Mechanisms of action of interferon-beta in multiple sclerosis

Interferon beta-1a induces expression of brain-derived neurotrophic factor in human T lymphocytes in vitro and not in vivo

Aim: To detect IFN β-1a-induced expression of brain-derived neurotrophic factor (BDNF) to undermine the hypothesis of IFN β-1a-associated neuroprotection in multiple sclerosis (MS). Methods: The influence of IFN β-1a on in vitro activated peripheral blood lymphocytes from healthy donors was tested. Proliferation analyses were made to detect T-cell growth. BDNF expression was measured by standard ELISA. To assess the influence of IFN β-1a on BDNF expression in vivo, BDNF serum levels of MS patients treated with IFN β-1a were compared with those of untreated patients. Results: IFN β-1a inhibited T-cell proliferation dose dependently. It induced BDNF expression at middle concentrations. MS patients treated with IFN β-1a exhibited significantly lower BDNF serum levels than untreated patients. Conclusion: IFN β-1a may promote neuroprotection by inducing BDNF expression, but its importance in vivo remains open.

Relationship between Neutrophil-to-Lymphocyte Ratio and Stress in Multiple Sclerosis Patients

INTRODUCTION

Multiple Sclerosis (MS), a disease of autoimmunity and inflammation, is characterized by deterioration of the myelin sheath that protects the nerve fibers. The high levels of neutrophils in serum may be related to the chronic inflammation and caused by other triggers such as infections that have been associated with relapses in MS.

AIM

To investigate the value of Neutrophil/Lymphocyte Ratio (NLR) as a possible marker and relationship with Depression, Anxiety and Stress (DAS) score in MS patients.

MATERIALS AND METHODS

A total of 60 MS patients and 60 age and sex matched healthy controls were recruited for the present study. We measured DAS score, NLR, calcium, phosphate, magnesium, chloride, alkaline phosphatase, albumin in serum levels in MS patients and in healthy controls.

RESULTS

The mean age was not significantly different in both case and control groups. The case and control groups were similar in terms of sex; however, the majority of the MS group was female. The NLR values of MS patients were significantly higher than those of the healthy controls (p=<0.001). The NLR values were also significantly (p<0.001) correlated with stress score.

CONCLUSION

NLR could be considered as a quick, cheap, easily measurable and inflammatory marker for assessment of inflammation in MS patients. The role of NLR in MS must be explored further.

Disease-modifying therapies and infectious risks in multiple sclerosis

Immunomodulatory and immunosuppressive treatments for multiple sclerosis (MS) are associated with an increased risk of infection, which makes treatment of this condition challenging in daily clinical practice. Use of the expanding range of available drugs to treat MS requires extensive knowledge of treatment-associated infections, risk-minimizing strategies and approaches to monitoring and treatment of such adverse events. An interdisciplinary approach to evaluate the infectious events associated with available MS treatments has become increasingly relevant. In addition, individual stratification of treatment-related infectious risks is necessary when choosing therapies for patients with MS, as well as during and after therapy. Determination of the individual risk of infection following serial administration of different immunotherapies is also crucial. Here, we review the modes of action of the available MS drugs, and relate this information to the current knowledge of drug-specific infectious risks and risk-minimizing strategies.

The clinical significance of the neutrophil-to-lymphocyte ratio in multiple sclerosis

Multiple sclerosis (MS) is one of the main chronic inflammatory diseases of the central nervous system that causes functional disability in young people. The aim of this study was to investigate the neutrophil-to-lymphocyte ratio (NLR) in patients with MS and the relationship between the NLR and the severity of the disease. One hundred and two MS patients (31 patients were in relapse; 71 patients were in remission) and 56 healthy controls were included. Complete blood counts as well as demographic and clinical data from MS patients were evaluated retrospectively. The NLRs were calculated for all participants and were compared; the cut-off value was also determined for the NLR and Expanded Disability Status Scale (EDSS). MS patients had a significantly higher NLR (p < 0.001) than the control group. The NLR levels were significantly higher in patients who were in relapse than patients in remission (p = 0.039). The cut-off value for the NLR to predict an MS diagnosis and activity were determined to be 2.04 and 3.90, respectively. The NLRs were directly correlated with erythrocyte sedimentation rate levels (r = 0.795, p < 0.001). Logistic regression analysis with dichotomous EDSS score showed that a high NLR was an independent predictor of the progression of disability. The NLR may be a biomarker that has simple, quick, inexpensive and reproducible properties in MS to predict patient's prognosis.

Induction of a unique isoform of the NCOA7 oxidation resistance gene by interferon β-1b

We demonstrate that interferon (IFN)-β-1b induces an alternative-start transcript containing the C-terminal TLDc domain of nuclear receptor coactivator protein 7 (NCOA7), a member of the OXR family of oxidation resistance proteins. IFN-β-1b induces NCOA7-AS (alternative start) expression in peripheral blood mononuclear cells (PBMCs) obtained from healthy individuals and multiple sclerosis patients and human fetal brain cells, astrocytoma, neuroblastoma, and fibrosarcoma cells. NCOA7-AS is a previously undocumented IFN-β-inducible gene that contains only the last 5 exons of full-length NCOA7 plus a unique first exon (exon 10a) that is not found in longer forms of NCOA7. This exon encodes a domain closely related to an important class of bacterial aldo-keto oxido-reductase proteins that play a critical role in regulating redox activity. We demonstrate that NCOA7-AS is induced by IFN and LPS, but not by oxidative stress and exhibits, independently, oxidation resistance activity. We further demonstrate that induction of NCOA7-AS by IFN is dependent on IFN-receptor activation, the Janus kinase-signal transducers and activators of transcription (JAK-STAT) signaling pathway, and a canonical IFN-stimulated response element regulatory sequence upstream of exon 10a. We describe a new role for IFN-βs involving a mechanism of action that leads to an increase in resistance to inflammation-mediated oxidative stress.

Interferon-beta-1b-induced short- and long-term signatures of treatment activity in multiple sclerosis

Interferon beta (IFNβ) reduces disease burden in relapsing-remitting multiple sclerosis (MS) patients. In this study, IFNβ-1b-treated MS patient gene expression profiles and biological knowledgebases were integrated to study IFNβ's pleiotropic mechanisms of action. Genes involved in immune regulation, mitochondrial fatty acid metabolism and antioxidant activity were discovered. Plausible mediators of neuronal preservation included NRF2, downregulation of OLA1, an antioxidant suppressor, and the antioxidant gene ND6, implicated in optic neuropathy and MS-like lesions. Network analysis highlighted IKBKE, which likely has a role in both viral response and energy metabolism. A comparative analysis of therapy-naive MS- and IFNβ-associated gene expression suggests an IFNβ insufficiency in MS. We observed more gene expression changes in long-term treatment than during acute dosing. These distinct short- and long-term effects were driven by different transcription factors. Multi-gene biomarker signatures of IFNβ treatment effects were developed and subsequently confirmed in independent IFNβ-1b-treated MS studies, but not in glatiramer acetate-treated patients.

