Systemic IFN-beta treatment induces apoptosis of peripheral immune cells in MS patients.
ABSTRACT In multiple sclerosis (MS), an impaired apoptotic deletion of activated CNS-specific immune cells, leading to their pathogenic persistence, has been suggested to maintain chronic brain inflammation. We here investigated whether interferon-beta (IFN-beta) therapy induces apoptosis of peripheral immune cells. Serial blood samples from 127 relapsing-remitting MS patients were analyzed prior to the initiation of a weekly IFN-beta 1a therapy and 4, 26, and 52 weeks thereafter. Peripheral immune cells were investigated for apoptosis and for the expression of apoptosis-regulatory genes CD95, CD95 ligand, FLIP, Bcl-2, Bcl-X(L), Bag-1, and caspase 3 by quantitative real-time PCR. Biological efficacy of IFN-beta treatment was checked by quantification of Mx expression (ELISA and real-time PCR). We found a significant increase in the apoptosis rate of immune cells in response to IFN-beta treatment, compared to baseline levels. While Bcl-2 levels were permanently and Bag-1 levels transiently elevated upon therapy, other apoptosis-regulatory genes revealed no alterations. Upregulation of Mx expression confirmed the activity of IFN-beta in vivo. These findings indicate that immunomodulatory IFN-beta therapy involves the induction of apoptotic cell death with the observed RNA upregulation of Bcl-2 family members rather reflecting a possible compensatory mechanism. The increased apoptosis susceptibility of peripheral immune cells may contribute to the known reduction of brain inflammatory lesions during IFN-beta treatment.
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ABSTRACT: T cell responses to myelin basic protein (MBP) may play an important role in the pathogenesis of multiple sclerosis (MS). If MBP-reactive T cells are involved in the disease processes and undergo clonal activation and expansion, their precursor frequency would be increased in patients with MS. The frequency of MBP-reactive T cells is also influenced by regulatory mechanisms in vivo, including apoptotic deletion. In this study, we examined changes in the frequency of MBP-reactive T cells in patients with MS as a function of the apoptotic deletional mechanism in vivo, using a cell culture-based assay. A significantly increased frequency of MBP-reactive T cells was found in patients with MS relative to healthy individuals only when Fas-ligand antibody was used to block apoptosis. This result indicates that a significant proportion of MBP-reactive T cells are sensitive to apoptosis and are not deleted in vivo in patients with MS, as opposed to healthy individuals, thus suggesting a functional deficit in apoptotic deletional mechanism. Surviving Fas-sensitive MBP-reactive T cell lines represent distinct subpopulations preferentially recognizing the 111-139 region of MBP and exhibiting a Th2 cytokine profile. The findings are relevant to our understanding of regulation of MBP-reactive T cells in vivo in MS.European Journal of Immunology 06/1999; 29(5):1692-700. · 4.97 Impact Factor
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ABSTRACT: Interferon beta reduces activity in multiple sclerosis as measured clinically and by magnetic resonance imaging (MRI). We assessed the effect of interferon beta-1a on the occurrence of relapses in patients after first presentation with neurological events, who are at high risk of conversion to clinically definite multiple sclerosis. Eligible patients had had a first episode of neurological dysfunction suggesting multiple sclerosis within the previous 3 months and had strongly suggestive brain MRI findings. Patients were randomly assigned interferon beta-1a 22 microg or placebo subcutaneously once weekly for 2 years. Neurological and clinical assessments were done every 6 months and brain MRI every 12 months. Analyses excluded one patient assigned placebo who received no study injections. 241 (78%) of 308 randomised patients received study treatment for 2 years; 278 (90%) remained in the study until termination. 57 (85%) of 67 who stopped therapy did so after conversion to clinically definite multiple sclerosis. Fewer patients developed clinically definite multiple sclerosis in the interferon group than in the placebo group (52/154 [34%] vs 69/154 [45%]; p=0.047). The time at which 30% of patients had converted to clinically definite multiple sclerosis was 569 days in the interferon group and 252 in the placebo group (p=0.034). The annual relapse rates were 0.33 and 0.43 (p=0.045). The number of new T2-weighted MRI lesions and the increase in lesion burden were significantly lower with active treatment. Interferon beta-1a treatment at an early stage of multiple sclerosis had significant positive effects on clinical and MRI outcomes.The Lancet 06/2001; 357(9268):1576-82. · 39.06 Impact Factor
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ABSTRACT: Four human cell lines derived from Ewing's sarcoma, EW-7, EW-1, COH and ORS, were investigated to establish the effects of human recombinant interferon-alpha2a and human recombinant interferon-beta on cell proliferation and apoptosis. All four cell lines were much more sensitive to the antiproliferative effects of IFN-beta than of IFN-alpha. Analysis of the early signals triggered by IFN-alpha and IFN-beta demonstrated that the two IFNs were similarly effective in inducing tyrosine phosphorylation of the Jak-1 and Tyk-2 kinases and the transcription factors Stat-1 and Stat-2. Interestingly, an additional rapid phosphorylation of Stat-1 on serine was observed after IFN-beta treatment, with concomitant activation of p38 mitogen-activated protein kinase. In these cells, Stat-1 Ser727 phosphorylation in response to IFN-beta was found to be impaired by p38 MAPkinase inhibitor (SB203580). IFN-beta induced the formation of the Interferon Stimulated Gene Factor 3 complex more efficiently than IFN-alpha, as well as sustained induction of IRF-1, which may account for its greater induction of 2'5'oligo(A)synthetase and greater inhibition of cell proliferation. IFN-beta, but not IFN-alpha, induced apoptosis in wild-type p53 EW-7 and COH cell lines, but not in the mutated p53 EW-1 or ORS cell lines. The apoptosis induced by IFN-beta in EW-7 and COH cell lines appeared to be mediated by IRF-1 and involved the activation of caspase-7. Ectopic expression of IRF-1 induced apoptosis in all four cell lines which correlated with the activation of caspase-7 and with the downregulation of the Bcl-2 oncoprotein, as observed for IFN-beta-induced apoptosis in parental EW-7 and COH cell lines.Oncogene 08/2000; 19(30):3372-83. · 7.36 Impact Factor