aggregates were screened for the presence of follicular dendritic cells, proliferating B cells and plasma cells. Ectopic B cell follicle-like structures were found, with variable frequency, in 49 cases (40%) and were distributed throughout the forebrain, where they were most frequently located in the deep sulci of the temporal, cingulate, insula and frontal cortex. Subpial grey matter demyelinated lesions were located both adjacent to, and some distance from such structures. The presence of B cell follicle-like structures was associated with an accompanying quantitative increase in diffuse meningeal inflammation that correlated with the degree of microglial activation and grey matter cortical demyelination. The median age of disease onset, time to disease progression, time to wheelchair dependence and age at death all differed significantly in these cases when compared with those without B cell follicle-like structures. Our findings suggest that meningeal infiltrates may play a contributory role in the underlying subpial grey matter pathology and accelerated clinical course, which is exacerbated in a significant proportion of cases by the presence of B cell follicle-like structures.

A Gradient of neuronal loss and meningeal inflammation in multiple sclerosis

OBJECTIVE

Prominent inflammation with formation of ectopic B-cell follicle-like structures in the meninges in secondary progressive multiple sclerosis (MS) (SPMS) is associated with extensive cortical pathology and an exacerbated disease course. Our objective was to evaluate the cellular substrates of the cortical damage to understand the role of meningeal inflammation in MS pathology.

METHODS

Using >600 tissue blocks from 37 cases of SPMS and 14 non-neurological controls, we carried out a detailed quantitative analysis of cortical atrophy and layer-specific changes in cell populations in SPMS cases with (F(+) SPMS) and without (F⁻ SPMS) B-cell follicle-like structures.

RESULTS

B-cell follicle-like structures were detected in the inflamed meninges of 20 of 37 SPMS cases (54%) and were associated with increased subpial cortical demyelination and cortical atrophy. A clear gradient of neuronal loss was observed in grey matter lesions and normal-appearing grey matter in the motor cortex of F(+) SPMS cases. The density of pyramidal neurons was significantly reduced in layers III and V of the motor cortex. Neuronal loss was accompanied by glia limitans damage with astrocyte loss and an opposite gradient of increased density of activated microglia. No gradient of neuronal loss was seen in F⁻ SPMS cases.

INTERPRETATION

We demonstrate substantial cortical neurodegeneration and generalized cell loss in progressive MS in association with meningeal inflammation and lymphoid tissue formation, supporting the hypothesis that cytotoxic factors diffusing from the meningeal compartment contribute to grey matter pathology and the consequent increase in clinical disability.

Effect of high-dose simvastatin on brain atrophy and disability in secondary progressive multiple sclerosis (MS-STAT): a randomised, placebo-controlled, phase 2 trial

BACKGROUND

Secondary progressive multiple sclerosis, for which no satisfactory treatment presently exists, accounts for most of the disability in patients with multiple sclerosis. Simvastatin, which is widely used for treatment of vascular disease, with its excellent safety profile, has immunomodulatory and neuroprotective properties that could make it an appealing candidate drug for patients with secondary progressive multiple sclerosis.

METHODS

We undertook a double-blind, controlled trial between Jan 28, 2008, and Nov 4, 2011, at three neuroscience centres in the UK. Patients aged 18-65 years with secondary progressive multiple sclerosis were randomly assigned (1:1), by a centralised web-based service with a block size of eight, to receive either 80 mg of simvastatin or placebo. Patients, treating physicians, and outcome assessors were masked to treatment allocation. The primary outcome was the annualised rate of whole-brain atrophy measured from serial volumetric MRI. Analyses were by intention to treat and per protocol. This trial is registered with ClinicalTrials.gov, number NCT00647348.

FINDINGS

140 participants were randomly assigned to receive either simvastatin (n=70) or placebo (n=70). The mean annualised atrophy rate was significantly lower in patients in the simvastatin group (0·288% per year [SD 0·521]) than in those in the placebo group (0·584% per year [0·498]). The adjusted difference in atrophy rate between groups was -0·254% per year (95% CI -0·422 to -0·087; p=0·003); a 43% reduction in annualised rate. Simvastatin was well tolerated, with no differences between the placebo and simvastatin groups in proportions of participants who had serious adverse events (14 [20%] vs nine [13%]).

INTERPRETATION

High-dose simvastatin reduced the annualised rate of whole-brain atrophy compared with placebo, and was well tolerated and safe. These results support the advancement of this treatment to phase 3 testing.

FUNDING

The Moulton Foundation [charity number 1109891], Berkeley Foundation [268369], the Multiple Sclerosis Trials Collaboration [1113598], the Rosetrees Trust [298582] and a personal contribution from A Pidgley, UK National Institute of Health Research (NIHR) University College London Hospitals/UCL Biomedical Research Centres funding scheme.