Multiple sclerosis-linked and interferon-beta-regulated gene expression in plasmacytoid dendritic cells

The cause of multiple sclerosis (MS) is not known and the mechanism of interferon-beta, a disease-modifying treatment, is not well-understood. We studied gene expression in plasmacytoid dendritic cells (pDCs), antigen-presenting cells implicated in MS pathogenesis. PDCs were separated from healthy donors and MS patients at two time points: before and after initiation of treatment with interferon-beta. Expression of selected MS-linked and interferon-beta-regulated genes was validated with single assays. We have identified 60 genes which were abnormally expressed in MS patients and were corrected after treatment. These genes could be studied as potential MS biomarkers and possible therapeutic targets in MS.

The mechanism of action of interferon-β in relapsing multiple sclerosis

Multiple sclerosis (MS) is characterized by autoimmune inflammation and subsequent neurodegeneration. It is believed that early in the disease course, proinflammatory T cells that are activated in the periphery by antigen presentation cross the blood-brain barrier (BBB) into the CNS directed by various chemotaxic agents. However, to date, there has been no formal demonstration of a specific precipitating antigen. Once inside the CNS, activated T cells including T helper-1 (T(h)1), T(h)17, γδ and CD8+ types are believed to secrete proinflammatory cytokines. Decreased levels of T(h)2 cells also correlate with relapses and disease progression in MS, since T(h)2-derived cytokines are predominantly anti-inflammatory. In healthy tissue, inflammatory effects are opposed by specific subsets of regulatory T cells (T(regs)) including CD4+, CD25+ and FoxP3+ cells that have the ability to downregulate the activity of proinflammatory T cells, allowing repair and recovery to generally follow inflammatory insult. Given their function, the pathogenesis of MS most likely involves deficits of T(reg) function, which allow autoimmune inflammation and resultant neurodegeneration to proceed relatively unchecked. Interferons (IFNs) are naturally occurring cytokines possessing a wide range of anti-inflammatory properties. Recombinant forms of IFNβ are widely used as first-line treatment in relapsing forms of MS. The mechanism of action of IFNβ is complex, involving effects at multiple levels of cellular function. IFNβ appears to directly increase expression and concentration of anti-inflammatory agents while downregulating the expression of proinflammatory cytokines. IFNβ treatment may reduce the trafficking of inflammatory cells across the BBB and increase nerve growth factor production, leading to a potential increase in neuronal survival and repair. IFNβ can also increase the number of CD56bright natural killer cells in the peripheral blood. These cells are efficient producers of anti-inflammatory mediators, and may have the ability to curb neuron inflammation. The mechanistic effects of IFNβ manifest clinically as reduced MRI lesion activity, reduced brain atrophy, increased time to reach clinically definite MS after the onset of neurological symptoms, decreased relapse rate and reduced risk of sustained disability progression. The mechanism of action of IFNβ in MS is multifactorial and incompletely understood. Ongoing and future studies will increase our understanding of the actions of IFNβ on the immune system and the CNS, which will in turn aid advances in the management of MS.

Differential gene expression and translational approaches to identify biomarkers of interferon beta activity in multiple sclerosis

More than 16 years ago human interferon-&#x03B2;-1b (IFN-&#x03B2;-1&#x03B2;) was shown to be effective in the treatment of the relapsing-remitting form of multiple sclerosis (MS). Over time, IFN-&#x03B2; has been demonstrated to be both a safe and effective treatment. However, the mechanism of action of IFN-&#x03B2; in MS remains unknown. To better understand the mechanism of action of IFN-&#x03B2;, considerable effort has been made in transcriptional profiling of peripheral blood mononuclear cells collected from MS patients. IFN-&#x03B2; is known to induce a large number of genes that play an important role in regulating responses to viral infection, immune modulation, and cell proliferation. Identifying differentially induced genes that are linked to the beneficial effects observed during treatment is under active investigation. IFN biomarkers in MS patients have been proposed but have not been clearly confirmed in independent studies or consistently correlated with clinical measures of disease progression. Organizing single genes or gene signatures grouped according to molecular mechanisms meaningful in MS may help to link IFN activity measurements to clinical outcomes. In this review, IFN activity measurements will be discussed with a specific emphasis on what is known about differential gene expression and treatment effects in MS.

Effects of human recombinant-interferon β in experimental autoimmune encephalomyelitis in guinea pigs

CONTEXT

Although clinical data for beneficial effects of Betaferon, human recombinant-interferon (r-IFN) β-1b, are accumulating, what is less evident is how and why it works.

OBJECTIVE

The present study was carried out to examine whether Betaferon suppresses progression of experimental autoimmune encephalomyelitis (EAE).

MATERIALS AND METHODS

The EAE model was employed in guinea pigs in vivo, and mononuclear cell proliferation and 2',5'-oligoadenylate synthetase activity were assessed in vitro.

RESULTS

Betaferon was more reactive in two assays of guinea pigs, mitogen-induced proliferation of peripheral blood mononuclear cells and 2',5'-oligoadenylate synthetase activity of blood, than in rats and rabbits. Guinea pigs were immunized actively by antigen, porcine myelin basic protein. The neurological deficits were assessed by clinical signs scored daily. Guinea pig Betaferon, replaced with guinea pig albumin (GPA), at 1.2 and 12.0 MIU/kg/day or vehicle was administered subcutaneously daily for 20 days in the immunized guinea pigs. GPA-Betaferon suppressed the manifestation of ataxia or more progression of chronic neurological deficits significantly at 1.2 MIU/kg (p <0.05). Two out of 10 animals manifested no clinical signs in the GPA-Betaferon-treated group with the higher dose, while all animals were worsened with typical clinical signs of EAE in the vehicle group where mononuclear cell infiltrates around blood vessels were seen in the spinal cord of vehicle-treated animals.

DISCUSSION AND CONCLUSION

Human r-IFN β-1b attenuates progression of neurological deficits in the EAE model of guinea pigs with evidence for higher susceptibility of animal cells/tissues to the human cytokine, in contrast with rodents and rabbits.

Chemotherapeutics in the treatment of multiple sclerosis

The likely pathogenic mechanisms of multiple sclerosis (MS) provide a sound rationale for investigating the efficacy of drugs possessing immunosuppressive or immunomodulatory properties. With proven efficacy, safety and tolerability, interferon beta formulations and glatiramer acetate have become the mainstay of initial treatment for patients with relapsing forms of MS. More recently, natalizumab, a humanized monoclonal antibody (mAb) against the cellular adhesion molecule α4-integrin, has been employed for patients with an inadequate response or lack of tolerability to an alternate MS therapy, or as initial therapy for patients with severe disease. Various agents initially developed for oncological indications, either as chemotherapeutics or mAbs, may also have current or future uses in MS treatment. Mitoxantrone is currently the only chemotherapeutic agent approved for treatment of MS in the United States, while in parts of Europe azathioprine is approved and widely used for MS treatment. Other chemotherapeutics that have been tested in MS to date include cyclophosphamide, methotrexate, cladribine, and the mAbs alemtuzumab and rituximab. While there has been varying evidence of efficacy for these compounds, each appears to be associated with serious risks that require careful consideration and management. Given the risks that have been demonstrated for available chemotherapeutic agents and while long-term postmarketing safety data are still not available for those agents in development, it seems prudent to carefully assess the possible use of chemotherapeutics in the treatment of MS. A thorough risk-benefit analysis is becoming increasingly important in the assessment of therapeutic options for this disabling disease.

