Anti-viral properties of interferon beta treatment in patients with multiple sclerosis

ECTRIMS/EAN consensus on vaccination in people with multiple sclerosis: Improving immunization strategies in the era of highly active immunotherapeutic drugs

BACKGROUND

With the new highly active drugs available for people with multiple sclerosis (pwMS), vaccination becomes an essential part of the risk management strategy.

OBJECTIVE

To develop a European evidence-based consensus for the vaccination strategy of pwMS who are candidates for disease-modifying therapies (DMTs).

METHODS

This work was conducted by a multidisciplinary working group using formal consensus methodology. Clinical questions (defined as population, interventions, and outcomes) considered all authorized DMTs and vaccines. A systematic literature search was conducted and quality of evidence was defined according to the Oxford Centre for Evidence-Based Medicine Levels of Evidence. The recommendations were formulated based on the quality of evidence and the risk-benefit balance.

RESULTS

Seven questions, encompassing vaccine safety, vaccine effectiveness, global vaccination strategy and vaccination in sub-populations (pediatric, pregnant women, elderly and international travelers) were considered. A narrative description of the evidence considering published studies, guidelines, and position statements is presented. A total of 53 recommendations were agreed by the working group after three rounds of consensus.

CONCLUSION

This first European consensus on vaccination in pwMS proposes the best vaccination strategy according to current evidence and expert knowledge, with the goal of homogenizing the immunization practices in pwMS.

SARS-CoV-2 infection in multiple sclerosis patients: interaction with treatments, adjuvant therapies, and vaccines against COVID-19

The SARS-CoV-2 pandemic has raised particular concern for people with Multiple Sclerosis, as these people are believed to be at increased risk of infection, especially those being treated with disease-modifying therapies. Therefore, the objective of this review was to describe how COVID-19 affects people who suffer from Multiple Sclerosis, evaluating the risk they have of suffering an infection by this virus, according to the therapy to which they are subjected as well as the immune response of these patients both to infection and vaccines and the neurological consequences that the virus can have in the long term. The results regarding the increased risk of infection due to treatment are contradictory. B-cell depletion therapies may cause patients to have a lower probability of generating a detectable neutralizing antibody titer. However, more studies are needed to help understand how this virus works, paying special attention to long COVID and the neurological symptoms that it causes.

Functional significance of the rare rs35667974 IFIH1 gene polymorphism, associated with multiple autoimmune diseases, using a structural biological approach

Autoimmune diseases, which affect approximately 5% of human population, are a range of diseases in which the immune response to self-antigens results in damage or dysfunction of tissues. Recent genome wide association studies (GWAS) have successfully identified novel autoimmune disease-associated loci, with many of them shared by multiple disease-associated pathways but much of the genetics and pathophysiological mechanisms remain still obscure. Considering that most of the potential causal variants are still unknown, many studies showed that the missense variant rs35667974 at interferon-induced with helicase C domain 1 (IFIH1) gene is protective for type 1 diabetes (T1D), psoriasis (PS) and psoriatic arthritis (PsA). Recently, this variant was found to be also associated with ankylosing spondylitis (AS), Crohn's disease (CD) and ulcerative colitis (UC). The IFIH1 gene encodes a cytoplasmic RNA helicase otherwise known as melanoma differentiation-associated 5 (MDA5) that recognizes viral RNA and is involved in innate immunity through recognition of viral RNA. In the present study we sought to investigate the association of the rare rs35667974 variant of IFIH1 gene, which resides in exon 14 and changes a conserved isoleucine at position #923 to valine, in the development of various autoimmune diseases and give a reason for the selectivity affecting different autoimmune diseases. Evolutionary studies and three-dimensional (3 D) homology modelling were employed on the MDA5 protein product, through its association with dsRNA, recognition factor controlling cytokine and chemokine signalling, to investigate the protective role of the MDA5 variant for certain autoimmune diseases.

Update on the management of multiple sclerosis during the COVID-19 pandemic and post pandemic: An international consensus statement

In this consensus statement, we provide updated recommendations on multiple sclerosis (MS) management during the COVID-19 crisis and the post-pandemic period applicable to neurology services around the world. Statements/recommendations were generated based on available literature and the experience of 13 MS expert panelists using a modified Delphi approach online. The statements/recommendations give advice regarding implementation of telemedicine; use of disease-modifying therapies and management of MS relapses; management of people with MS at highest risk from COVID-19; management of radiological monitoring; use of remote pharmacovigilance; impact on MS research; implications for lowest income settings, and other key issues.

SARS-CoV-2 Infection and Risk Management in Multiple Sclerosis

The novel coronavirus can cause a severe respiratory disease with impact on the central nervous system, as has been reported by several medical health services. In the COVID-19 pandemic caused by the SARS-CoV-2 neurotrophic virus, neurologists have focused their attention on the early identification of suggestive manifestations of the neurological impact of the disease. In this context, they are exploring related chronic disease and the possibility of achieving a more effective understanding of symptoms derived from COVID-19 infection and those derived from the course of preexisting neurological disease. The present review summarizes evidence from the infection with SARS-CoV-2 and the management of the risks of multiple sclerosis and how it is related to the risks of general comorbidities associated with COVID-19. In addition, we reviewed other factors characteristic of MS, such as relapses, and the maximum tolerated dose of treatment medications from clinical and experimental evidence.

