Clinical importance of neutralising antibodies against interferon beta in patients with relapsing-remitting multiple sclerosis

BACKGROUND

Interferon beta is the first-line treatment for relapsing-remitting multiple sclerosis, but the drug can induce neutralising antibodies against itself, which might reduce effectiveness. We aimed to assess the clinical effect of neutralising antibodies.

METHODS

We measured neutralising antibodies every 12 months for up to 60 months in 541 patients with multiple sclerosis, randomly selected from all patients who started treatment with interferon beta between 1996 and 1999. Patients left the study if they changed or discontinued therapy. Antibodies were measured blindly, using antiviral neutralisation bioassays with high, medium, and low sensitivity, and with different neutralising capacities as cutoff value for definition of a neutralising-antibody-positive result.

FINDINGS

Patients developed neutralising antibodies independent of age, sex, disease duration, and progression index at start of treatment. Relapse rates were significantly higher during antibody-positive periods (0.64-0.70) than they were during antibody-negative periods (0.43-0.46; p<0.03). When comparing the number of relapses in the neutralising-antibody-positive and neutralising-antibody-negative periods we found odds ratios in the range 1.51 to 1.58 (p<0.03). Time to first relapse was significantly increased by 244 days in patients who were antibody-negative at 12 months (log rank test 6.83, p=0.009). During this short-term study, presence of neutralising antibodies did not affect disease progression measured with the expanded disability status scale.

INTERPRETATION

Our findings suggest that the presence of neutralising antibodies against interferon beta reduces the clinical effect of the drug. In patients who are not doing well on interferon beta, the presence of such antibodies should prompt consideration about change of treatment.

Interferon-β in the treatment of relapsing–remitting multiple sclerosis

The role of interferon-beta as a disease-modifying drug (DMD) for the treatment of relapsing-remitting multiple sclerosis (RRMS) is now well established, and its efficacy has been demonstrated unequivocally in large-scale clinical trials. However, current evidence suggests that in order to increase the benefit of therapy, use of an effective drug and dosing regimen should be commenced early in the course of the disease, a finding that places new emphasis on the need for early diagnosis. Indeed, it is now known that MS lesions often develop at a subclinical level and that axonal damage occurs even in the very early stages of the disease. Moreover, such damage may be irreversible, and there is strong evidence to suggest that efficacy lost as a consequence of delay in the onset of treatment or the use of a suboptimal drug regimen cannot be regained. At present, the choice of interferon-beta is complicated by the availability of 3 different products, each with a different dosing regimen. Although the optimal interferon-beta dosing regimen for RRMS has been the focus of much discussion, the issues of dose, and particularly dosing frequency, have not been satisfactorily addressed in clinical trials until recently. Over the last 2 years, however, 3 comparative studies of interferon-beta products have been conducted. The results obtained from these recent trials underline the importance of both dose and dosing frequency and indicate that for improved efficacy in RRMS, interferon-beta therapy should be administered frequently at the highest tolerable, and thus most effective, dose.

Autoimmune aspects of cytokine and anticytokine therapies

Cytokines and anticytokines are used increasingly in the treatment of immune, autoimmune, inflammatory, infectious, and malignant disorders. Commonly used treatments include the anti-tumor necrosis factor agents interferon alpha, interferon beta, interferon gamma, and interleukin 2. Several autoimmune phenomena have been reported in patients treated with these substances. This review summarizes the published data on the autoimmune manifestations associated with cytokine and anticytokine therapies, as well as describes possible mechanisms of these phenomena.

Type C-chronic hepatitis patients who had autoimmune phenomenon and developed jaundice during interferon therapy

Of a total of 2342 patients with type-C chronic hepatitis treated with interferon (IFN) at this hospital, 3 patients developed jaundice during the course of IFN therapy, but all 3 of them exhibited negative conversion of hepatitis C virus (HCV)-RNA following readministration of IFN. All 3 patients were assessed as having "probable autoimmune hepatitis (AIH)" in accordance with the AIH scoring system, indicating association with an "autoimmune phenomenon". Readministration of IFN at a low-dose induced activation of the autoimmune phenomenon, leading to fulminant hepatocellular impairment. As a result, HCV-RNA content dropped dramatically, possibly contributing to the negative conversion of HCV-RNA noted following the readministration of IFN. At present, no adequate therapy has been established for type-C chronic hepatitis with autoimmune manifestations. However, in conclusion, our findings suggested that: IFN should be a frontline regiment: (1). if autoantibody titers are low or patients are rated as having "probable AIH" or lower in accordance with the AIH scoring system, indicating a strong link to chronic hepatitis or (2). if IFN is expected to be efficacious on the basis of genotype of HCV-RNA level; even if there is acute exacerbation of type-C chronic hepatitis, IFN should be re-administered in the HCV-RNA level has dropped subsequently.