Interferon-β stabilizes barrier characteristics of the blood–brain barrier in four different species in vitro

Background

Blood–brain barrier (BBB) breakdown is an early event in the pathogenesis of multiple sclerosis (MS). In a previous study we have found a direct stabilization of barrier characteristics after treatment of bovine brain capillary endothelial cells (BCECs) with human recombinant interferon-β-1a (IFN-β-1a) in an in vitro BBB model. In the present study we examined the effect of human recombinant IFN-β-1a on the barrier properties of BCECs derived from four different species including humans to predict treatment efficacy of IFN-β-1a in MS patients.

Methods

We used primary bovine and porcine BCECs, as well as human and murine BCEC cell lines. We investigated the influence of human recombinant IFN-β-1a on the paracellular permeability for 3H-inulin and 14C-sucrose across monolayers of bovine, human, and murine BCECs. In addition, the transendothelial electrical resistance (TEER) was determined in in vitro systems applying porcine and murine BCECS.

Results

We found a stabilizing effect on the barrier characteristics of BCECs after pretreatment with IFN-β-1a in all applied in vitro models: addition of IFN-β-1a resulted in a significant decrease of the paracellular permeability across monolayers of human, bovine, and murine BCECs. Furthermore, the TEER was significantly increased after pretreatment of porcine and murine BCECs with IFN-β-1a.

Conclusion

Our data suggest that BBB stabilization by IFN-β-1a may contribute to its beneficial effects in the treatment of MS. A human in vitro BBB model might be useful as bioassay for testing the treatment efficacy of drugs in MS.

High dose of intravenously given glucocorticosteroids decrease IL-8 production by monocytes in multiple sclerosis patients treated during relapse

The aim of our study was to determine whether high doses of intravenous methylprednisolone have significant impact on immune parameters during the multiple sclerosis (MS) exacerbations. Peripheral blood of 32 MS patients was evaluated, using two-color flow cytometry before glucocorticosteroids and after 7 days from starting therapy. Significant increase of B cells, decrease of NK cells and monocytes producing IL-8 were observed after treatment. IL-8 is one of the cytokines responsible for blood-brain-barrier disruption and migration of immune cells to the central nervous system; in this aspect, explaining glucocorticosteroid effects during MS exacerbations.

Interferon-β: A Therapeutic for Autoimmune Lupus in MRL-Faslpr Mice

Type I interferons are associated with lupus. Genes that are regulated by IFN-alpha are upregulated in pediatric lupus patients. Gene deletion of the IFN-alpha/beta receptor in experimental lupus-like NZB mice results in reduced disease activity. Conversely, IFN-beta is a well-established treatment in multiple sclerosis, another autoimmune disease. For determining whether IFN-beta treatment is harmful or beneficial in lupus, MRL-Fas(lpr) mice were injected with this type I IFN. Treatment was initiated in MRL-Fas(lpr) mice with mild and advanced disease. IFN-beta was highly effective in prolonging survival and ameliorating the clinical (renal function, proteinuria, splenomegaly, and skin lesions), serologic (autoantibodies and cytokines), and histologic parameters of the lupus-like disease in mice that had mild and advanced disease. Several underlying mechanisms of IFN-beta therapy involving cellular (decreased T cell proliferation and infiltration of leukocytes into the kidney) and humoral (decrease in IgG3 isotypes) immune responses and a reduction in nephrogenic cytokines were identified. In conclusion, IFN-beta treatment of lupus nephritis in MRL-Fas(lpr) mice is remarkably beneficial and suggests that IFN-beta may be an appealing therapeutic candidate for subtypes of human lupus.

Immunomodulatory Effects of IFN-β1a Treatment Alone or Associated with Pentoxifylline in Patients with Relapsing-Remitting Multiple Sclerosis (RRMS)

Interferon-beta1a (IFN-beta1a) and pentoxifylline (PTX) are reported to be active in relapsing-remitting multiple sclerosis (RRMS), but the mechanisms are not completely understood. In two groups of RRMS patients, we studied the phenotype of peripheral lymphocytes and the level of several cytokines both in sera and in supernatants of activated peripheral blood mononuclear cells (PBMC) before and after 8 months of therapy with IFN-beta1a alone or associated with PTX. Our data indicate that patients with RRMS, treated with IFN-beta1a, exhibited a significant increase in CD4(+)CD25(++) T suppressor cells, accompanied by a significant decrease in cytotoxic lymphocytes (CD8(+)CD28(-) and natural killer [NK] cells) and IFN-gamma production, which could both contribute to an explanation of the previously described beneficial effects of IFN-beta treatment in MS. The addition of PTX to IFN-beta1a treatment did not modify the immunomodulatory effects obtained with IFN-beta1a alone. Future studies are needed to demonstrate which immunologic parameters correlate with the clinical benefit of IFN-beta1a treatment.

Interferon-gamma and interferon-beta affect endogenous catecholamines in human peripheral blood mononuclear cells: implications for multiple sclerosis

Interferon (IFN)-gamma plays a pivotal role in the pathogenesis of multiple sclerosis (MS), while IFN-beta may be able to modify the clinical course of the disease, eventually also by counterbalancing IFN-gamma-mediated effects. Catecholamines (CA) exert important effects on the immune response, both as transmitters between the nervous and the immune system, as well as autocrine/paracrine mediators in immune cells, and several lines of evidence support their involvement in MS. In particular, dysregulated production of CA seems to occur in peripheral blood mononuclear cells (PBMCs) of MS patients. We assessed the effects of IFN-beta and IFN-gamma on endogenous CA in PBMCs. In cultured PBMCs stimulated with phytohaemagglutinin (PHA), IFN-beta increased CA production and induced CA release in the culture medium, while IFN-gamma decreased both CA production and the expression of mRNA for the CA-synthesizing enzyme tyrosine hydroxylase. Coincubation with both IFNs prevented the inhibitory effect of IFN-gamma, as well as the stimulatory effect of IFN-beta. IFNs are the first physiological compounds shown to affect endogenous CA in PBMCs: in view of the role of CA-dependent mechanisms in the immune response, these findings may help to better understand the mechanisms of action of IFN-beta as an immunomodulatory drug in MS.

