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Immunotherapeutic Approaches in MS: Update on Pathophysiology and Emerging Agents or Strategies 2006
Abstract and Figures
Multiple sclerosis (MS) is a chronic disabling disease with significant implications for patients and society. The individual disease course is difficult to predict due to the heterogeneity of clinical presentation as well as radiological and pathological findings. Although its etiology still remains unknown, the last decade has generated considerable success in understanding the underlying pathophysiology of MS. In addition to its view as a prototypic inflammatory autoimmune disorder, recent data support the importance of primary and secondary neurodegenerative mechanisms such as oligodendrocyte death, axonal loss and ion channel dysfunction. The deepened understanding of the immunopathogenesis as well as the limited effectiveness of the currently approved disease modifying therapies have led to a tremendous number of trials investigating potentially new drug targets. Emerging treatments take into account the different immunopathological mechanisms as well as strategies to protect against axonal damage or to promote remyelination. This review provides a compilation of novel immunotherapeutic strategies or new aspects of known immunotherapeutic agents which have evolved recently. The pathogenetic rationale of these novel drug targets for the treatment of MS as well as accompanying preclinical and clinical data are highlighted.
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... As pre-eclampsia occurs mostly in 32 nd week of the pregnancy. (11) Nifidipine is present in 52 % of prescriptions which is again more than MgSO4. 100.0 100.0 ...
... the Abbottabad data the gestational age in which pre-eclampsia occurs 87% is 3 rd trimester which is according to the standard studies. As pre-eclampsia occurs mostly in 32 nd week of the pregnancy.(11) ...
World Health Organization introduced standard treatment guidelines for a killer disease of pregnant women worldwide, Preeclampsia, are compared with current practices in the tertiary care centers. Magnesium sulphate and delivery is the treatment of choice for pre-eclampsia. Implementation of STGs in the tertiary care centers of Islamabad that is Federal Government Services Hospital, Pakistan Institute of Medical Sciences and Shifa international Hospital are assessed. Furthermore the prescribing practice of Islamabad (three hospitals) sector is compared with such of the Abbottabad (Ayub Medical Complex), for pre-eclampsiac women. Knowledge of physicians in gynecology department at Islamabad and Abbottabad are assessed. In the tertiary care centers of Islamabad 45% patients are receiving magnesium sulphate as recommended by WHO 5% cases are delivery which is also standard way of treatment during preeclampsia. In Abbottabad sector 93% patients are receiving magnesium sulphate and 4% are delivery cases. The variation from WHO guidelines is least in Ayub Medical complex Abbottabad. This small researchon 200 patients also depicts the individual tertiary care center reports for STGs in pre-eclampsiac women. The knowledge of physician changes where a question occurs that their course of study do not contain précised WHO recognized book. There are some mind blowing facts inside this report. As a result I proudly say that our health sector is not very far away from standards proposed by World Health Organization for a better healthy
environment.
... Multiple sclerosis (MS) is a chronic and debilitating autoimmune disorder of the central nervous system (CNS), in which T and B cells are believed to play a major pathophysiological role. It can result in neurological impairment and severe disability [1][2][3]. In most MS patients, the first symptoms appear around the age of 20-40 years. ...
Aim: To gain insight into current treatment and barriers to optimal treatment for high disease activity relapsing remitting multiple sclerosis (MS) in the Netherlands. Materials & methods: A two-round Delphi panel using an online questionnaire was conducted. Seven MS neurologists from diverse locations in the Netherlands were invited to participate. Result: Out of the seven MS neurologists, five completed both questionnaire rounds. Conclusion: Effectiveness and side effects along with patient’s lesion load were the most important factors for choosing a disease modifying therapy (DMTs). Respondents felt restricted to optimally treat their patients due to reimbursement restrictions for certain disease modifying therapies, although agreed that satisfactory treatment options are currently available. The answers show consensus between the participating MS neurologists with high certainty of answers.