Phagocytosis of apoptotic inflammatory cells by microglia and its therapeutic implications: termination of CNS autoimmune inflammation and modulation by interferon-beta

Apoptosis of autoaggressive T-cells in the CNS is an effective, noninflammatory mechanism for the resolution of T-cell infiltrates, contributing to clinical recovery in T-cell-mediated neuroinflammatory diseases. The clearance of apoptotic leukocytes by tissue-specific phagocytes is critical in the resolution of the inflammatory infiltrate and leads to a profound downregulation of phagocyte immune functions. Adult human microglia from surgically removed normal brain tissue was used in a standardized, light-microscopic in vitro phagocytosis assay of apoptotic autologous peripheral blood-derived mononuclear cells (MNCs). Microglia from five different patients had a high capacity for the uptake of apoptotic MNCs in contrast to nonapoptotic target cells with the phagocytosis rate for nonapoptotic MNCs amounting to only 61.6% of the apoptotic MNCs. A newly described phosphatidylserine receptor, critical in the phagocytosis of apoptotic cells by macrophages, is also expressed at similar levels on human microglia. The effects of the therapeutically used immunomodulatory agent interferon-beta (IFNbeta) were investigated using Lewis rat microglia and apoptotic, encephalitogenic, myelin basic protein-specific autologous T-cells. Also, rat microglia had a high capacity to phagocytose apoptotic T-cells specifically. IFNbeta increased the phagocytosis of apoptotic T-cells to 36.8% above the untreated controls. The enhanced phagocytic activity was selective for apoptotic T-cells and was not mediated by increased IL-10 secretion. Apoptotic inflammatory cells may be efficiently and rapidly removed by microglial cells in the autoimmune-inflamed human CNS. The in vitro increase of phagocytosis by IFNbeta merits further investigations whether this mechanism could also be therapeutically exploited.

Interferon-beta treatment in patients with multiple sclerosis does not alter CYP2C19 or CYP2D6 activity

AIMS

To determine CYP2C19 and CYP2D6 activity in patients with multiple sclerosis (MS) before and during interferon (IFN)-beta treatment.

METHODS

CYP2C19 and CYP2D6 activities were assessed using the probe drugs mephenytoin and debrisoquine, respectively. Urinary mephenytoin (S/R) and debrisoquine (debrisoquine/hydroxy-debrisoquine) metabolic ratios (MR) were determined in 10 otherwise healthy Caucasian multiple sclerosis (MS) patients in the initial stage of the disease, prior to and 1 month after commencing treatment with IFN-beta (Avonex, Rebif or Betaferon). In addition, CYP2C19*2, CYP2C19*3, CYP2D6*3, CYP2D6*4, and CYP2D6*5 genotyping was performed.

RESULTS

There was no significant difference in the (S)/(R) mephenytoin ratio (mean difference 0.04; 95% CI -0.03, 0.11) or the debrisoquine MR (mean difference 0.29; 95% CI -0.44, 1.02) before and during regular IFN-beta treatment in extensive metabolizers (EM) (P = 0.5 and P = 0.4 for the respective probe drugs; n = 9 subjects). There were also no differences between the different IFN-beta treatments (P = 0.6 for the (S)/(R) mephenytoin ratio and P = 0.7 for the debrisoquine MR; anova; n = 10).

CONCLUSIONS

IFN-beta treatment did not affect the activity of CYP2C19 or CYP2D6. The results suggest that it is safe to administer CYP2C19 or CYP2D6 substrates, without dose adjustment, to patients treated with IFN-beta.

A sensitive radioimmunoprecipitation assay for assessing the clinical relevance of antibodies to IFN beta

BACKGROUND

Some multiple sclerosis (MS) patients treated with interferon beta (IFN beta) develop antibodies to the drug. Neutralising antibody (NAB) assays for IFN beta are expensive and the clinical relevance of the results has been debated.