N-acetyl-L-cysteine ameliorates the inflammatory disease process in experimental autoimmune encephalomyelitis in Lewis rats

We report that N-acetyl-L-cysteine (NAC) treatment blocked induction of TNF-alpha, IL-1beta, IFN-gamma and iNOS in the CNS and attenuated clinical disease in the myelin basic protein induced model of experimental allergic encephalomyelitis (EAE) in Lewis rats. Infiltration of mononuclear cells into the CNS and induction of inflammatory cytokines and iNOS in multiple sclerosis (MS) and EAE have been implicated in subsequent disease progression and pathogenesis. To understand the mechanism of efficacy of NAC against EAE, we examined its effect on the production of cytokines and the infiltration of inflammatory cells into the CNS. NAC treatment attenuated the transmigration of mononuclear cells thereby lessening the neuroinflammatory disease. Splenocytes from NAC-treated EAE animals showed reduced IFN-gamma production, a Th1 cytokine and increased IL-10 production, an anti-inflammatory cytokine. Further, splenocytes from NAC-treated EAE animals also showed decreased nitrite production when stimulated in vitro by LPS. These observations indicate that NAC treatment may be of therapeutic value in MS against the inflammatory disease process associated with the infiltration of activated mononuclear cells into the CNS.

Biological activity of interferon betas in patients with multiple sclerosis is affected by treatment regimen and neutralising antibodies

BACKGROUND

MxA gene expression is one of the most appropriate markers of biological activity of exogenous interferon (IFN) beta.

METHODS

We quantified MxA mRNA for five consecutive days in 62 patients treated with IFN beta (16, Avonex; 10, Betaferon; 24, Rebif 22; 12, Rebif 44), by quantitative-competitive polymerase chain reaction. Every three months, IFN beta induced neutralising antibodies (NAbs) were evaluated in sera using a cytopathic effect assay.

RESULTS

Two categories of patients were identified: one group (49/62) had a sharp post-injection increase in MxA expression (defined as "IFN beta biological responder"), whereas the other group (13/62) had no MxA induction after IFN beta administrations (defined as "IFN beta biological non-responder"). In 11/13 biological non-responders, the persistent presence of NAbs correlated with abolished biological activity, independently of treatment regimen. The two remaining IFN beta biological non-responders were NAb-. Among the 49 IFN beta biological responders, biological activity was comparable between the four preparations on day 2 and 3 (+12 and +36 hours post-injection), but it was greater in Betaferon and both Rebif preparations on day 1, 4, and 5. In biological responders treated three times a week, only 82% (59/72) of injections were considered effective, compared with 100% (13/13) of Avonex injections.

CONCLUSION

Our results suggest that an optimal IFN beta regimen is not yet available: Avonex, given once a week, shows lower cumulative biological activity. On the other hand, both Betaferon and Rebif, given three times a week, show 18% biologically ineffective injections and higher risk of developing NAbs, which abolish biological activity.

Serial analysis of soluble intercellular adhesion molecule-1 level in relapsing-remitting multiple sclerosis patients during IFN-beta1b treatment

In this controlled study, we investigated the serum and cerebrospinal fluid (CSF) levels of soluble intercellular adhesion molecule-1 (sICAM-1) in relapsing-remitting multiple sclerosis (RRMS) patients and changes in the levels of this adhesion molecule during interferon-beta1b (IFN-beta1b) treatment. We also investigated the changes in the levels of sICAM-1 in correlation with disease activity and with findings on magnetic resonance images (MRI). The study included 24 patients (16 females and 8 males) who were confirmed to have RRMS based on the criteria of Poser et al. Sixteen of the patients received IFN-beta1b (Betaseron, Berlex Laboratories, Schering AG Germany, Berlin) treatment, and 8 did not receive this therapy. The levels of sICAM-1 in the MS patients' serum and CSF were significantly higher than levels in individuals with noninflammatory neurologic disease (p = 0.0081 and p = 0.0001, respectively). In the first 3 months of the study, MS patients treated with IFN-beta1b showed a significant rise in sICAM-1 levels (p = 0.0023), whereas their untreated counterparts showed no significant change. Neither of the groups showed a significant correlation between sICAM-1 level and disease activity demonstrated by MRI or between sICAM-1 level and clinical disease activity. The findings suggest that IFN-beta1b treatment may have a short-term upregulating effect on sICAM-1.

Persistent neutralizing antibodies abolish the interferon beta bioavailability in MS patients

BACKGROUND

MxA is an antiviral protein exclusively induced by type I interferons (IFN) and some viruses, and MxA gene expression is one of the most appropriate markers for measuring the biologic activity of exogenous IFNbeta.

METHODS

A new quantitative-competitive PCR method was used to quantify MxA mRNA in peripheral blood mononuclear cells of 99 treatment-naïve and 92 IFNbeta-treated patients with MS (22 Avonex, 17 Betaferon, and 53 Rebif-22). Every 3 months, IFNbeta-induced neutralizing antibodies (NAb) were evaluated in sera using a cytopathic effect assay. Three categories of patients were identified: NAb negative (NAb-), persistent NAb positive (NAb+, >or=2 consecutive positive samples), and isolated NAb+ (one positive sample).

RESULTS

Treatment-naïve patients expressed detectable MxA mRNA levels (mean = 36 +/- 32 fg MxA/pg glyceraldehyde-3-phosphate dehydrogenase (GAPDH); range 1 to 160) and an upper normal threshold was established (mean + 3 SD = 132 fg MxA/pg GAPDH). IFNbeta-treated patients exhibited more than 11-fold higher levels (mean = 412 +/- 282 fg MxA/pg GAPDH; range 16 to 1,172). However, 17 patients did not exhibit an increase in MxA mRNA level; 15 of these 17 patients showed a concurrent Nab+ titer. Moreover, 13 were persistent NAb+. Isolated NAb+ patients did not show a decrease in bioavailability of IFNbeta (n = 9; mean = 567 +/- 366 fg MxA/pg GAPDH; range 83 to 1,120). In NAb- patients, bioavailability was comparable among the three different IFNbeta preparations 12 hours after injection.

CONCLUSION

During IFNbeta therapy, the presence of NAb reduced or abolished bioavailability in a relevant percentage of patients. These data could be important for the early detection of patients with MS who are not responsive to IFNbeta therapy.

Novel therapies for the treatment of juvenile rheumatoid arthritis (juvenile idiopathic arthritis)

The majority of children with juvenile idiopathic arthritis respond well to conventional treatment. However, some children will have a more aggressive disease course and will be resistant to standard management. Over the past 20 years, growth in our understanding of the immunopathogenesis of juvenile idiopathic arthritis and related diseases has facilitated significant therapeutic advances. In this report, recently released antirheumatic drugs, as well as some treatments currently in development, will be discussed. Biological agents, such as antiTNF and other cytokines inhibitors, and unique drugs, such as thalidomide, provide new opportunities to suppress the inflammation found in severe cases of systemic onset juvenile idiopathic arthritis and can obtain a satisfactory outcome.

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.