Interferons and Multiple Sclerosis: Lessons from 25 Years of Clinical and Real-World Experience with Intramuscular Interferon Beta-1a (Avonex)

Recombinant interferon (IFN) β-1b was approved by the US Food and Drug Administration as the first disease-modifying therapy (DMT) for multiple sclerosis (MS) in 1993. Since that time, clinical trials and real-world observational studies have demonstrated the effectiveness of IFN therapies. The pivotal intramuscular IFN β-1a phase III trial published in 1996 was the first to demonstrate that a DMT could reduce accumulation of sustained disability in MS. Patient adherence to treatment is higher with intramuscular IFN β-1a, given once weekly, than with subcutaneous formulations requiring multiple injections per week. Moreover, subcutaneous IFN β-1a is associated with an increased incidence of injection-site reactions and neutralizing antibodies compared with intramuscular administration. In recent years, revisions to MS diagnostic criteria have improved clinicians' ability to identify patients with MS and have promoted the use of magnetic resonance imaging (MRI) for diagnosis and disease monitoring. MRI studies show that treatment with IFN β-1a, relative to placebo, reduces T2 and gadolinium-enhancing lesions and gray matter atrophy. Since the approval of intramuscular IFN β-1a, a number of high-efficacy therapies have been approved for MS, though the benefit of these high-efficacy therapies should be balanced against the increased risk of serious adverse events associated with their long-term use. For some subpopulations of patients, including pregnant women, the safety profile of IFN β formulations may provide a particular benefit. In addition, the antiviral properties of IFNs may indicate potential therapeutic opportunities for IFN β in reducing the risk of viral infections such as COVID-19.

Managing Disease-Modifying Therapies and Breakthrough Activity in Multiple Sclerosis Patients During the COVID-19 Pandemic: Toward an Optimized Approach

The emergence of the novel coronavirus disease 2019 (COVID-19) pandemic has become a major public health challenge of global concern since December 2019, when the virus was recognized in Wuhan, the capital city of Hubei province in China and epicenter of the COVID-19 epidemic. Given the novelty of COVID-19 and the lack of specific anti-virus therapies, the current management is essentially supportive. There is an absence of consensus on guidelines or treatment strategies for complex disorders such as multiple sclerosis (MS), in which the risk of infections is higher than in the general population. This is due to the overall impairment of the immune system typical of autoimmune diseases, in addition to accumulation of disabilities, and the iatrogenic effect generated by corticosteroids and the recommended disease-modifying therapies (DMTs). DMTs have different modes of action, but all modulate and interfere with the patient's immune response, thereby raising concerns about adverse effects, such as an increased susceptibility to infections. In this review, we analyze the evidence for use of DMTs during the current critical period and ratify an algorithmic approach for management to optimize care between keeping DMTs, with their infection hazards, or coming off them, with the risk of disease activation. We also provide an algorithmic approach to the management of breakthrough activity during the COVID-19 pandemic.

COVID-19 and MS disease-modifying therapies

OBJECTIVE

To address concerns regarding the effect of MS disease-modifying therapies (DMTs) on the expression of coronavirus 2019 (COVID-19).

METHODS

Review of the current state of knowledge regarding the viral etiology of COVID-19, mechanisms of injury by SARS-CoV-2 infection, and the effect of individual DMTs on the risk of infection and COVID-19 disease expression.

RESULTS

Although data are limited, MS DMTs do not obviously increase the risk of acquiring symptomatic SARS-CoV-2 infection. The severe morbidity and mortality of SARS-CoV-2 appear to be largely the consequence of an overly robust immune response rather than the consequence of unchecked viral replication. The effects of specific MS DMTs on the immune response that may increase the risk of impaired viral clearance and their potential counterbalancing beneficial effects on the development of COVID-19-associated acute respiratory distress syndrome are reviewed.

CONCLUSION

Although there is currently insufficient real-world experience to definitively answer the question of the effect of a specific MS DMT on COVID-19, registries presently in nascent form should provide these answers. This review provides an approach to addressing these concerns while the data are being accumulated. Early insights suggest that the risk of infection and associated morbidity of COVID-19 in this population is little different than that of the population at large.

Merkel cell polyomavirus DNA in the blood of patients with neurological diseases and healthy controls

Aim: Merkel cell polyomavirus (MCPyV) is the etiological agent of Merkel cell carcinoma. Its genome has been detected in anatomic districts from healthy and ill subjects. Data regarding the MCPyV DNAemia in neurological patients are lacking. Materials & methods: Blood was obtained from 129 neurological patients and 181 controls (HIV positive or negative). Real-time polymerase chain reaction (Q-PCR) was conducted to quantify MCPyV loads in blood specimens. Results: MCPyV DNA was detected in 17.1% of cases and 11.0% of controls in <1% of cells. No association between MCPyV DNA presence and HIV status was observed. Conclusion: Blood cells may be a reservoir for MCPyV. The presence of MCPyV genome in blood of healthy subjects might be relevant for transfusion medicine.