OBJECTIVE

To establish a cheap, sensitive, and reliable assay for antibodies to (125)I-IFN beta, and to correlate levels of antibodies with clinical response to IFN beta treatment.

METHODS

We established a radioimmunoprecipitation assay (RIPA) using (125)I-IFN beta. We tested NAB positive sera, healthy control sera, and serial samples of 33 IFN beta-1b treated MS patients from the Vancouver cohort of the Berlex pivotal trial who had a high incidence of NABs.

RESULTS

We found that the RIPA was highly sensitive for the detection of antibodies to IFN beta-1a and -1b, and that there was a strong correlation between reactivity of NAB positive sera for (125)I-IFN beta-1b and for (125)I-IFN beta-1a. The RIPA was more sensitive and consistent than the NAB. Moreover, there was a trend towards poorer MRI outcomes in RIPA positive patients, but not in NAB-positive patients.

CONCLUSIONS

The RIPA assay is sensitive and easy to perform. It should be of value in assessing the clinical impact of IFN beta antibodies, and its use could help target expensive INF beta treatments to those who will respond best.

Genomic effects of IFN-beta in multiple sclerosis patients

The purpose of this report was to characterize the dynamics of the gene expression cascades induced by an IFN-beta-1a treatment regimen in multiple sclerosis patients and to examine the molecular mechanisms potentially capable of causing heterogeneity in response to therapy. In this open-label pharmacodynamic study design, peripheral blood was obtained from eight relapsing-remitting multiple sclerosis patients just before and at 1, 2, 4, 8, 24, 48, 120, and 168 h after i.m. injection of 30 micro g of IFN-beta-1a. The total RNA was isolated from monocyte-depleted PBL and analyzed using cDNA microarrays containing probes for >4000 known genes. IFN-beta-1a treatment resulted in selective, time-dependent effects on multiple genes. The mRNAs for genes implicated in the anti-viral response, e.g., double-stranded RNA-dependent protein kinase, myxovirus resistance proteins 1 and 2, and guanylate binding proteins 1 and 2 were rapidly induced within 1-4 h of IFN-beta treatment. The mRNAs for several genes involved in IFN-beta signaling, such as IFN-alpha/beta receptor-2 and Stat1, were also increased. The mRNAs for lymphocyte activation markers, such as IFN-induced transmembrane protein 1 (9-27), IFN-induced transmembrane protein 2 (1-8D), beta(2)-microglobulin, and CD69, were also increased in a time-dependent manner. The findings demonstrate that IFN-beta treatment induces specific and time-dependent changes in multiple mRNAs in lymphocytes of multiple sclerosis patients that could provide a framework for rapid monitoring of the response to therapy.

Effect of immunomodulatory treatment of multiple sclerosis on lymphocyte surface immunomarkers

The aim of this study was to analyze the effect of immunomodulatory treatment of multiple sclerosis (MS) on lymphocyte surface immunomarkers. The special attention was given to TCR alpha/beta, gamma/delta and alpha/beta HLA-DR markers. Peripheral blood was obtained from 39 patients with clinically definite R-R MS, fulfilling the criteria of McDonald et al.[5]. The group of 15 patients was treated with interferon beta-1a (Avonex) intramuscularly once a week. The blood was obtained before and after two years of treatment. The other group of 10 patients was treated every day with 20 mg of glatiramer acetate (Copaxone) intracutaneously. Subsets of lymphocytes were analyzed by the method of flow cytometry, using monoclonal antibodies produced by Ortho Diagnostic System. The relative results were evaluated using Immuno Count II program. The frequency of the studied subsets in MS was markedly different from that in healthy persons. The higher number of CD4, TCR alpha/beta positive cells and higher CD4/CD8 ratio was observed. In comparison to healthy individuals, in MS patients a decreased number of TCR gamma/delta, and alpha/beta HLA-DR was found. After therapy with glatiramer acetate, CD3 and CD8 positive lymphocytes were more frequently observed than before the drug administration. The CD4/CD8 ratio was markedly decreased. The effect of interferon beta-1a treatment was similar as in the previous group, i.e. a slight increase in CD3 and CD8 was noticed after therapy. Despite the differences in action of both immunomodulatory drugs, which was established in several studies, we like to stress some similarity in their effect on CD3, CD8, alpha/beta HLA-DR and gamma/delta HLA-DR immunomarkers frequency in lymphocyte, and on the CD4/CD8 ratio. This may mean that there are some common immunological steps of special importance for the clinical effect in MS.