Cytokines and anti-cytokine biologicals in autoimmunity: present and future

The increasing understanding of the role of cytokines in autoimmunity, and the observation that tumour necrosis factor alpha (TNFalpha) is central to the inflammatory and destructive process common to several human autoimmune diseases, has led to a new generation of therapeutics, the TNFalpha blocking agents. In this article, we review the current knowledge of the role of cytokines in autoimmunity as unravelled by studies both in the laboratory and the clinic. In addition, we discuss future prospects of the anti-TNFalpha therapy that may involve combination therapy with other anti-cytokine or anti-T cell biologicals, or the use of small chemicals targeting molecules involved in TNFalpha production such as NF-kappaB and p38 MAPK. The future developments of anti-TNFalpha and anti-cytokine therapy in general will be interesting.

Discordant effect of IFN-beta1a therapy on anti-IFN antibodies and thyroid disease development in patients with multiple sclerosis

Interferon-beta1b (IFN-beta1b) therapy is associated with a relatively high risk of developing thyroid disease. IFN-beta1a is regarded as less immunogenic than IFN-beta1b because of its structural homology to natural IFN-beta. We assessed the effect of 1 year of IFN-beta1a treatment on thyroid function and autoimmunity in 14 multiple sclerosis (MS) patients. The results were compared with those obtained in a series of 31 MS patients treated with IFN-beta1b. The prevalence of positive binding antibody (BAb) titer and neutralizing (NAb) anti-IFN antibody titer in the two groups was also assessed. The BAb and NAb positivity rate in IFN-beta1a-treated patients was significantly lower than in the group submitted to IFN-beta1b therapy (7% vs. 84% and 0% vs. 30%, respectively). Although the incidence of thyroid dysfunction was slightly higher in IFN-beta1b-treated patients than in those undergoing IFN-beta1a treatment (33% vs. 23%, respectively), it did not reach statistical significance. Thyroid disease was unrelated to the presence of positive serum BAb or NAb titer in both the group undergoing IFN-beta1a therapy and in that treated with IFN-beta1b. In both groups, thyroid disease developed mostly in women (71%) against a background of preexisting thyroiditis and a diffuse hypoechoic ultrasound thyroid pattern (80%). IFN-beta1a treatment was associated with a significantly lower prevalence of both BAb and NAb-positive titers than was IFN-beta1b. Conversely, thyroid disease was similar and unrelated to the presence of positive anti-IFN-beta antibody titer. Therefore, routine thyroid assessment may be advised during IFN-beta1a treatment, especially in patients with preexisting thyroiditis.

Induction and maintenance of clinical remission by interferon-beta in patients with steroid-refractory active ulcerative colitis-an open long-term pilot trial

BACKGROUND

The imbalance of pro- and anti-inflammatory cytokines plays an important role in the pathogenesis of inflammatory bowel disease. Shifting this disturbed ratio by means of TNF-antibodies or interferon has been shown to be helpful in treating Crohn's disease and multiple sclerosis, respectively.

AIM

This pilot study investigated whether interferon-beta can induce clinical remission in corticoid-refractory ulcerative colitis.

METHODS

Twenty-five patients with steroid-refractory active ulcerative colitis (Clinical activity index according to Rachmilewitz: 13.5 +/- 5.2) were treated in an open pilot trial with 0.5 MIU human natural interferon-beta (hn-IFN-beta) i.v. (n=18) or 1 MIU recombinant interferon-beta-1a (r-IFN-beta-1-a) s.c. (n=7) daily with the goal of induction of remission. Subsequent maintenance treatment was carried out for 52.0 +/- 78.8 weeks (range 4-336 weeks) with the same dose, three times per week.

RESULTS

Twenty-two of 25 patients (88%) went into remission during induction treatment (hn-IFN-beta 16/18, r-IFN-beta-1a 6/7). Mean time to response was 3.0 +/- 1.3 weeks. Mean length of remission was 13.0 +/- 19.7 months. Only eight of 22 patients in remission relapsed during maintenance treatment. Five of these went into remission again after increasing the dose. Adverse events consisted of slight to moderate flu-like symptoms and slight to moderate hair loss in five of 15 female patients.

CONCLUSION

Although this open pilot study included only a small number of patients, the high response rate suggests that interferon-beta may be a safe and effective treatment for steroid-refractory active ulcerative colitis.

Cost-effectiveness analysis of interferon beta in multiple sclerosis: a Markov process analysis

OBJECTIVE

The objective of this study was to examine the cost-effectiveness of preventive treatment with interferon beta (IFNB) versus no preventive treatment in patients with multiple sclerosis.

METHODS

The setting for this study was the United Kingdom. A lifetime Markov process model was constructed to model the average quality-adjusted life years (QALYs) and the costs of both treatment strategies. Data for the construction of the model came from published literature, including large multicenter randomized clinical trials in relapsing-remitting and secondary progressive multiple sclerosis. Costs were obtained from published sources.

RESULTS

The results of the baseline analysis from the National Health Service (NHS) perspective showed that the use of interferon beta as preventive treatment for MS increased the total average discounted cost from 51,214 Pounds to 221,436 Pounds per patient. The undiscounted effectiveness increased from 24.9 QALYs to 28.2 QALYs, resulting in an incremental cost-effectiveness ratio of 51,582 Pounds per QALY. Sensitivity analyses showed the robustness of this model for other interferons.

CONCLUSION

The study showed that preventive treatment with interferon beta in patients with multiple sclerosis may not be fully justified from a health-economic perspective, although interferon beta is associated with an improved effectiveness compared with no preventive treatment.

Gene therapy in rheumatic diseases

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by joint inflammation as well as progressive cartilage and bone destruction. Advances in the understanding of the pathophysiology of RA have led to the development of new therapeutic strategies, including gene therapy. Gene therapy offers a new approach to deliver therapeutic proteins to the joints of arthritis patients. Local as well as systemic gene therapy can be envisaged for the treatment of arthritis. Several viral and non-viral vectors have been used in animal models for rheumatoid arthritis for ex vivo and in vivo delivery of therapeutic genes. Promising pre-clinical data have resulted from the application of these strategies. Using ex vivo gene delivery, successful and safe gene transfer has been demonstrated in the joints of RA patients. Although new insights into the role of cytokines and other mediators of chronic inflammation have provided novel targets for therapeutic intervention, the development of vectors that induce long-term and regulated gene expression remains a challenge.

Immunological aspects of microglia: relevance to Alzheimer's disease

Alzheimer's disease (AD) is a progressive dementing neurologic illness, and the most frequent cause of dementia in the elderly. Neuritic plaques are one of the main neuropathological findings in AD, and the major protein component is the beta-amyloid protein (A beta). Another striking feature of neuritic plaques is the presence of activated microglia, cytokines, and complement components, suggestive of "inflammatory foci" within AD brain. In this review, we will examine the mechanisms by which microglia become activated in AD, emphasizing the role in the A beta protein and proinflammatory cytokines. As well, pathways for suppression of microglial activation by immunosuppressive cytokines will be described. Inflammation mediated by activated microglia is an important component of AD pathophysiology, and strategies to control this response could provide new therapeutic approaches for the treatment of AD.