Synergetic and antagonistic effects of combined calcitriol and interferon-β treatment on cytokine production by stimulated PBMCs

BACKGROUND

We evaluated the effects of calcitriol and interferon-β on in vitro PBMC cytokine production from a cohort of 22 healthy adults not on medication.

METHODS

PBMCs were incubated with calcitriol and/or 100 or 400IU interferon-β or nothing, followed by stimulation with concanavalin A.

RESULTS

When combined, calcitriol and interferon-β appeared to potentiate the effects of one another on reducing IL-6. Calcitriol significantly reduced the production of IL-2, IL-4, IL-6, and IFN-γ, while interferon-β significantly reduced production of IL-6 and TNF-α, and increased IL-10.

DISCUSSION

This is the first study to evaluate the effects of combined calcitriol and interferon-β on cytokine production in PBMCs in vitro, demonstrating novel synergetic effects.

Targeted mutations in Val101 and Arg27 interferon beta protein increase its transcriptional and translational activities

Interferon β (IFNβ) is the most prescribed drug that has been used frequently for the treatment of multiple sclerosis (MS) patients. The aim of this study is to improve the production of IFNβ by induction of site directed mutagenesis. Accordingly, recombinant constructs were designed in order to enhance the expression of IFNβ mRNA and protein. The recombinant plasmids were transfected to the CHO cell line, following RNA extractions and cDNA synthesis. The effects of recombinant constructs were analyzed by real time PCR, ELISA and MTT assay. Transfected samples with either IFNβ101 or IFNβ101+27 have shown 11.55 and 2.26 fold elevation and over-expression compare to the wild type construct respectively. Our data also indicated that the IFNβ101 and IFNβ101+27 constructs increase IFNβ protein expression more than 2.2 and 4.5 fold, respectively compared to the control group. It could be concluded that the substitution of Phe in the codon 101 position, which may increase the binding activity of IFNβ with its receptors and introduction of an additional N glycosylation site (Asn-X-Thr) in the position 27 of IFNβ protein may cause such an effect. The proliferative activity of transfected cells by a recombinant IFNβ101 decreases in comparison to the wild type, although it was not statistically significant. Over-expression of IFNβ in such a level is promising not only for the patients but also for the pharmaceutical industries.

Effects of disruption of the nucleotide pattern in CRID element and Kozak sequence of interferon β on mRNA stability and protein production

Interferon β (IFNβ) is the most important drug that has been used frequently for multiple sclerosis treatment. This study has tried to improve the IFNβ production by introducing mutations in the coding region of IFNβ, while its amino acid sequence is intact. Two recombinant vectors IFNβ(K) and IFNβ(K+CRID )were designed by site-directed mutagenesis. The IFNβ(K) and IFNβ(K+CRID) have two substitutions in Kozak sequence and four substitutions in CRID sequence, respectively. The Chinese hamster ovary (CHO) cell codon usage optimization was also performed for both of them. They were transiently transfected to CHO-dhfr(-) cell line using Lipofectamine kit (Invitrogen, Grand Island, NY). The amount of mRNA and protein was determined by real time PCR and ELISA. The results of this study indicate that the amount of IFNβ protein produced by CHO cells containing IFNβ(K) has been elevated up to 3.5-fold. On the other hand, enormous amounts of IFNβ mRNA and protein were produced by cells containing IFNβ(K+CRID) construct; more than 4.6-fold and 6-fold, respectively. It could be concluded that disruption of AT pattern in CRID element increase RNA and protein production, improve IFNβ mRNA stability and, may also enhance mRNA half-life. In a similar way, more proteins are produced by modification of Kozak sequence.

Anti-human herpesvirus 6A/B IgG correlates with relapses and progression in multiple sclerosis

OBJECTIVE

To analyze the titers of the IgG and IgM antibodies against human herpesvirus 6A/B (HHV-6A/B) in multiple sclerosis (MS) patients treated with different disease modified therapies (DMTs) along two-years of follow-up.

METHODS

We collected 2163 serum samples from 596 MS; for 301 MS patients a 2-years follow-up was performed. Serum samples of 337 healthy controls were also analyzed. Anti-HHV-6A/B IgG and IgM were analyzed by ELISA (Panbio).

RESULTS

We found that 129/187 (69.0%) MS patients with a decrease of the anti-HHV-6A/B IgG titers after 2-years with DMTs were free of relapses and progression vs. 46/113 (40.7%) of MS patients with an increase of the anti-HHV-6A/B IgG titers (p = 0.0000015); the higher significance was found for natalizumab. Furthermore, we found that anti-HHV-6A/B IgG titers reached their highest value two weeks before the relapse (p = 0.0142), while the anti-HHV-6A/B IgM titers reached their highest value one month before the relapse (p = 0.0344).