Therapeutic effect of intravenous delivery of lipoplexes containing the interferon-beta gene and poly I: poly C in a murine lung metastasis model

We have evaluated and compared the efficacy of systemic administration of lipoplex formulations containing plasmids encoding IFN-beta or IFN-gamma, and a synthetic double-strand RNA poly I:poly C (pI:pC), a type I IFN inducer, in a lung metastasis model in which colon carcinoma CT-26 cells were inoculated intravenously into immunocompatible mice. Injection of lipoplexes containing plasmid DNA, regardless of IFN gene insertion, stimulated a transient increase in the serum concentration of proinflammatory cytokines such as tumor necrosis factor (TNF)-alpha and IFN-gamma, while injection of lipoplexes containing pI:pC led to a low level of TNF-alpha and undetectable IFN-gamma production. Furthermore, injection of these lipoplexes containing plasmids resulted in the production of a mixture of type I and type II IFNs, partly derived from the inserted IFN genes, in lung tissue cultures. In tumor-prophylactic experiments, intravenous injection of lipoplexes containing plasmid, regardless of IFN gene insertion, showed a significant reduction in lung metastatic nodules probably due to proinflammatory cytokines such as TNF-alpha and IFN-gamma nonspecifically induced by the CpG motifs in the plasmid and the type I IFNs produced. On the other hand, the antimetastatic effect of pI:pC-lipoplex seemed to be due mainly to IFN-beta induced by pI:pC. In established lung metastasis experiments, a single intravenous administration of lipoplexes containing IFN-beta gene or pI:pC, but not other lipoplexes, showed a significant therapeutic effect on the tumor metastasis: reduction in tumor nodules and prolongation of survival time of tumor-burden mice. The therapeutic effects were specifically impaired by anti-IFN-beta antibody treatment, indicating that IFN-beta produced by the lipoplexes played an important role in the suppression of established metastatic lung tumors. Thus, the local IFN-beta in the lung delivered by intravenous administration of lipoplex containing IFN-beta gene or pI:pC may be a convenient and useful method of inhibiting established metastatic lung tumors.

Disease-modifying drugs in multiple sclerosis

This article is a description of practice and a comment on the evolution of a disease-modifying drug (DMD) treatment service for multiple sclerosis (MS) in a tertiary referral centre. It is hoped it will help other MS nurses who are involved in the establishment of DMD clinics in their area. It aims to offer an update on practical management of DMDs that may prove useful for any nurse involved in caring for people with MS. It describes lessons learnt in the establishment and growth of the service and protocols put in place to ensure best practice. The importance of partnership in care with patients and multidisciplinary collaboration is highlighted, while the pivotal role of the MS nurse in the delivery of an effective service is emphasised.

Interrupted therapy: stopping and switching of the beta-interferons prescribed for MS

A retrospective chart review of patients in British Columbia with multiple sclerosis prescribed beta-interferon (IFNbeta) between 1995 and 2001 was carried out to investigate reasons for the interruption of therapy. The highest proportion of interruptions (76/281; 27%) occurred in the first 6 months. The single most common reason was perceived lack of efficacy, cited by 84 of 281 (30%). Gender, disability, and disease duration were identified as factors influencing interruption of IFNbeta therapy.

[Chemokines and chemokine receptors in multiple sclerosis]

Findings of chemokines and chemokine receptors in multiple sclerosis(MS) are reviewed. MS is a T-helper type 1 (Th1) dominant condition, and Th1-associated chemokine receptors(CCR5 and CXCR3) on CD4- and CD8-positive T cells and their ligands are upregulated in the CNS of the patients with active disease. Meanwhile, Th2-associated chemokine receptors(CCR3 and CCR4) on CD4- and CD8-positive T cells are suppressed during relapse. Their expressions are useful immunological measures of disease activity, clinical subtypes and therapy. CCR7 and the ligands are expressed in the CNS of MS and may be important for the recruitment of immune cells committed to immunological memory and antigen presentation.

[Interferon beta treatment in multiple sclerosis]

Medical treatment of multiple sclerosis(MS) consists primarily of corticosteroid therapy to enhance recovery from relapse and drug interventions to help manage symptoms. However, disease-modifying drugs for the treatment of MS have been developed recent years, including interferon(IFN) beta, glatiramer acetate, and mitoxantrone. In addition to reductions in annual relapse rates and other measures of clinical disability, these drugs appear to reduce disease activity on MRI. In Japan, IFN beta-1b(Betaferon) is available as a disease-modifying drug from September 2000. This article focuses on the use of IFN beta for MS on the basis of available clinical data.