Regulation of chemokine receptor CCR5 and production of RANTES and MIP-1alpha by interferon-beta

Trafficking of inflammatory T cells into the brain is associated with interactions of certain chemokines with their receptors, which plays an important role in the pathogenesis of multiple sclerosis (MS). We examined whether interferon-beta (IFN-beta) had the ability to regulate the production of chemokines and the expression of their receptors in T cells derived from patients with MS. It was demonstrated for the first time that in vitro exposure of T cells to IFN-beta-1a selectively inhibited mRNA expression for RANTES and MIP-1alpha and their receptor CCR5. T cell surface expression of CCR5 was significantly reduced in MS patients treated with IFN-beta, correlating with decreased T cell transmigration toward RANTES and MIP-1alpha. The study provides new evidence suggesting that IFN-beta treatment impairs chemokine-induced T cell trafficking by reducing the production of RANTES and MIP-1alpha and the expression of their receptors CCR5.

Long-term treatment of multiple sclerosis with interferon-beta may be cost effective

Multiple sclerosis (MS) is a devastating disease that can occur in early life, progressing to rapid disability and loss of physical, psychosocial and economic functioning, significantly affecting quality of life. The traditional treatment for MS has been symptomatic, treating acute relapses without affecting the underlying disease. The introduction of interferon-beta (IFN beta) has offered significant clinical benefits by reducing the frequency of relapses and slowing disease progression. Although the costs of this treatment are high, the costs to society of caring for a patient disabled by MS are greater, and if IFN beta can delay disease progression in the longer term, the economic impact would be substantial. Previous pharmacoeconomic studies of IFN beta have suggested that benefits can only be achieved at extremely high cost, with reported cost-effectiveness measures of up to 1 million pounds sterling (Pound) per quality-adjusted life year (QALY) [1995 values]. However, these studies have considered only the short term benefits of IFN beta treatment: over 2 to 3 years, the impact of treatment on patients' quality of life is relatively small, and cost-utility analyses that do not consider longer term benefits nor include societal costs may be misleading. The model reported here is based on the hypothesis that the delay in disease progression seen in short term clinical trials is likely to continue if treatment is continued. The model also assumes that the delay in disease progression, which represents a reduction in brain atrophy, will result in lasting clinical benefits even if treatment is stopped. These assumptions are strongly supported by clinical trial data and the treatment hypothesis itself. A delay in disease progression will result in a significant improvement in functioning and quality of life, and if the costs associated with increased disability can be postponed, even long term treatment of MS with IFN beta can be shown to be cost effective. Using resource utilisation costs derived from an economic evaluation of MS in the UK, it was possible to calculate the impact of delaying disease progression in terms of both health service and societal costs. An estimate of mean disease progression in patients with MS treated with IFN beta-1a compared with patients who did not receive disease-modifying agents suggested that significant cost savings would be realised after about 12 years' treatment with IFN beta-1a. The application of utility scores to the disease progression curves also facilitated estimates of cost effectiveness, with cost per QALY values ranging from 27,036 Pounds after 2 years' treatment with IFN beta-1a to 37,845 Pounds after 20 years' treatment (1995 values).

Short-term treatment of relapsing remitting multiple sclerosis patients with interferon (IFN)-beta1B transiently increases the blood levels of interleukin (IL)-6, IL-10 and IFN-gamma without significantly modifying those of IL-1beta, IL-2, IL-4 and tumour necrosis factor-alpha

We have studied the impact of short-term treatment with interferon (IFN)-beta1b of relapsing remitting (RR) multiple sclerosis (MS) patients' blood levels of type 1 and type 2 cytokines such as IFN-gamma, interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-10 and tumour necrosis factor (TNF)-alpha. These cytokines were measured by solid-phase ELISA. Serum samples were obtained prior to, and 2 and 12 hours after beginning of the treatment and 48 h after the last of 5 s.c. injections with 8 million IU IFN-beta1b given on alternate days for 10 days. The treatment was found to increase the circulating levels of IL-2, IL-6, IL-10 and IFN-gamma at some of the time points considered, with the effect acquiring statistical significance for IL-6, IL-10 and IFN-gamma. The blood levels of IL-1beta, IL-4 and TNF-alpha remained below the limit of sensitivity of the assays at any of the time points considered. If this in vivo study mirrors the impact of IFN-beta1b on MS patients' immune cells, these data demonstrate an activation of the immune system upon early treatment with the drug that does not lead to either type 1 or type 2 cytokine prevalence.

Multiple sclerosis, acute disseminated encephalomyelitis, and related conditions

Multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM) are conditions whose closely related pathology suggests shared pathophysiological elements, but whose clinical courses are usually, but not always quite dissimilar. The former is largely a disease of adulthood, the latter of childhood. Optic neuritis, demyelinative transverse myelitis, and Devic's syndrome are neurological syndromes that may occur as manifestations of either MS or ADEM. Patients with Miller-Fisher syndrome and encephalomyelradiculoneuropathy usually have features suggesting ADEM in combination with acute demyelinative polyneuropathy. These various conditions and other forms of ADEM share an indistinct border with encephalitides, granulomatous, and vasculitic conditions. MS, ADEM, and the pertinent syndromic subtypes, their differential diagnosis, treatment, and prognosis are considered in this review. Acute cerebellar ataxia is a syndrome that is likely to be pathophysiologically distinct from ADEM, although its occurrence as a postinfectious illness suggests a distant kinship. It is also reviewed.

Synovial tissue analysis in rheumatoid arthritis

In rheumatoid arthritis, synovial tissue is easily accessible for systematic analysis. Blind needle biopsy is a simple and safe procedure, but is restricted to smaller tissue samples. Arthroscopic biopsy is also safe but is more complicated as it allows access to most sites in the joint and provides adequate tissue for extensive laboratory investigations. Synovial tissue analysis has been successfully applied to studies of disease mechanisms, response to treatment and prognosis. The immuno-histological features in synovial tissue have consistently reflected disease status. Synovial tissue analysis has been particularly informative in the study of novel therapeutic agents.

Treatment of multiple sclerosis with interferon beta

Interferon beta is a cytokine that modulates immune responsiveness. Treatment with recombinant interferon b, either subcutaneously or intramuscularly, favorably affects the natural history of multiple sclerosis. Attack frequency and attack severity are both reduced and the progression of accumulating disability is slowed. Magnetic resonance image scanning of treated patients reveals a lessening of accumulating permanent disease burden and an up to 80% reduction in newly active lesions, the majority subclinical, within the white matter of the brain. Many newly active lesions resolve spontaneously. The drug is well tolerated and safe. Systemic flu-like symptoms, transient in nature, commonly follow drug injection when treatment begins, but these usually lessen in frequency and severity over the first few weeks on drug. Red skin reactions are usual at sites of subcutaneous injection. Interferon b treatment is only partially effective. There is an unmet need to do better in the therapy of multiple sclerosis.