CONCLUSION

The measurement of the anti-HHV-6A/B IgG titers could be a good biomarker of clinical response to the different DMTs. The increase of the anti-HHV-6A/B IgG and IgM titers predicts the upcoming clinical relapses. However, further longitudinal studies are needed to validate these results.

HHV-6 and Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease affecting the central nervous system, thought to be an autoimmune disease mediated by autoreactive lymphocytes. The pathogenesis of MS is multifactorial and is thought to be triggered by multiple environmental factors in genetically susceptible individuals. Viruses have long been postulated as potential environmental triggers in MS, and there is increasing evidence of a link between viruses and MS. Some of the most compelling data have been found in human herpesvirus 6 (HHV-6) research. HHV-6 is a ubiquitous, neurotropic herpesvirus; HHV-6 DNA has been found in MS plaques compared to healthy brain tissue. Studies have also shown that MS patients have higher viral titers and higher DNA detection in serum and CSF compared to controls, and that the virus seems to be more actively replicating in MS patients. Potential mechanisms for HHV-6 leading to autoimmunity include molecular mimicry, bystander activation, and epitope spreading, among others.

MHC2TA mRNA levels and human herpesvirus 6 in multiple sclerosis patients treated with interferon beta along two-year follow-up

Background

In previous studies we found that MHC2TA +1614 genotype frequency was very different when MS patients with and without human herpesvirus 6 (HHV-6) in serum samples were compared; a different clinical behavior was also described. The purpose of the study was: 1. To evaluate if MHC2TA expression in MS patients was influenced by interferon beta (IFN-beta) treatment. 2. To study MHC2TA expression in MS patients with and without minor allele C. 3. To analyze the relation between MHC2TA mRNA levels and HHV-6 active infection in MS patients.

Methods

Blood and serum samples of 154 MS patients were collected in five programmed visits: basal (prior to beginning IFN-beta treatment), six, twelve, eighteen and twenty-four months later. HHV-6 in serum and MHC2TA mRNA levels were evaluated by PCR and RT-PCR, respectively. Neutralizing antibodies (NAbs) against IFN-beta were analyzed by the cytopathic effect assay.

Results

We found that MHC2TA mRNA levels were significantly lower among MS patients with HHV-6 active infection at the basal visit (without treatment) than in those MS patients without HHV-6 active infection at the basal visit (p = 0.012); in all the positive samples we only found variant A. Furthermore, 58/99 (58.6%) MS patients without HHV-6 along the five programmed visits and an increase of MHC2TA expression after two-years of IFN-beta treatment were clinical responders vs. 5/21 (23.8%) among those MS patients with HHV-6 and a decrease of MHC2TA mRNA levels along the two-years with IFN-beta treatment (p = 0.004); no differences were found between patients with and without NAbs.

Conclusions

MHC2TA mRNA levels could be decreased by the active replication of HHV-6; the absence of HHV-6 in serum and the increase of MHC2TA expression could be further studied as markers of good clinical response to IFN-beta treatment.

IL28B polymorphisms are not associated with the response to interferon-β in multiple sclerosis

Recent studies have revealed an association between interleukin 28B (IL28B) and response to IFN-alpha treatment in hepatitis C patients. Here we investigated the influence of IL28B polymorphisms in the response to interferon-beta (IFNβ) in multiple sclerosis (MS) patients. We genotyped two SNPs of the IL28B gene (rs8099917 and rs12979860) in 588 MS patients classified into responders (n=281) and non-responders (n=307) to IFNβ. Combined analysis of the study cohorts showed no significant associations between SNPs rs8099917 and rs12979860 and the response to treatment. These findings do not support a role of IL28B polymorphisms in the response to IFNβ in MS patients.

Immunomodulators as adjuvants for vaccines and antimicrobial therapy

A highly effective strategy for combating infectious diseases is to enhance host defenses using immunomodulators, either preventatively, through vaccination, or therapeutically. The effectiveness of many vaccines currently in use is due in part to adjuvants, molecules that have little immunogenicity by themselves but which help enhance and appropriately skew the immune response to an antigen. The development of new vaccines necessitates the development of new types of adjuvants to ensure an appropriate immune response. Herein, we review commonly used vaccine adjuvants and discuss promising adjuvant candidates. We also discuss various other immunomodulators (namely cytokines, Toll-like receptor agonists, and host defense peptides) that are, or have potential to be, useful for antimicrobial therapies that exert their effects by boosting host immune responses rather than targeting pathogens directly.