Meningeal inflammation plays a role in the pathology of primary progressive multiple sclerosis

The primary progressive form of multiple sclerosis is characterized by accrual of neurological dysfunction from disease onset without remission and it is still a matter of debate whether this disease course results from different pathogenetic mechanisms compared with secondary progressive multiple sclerosis. Inflammation in the leptomeninges has been identified as a key feature of secondary progressive multiple sclerosis and may contribute to the extensive cortical pathology that accompanies progressive disease. Our aim was to investigate the extent of perivascular and meningeal inflammation in primary progressive multiple sclerosis in order to understand their contribution to the pathogenetic mechanisms associated with cortical pathology. A comprehensive immunohistochemical analysis was performed on post-mortem brain tissue from 26 cases with primary progressive multiple sclerosis. A variable extent of meningeal immune cell infiltration was detected and more extensive demyelination and neurite loss in the cortical grey matter was found in cases exhibiting an increased level of meningeal inflammation. However, no tertiary lymphoid-like structures were found. Profound microglial activation and reduction in neuronal density was observed in both the lesions and normal appearing grey matter compared with control cortex. Furthermore, cases with primary progressive multiple sclerosis with extensive meningeal immune cell infiltration exhibited a more severe clinical course, including a shorter disease duration and younger age at death. Our data suggest that generalized diffuse meningeal inflammation and the associated inflammatory milieu in the subarachnoid compartment plays a role in the pathogenesis of cortical grey matter lesions and an increased rate of clinical progression in primary progressive multiple sclerosis.

Inflammatory intrathecal profiles and cortical damage in multiple sclerosis

OBJECTIVE

Gray matter (GM) damage and meningeal inflammation have been associated with early disease onset and a more aggressive disease course in multiple sclerosis (MS), but can these changes be identified in the patient early in the disease course?

METHODS

To identify possible biomarkers linking meningeal inflammation, GM damage, and disease severity, gene and protein expression were analyzed in meninges and cerebrospinal fluid (CSF) from 27 postmortem secondary progressive MS and 14 control cases. Combined cytokine/chemokine CSF profiling and 3T magnetic resonance imaging (MRI) were performed at diagnosis in 2 independent cohorts of MS patients (35 and 38 subjects) and in 26 non-MS patients.

RESULTS

Increased expression of proinflammatory cytokines (IFNγ, TNF, IL2, and IL22) and molecules related to sustained B-cell activity and lymphoid-neogenesis (CXCL13, CXCL10, LTα, IL6, and IL10) was detected in the meninges and CSF of postmortem MS cases with high levels of meningeal inflammation and GM demyelination. Similar proinflammatory patterns, including increased levels of CXCL13, TNF, IFNγ, CXCL12, IL6, IL8, and IL10, together with high levels of BAFF, APRIL, LIGHT, TWEAK, sTNFR1, sCD163, MMP2, and pentraxin III, were detected in the CSF of MS patients with higher levels of GM damage at diagnosis.

INTERPRETATION

A common pattern of intrathecal (meninges and CSF) inflammatory profile strongly correlates with increased cortical pathology, both at the time of diagnosis and at death. These results suggest a role for detailed CSF analysis combined with MRI as a prognostic marker for more aggressive MS. Ann Neurol 2018 Ann Neurol 2018;83:739-755.

Autologous haematopoietic stem cell transplantation for treatment of multiple sclerosis

Autologous haematopoietic stem cell transplantation (AHSCT) is a multistep procedure that enables destruction of the immune system and its reconstitution from haematopoietic stem cells. Originally developed for the treatment of haematological malignancies, the procedure has been adapted for the treatment of severe immune-mediated disorders. Results from ∼20 years of research make a compelling case for selective use of AHSCT in patients with highly active multiple sclerosis (MS), and for controlled trials. Immunological studies support the notion that AHSCT causes qualitative immune resetting, and have provided insight into the mechanisms that might underlie the powerful treatment effects that last well beyond recovery of immune cell numbers. Indeed, studies have demonstrated that AHSCT can entirely suppress MS disease activity for 4-5 years in 70-80% of patients, a rate that is higher than those achieved with any other therapies for MS. Treatment-related mortality, which was 3.6% in studies before 2005, has decreased to 0.3% in studies since 2005. Current evidence indicates that the patients who are most likely to benefit from and tolerate AHSCT are young, ambulatory and have inflammatory MS activity. Clinical trials are required to rigorously test the efficacy, safety and cost-effectiveness of AHSCT against highly active MS drugs.