Interferon (IFN)-beta treatment enhances CD95 and interleukin 10 expression but reduces interferon-gamma producing T cells in MS patients

Interferon (IFN)-beta has been shown to favorably alter the disease course of relapsing-remitting multiple sclerosis (RRMS) patients. Although its mode of action is still unclear, there is ample evidence from in vitro studies that IFN-beta directly modulates the function of immune cells. We analyzed here the effects of IFN-beta treatment on immune functions in vivo in a group of 25 RRMS patients who received IFN-beta (8 MIU) on alternate days. At baseline and at 1, 3 and 6 months from the start of the treatment, parameters for differentiation and activation states of both monocytes and T lymphocytes were assessed. A transient increase was seen in plasma (p) interleukin (IL)-10 level whereas pIL-12 (p40) was not affected. A similar change was found in the ability of monocytes to secrete these cytokines in vitro. Notably, patients who in vitro readily responded to IFN-beta with enhanced IL-10 production had the highest pIL-10 levels. Concerning T-cell differentiation, flow cytometric analysis of cytokine production showed that treatment with IFN-beta moderately decreased the mean percentages of CD8pos T cells producing IL-2 and IFN-gamma and CD8neg T cells producing IL-4 (p<0.05 for all cytokines), whereas a more significant decline was seen in the mean percentage of CD8neg T cells producing IFN-gamma (p<0.01). This resulted in a significant lower ratio T(HELPER(H))1 vs. T(HELPER(H))2 type cells in the CD8pos T-cell subset (p<0.05), but not in the CD8neg T-cell subset. Finally, IFN-beta treatment resulted in an initial rise in the mean percentage of CD95pos T cells and in a gradual increase in the mean level of soluble CD95 (sCD95) in plasma (p<0.01). Additional in vitro studies showed that IFN-beta indeed rapidly (within 24 h) upregulates CD95 expression on both primed and unprimed T cells and augments the release of sCD95 in culture supernatants. Thus, we confirm here that IFN-beta treatment leads to similar changes in cytokine production of T cells and monocytes as previously described in vitro. Enhanced IL-10 secretion may downmodulate cytokine secretion by activated T cells and in this way dampen newly-induced and/or ongoing immune responses. In addition, we identified a novel effect of IFN-beta treatment, i.e., induction of CD95 expression. The augmentation of CD95 expression may directly interfere with T-cell selection, notably of autoaggressive T cells. Future studies are needed to show whether this increased CD95 expression indeed leads to increased apoptosis of immune cells.

Amelioration of collagen-induced arthritis and suppression of interferon-gamma, interleukin-12, and tumor necrosis factor alpha production by interferon-beta gene therapy

OBJECTIVE

To investigate the therapeutic effects and possible mechanisms of action of constitutive expression of interferon-beta (IFNbeta) by syngeneic fibroblasts from DBA/1 mice in the collagen-induced arthritis (CIA) model.

METHODS

Immortalized embryonic DBA/1 fibroblasts were infected with a retrovirus expressing murine IFNbeta. IFNbeta-expressing fibroblasts were then implanted intraperitoneally into mice immunized with bovine type II collagen. The effect of IFNbeta on paw swelling, anticollagen antibody levels, IgG1/IgG2a isotype profiles, arthritis score, histologic joint damage, and cytokine secretion from lymph node cells and from bone marrow-derived macrophages was assessed.

RESULTS

A single injection of IFNbeta-secreting fibroblasts was sufficient to prevent arthritis or to ameliorate existing disease. Thus, IFNbeta reduced the clinical score and paw swelling irrespective of whether the injection was administered before or after disease onset in treated mice, compared with that in the untreated control group (P < 0.05). Histologic findings in the IFNbeta-treated mice were markedly less severe than in the control group (P < 0.001). This effect was accompanied by a decrease in total anticollagen IgG levels, a decrease in anticollagen IgG2a, and an increase in IgG1. In vitro, supernatants from these engineered fibroblasts inhibited collagen-induced interferon-gamma secretion from lymph node cells, and reduced the levels of tumor necrosis factor alpha and interleukin-12 produced by lipopolysaccharide/IFNgamma-treated bone marrow-derived macrophages. This effect was specific, since it was reversed with anti-IFNbeta polyclonal antibodies.

CONCLUSION

These results indicate that IFNbeta, which is currently used as a treatment for relapsing, remitting multiple sclerosis, is a potent immunomodulatory and antiinflammatory cytokine in CIA and should be considered for the treatment of rheumatoid arthritis.

Differential Effects of Type I IFNs on the Growth of WC1− CD8+ γδ T Cells and WC1+ CD8− γδ T Cells In Vitro

Type I IFNs have a broad array of immunoregulatory functions that include up-regulation of type 1 immune responses through enhancing differentiation and activation of CD8+ T cells and CD4+ Th1 cells. Ovine trophoblast IFN-τ is a recently described type I IFN with the potential for therapeutic use, based on its potent antiviral activity yet low toxicity. Studies were designed to determine the immunoregulatory effects of IFN-τ on Ag-stimulated T cells, and a novel effect of type I IFNs on γδ T cells was observed. In cultures of parasite Ag-stimulated bovine T cells that contained a mixture of αβ and γδ T cells, both IFN-τ and IFN-α suppressed the expansion of WC1+ CD2− CD6− CD8− γδ T cells, yet stimulated the growth of WC1− CD2+ CD6+ CD8+ γδ T cells and CD8+ αβ T cells. The CD8+ γδ T cell subset expressed high levels of the IL-2R α-chain. Furthermore, we showed that type I IFN enhanced IL-2 production by these Ag-stimulated T cell lines. In short term cultures of PBMC, IL-2 stimulated an expansion of WC1− CD6+ CD8+ γδ T cells, which was significantly increased by IFN-τ, even though IFN-τ alone did not support cell survival. These studies demonstrate for the first time that type I IFNs differentially modulate the proliferation of different subsets of γδ T cells, which appears to act in part via IL-2.

Effect of type I interferon on experimental autoimmune uveoretinitis in rats

In order to establish a scientific basis for the potential use of type I interferons (IFNs) in clinical uveitis, we examined the effect of a preparation of IFN-alpha/beta on experimental autoimmune uveoretinitis (EAU). Lewis rats were immunized with bovine interphotoreceptor retinoid-binding protein (IRBP) and given daily intramuscular injections of 10(5) IU mouse natural IFN-alpha/beta. Intraocular inflammation was assessed by slit-lamp biomicroscopy and histopathological examination. Rats treated daily with IFN-alpha/beta starting on the day of IRBP immunization showed decreased intraocular inflammation as well as a slight delay in onset of inflammation when compared to control rats. This effect was also observed to a lesser extent in rats treated during either the induction phase of EAU only, or starting immediately after the onset of inflammation in the effector phase of EAU. Measurement of IRBP-stimulated splenocyte proliferation and serum anti-IRBP antibody subtypes did not reveal a significant difference between IFN-alpha/beta-treated rats and control rats. Measurement of cytokine production by IRBP-stimulated splenocytes in vitro showed significantly decreased TNF-alpha for IFN-alpha/beta-treated rats compared to control, but no difference for IFN-gamma, IL-2, IL-4, and IL-10. These results indicate that systemic administration of IFN-alpha/beta suppresses IRBP-induced EAU in rats, and suggest that such suppression may be mediated in part by a reduction in TNF-alpha production.