[IL-18 in multiple sclerosis]

IL-18, previously named interferon-gamma inducing factor, is produced by monocytes/macropharges, dendritic cells, B cells and other APC cells as well as by astrocytes, microglia. IL-18 is a unique cytokine that stimulates both Th1 and Th2 responses depending on its cytokine milieu. Caspase-1 regulates the cellular export of IL-18. Anti IL-18 antibodies prevent EAE. IL-18 directs autoreactive T cells and promotes autodestruction in CNS via induction of IFN-gamma by NK cells in EAE. IL-18 is expressed in MS plaque. Common IL-18 promoter polymorphisms influence the expression on IL-18. IL-18 is linked to raised IFN-gamma in MS and is induced by activated CD4(+) T cells via CD40-CD40 ligand interaction. IL-18 in MS is suppressed by treatments such as GA and IFN-beta.

Quantitative CT indexes in idiopathic pulmonary fibrosis: relationship with physiologic impairment

PURPOSE

To determine whether measurements of skewness, kurtosis, and mean lung attenuation on thin-section computed tomographic (CT) histograms in patients with idiopathic pulmonary fibrosis (IPF) correlate with pulmonary physiologic abnormality in a nonspirometrically controlled multicenter study.

MATERIALS AND METHODS

The authors analyzed baseline digital thin-section CT data from 144 patients with IPF who enrolled in a double-blind placebo-controlled clinical effectiveness trial of interferon beta 1a in the treatment of IPF. All patients underwent thin-section CT in the supine position at full inspiration. The lungs were isolated by using a semiautomated thresholding technique, with an upper threshold of -200 HU. An attenuation correction algorithm was used. Pulmonary function tests (PFTs) included forced vital capacity, total lung capacity, forced expiratory volume in 1 second, and diffusing lung capacity. Univariate and multiple correlation and regression statistical analyses were used to determine relationships between histogram features and results of PFTs.

RESULTS

Moderate correlations existed between histogram features and PFT results. Kurtosis showed the greatest degree of correlation with physiologic abnormality (r = 0.53, P <.01). Strength of correlation increased with exclusion of suboptimal scans but did not change significantly after application of an attenuation correction algorithm. Attenuations for lungs, gas, and soft tissue varied considerably between scanner manufacturers. Kurtosis alone provided predictions of pulmonary function that were virtually as good as those from all histogram features combined.

CONCLUSION

Thin-section CT histograms of the lungs were found to correlate with results of PFTs in patients with IPF, which supports the claim that histogram features can be used as valid indexes of IPF in a multiinstitutional nonspirometrically controlled study.

[Blood-brain barrier in multiple sclerosis: mechanisms of its breakdown and repair]

The blood-brain barrier(BBB) restricts exchanges of soluble factors and cells between the blood and brain, thus playing a crucial role in maintenance of cerebral homeostasis. In multiple sclerosis(MS), disruption of the BBB is the initial key step in the development of inflammatory lesions. BBB impairment may occur before the formation of demyelinative foci or T cell infiltration around small vessels; however, once the BBB breaks, massive infiltration of T cells, augmented expression of adhesion molecules on endothelial cell surface, and leakage of inflammatory cytokines and antibodies will aggravate the MS lesions. Although glucocorticoids and type 1 interferons are now widely used and are known to decrease BBB permeability additively, the development of novel therapeutic strategy focusing on the repairment of BBB integrity should be awaited.

[Immunologic therapy for secondary and primary progressive multiple sclerosis]

Immunological treatments of progressive multiple sclerosis are discussed. Recent trials of interferon-beta 1b(IFN beta-1b) and IFN beta-1a in secondary progressive MS (SPMS) have demonstrated treatment benefits on relapse rate and accumulation of MRI lesions, and one trial of IFN beta-1b showed significant slowing of disability progression. In another recent study, mitoxantrone, a potent immunosuppressive agent, was reported to reduce progression of disability in SPMS. As regards primary progressive MS, there is currently no convincing disease-modifying treatment. Pathologic studies have revealed that axonal injury is prominent in MS and may be the explanation for irreversible disability. It is hoped that therapeutic strategies will be aimed at axonal loss as well as inflammation and demyelination.