The neuropathological basis of clinical progression in multiple sclerosis

Multiple sclerosis is the major inflammatory condition affecting the central nervous system (CNS) and is characterised by disseminated focal immune-mediated demyelination. Demyelination is accompanied by variable axonal damage and loss and reactive gliosis. It is this pathology that is thought to be responsible for the clinical relapses that often respond well to immunomodulatory therapy. However, the later secondary progressive stage of MS remains largely refractory to treatment and it is widely suggested that accumulating axon loss is responsible for clinical progression. Although initially thought to be a white matter (WM) disease, it is increasingly apparent that extensive pathology is also seen in the grey matter (GM) throughout the CNS. GM pathology is characterised by demyelination in the relative absence of an immune cell infiltrate. Neuronal loss is also seen both in the GM lesions and in unaffected areas of the GM. The slow progressive nature of this later stage combined with the presence of extensive grey matter pathology has led to the suggestion that neurodegeneration might play an increasing role with increasing disease duration. However, there is a paucity of studies that have correlated the pathological features with clinical milestones during secondary progressive MS. Here, we review the contributions that the various types of pathology are likely to make to the increasing neurological deficit in MS.

COVID-19-related acute necrotizing encephalopathy with brain stem involvement in a patient with aplastic anemia

Objective

To describe a novel case of coronavirus disease 2019 (COVID-19)-associated acute necrotizing encephalopathy (ANE) in a patient with aplastic anemia where there was early brain stem-predominant involvement.

Methods

Evaluation of cause, clinical symptoms, and treatment response.

Results

A 59-year-old woman with a background of transfusion-dependent aplastic anemia presented with seizures and reduced level of consciousness 10 days after the onset of subjective fever, cough, and headache. Nasopharyngeal swab testing for severe acute respiratory syndrome coronavirus (SARS-CoV-2) was positive, and CT during admission demonstrated diffuse swelling of the brain stem. She required intubation and mechanical ventilation for airway protection, given her reduced level of consciousness. The patient's condition deteriorated, and MRI on day 6 demonstrated worsening brain stem swelling with symmetrical hemorrhagic lesions in the brain stem, amygdalae, putamina, and thalamic nuclei. Appearances were consistent with hemorrhagic ANE with early brain stem involvement. The patient showed no response to steroid therapy and died on the eighth day of admission.

Conclusions

COVID-19 may be associated with an acute severe encephalopathy and, in this case, was considered most likely to represent an immune-mediated phenomenon. As the pandemic continues, we anticipate that the spectrum of neurologic presentation will broaden. It will be important to delineate the full clinical range of emergent COVID-19-related neurologic disease.

Substantial archaeocortical atrophy and neuronal loss in multiple sclerosis

Recent studies have revealed extensive neocortical pathology in multiple sclerosis (MS). The hippocampus is a unique archaeocortical structure understudied in MS. It plays a central role in episodic and anterograde memory-the most frequently impaired cognitive modalities in MS. This histopathological study aimed to investigate inflammatory demyelination and neurodegenerative changes in the MS archaeocortex. A detailed quantitative analysis was performed on hippocampal autopsy tissue from 45 progressive MS cases and seven controls. Forty-one lesions were identified in 28 of the 45 hippocampal MS-blocks examined, with percentage area of demyelination averaging 30.4%. The majority of lesions were chronic and subpially or subependymally located. Compared to controls, neuronal numbers were decreased by 27% in CA1 and 29.7% in CA3-2. Furthermore, the size of neurones was decreased by 17.4% in CA1. There was evidence of gross hippocampal atrophy with a 22.3% reduction in the average cross-sectional area, which correlated with neuronal loss. Our study provides evidence of substantial archaeocortical pathology largely resembling patterns seen in the neocortex and suggests that hippocampal involvement could contribute to memory impairments often seen in MS.

Regulation of the immune response. I. Reduction in ability of specific antibody to inhibit long-lasting IgG immunological priming after removal of the Fc fragment

The ability of 7S and F(ab')(2) antibody fragments to suppress priming with low doses of antigen was compared. The 7S preparation was approximately 100-1000 times more potent than the F(ab')(2) preparation when the agglutinin titers of the two preparations were the same. The presence of any ability to suppress priming in the F(ab')(2) preparation may reflect an inherent capacity of the F(ab')(2) antibody or contamination with small amounts of 7S antibody. The difference between 7S and F(ab')(2) antibody in ability to suppress priming is attributed to the lack of the Fc portion on the F(ab')(2) antibody. The Fc portion may be needed to prevent rapid excretion of antibody from the body, to induce rapid phagocytosis of antigen-antibody complexes with consequent breakdown and elimination of antigen, or to inactivate or suppress the antigen-sensitive cells from reacting to antigenic determinants. More detailed studies will permit a better assessment of the importance of these three possible regulatory roles of the Fc portion of the immunoglobulin in the immune response.