... Migration into the immune-privileged CNS is tightly regulated and accordingly alterations of this process are involved in CNS-related diseases like encephalomyelitis 3 , neuromyelitis optica, stroke, and multiple sclerosis (MS) 2,4,5,6,7 . Therefore, it is important to study lymphocyte extravasation to better understand disease pathophysiology and to develop tools for amelioration of disease burden 8,9,10,11,12 . ...
Lymphocyte extravasation into the central nervous system (CNS) is critical for immune surveillance. Disease-related alterations of lymphocyte extravasation might result in pathophysiological changes in the CNS. Thus, investigation of lymphocyte migration into the CNS is important to understand inflammatory CNS diseases and to develop new therapy approaches. Here we present an in vitro model of the human blood-brain barrier to study lymphocyte extravasation. Human brain microvascular endothelial cells (HBMEC) are confluently grown on a porous polyethylene terephthalate transwell insert to mimic the endothelium of the blood-brain barrier. Barrier function is validated by zonula occludens immunohistochemistry, transendothelial electrical resistance (TEER) measurements as well as analysis of evans blue permeation. This model allows investigation of the diapedesis of rare lymphocyte subsets such as CD56brightCD16dim/- NK cells. Furthermore, the effects of other cells, cytokines and chemokines, disease-related alterations, and distinct treatment regimens on the migratory capacity of lymphocytes can be studied. Finally, the impact of inflammatory stimuli as well as different treatment regimens on the endothelial barrier can be analyzed.
Die Multiple Sklerose (MS) ist eine autoimmunentzündliche Erkrankung des zentralen Nervensystems (ZNS), die zu Entmarkung (Demyelinisierung) sowie Zerstörung von Axonen und Neuronen führt. Sie stellt nach wie vor die häufigste Ursache erworbener Behinderung im jungen Erwachsenenalter dar. Weltweit leiden ca. 2,5 Mio. Menschen an MS, in Deutschland wird die Zahl der Betroffenen auf 100.000–120.000 geschätzt [180]. Die Inzidenz in Europa und Nordamerika beträgt 4–8/100.000 Einwohner, die Prävalenz zwischen 60–100/100.000 [313]. Der Erkrankungsmedian liegt bei 28 Jahren, wobei die MS in jüngster Zeit gehäuft bei Kindern und Jugendlichen diagnostiziert wird [72], [366]. Anderen Autoimmunerkrankungen folgend sind Frauen 1,5–2mal häufiger betroffen als Männer. Etwa 50 % der MS-Patienten benötigen nach 15 Jahren eine Gehhilfe [444], allerdings sind rund 10 % nach 25 Jahren auch ohne Therapie nicht wesentlich beeinträchtigt [208].
In the age of therapeutic immune modulation in terms of the capability of medical treatment directly affecting pathomechanisms of autoimmune and tumour diseases, the knowledge of immunological basics is growing rapidly. Starting with basic immunology, e. g. immune organs, cellular elements, antigen-antibody, antigen presentation, cytokines, this review will address topics having been brought into focus recently: 1) Autoreactive immune cells circulating in the healthy human immune system; 2) autoreactive cells in normal immune repertoire, being controlled by peripheral tolerance induction mechanisms, e. g. regulatory T-cells (Treg); 3) innovative therapies targeting B-cells, showing that this immune cell subpopulation may play a dual pathologic role as producers of autoantibodies, as well as antigen-presenting cells during activation of potentially autoreactive T cells.
Background
Patients who develop relapsing-remitting multiple sclerosis (MS) present with a first clinical demyelinating event. In this double-blind, multicentre, randomised, phase 3 study we investigated the effect of oral cladribine on conversion to clinically definite MS in patients with a first clinical demyelinating event, when given at the same doses shown to be effective in relapsing-remitting MS.