Comparative study of the pharmacodynamic and pharmacologic effects of Betaseron and AVONEX

The aim of this 1 week study was to compare the biologic effects induced by Betaseron and AVONEX using their approved dose, route, and schedule. Sixteen healthy volunteers were randomly assigned to receive either a single i.m. dose of AVONEX (6 million International Units [MIU]) or, every other day s.c. doses of Betaseron (8 MIU). Common side effects associated with interferon-beta (IFN-beta) treatment and biologic response parameters (neopterin, beta2-microglobulin, interleukin-10 [IL-10], and MxA protein levels in blood) were measured. Ibuprofen was administered to all subjects throughout the study. Fever, chills, and myalgia occurred most frequently and with the greatest severity between 6 and 12 h after the first dose of either IFN-beta. Despite the additional dosing of subjects in the Betaseron group, the incidence, duration, and severity of the side effects were not significantly different from those in the AVONEX group. Biologic response parameters reached similar maximum concentrations in both treatment groups. In the Betaseron group, neopterin and beta2-microglobulin levels remained significantly greater than baseline throughout the 7 day study, whereas those in the AVONEX group were elevated only through day 5. Betaseron treatment significantly increased IL-10 levels above baseline, but AVONEX treatment did not. The overall induction of neopterin, beta2-microglobulin, and IL-10 (as measured by area under the concentration-time curve) was significantly greater in the Betaseron group than the AVONEX group (p = 0.031). The results of this study demonstrate that the approved Betaseron dosing regimen, in combination with ibuprofen use, provided a significantly greater and more consistently elevated biologic response compared with that of AVONEX and did so with a side effects profile comparable to that of once a week AVONEX dosing.

IFNs Are Critical Regulators of IL-1 Receptor Antagonist and IL-1 Expression in Human Microglia

Because IL-1 is implicated in the pathogenesis of multiple sclerosis, and IFNs are known to alter disease course, we sought to determine whether IFNs can regulate the expression of IL-1 and IL-1R antagonist (IL-1Ra) in primary cultures of human microglia and astrocytes. We found that IL-1 and IL-1Ra are products of microglia but not astrocytes, and IFN-β and IFN-γ differentially modulate LPS- and cytokine-induced IL-1 and IL-1Ra. IFN-β induces IL-1Ra and augments LPS- and IL-4-induced IL-1Ra, but suppresses LPS- and IL-1-induced IL-1, shifting the balance toward the expression of the IL-1Ra. Like IFN-β, IFN-γ suppresses the expression of both LPS and IL-1-induced IL-1β. However, IFN-γ also suppresses the expression of IFN-β- and IL-4-induced IL-1Ra so that IFN-γ may enhance or suppress IL-1 activity depending on the other cytokines present. IL-4 has similar effects to IFN-β; however, other anti-inflammatory cytokines, did not regulate IL-1 or IL-1Ra in human microglia. Our data demonstrate a novel suppressive effect of IFN-β and IL-4 on IL-1 activity in human microglia, suggesting that IFN-β, a therapeutic agent used for multiple sclerosis, could have wider applications in the treatment of other central nervous system disorders in which IL-1 activity has been implicated in the pathogenesis.

Intraocular cytokine quantification of experimental autoimmune uveoretinitis in rats

Elevations of inflammatory cytokines have been implicated in the pathogenesis of experimental autoimmune uveoretinitis (EAU) in rats, although such analysis has relied on indirect methods of assessment such as measurement of mRNA content. In this study, we examined the feasibility of directly measuring cytokine concentrations in intraocular extracts prepared by ultrasonic disruption. Cytokines were measured by ELISA in eyes from EAU-induced Lewis rats immunized with interphotoreceptor retinoid-binding protein (IRBP), and compared to eyes from rats immunized with adjuvant only and from normal rats. Interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-2 (IL-2), interleukin-4 (IL-4), and interleukin-10 (IL-10) were detectable in EAU eyes at near peak inflammation, with IFN-gamma achieving the highest mean concentration (331 pg/ml). In eyes from rats immunized with adjuvant only and in normal eyes, IFN-gamma, TNF-alpha, and IL-10 were nondetectable. IL-2 and IL-4 were detected at significantly lower mean concentrations (32.3 pg/ml and 69.4 pg/ml, respectively) compared to EAU eyes (217 pg/ml and 230 pg/ml, respectively); IL-4 was also detected in eyes from rats immunized with adjuvant alone (141 pg/ml). Thus, a direct method of measuring intraocular cytokine concentrations was successfully applied to reveal an elevation of IFN-gamma, TNF-alpha, IL-2, IL-4, and IL-10 in EAU eyes from rats immunized with IRBP, compared to rats immunized with adjuvant alone and to normal rats. These cytokine elevations reflect the local intraocular environment near peak inflammation, and suggest an important role for these cytokines in the mechanisms of onset and resolution of EAU in rats.

Development of neutralizing antibodies in patients with relapsing-remitting multiple sclerosis treated with IFN-beta1a

Sixty-eight patients with relapsing-remitting multiple sclerosis (RRMS) were treated with 3 million or 9 million i.u. of recombinant interferon-beta1a (recIFN-beta1a) s.c. three times a week for 2 years. Their sera were tested for antibodies neutralizing the IFN (NAb) in a bioassay. Sera with titers > or = 1:20 were considered positive. We detected NAb in 3.2%, 13.8%, and 15.9% of the patients in sera obtained at 3, 6, and 24 months, respectively. The incidence was not related to the IFN dose. Interestingly, during the 6 month baseline period before the start of the study, relapse rates, baseline disability, and the volume of lesions on T2-weighted images were significantly higher in patients who developed NAb during treatment. Because of interpatient variability, no definitive relationship was observed between NAb formation and loss of clinical or magnetic resonance imaging (MRI) response.

Chemokine-enhanced migration of human peripheral blood mononuclear cells is antagonized by interferon beta-1b through an effect on matrix metalloproteinase-9

The increased migration of peripheral blood mononuclear cells (PBMNCs) across a fibronectin (FN) matrix in response to the chemokines RANTES, MIP-1 alpha and MCP-1 is antagonized by interferon-beta-1b (IFN beta-1b). MCP-1 treatment of PBMNCs elevates their mRNA level and secretion of a matrix degrading enzyme, matrix metalloproteinase (MMP)-9, which is abrogated by IFN beta-1b. The clinical benefits of IFN beta-1b treatment in multiple sclerosis patients may in part be a result of this drug's ability to decrease the migration of PBMNCs in spite of a chemotactic gradient. Furthermore, the elevation of MMP-9 production by PBMNCs may be an important mechanism of action of chemokines.