Increased PK11195 PET binding in the cortex of patients with MS correlates with disability

OBJECTIVE

Activated microglia are thought to play a major role in cortical gray matter (GM) demyelination in multiple sclerosis (MS). Our objective was to evaluate microglial activation in cortical GM of patients with MS in vivo and to explore its relationship to measures of disability.

METHODS

Using PET and optimized modeling and segmentation procedures, we investigated cortical (11)C-PK11195 (PK11195) binding in patients with relapsing-remitting MS (RRMS), patients with secondary progressive MS (SPMS), and healthy controls. Disability was assessed with the Expanded Disability Status Scale (EDSS) and Multiple Sclerosis Impact Scale (MSIS-29).

RESULTS

Patients with MS showed increased cortical GM PK11195 binding relative to controls, which was multifocal and highest in the postcentral, middle frontal, anterior orbital, fusiform, and parahippocampal gyri. Patients with SPMS also showed additional increases in precentral, superior parietal, lingual and anterior superior, medial and inferior temporal gyri. Total cortical GM PK11195 binding correlated with EDSS scores, with a stronger correlation for the subgroup of patients with SPMS. In patients with SPMS, PK11195 binding also correlated with MSIS-29 scores. No correlation with disability measures was seen for PK11195 binding in white matter. Higher EDSS scores correlated with higher levels of GM PK11195 binding in the postcentral gyrus for patients with RRMS and in precentral gyrus for those with SPMS.

CONCLUSIONS

Microglial activation in cortical GM of patients with MS can be assessed in vivo. The distribution is not uniform and shows a relationship to clinical disability. We speculate that the increased PK11195 binding corresponds to enhanced microglial activation described in postmortem SPMS cortical GM.

Hippocampal Neuroinflammation, Functional Connectivity, and Depressive Symptoms in Multiple Sclerosis

BACKGROUND

Depression, a condition commonly comorbid with multiple sclerosis (MS), is associated more generally with elevated inflammatory markers and hippocampal pathology. We hypothesized that neuroinflammation in the hippocampus is responsible for depression associated with MS. We characterized the relationship between depressive symptoms and hippocampal microglial activation in patients with MS using the 18-kDa translocator protein radioligand [(18)F]PBR111. To evaluate pathophysiologic mechanisms, we explored the relationships between hippocampal neuroinflammation, depressive symptoms, and hippocampal functional connectivities defined by resting-state functional magnetic resonance imaging.

METHODS

The Beck Depression Inventory (BDI) was administered to 11 patients with MS and 22 healthy control subjects before scanning with positron emission tomography and functional magnetic resonance imaging. We tested for higher [(18)F]PBR111 uptake in the hippocampus of patients with MS relative to healthy control subjects and examined the correlations between [(18)F]PBR111 uptake, BDI scores, and hippocampal functional connectivities in the patients with MS.

RESULTS

Patients with MS had an increased hippocampal [(18)F]PBR111 distribution volume ratio relative to healthy control subjects (p = .024), and the hippocampal distribution volume ratio was strongly correlated with the BDI score in patients with MS (r = .86, p = .006). Hippocampal functional connectivities to the subgenual cingulate and prefrontal and parietal regions correlated with BDI scores and [(18)F]PBR111 distribution volume ratio.

CONCLUSIONS

Our results provide evidence that hippocampal microglial activation in MS impairs the brain functional connectivities in regions contributing to maintenance of a normal affective state. Our results suggest a rationale for the responsiveness of depression in some patients with MS to effective control of brain neuroinflammation. Our findings also lend support to further investigation of the role of inflammatory processes in the pathogenesis of depression more generally.

Inflammatory processes may predispose children to high-altitude pulmonary edema

We investigated retrospectively whether the preexistence of inflammation-producing illnesses such as viral respiratory tract infections contributed to the development of high-attitude pulmonary edema in children. We found that the large majority of native low-attitude children, but not adults, who had this form of edema after traveling to high altitude also had evidence of a preexisting illness. We speculate that the release of inflammatory mediators associated with these illnesses may be tolerated at sea level but may predispose children to increased capillary permeability when superimposed on hypoxia and, possibly, cold and exercise.

Intensive Therapy With Growth Factor Support for Patients With Ewing Tumor Metastatic at Diagnosis: Pediatric Oncology Group/Children's Cancer Group Phase II Study 9457—A Report From the Children's Oncology Group

Purpose

Prognosis is poor for Ewing sarcoma patients with metastasis at diagnosis. We intensified a five-drug therapy (ifosfamide, etoposide alternated with vincristine, doxorubicin, and cyclophosphamide) using filgrastim but not stem-cell support. We studied topotecan alone and combined with cyclophosphamide in therapeutic windows before the five-drug therapy. A randomly assigned proportion of patients received amifostine as a cytoprotective agent.