Methods
Between Oct 21, 2008, and Oct 11, 2010, we recruited patients aged 18–55 years, inclusive, from 160 hospitals, private clinics, or treatment centres in 34 countries. Eligible patients had a first clinical demyelinating event within 75 days before screening, at least two clinically silent lesions of at least 3 mm on a T2-weighted brain MRI scan, and an Expanded Disability Status Scale score of 5·0 or lower. Patients with a first clinical demyelinating event ≤75 days before screening were randomly assigned (1:1:1) to receive cladribine tablets at cumulative doses of 5·25 mg/kg or 3·5 mg/kg or placebo. Randomisation was done with a central web-based randomisation system and was stratified by geographic region. Masking was maintained using a two-physician model. The primary endpoint of this 96-week study was time to conversion to clinically definite MS according to the Poser criteria. This study is registered with ClinicalTrials.gov, number NCT00725985.
Findings
Of 903 participants assessed for eligibility, 616 patients received cladribine 5·25 mg/kg (n=204), cladribine 3·5 mg/kg (n=206), or placebo (n=206). At trial termination on Oct 25, 2011, cladribine was associated with a risk reduction versus placebo for time to conversion to clinically definite MS (hazard ratio [HR] for 5·25 mg/kg=0·38, 95% CI 0·25–0·58, p<0·0001; HR for 3·5 mg/kg=0·33, 0·21–0·51, p<0·0001). Adverse events were reported in 165 (81%) patients in the cladribine 5·25 mg/kg group, 168 (82%) patients in the cladribine 3·5 mg/kg group, and 162 (79%) patients in the placebo group. We noted no increase in risk of adverse events with active treatment versus placebo apart from lymphopenia, which was a severe event in 10 (5%) patients in the 5·25 mg/kg group and four (2%) patients in the 3·5 mg/kg group.
Interpretation
Both doses of cladribine significantly delayed MS diagnosis compared with placebo. The safety profile of cladribine was similar to that noted in a trial in patients with relapsing-remitting MS. Further research could clarify the potential effects of oral cladribine treatment in the early stages of MS.
Funding
Merck Serono SA Geneva, a subsidiary of Merck KGaA, Darmstadt, Germany.
BACKGROUND:
Cladribine provides immunomodulation through selective targeting of lymphocyte subtypes. We report the results of a 96-week phase 3 trial of a short-course oral tablet therapy in patients with relapsing-remitting multiple sclerosis.
METHODS:
We randomly assigned 1326 patients in an approximate 1:1:1 ratio to receive one of two cumulative doses of cladribine tablets (either 3.5 mg or 5.25 mg per kilogram of body weight) or matching placebo, given in two or four short courses for the first 48 weeks, then in two short courses starting at week 48 and week 52 (for a total of 8 to 20 days per year). The primary end point was the rate of relapse at 96 weeks.
RESULTS:
Among patients who received cladribine tablets (either 3.5 mg or 5.25 mg per kilogram), there was a significantly lower annualized rate of relapse than in the placebo group (0.14 and 0.15, respectively, vs. 0.33; P<0.001 for both comparisons), a higher relapse-free rate (79.7% and 78.9%, respectively, vs. 60.9%; P<0.001 for both comparisons), a lower risk of 3-month sustained progression of disability (hazard ratio for the 3.5-mg group, 0.67; 95% confidence interval [CI], 0.48 to 0.93; P=0.02; and hazard ratio for the 5.25-mg group, 0.69; 95% CI, 0.49 to 0.96; P=0.03), and significant reductions in the brain lesion count on magnetic resonance imaging (MRI) (P<0.001 for all comparisons). Adverse events that were more frequent in the cladribine groups included lymphocytopenia (21.6% in the 3.5-mg group and 31.5% in the 5.25-mg group, vs. 1.8%) and herpes zoster (8 patients and 12 patients, respectively, vs. no patients).
CONCLUSIONS:
Treatment with cladribine tablets significantly reduced relapse rates, the risk of disability progression, and MRI measures of disease activity at 96 weeks. The benefits need to be weighed against the risks. (ClinicalTrials.gov number, NCT00213135.)