Divergent susceptibilities of human herpesvirus 6 variants to type I interferons

Two distinct human herpesvirus 6 (HHV-6) variants infect humans. HHV-6B is the etiologic agent of roseola and is associated with life-threatening neurological diseases, such as encephalitis, as well as organ transplant failure. The epidemiology and disease association for HHV-6A remain ill-defined. Specific anti-HHV-6 drugs do not exist and classic antiherpes drugs have secondary effects that are often problematic for transplant patients. Clinical trials using IFN were also performed with inconclusive results. We investigated the efficacy of type I IFN (alpha/beta) in controlling HHV-6 infection. We report that cells infected with laboratory strains and primary isolates of HHV-6B are resistant to IFN-alpha/beta antiviral actions as a result of improper IFN-stimulated gene (ISGs) expression. In contrast, HHV-6A-infected cells were responsive to IFN-alpha/beta with pronounced antiviral effects observed. Type II IFN (gamma)-signaling was unaltered in cells infected by either variant. The HHV-6B immediate-early 1 (IE1) physically interacts with STAT2 and sequestrates it to the nucleus. As a consequence, IE1B prevents the binding of ISGF3 to IFN-responsive gene promoters, resulting in ISG silencing. In comparison, HHV-6A and its associated IE1 protein displayed marginal ISG inhibitory activity relative to HHV-6B. The ISG inhibitory domain of IE1B mapped to a 41 amino acid region absent from IE1A. Transfer of this IE1B region resulted in a gain of function that conferred ISG inhibitory activity to IE1A. Our work is unique in demonstrating type I IFN signaling defects in HHV-6B-infected cells and highlights a major biological difference between HHV-6 variants.

Association between human herpesvirus 6 and occurrence of multiple sclerosis among Jordanian patients

OBJECTIVES

Multiple sclerosis (MS) is hypothesized to be caused by an infectious agent that initiates an autoimmune reaction. Among the infectious agents linked to MS is human herpesvirus 6 (HHV-6). Due to the high occurrence of MS among Jordanian population and the deficiency of MS studies in Jordan, the prevalence of HHV-6 in sera and cerebrospinal fluids (CSFs) of 36 MS patients was investigated.

MATERIALS AND METHODS

To increase the sensitivity of detection, nested polymerase chain reaction was utilized.

RESULTS

Although we were able to detect HHV-6 DNA in serum samples of 26% MS patients, no significant difference was found when compared to control individuals. In addition, lack of association between MS and presence of viral DNA in CSF samples was observed. Even within the analyzed MS patient population, an association of HHV-6 and MS in terms of gender, type of diagnosis, symptoms and disease score was not identified among Jordanian patients.

CONCLUSIONS

Although these results indicate lack of apparent association between HHV-6 to MS among Jordanian patients, heterogeneity related to genetic polymorphism as well as geographical distribution of the disease and of pathogens may be of significance.

Varicella-zoster virus in cerebrospinal fluid at relapses of multiple sclerosis

OBJECTIVE

Recent studies in peripheral blood mononuclear cells (PBMCs) have indicated that exacerbations of multiple sclerosis (MS) could be associated with the reactivation of latent varicella-zoster virus (VZV).

METHODS

Ultrastructural observations for viral particles were made by electron microscopy in cerebrospinal fluid (CSF) from 15 MS patients during relapse, 19 MS patients during remission, and 28 control subjects. Initial findings were reproduced in a confirmation cohort. In addition, DNA from VZV was quantified by real-time polymerase chain reaction in PBMCs and CSF from a large number of MS patients (n = 78).

RESULTS

We found by electron microscopy the presence of abundant viral particles identical to VZV in CSF obtained from MS patients within the first few days of an acute relapse. In contrast, viral particles were not seen in CSF samples from MS patients in remission or from neurological control subjects. Also, DNA from VZV was present in CSF and in PBMCs during relapse, disappearing in most patients during remission. The mean viral load was 542 times greater in CSF at relapse than in CSF at remission and 328 times greater in CSF at relapse than in PBMCs at relapse.

INTERPRETATION

The ultrastructural finding of viral particles identical to VZV, together with the simultaneous presence of large quantities of DNA from VZV in the subarachnoid space, almost restricted to the periods of exacerbation, as well as its steady diminution and eventual disappearance from clinical relapse to clinical remission are surprising and constitute the strongest evidence to support the participation of VZV in the pathogenesis of MS.

Beta-interferon protects multiple sclerosis patients against enhanced susceptibility to infections caused by poor air quality

BACKGROUND

The monthly multiple sclerosis relapse rate was studied from January 1995 to March 2001 from hospital records in Southwestern Finland as a retrospective open-label study.

METHODS

The relapse rates of beta-interferon users and nonusers were compared to ambient air inhalable particle levels and viral infections in the population with logistic regression.

RESULTS

In the non-user group, relapses were more frequent 1 month following the episodes when PM(10) was in the highest quartile [logistic regression odds ratio = 1.196 (95% CI = 1.019-1.404), p = 0.028] and following adenovirus epidemics in the general population [logistic regression odds ratio = 2.234 (95% CI = 1.013-4.926), p = 0.046]. PM(10) and virus infections had no significant effects in interferon users.

CONCLUSION

In addition to being antiviral, interferon also protected multiple sclerosis patients against an enhanced susceptibility to infections caused by PM(10).