Patients and Methods

Eligible patients were ≤ 30 years old and had histologically proven Ewing sarcoma or primitive neuroectodermal tumor (PNET) and metastasis at diagnosis. Chemotherapeutic cycles began every 21 days, after recovery from toxicities.

Results

One hundred ten of the 117 patients enrolled were eligible. Thirty-six patients received initial topotecan. Three had partial responses (PRs), and 17 had progressive disease (PD). Thirty-seven patients were administered topotecan and cyclophosphamide; 21 of these patients achieved PR, and one patient had PD. In a randomly assigned group of 69 patients, amifostine did not provide myeloprotection, which was measured by absolute neutrophil count, platelet count, or cycle intervals. The best responses to the overall therapy included 45 complete responses, 41 PRs, stable disease in 14 patients, and PD in five patients. For all patients, the 2-year event-free survival (EFS) rate was 24% (± 4%), and the overall survival rate was 46% (± 5%). For the 39 patients with isolated pulmonary metastases, the 2-year EFS rate was 31% (± 7%) compared with 20% (± 5%) for patients with more widespread disease.

Conclusion

Topotecan had limited activity in patients with Ewing sarcoma or PNET metastatic at diagnosis. The topotecan-cyclophosphamide combination was active. Amifostine was not myeloprotective. Overall results showed no improvement compared with previous studies.

Longitudinal Assessment of Multiple Sclerosis with the Brain-Age Paradigm

OBJECTIVE

During the natural course of multiple sclerosis (MS), the brain is exposed to aging as well as disease effects. Brain aging can be modeled statistically; the so-called "brain-age" paradigm. Here, we evaluated whether brain-predicted age difference (brain-PAD) was sensitive to the presence of MS, clinical progression, and future outcomes.

METHODS

In a longitudinal, multicenter sample of 3,565 magnetic resonance imaging (MRI) scans, in 1,204 patients with MS and clinically isolated syndrome (CIS) and 150 healthy controls (mean follow-up time: patients 3.41 years, healthy controls 1.97 years), we measured "brain-predicted age" using T1-weighted MRI. We compared brain-PAD among patients with MS and patients with CIS and healthy controls, and between disease subtypes. Relationships between brain-PAD and Expanded Disability Status Scale (EDSS) were explored.

RESULTS

Patients with MS had markedly higher brain-PAD than healthy controls (mean brain-PAD +10.3 years; 95% confidence interval [CI] = 8.5-12.1] versus 4.3 years; 95% CI = 2.1 to 6.4; p < 0.001). The highest brain-PADs were in secondary-progressive MS (+13.3 years; 95% CI = 11.3-15.3). Brain-PAD at study entry predicted time-to-disability progression (hazard ratio 1.02; 95% CI = 1.01-1.03; p < 0.001); although normalized brain volume was a stronger predictor. Greater annualized brain-PAD increases were associated with greater annualized EDSS score (r = 0.26; p < 0.001).

INTERPRETATION

The brain-age paradigm is sensitive to MS-related atrophy and clinical progression. A higher brain-PAD at baseline was associated with more rapid disability progression and the rate of change in brain-PAD related to worsening disability. Potentially, "brain-age" could be used as a prognostic biomarker in early-stage MS, to track disease progression or stratify patients for clinical trial enrollment. ANN NEUROL 2020 ANN NEUROL 2020;88:93-105.

Biochemical and genetic characterization of the action of triclosan on Staphylococcus aureus

Triclosan, a widely used antibacterial agent, possesses potent activity against Staphylococcus aureus. This study reports on an investigation of the antibacterial target of triclosan in this pathogen. A strain of S. aureus overexpressing the enoyl-[acyl-carrier-protein] reductase (FabI), demonstrated by Western immunoblotting, gave rise to an increase in the MIC of triclosan, while susceptibilities to a range of unrelated antibacterials were unaffected. There are approximately 12 000 molecules of FabI per cell in mid-log phase growth. This number increased by approximately three- to four-fold in the S. aureus FabI overexpressor. Triclosan selectively inhibited the incorporation of [(14)C]acetate into TCA-precipitable product, an indicator of fatty acid biosynthesis. Furthermore, it inhibited de novo fatty acid biosynthesis in this organism. In vitro, triclosan inhibited recombinant, purified S. aureus FabI with an IC(50) of approximately 1 microM. The combination of these biochemical and genetic data provide further evidence that the mode of action of triclosan in S. aureus is via inhibition of FabI.