2010 Massachusetts Medical Society
Comment in
Oral cladribine and fingolimod for relapsing multiple sclerosis. [N Engl J Med. 2010]
Oral therapy for multiple sclerosis--sea change or incremental step? [N Engl J Med. 2010]
ACP Journal Club. Oral cladribine was more effective than placebo for relapsing-remitting multiple sclerosis. [Ann Intern Med. 2010]
Oral cladribine and fingolimod for relapsing multiple sclerosis. [N Engl J Med. 2010]
BACKGROUND:
Cladribine provides immunomodulation through selective targeting of lymphocyte subtypes. We report the results of a 96-week phase 3 trial of a short-course oral tablet therapy in patients with relapsing-remitting multiple sclerosis.
METHODS:
We randomly assigned 1326 patients in an approximate 1:1:1 ratio to receive one of two cumulative doses of cladribine tablets (either 3.5 mg or 5.25 mg per kilogram of body weight) or matching placebo, given in two or four short courses for the first 48 weeks, then in two short courses starting at week 48 and week 52 (for a total of 8 to 20 days per year). The primary end point was the rate of relapse at 96 weeks.
RESULTS:
Among patients who received cladribine tablets (either 3.5 mg or 5.25 mg per kilogram), there was a significantly lower annualized rate of relapse than in the placebo group (0.14 and 0.15, respectively, vs. 0.33; P<0.001 for both comparisons), a higher relapse-free rate (79.7% and 78.9%, respectively, vs. 60.9%; P<0.001 for both comparisons), a lower risk of 3-month sustained progression of disability (hazard ratio for the 3.5-mg group, 0.67; 95% confidence interval [CI], 0.48 to 0.93; P=0.02; and hazard ratio for the 5.25-mg group, 0.69; 95% CI, 0.49 to 0.96; P=0.03), and significant reductions in the brain lesion count on magnetic resonance imaging (MRI) (P<0.001 for all comparisons). Adverse events that were more frequent in the cladribine groups included lymphocytopenia (21.6% in the 3.5-mg group and 31.5% in the 5.25-mg group, vs. 1.8%) and herpes zoster (8 patients and 12 patients, respectively, vs. no patients).
CONCLUSIONS:
Treatment with cladribine tablets significantly reduced relapse rates, the risk of disability progression, and MRI measures of disease activity at 96 weeks. The benefits need to be weighed against the risks. (ClinicalTrials.gov number, NCT00213135.)
Currently approved multiple sclerosis (MS) therapeutics have a mainly anti-inflammatory mode of action. However, a number of promising clinical trials have been initiated that either focus on neuroprotection or follow completely different treatment strategies. So far, all of these clinical trials have failed to show efficacy or had to be halted prematurely because of unexpected adverse events. Some others show results that are of unknown significance with regard to a reliable assessment of true efficacy versus safety. For example, trials addressing the highly promising sodium channel blockers are under close observation because of potential adverse effects after drug withdrawal.
Previously failed therapeutic approaches in MS have indicated that there are discrepancies between the theoretical expectations and practical outcomes of different compounds. Learning from these failures helps to optimize future study designs and to reduce risks to patients. This review summarizes trials on MS treatments since 2001 that failed or were interrupted, attempts to analyze the underlying reasons for failure, and discusses the implications for our current view of MS pathogenesis, clinical practice, and the design of future studies. In order to maintain clarity, this review focuses on neuroprotective and various other treatment strategies. Clinical trials addressing anti-inflammatory research strategies are presented elsewhere.
Experimental autoimmune encephalomyelitis (EAE) is an experimental demyelinating disease of rodents. In (PL/J x SJL) F1 mice, it is induced by immunization with the myelin basic protein peptide Ac1-11. Ac1-11 [4A], a myelin basic protein peptide analog with a single amino acid substitution, (i) binds to class II major histocompatibility complex molecules and stimulates encephalitogenic T cells in vitro better than Ac1-11, (ii) is nonimmunogenic and nonencephalitogenic in vivo in (PL/J x SJL)F1 mice, (iii) prevents EAE when administered before or at the time of immunization with Ac1-11, and (iv) prevents EAE when administered later, near the time of disease onset. Initial studies suggest that Ac1-11 [4A] does not prevent EAE by competitive inhibition or by activation of regulatory cells. Thus, substitution of a single amino acid in a myelin basic protein peptide confers the capacity to prevent rather than induce EAE, even after peptide-specific encephalitogenic T cells have been activated.