JC virus viremia in interferon-beta -treated and untreated Italian multiple sclerosis patients and healthy controls

Following the development of progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) patients treated with natalizumab and interferon-beta (IFNbeta), a possible correlation between JC virus (JCV), the etiological agent of PML, and MS has received heightened interest. In particular, attention has focused on assessing whether IFNbeta treatment could affect the replication of JCV and thus its frequency in the peripheral blood of MS patients and whether the presence of JCV DNA in peripheral blood could be a predictive marker of the risk of developing PML. In order to answer to these questions, peripheral blood samples were collected from 59 INFbeta-treated, 39 untreated relapsing-remitting MS patients, and 98 healthy controls (HCs) and JCV DNA levels were determined and quantified by means of a real-time polymerase chain reaction (Q-PCR) assay. Overall, no differences were found in the presence or viral load of JCV DNA of MS patients and the HCs, but JCV DNA was significantly less frequent in the peripheral blood of IFNbeta-treated patients (13.6%) compared to the untreated MS patients (46.1%) and the healthy controls (28.6%). These results suggest that the presence of JCV in the blood of MS patients cannot be considered as a marker or a risk factor for PML development. In addition, they indicate that treatment with INFbeta can lead to the reduction of presence of the JCV genome in the peripheral blood of MS patients and, thus, that this drug probably does not increase the risk of PML in MS patients treated with IFNbeta.

Optimization of culture conditions for a synthetic gene expression in Escherichia coli using response surface methodology: The case of human interferon beta

A human interferon beta (hINF-beta) synthetic gene was optimized and expressed in Escherichia coli BL21-SI using a vector with the T7 promoter. To determine the best culture conditions such as culture medium, temperature, cell density and inducer concentration, we used the response surface methodology and a Box-Behnken design to get the highest hINF-beta production. The maximum hINF-beta production of 61 mg l(-1) was attained using minimum medium and the following predicted optimal conditions: temperature of 32.5 degrees C, cell density of 0.64, and inducer concentration of 0.30 M NaCl. This is the first report showing the successful performance of the BL21-SI system in a minimum medium. The response surface methodology is effective for the optimization of recombinant protein production using synthetic genes.

Varicella-zoster virus at relapses of multiple sclerosis

The possible participation of different herpes viruses was studied during exacerbations of multiple sclerosis (MS). We searched for the presence of DNA from the following herpes viruses: varicella zoster virus (VZV), herpes-simplex viruses 1 and 2; Epstein-Barr virus (EBV) and human herpes-virus-6 (HHV6) in mononuclear cells from patients with MS during relapse (n = 40), MS during remission (n = 131) and controls (n = 125). Additionally, immune cells containing viral antigens were quantified by flow cytometry, and VZV load was determined by real time PCR in 2 MS patients at various times during relapse and remission. DNA from VZV was found in 95% of MS patients during relapse and in 17% during remission; all controls were negative; by contrast, DNA from HHV6 was found in 24% of MS patients during relapse and in 2% during remission; DNA from herpes simplex viruses was not found in any subject; and DNA from EBV was found in a similar percentage of subjects from all groups. Sequential quantification of VZV-load showed a curve that increased during relapse and disappeared at remission. Also, VZV antigens were found inside a large number of immune cells from MS patients during relapse as compared with MS patients on remission and controls. In the typical forms of VZV infection, varicella and herpes-zoster, DNA from VZV is found in mononuclear cells exclusively during brief periods at the beginning of the active infection, but not during latency; thus, the conspicuous presence of VZV during relapses of MS may indicate a period of active infection and suggests the participation of VZV in the pathogenesis of MS.

Interferon-beta treatment and active replication of the JC virus in relapsing-remitting multiple sclerosis patients

We analyzed the effect of beta-interferon (beta-IFN) treatment over the active replication of JC virus (JCV) through the evaluation of JCV DNA prevalence and viral load in peripheral blood mononuclear cells (PBMCs) and serum samples, and mRNA prevalence and viral load, in relapsing-remitting multiple sclerosis (RRMS) patients. DNA extracted from PBMCs and serum, and mRNA extracted from PBMCs were analyzed in 146 RRMS patients (73 treated with beta-IFN, and 73 untreated patients), and 73 matched healthy blood donors for the presence of JCV genomes by quantitative real-time PCR assay. We found the same DNA prevalence in PBMC samples in RRMS patients treated with beta-IFN and in untreated ones: 6.8% (5/73). When we analyzed the viral active replication in both groups through the analysis of DNA prevalence in serum samples and the mRNA extracted from PBMCs, we did not find any positive sample. Regarding the viral load of those positive samples, we did not find any statistical significant difference between treated and untreated RRMS patients: 28.6 +/- 7.2 and 32.3 +/- 8.4 copies/microg of DNA, respectively. These results lead us to conclude that beta-IFN treatment in monotherapy has not any effect on JCV active replication.

Human herpesvirus 6 and multiple sclerosis: a one-year follow-up study

BACKGROUND

This study was undertaken in order to investigate the possible relation of HHV-6 and EBV in relapsing-remitting MS (RRMS).

MATERIALS AND METHODS

A one-year follow up study was performed analysing peripheral blood mononuclear cells and serum samples of 57 patients with RRMS and 57 healthy blood donors (HBD) by a quantitative real time PCR, to detect HHV-6 and EBV. Clinical data (starting age and EDSS increase) were collected.