Effect of high-dose simvastatin on cognitive, neuropsychiatric, and health-related quality-of-life measures in secondary progressive multiple sclerosis: secondary analyses from the MS-STAT randomised, placebo-controlled trial

Background

In the 24-month MS-STAT phase 2 trial, we showed that high-dose simvastatin significantly reduced the annualised rate of whole brain atrophy in patients with secondary progressive multiple sclerosis (SPMS). We now describe the results of the MS-STAT cognitive substudy, in which we investigated the treatment effect on cognitive, neuropsychiatric, and health-related quality-of-life (HRQoL) outcome measures.

Methods

We did a secondary analysis of MS-STAT, a 24-month, double-blind, controlled trial of patients with SPMS done at three neuroscience centres in the UK between Jan 28, 2008, and Nov 4, 2011. Patients were randomly assigned (1:1) to either 80 mg simvastatin (n=70) or placebo (n=70). The cognitive assessments done were the National Adult Reading Test, Wechsler Abbreviated Scale of Intelligence, Graded Naming Test, Birt Memory and Information Processing Battery (BMIPB), Visual Object and Space Perception battery (cube analysis), Frontal Assessment Battery (FAB), and Paced Auditory Serial Addition Test. Neuropsychiatric status was assessed using the Hamilton Depression Rating Scale and the Neuropsychiatric Inventory Questionnaire. HRQoL was assessed using the self-reported 36-Item Short Form Survey (SF-36) version 2. Assessments were done at study entry, 12 months, and 24 months. Patients, treating physicians, and outcome assessors were masked to treatment allocation. Analyses were by intention to treat. MS-STAT is registered with ClinicalTrials.gov, number NCT00647348.

Findings

Baseline assessment revealed impairments in 60 (45%) of 133 patients on the test of frontal lobe function (FAB), and in between 13 (10%) and 43 (33%) of 130 patients in tests of non-verbal and verbal memory (BMIPB). Over the entire trial, we noted significant worsening on tests of verbal memory (T score decline of 5·7 points, 95% CI 3·6–7·8; p<0·0001) and non-verbal memory (decline of 6·8 points, 4·8–8·7; p<0·0001). At 24 months, the FAB score was 1·2 points higher in the simvastatin-treated group than in the placebo group (95% CI 0·2–2·3). The simvastatin group also had a 2·5 points better mean physical component score of the SF-36 (95% CI 0·3–4·8; p=0·028). A treatment effect was not noted for any other outcomes.

Interpretation

To our knowledge, this SPMS cohort is the largest studied to date with comprehensive longitudinal cognitive, neuropsychiatric, and HRQoL assessments. We found evidence of a positive effect of simvastatin on frontal lobe function and a physical quality-of-life measure. Although we found no effect of simvastatin on the other outcome measures, these potential effects warrant confirmation and underline the importance of fully assessing cognition and quality of life in progressive multiple sclerosis treatment trials.

Funding

The Moulton Foundation, the Berkeley Foundation, the Multiple Sclerosis Trials Collaboration, the Rosetrees Trust, a personal contribution from A W Pidgley CBE, and the National Institute for Health Research University College London Hospitals Biomedical Research Centre and University College London.

B cell rich meningeal inflammation associates with increased spinal cord pathology in multiple sclerosis

Increased inflammation in the cerebral meninges is associated with extensive subpial cortical grey matter pathology in the forebrain and a more severe disease course in a substantial proportion of secondary progressive multiple sclerosis (SPMS) cases. It is not known whether this relationship extends to spinal cord pathology. We assessed the contribution of meningeal and parenchymal immune infiltrates to spinal cord pathology in SPMS cases characterized in the presence (F+) or absence (F-) of lymphoid-like structures in the forebrain meninges. Transverse cryosections of cervical, thoracic and lumbar cord of 22 SPMS and five control cases were analyzed for CD20+ B cells, CD4+ and CD8+ T cells, microglia/macrophages (IBA-1+), demyelination (myelin oligodendrocyte glycoprotein+) and axon density (neurofilament-H+). Lymphoid-like structures containing follicular dendritic cell networks and dividing B cells were seen in the spinal meninges of 3 out of 11 F+ SPMS cases. CD4+ and CD20+ cell counts were increased in F+ SPMS compared to F- SPMS and controls, whilst axon loss was greatest in motor and sensory tracts of the F+ SPMS cases (P < 0.01). The density of CD20+ B cells of the spinal leptomeninges correlated with CD4+ T cells and total B and T cells of the meninges; with the density of white matter perivascular CD20+ and CD4+ lymphocytes (P < 0.05); with white matter lesion area (P < 0.05); and the extent of axon loss (P < 0.05) in F+ SPMS cases only. We show that the presence of lymphoid-like structures in the forebrain is associated with a profound spinal cord pathology and local B cell rich meningeal inflammation associates with the extent of cord pathology. Our work supports a principal role for B cells in sustaining inflammation and tissue injury throughout the CNS in the progressive disease stage.