T cells expressing the alpha beta T-cell receptor (TCR) for antigen can elicit anti-idiotypic antibodies specific for the TCR that regulate T-cell function. Defined sequences of the TCR, however, have not been used to elicit specific antibodies and the role of cellular immunity directed against TCR determinants has not been studied. We immunized Lewis rats with a synthetic peptide representing a hypervariable region of the TCR V beta 8 molecule. Subsequent induction of experimental autoimmune encephalomyelitis, a paralytic disease of the central nervous system mediated primarily by V beta 8+ T cells specific for myelin basic protein was prevented. T cells specific for the TCR V beta 8 peptide conferred passive protection against the disease to naive rats, apparently by shifting the predominant T-cell response away from the major encephalitogenic epitope of basic protein. This is the first report demonstrating the use of a synthetic TCR V-region peptide to induce specific regulatory immunity and has important implications for the regulation of human disease characterized by common TCR V-gene usage.
More precise understanding of the immune response against T-cell receptors (TCRs) is a prerequisite for successful TCR vaccination therapy of multiple sclerosis and other neurological autoimmune diseases. We conducted a detailed analysis of a paradigmatic anti-TCR response, using synthetic TCR peptides and highly purified recombinant TCR V alpha and Vbeta variable chains for the selection of CD4+ T-cell lines from a healthy volunteer. The target TCR (designated TCR(HWBP-3)) was obtained from HWBP-3, an autologous CD4+ T-cell line specific for myelin basic protein. The V alpha and Vbeta chains of TCR(HWBP-3) were expressed in Escherichia coli and purified by Ni-chelate chromatography and SDS (sodium dodecyl sulphate) gel electrophoresis. Further, we synthesized a set of 13- to 22-mer peptides spanning the complementarity-determining regions (CDR) 1, 2 and 3 and the framework regions (FR) of the alpha and beta chains of TCR(HWBP-3). The TCR peptides and proteins were then used to select a panel of TCR-specific CD4+ T-cell lines from donor HW. Several T-cell lines cross-reacted with a recombinant V chain and synthetic peptide. Cross-reactive immunogenic TCR epitopes were identified in the FR1 and CDR3 regions of the TCR(HWBP-3) alpha chain and in the FR1, CDR1 and CDR2 regions of the TCR(HWBP-3) beta chain. The TCR proteins and peptides were recognized in the context of at least three different HLA-DR molecules [DR2a (DRB5*0101), DR2b (DRB1*1501) and DRB1\*1401/DRB3\*0202]. Notably, the majority of the TCR peptide-selected T-cell lines did not react with the full-length recombinant V chains, suggesting they recognize 'cryptic' determinants. Based on the diversity of the anti-TCR immune response, we suggest that candidate TCR peptides should be screened in vitro in functional experiments before they are clinically applied for TCR vaccination therapy.
Human peripheral blood T lymphocytes possess two types of K+ channels: the voltage-gated Kv1.3 and the calcium-activated IKCa1 channels. The use of peptidyl inhibitors of Kv1.3 and IKCa1 indicated that these channels are involved in the maintenance of membrane potential and that they play a crucial role in Ca2+ signaling during T-cell activation. Thus, in vitro blockade of Kv1.3 and IKCa1 leads to inhibition of cytokine production and lymphocyte proliferation. These observations prompted several groups of investigators in academia and pharmaceutical companies to characterize the expression of Kv1.3 and IKCa1 in different subsets of human T lymphocytes and to evaluate their potential as novel targets for immunosuppression. Recent in vivo studies showed that chronically activated T lymphocytes involved in the pathogenesis of multiple sclerosis present unusually high expression of Kv1.3 channels and that the treatment with selective Kv1.3 inhibitors can either prevent or ameliorate the symptoms of the disease. In this model of multiple sclerosis, blockade of IKCa1 channels had no effect alone, but improved the response to Kv1.3 inhibitors. In addition, the expression of Kv1.3 and IKCa1 channels in human cells is very restricted, which makes them attractive targets for a more cell-specific and less harmful action than what is typically obtained with classical immunosuppressants. Studies using high-throughput toxin displacement, 86Rb-efflux screening or membrane potential assays led to the identification of non-peptidyl small molecules with high affinity for Kv1.3 or IKCa1 channels. Analysis of structure-function relationships in Kv1.3 and IKCa1 channels helped define the binding sites for channel blockers, allowing the design of a new generation of small molecules with selectivity for either Kv1.3 or IKCa1, which could help the development of new drugs for safer treatment of auto-immune diseases.