RESULTS

We did not find any statistically significant difference for EBV between RRMS patients and HBD. Regarding HHV-6: i) There was a higher prevalence of HHV-6 in RRMS patients than in controls: 80.7% versus 29.8% respectively. ii) HHV-6 active replication seems to be related to exacerbations. iii) Only variant A was detected among RRMS patients with HHV-6 active replication. iv) Although some difference was found when we compared clinical data in RRMS patients with and without HHV-6 active replication, the results did not reach statistical significance.

CONCLUSIONS

A higher HHV-6A frequency of active infection (reactivation or new infection) would lead to a more frequent exposure of HHV-6A antigens to the immune system of RRMS patients; this active replication of HHV-6A seems to be specifically related with the exacerbations in a subset of RRMS patients.

Mechanisms of action for treatments in multiple sclerosis: Does a heterogeneous disease demand a multi-targeted therapeutic approach?

The etiology of multiple sclerosis (MS) is incompletely understood, and evidence suggests there may be more than one underlying cause in this disorder. Furthermore, this complex and heterogeneous autoimmune disease shows a high degree of clinical variability between patients. Therefore, in the absence of a single therapeutic target for MS, it is difficult to apply conventional drug design strategies in the search for new treatments. We review the potential mechanisms of action of several effective therapies for MS that are currently available or in development. The effects of each treatment are described in terms of their actions on key processes in a five-step model of MS pathogenesis. Conventional immunosuppressants targeting intracellular ligands (e.g. mitoxantrone) have broad cytotoxic effects on B cells, T cells, and macrophages. This suppresses the pathogenic immune response in MS with high efficacy but is also associated with high toxicity, limiting the long-term use of these agents. Monoclonal antibodies (e.g. natalizumab and alemtuzumab) are a new generation of immunosuppressants that act on immune-cell surface ligands. These agents have narrower immunosuppressive actions and different safety profiles compared with conventional immunosuppressants. Immunomodulators (interferon-beta and glatiramer acetate), which shift the immune balance toward an anti-inflammatory response, are at the frontline of treatments for MS. Immunomodulators have targeted actions on the immune system, but affect a greater number of immunopathogenic processes than monoclonal antibodies. Given the inherent heterogeneity of MS, such treatments, which act at many levels of the disease, may achieve the best clinical results. Using our understanding of the interplay between mechanism of action and clinical effects in MS therapies may help us to better design and select new treatments for the future.

Network communications: lymphotoxins, LIGHT, and TNF

Lymphotoxins (LT) provide essential communication links between lymphocytes and the surrounding stromal and parenchymal cells and together with the two related cytokines, tumor necrosis factor (TNF) and LIGHT (LT-related inducible ligand that competes for glycoprotein D binding to herpesvirus entry mediator on T cells), form an integrated signaling network necessary for efficient innate and adaptive immune responses. Recent studies have identified signaling pathways that regulate several genes, including chemokines and interferons, which participate in the development and function of microenvironments in lymphoid tissue and host defense. Disruption of the LT/TNF/LIGHT network alleviates inflammation in certain autoimmune disease models, but decreases resistance to selected pathogens. Pharmacological disruption of this network in human autoimmune diseases such as rheumatoid arthritis alleviates inflammation in a significant number of patients, but not in other diseases, a finding that challenges our molecular paradigms of autoimmunity and perhaps will reveal novel roles for this network in pathogenesis.

Update on human herpesvirus 6 biology, clinical features, and therapy

Human herpesvirus 6 (HHV-6) is a betaherpesvirus that is closely related to human cytomegalovirus. It was discovered in 1986, and HHV-6 literature has expanded considerably in the past 10 years. We here present an up-to-date and complete overview of the recent developments concerning HHV-6 biological features, clinical associations, and therapeutic approaches. HHV-6 gene expression regulation and gene products have been systematically characterized, and the multiple interactions between HHV-6 and the host immune system have been explored. Moreover, the discovery of the cellular receptor for HHV-6, CD46, has shed a new light on HHV-6 cell tropism. Furthermore, the in vitro interactions between HHV-6 and other viruses, particularly human immunodeficiency virus, and their relevance for the in vivo situation are discussed, as well as the transactivating capacities of several HHV-6 proteins. The insight into the clinical spectrum of HHV-6 is still evolving and, apart from being recognized as a major pathogen in transplant recipients (as exemplified by the rising number of prospective clinical studies), its role in central nervous system disease has become increasingly apparent. Finally, we present an overview of therapeutic options for HHV-6 therapy (including modes of action and resistance mechanisms).

Subcutaneous Recombinant Interferon-??-1a (Rebif??)