Stratification and monitoring of natalizumab-associated progressive multifocal leukoencephalopathy risk: recommendations from an expert group

The use of natalizumab for highly active relapsing-remitting multiple sclerosis (MS) is influenced by the occurrence of progressive multifocal leukoencephalopathy (PML). Through measurement of the anti-JCV antibody index, and in combination with the presence or absence of other known risk factors, it may be possible to stratify patients with MS according to their risk of developing PML during treatment with natalizumab and detect early suspected PML using MRI including a diffusion-weighted imaging sequence. This paper describes a practical consensus guideline for treating neurologists, based on current evidence, for the introduction into routine clinical practice of anti-JCV antibody index testing of immunosuppressant-naïve patients with MS, either currently being treated with, or initiating, natalizumab, based on their anti-JCV antibody status. Recommendations for the frequency and type of MRI screening in patients with varying index-associated PML risks are also discussed. This consensus paper presents a simple and pragmatic algorithm to support the introduction of anti-JCV antibody index testing and MRI monitoring into standard PML safety protocols, in order to allow some JCV positive patients who wish to begin or continue natalizumab treatment to be managed with a more individualised analysis of their PML risk.

Functional role of the cytoplasmic domain of the integrin alpha 5 subunit

The purpose of this study was to explore the functional role of the cytoplasmic domain of the alpha subunit of the alpha 5/beta 1 integrin, a fibronectin receptor. Mutant CHO cells that express very low levels of endogenous hamster alpha 5 subunit (CHO clone B2) were transfected with an expression vector containing full-length or truncated human alpha 5 cDNAs to form chimeric human alpha 5/hamster beta 1 integrins. Three transfectants were examined: B2a27 expresses a full-length human alpha 5 subunit with 27 amino acids in the cytoplasmic domain; B2a10 expresses an alpha 5 with a 17-amino acid cytoplasmic truncation; B2a1 expresses an alpha 5 with a 26-amino acid truncation. Levels of alpha 5/beta 1 surface expression in B2a27 and B2a10 cells were similar to that in wild type CHO cells. The expression of alpha 5/beta 1 in B2a1 cells was less, amounting to 15-20% of WT levels, despite message levels that were three to five times greater than those of B2a27. The transfectants were used to examine the role of the alpha 5 cytoplasmic domain in cell adhesion, cell motility, cytoskeletal organization, and integrin-mediated tyrosine phosphorylation. The adhesion characteristics of B2a27 and B2a10 cells on fibronectin substrata were similar to each other and to wild type CHO cells. B2a1 cells displayed slight reductions in the strength and rate of adhesion to fibronectin. Cell motility in the presence of fibronectin was similar for B2a27, B2a10, and wild type CHO cells, while the B2a1 cells were substantially less motile. Comparable degrees of cell spreading and extensive organization of actin filaments were observed for B2a27, B2a10, and wild type CHO cells on fibronectin substrata. The B2a1 cells spread to a lesser degree, and some organization of actin was observed; the untransfected B2 cells remained round on fibronectin substrata and showed no actin reorganization. Since the reduced motility and cell spreading observed in the B2a1 cells might be due either to reduced surface expression of alpha 5/beta 1 or to the truncation in the alpha 5 cytoplasmic domain, we used flow cytometric cell sorting to select populations of B2a1 and B2a27 cells expressing similar levels of cell surface alpha 5. The deficits in spreading and motility were present in B2a1 cells expressing high levels of alpha 5. Thus the region of the alpha 5 cytoplasmic domain adjacent to the membrane seems to play an important role in cytoskeletal organization and cell motility. We also examined whether alpha subunit truncation would affect integrin-mediated tyrosine phosphorylation.(ABSTRACT TRUNCATED AT 400 WORDS)

Extensive grey matter pathology in the cerebellum in multiple sclerosis is linked to inflammation in the subarachnoid space

AIMS

Multiple sclerosis (MS) is a progressive inflammatory neurological disease affecting myelin, neurons and glia. Demyelination and neurodegeneration of cortical grey matter contribute to a more severe disease, and inflammation of the forebrain meninges associates with pathology of the underlying neocortical grey matter, particularly in deep sulci. We assessed the extent of meningeal inflammation of the cerebellum, another structure with a deeply folded anatomy, to better understand the association between subarachnoid inflammation and grey matter pathology in progressive MS.

METHODS

We examined demyelinating and neuronal pathology in the context of meningeal inflammation in cerebellar tissue blocks from a cohort of 27 progressive MS cases previously characterized on the basis of the absence/presence of lymphoid-like aggregates in the forebrain meninges, in comparison with 11 non-neurological controls.