Efalizumab (Raptiva; Genentech/Xoma/Serono) is a monoclonal antibody that binds to CD11a, a cell-surface protein that has a key role in the pathological immune response in the skin disorder psoriasis. Following its approval by the FDA in October 2003 for the treatment of moderate-to-severe psoriasis, how is efalizumab likely to fare in this increasingly competitive market?
Myelin basic protein (MBP)-specific T cell lines and clones have been established from rats of the major histocompatibility complex (MHC)-compatible Lewis and BS strains. All lines and clones are MHC class II restricted and share the CD4 phenotype. The cells proliferate specifically in response to either a peptide representing amino acids #68–88 of guinea pig MBP, to residues #47–67 or to an unidentified myelin antigen which is distinct from MBP. All lines and clones specific for MBP express the same T cell receptor (TcR) variable (V) β chain element, which is homologous to the mouse Vβ8.2 gene segment. Three lines/clones with the same antigen fine specificity have identical VβDβJβ junctions on the protein level, a region which represents part of the potential antigen-binding protion of the TcR; two of the lines express members of the Vα2 family. These results suggest biased usage of TcR Vβ elements in rat T cells specific for MBP. Our findings broaden the basis for a rational therapeutic strategy to specifically intervene in the rodent model system of experimental allergic encephalomyelitis.
We performed immunocytochemical studies to analyze the inflammatory infiltrate and major histocompatibility complex class II (Ia) antigen expression in the spinal cord of Lewis rats with acute experimental allergic encephalomyelitis (EAE) induced by inoculation with myelin basic protein and adjuvants. Using antibodies to lymphocyte markers and other monoclonal antibodies we found that during clinical episodes the inflammatory infiltrate was chiefly composed of T lymphocytes and macrophages. The majority of cells in the inflammatory infiltrate were stained by the W3/25 antibody to CD4 and a proportion was stained by OX22 which labels the high molecular weight form of the leucocyte common antigen (CD45RC). CD8+ T cells were sparse and B cells were not detected. There was minimal staining with the OX39 antibody to the interleukin-2 receptor. Presumptive microglia, identified by their dendritic morphology, expressed Ia antigen during the clinical episodes and after recovery. The prominence of Ia antigen expression after recovery could indicate that this Ia expression was associated with downregulation of the encephalitogenic immune response. We also performed flow cytometry studies on cells extracted from the spinal cord of rats before and during attacks of EAE. With flow cytometry, we found that in established disease a mean of 83(SD, 23)% of CD2+ cells were CD4+, and a mean of 27(SD, 12)% of CD2+ cells were CD45RC+. In rats sampled on the first day of signs, a mean of 43(SD, 22)% of CD2+ cells were CD45RC+. In the cells extracted from the spinal cord of rats with established disease a mean of 47(SD, 32)% of macrophages were CD45RC+. Our study has combined an immunocytochemical assessment of tissue sections with quantitative flow cytometry assessment of cells extracted from the spinal cord of rats with acute EAE. We have shown that the majority of T lymphocytes in the spinal cord are CD45RC-. We have also found prominent Ia expression on dendritic cells in acute EAE and after clinical recovery.