Subcutaneous recombinant interferon-beta-1a (Rebif) 22 or 44 microg three times weekly is a valuable option in the first-line treatment in patients with relapsing-remitting multiple sclerosis (RRMS). It has shown benefits on outcome measures related to relapses, progression of disability and magnetic resonance imaging (MRI) in clinical trials. A significant efficacy advantage for subcutaneous interferon-beta-1a three times weekly over intramuscular interferon-beta-1a 30 microg once weekly was shown at 24 and 48 weeks. The most common adverse events are generally mild and clinically manageable. Considering both direct and indirect comparative clinical trial data, an assessment suggests that subcutaneous interferon-beta-1a 44 microg three times weekly has the best benefit-to-risk values of the available disease-modifying drugs used to treat RRMS.

Beta-Interferon Treatment Reduces Human Herpesvirus-6 Viral Load in Multiple Sclerosis Relapses but Not in Remission

To determine whether the DNA prevalence of human herpesvirus-6 (HHV-6), the viral load and the prevalence of both HHV-6 variants in relapsing-remitting multiple sclerosis (RRMS) patients in exacerbation are altered by beta-interferon (IFN-beta) treatment, in comparison with RRMS patients in remission, we analyzed HHV-6 (A and B) genomes in 189 serum samples by quantitative real-time polymerase chain reaction: 105 of the RRMS patients were receiving IFN-beta treatment (48 in exacerbation) and 84 were untreated (36 in relapse). The results were as follows. (1) Prevalence decrease because of IFN-beta treatment was not significant: 25% of RRMS patients in relapse vs. 15.9% in remission (p = 0.45). (2) Viral load was twice as much in untreated patients in relapse than in treated ones. (3) We only found variant A. Since IFN-beta treatment is able to significantly reduce HHV-6 viral load in RRMS patients in relapse, but not in remission, we suggest a role for HHV-6 in the pathogenesis of multiple sclerosis exacerbations and an antiviral role for IFN-beta treatment in RRMS.

Hit-Hit and hit-Run: viruses in the playing field of multiple sclerosis

Viruses have been major players in the search for the cause of multiple sclerosis (MS). In support of the viral theory is the predominance of CD8+ T cells and class-I major histocompatibility complex in lesions, the powerful therapeutic effects of beta interferons, the ease of inducing demyelination in experimental models following virus challenge, and the documented examples of several human demyelinating diseases conclusively demonstrated to be of viral origin. We propose two hypotheses of how viruses may cause MS. In the "Hit-Hit" hypothesis, the virus persists or may be reactivated in the central nervous system (CNS). Injury is the result of direct viral damage and by an attempt of the immune response to clear the infectious agent. In the "Hit-Run" hypothesis, virus infects the periphery but never enters the CNS. The virus sets up an abnormal immunologic milieu for subsequent autoimmunity. In both scenarios, knowing the inciting virus would be expected to eliminate disease if the population were vaccinated to prevent infection. In the treatment of patients with fully established disease, the Hit-Hit hypothesis would require that antiviral agents enter the CNS and stop replication. In the case of the Hit-Run hypothesis, treatment of patients with established disease with antiviral agents would be futile.

Human Herpesvirus-6: A Short Review of Its Biological Behavior

HHV-6 shows a widespread distribution with life-long persistence. The virus is frequently reactivated, yet remains clinically inapparent unless the patient is immunodeficient in some way. Even then, HHV-6 reactivation may simply enhance the pathogenicity of other viruses or existing autoimmune disorders rather than becoming a pathogen itself. Future clinical studies need to focus on such indirect viral influences mediated through molecular mimicry and interference with cell receptor expression, and cytokine and chemokine network regulation. Nevertheless, such disturbances may afford therapeutic intervention to disrupt herpesvirus interference and improve certain disease processes. There are only a few diseases for which an immediate causal relationship to HHV-6 infection has been suggested.

A comparison of the mechanisms of action of interferon beta and glatiramer acetate in the treatment of multiple sclerosis

BACKGROUND

The development of immunomodulatory agents has represented a major advance in the treatment of multiple sclerosis (MS). To date, immunomodulatory agents approved for the treatment of relapsing MS in the United States include 3 forms of recombinant interferon (IFN) beta (2 formulations of IFN beta-1a and 1 of IFN beta-1b) and synthetic glatiramer acetate (GA). Recognition of how these agents work to regulate the immune system may lead to a better understanding of disease mechanisms, as well as to development of more effective therapies or combinations of therapy.

OBJECTIVE

This article reviews the potential mechanisms of action of IFN beta products and GA in the context of their regulatory effects on autoimmune components that may be of importance in MS.

METHODS

MEDLINE and Current Contents/Clinical Medicine were searched for articles published in English from 1993 to the present using the search terms interferon beta, glatiramer acetate, and multiple sclerosis.

RESULTS

IFN beta products affect the disease process in MS through multiple potential mechanisms of action, including antiviral, antiproliferative, and anti-inflammatory effects. The mechanisms of action of GA are less clear, but may involve immune regulation induced by a gradual shift of T-cell phenotype from proinflammatory (type 1 T-helper cells) to anti-inflammatory (type 2 T-helper cells) and interference with antigen presentation.

CONCLUSION

Understanding the mechanisms of action of IFN beta products and GA provides important insights into the disease processes involved in MS.