RESULTS

Demyelination and meningeal inflammation of the cerebellum was greatest in those cases previously characterized as harbouring lymphoid-like structures in the forebrain regions. Meningeal inflammation was mild to moderate in cerebellar tissue blocks, and no lymphoid-like structures were seen. Quantification of meningeal macrophages, CD4+, CD8+ T lymphocytes, B cells and plasma cells revealed that the density of meningeal macrophages associated with microglial activation in the grey matter, and the extent of grey matter demyelination correlated with the density of macrophages and plasma cells in the overlying meninges, and activated microglia of the parenchyma.

CONCLUSIONS

These data suggest that chronic inflammation is widespread throughout the subarachnoid space and contributes to a more severe subpial demyelinating pathology in the cerebellum.

Meningeal inflammation changes the balance of TNF signalling in cortical grey matter in multiple sclerosis

Background

Recent studies of cortical pathology in secondary progressive multiple sclerosis have shown that a more severe clinical course and the presence of extended subpial grey matter lesions with significant neuronal/glial loss and microglial activation are associated with meningeal inflammation, including the presence of lymphoid-like structures in the subarachnoid space in a proportion of cases.

Methods

To investigate the molecular consequences of pro-inflammatory and cytotoxic molecules diffusing from the meninges into the underlying grey matter, we carried out gene expression profiling analysis of the motor cortex from 20 post-mortem multiple sclerosis brains with and without substantial meningeal inflammation and 10 non-neurological controls.

Results

Gene expression profiling of grey matter lesions and normal appearing grey matter not only confirmed the substantial pathological cell changes, which were greatest in multiple sclerosis cases with increased meningeal inflammation, but also demonstrated the upregulation of multiple genes/pathways associated with the inflammatory response. In particular, genes involved in tumour necrosis factor (TNF) signalling were significantly deregulated in MS cases compared with controls. Increased meningeal inflammation was found to be associated with a shift in the balance of TNF signalling away from TNFR1/TNFR2 and NFkB-mediated anti-apoptotic pathways towards TNFR1- and RIPK3-mediated pro-apoptotic/pro-necroptotic signalling in the grey matter, which was confirmed by RT-PCR analysis. TNFR1 was found expressed preferentially on neurons and oligodendrocytes in MS cortical grey matter, whereas TNFR2 was predominantly expressed by astrocytes and microglia.

Conclusions

We suggest that the inflammatory milieu generated in the subarachnoid space of the multiple sclerosis meninges by infiltrating immune cells leads to increased demyelinating and neurodegenerative pathology in the underlying grey matter due to changes in the balance of TNF signalling.

In Vivo Assessment of Brain White Matter Inflammation in Multiple Sclerosis with (18)F-PBR111 PET

PET radioligand binding to the 18-kD translocator protein (TSPO) in the brains of patients with multiple sclerosis (MS) primarily reflects activated microglia and macrophages. We previously developed genetic stratification for accurate quantitative estimation of TSPO using second-generation PET radioligands. In this study, we used (18)F-PBR111 PET and MR imaging to measure relative binding in the lesional, perilesional, and surrounding normal-appearing white matter of MS patients, as an index of the innate immune response.

METHODS

(18)F-PBR111 binding was quantified in 11 MS patients and 11 age-matched healthy volunteers, stratified according to the rs6971 TSPO gene polymorphism. Fluid-attenuated inversion recovery and magnetization transfer ratio (MTR) MR imaging were used to segment the white matter in MS patients as lesions, perilesional volumes, nonlesional white matter with reduced MTR, and nonlesional white matter with normal MTR.

RESULTS

(18)F-PBR111 binding was higher in the white matter lesions and perilesional volumes of MS patients than in white matter of healthy controls (P < 0.05). Although there was substantial heterogeneity in binding between different lesions, a within-subject analysis showed higher (18)F-PBR111 binding in MS lesions (P < 0.05) and in perilesional (P < 0.05) and nonlesional white matter with reduced MTR (P < 0.005) than in nonlesional white matter with a normal MTR. A positive correlation was observed between the mean (18)F-PBR111 volume of distribution increase in lesions relative to nonlesional white matter with a normal MTR and the MS severity score (Spearman ρ = 0.62, P < 0.05).

CONCLUSION

This study demonstrates that quantitative TSPO PET with a second-generation radioligand can be used to characterize innate immune responses in MS in vivo and provides further evidence supporting an association between the white matter TSPO PET signal in lesions and disease severity. Our approach is practical for extension to studies of the role of the innate immune response in MS for differentiation of antiinflammatory effects of new medicines and their longer term impact on clinical outcome.