Low expression of interferon-stimulated genes in active multiple sclerosis is linked to subnormal phosphorylation of STAT1
Multiple sclerosis is an immune-mediated brain disease ameliorated by interferon-beta therapy. Immune responses to IFN-alpha and IFN-beta are sometimes subnormal in MS peripheral blood mononuclear cells (MNCs), suggesting an underlying defect in type I IFN signaling. We studied IFN-beta regulation of mRNA and protein induction for IFN regulatory factor-1 (IRF-1) and IRF-2, which control multiple IFN-stimulated genes, and for 2',5'-oligoadenylate synthetase (2',5'-OAS) and MxA, which are antiviral proteins. First, mRNA levels in resting MNC from untreated patients with clinically active MS contained IRF-1 at 38% of normal controls, 45% for IRF-2, 44% for 2',5'-OAS (all p<0.005), and 46% for MxA protein (p<0.007). Stable MS patients had intermediate levels of 2',5'-OAS and MxA. IFN-beta-1b therapy increased IRF-1, IRF-2, and 2',5'-OAS mRNA in resting MNC-but only up to levels seen in unstimulated control cells. In untreated patients with active MS, serine phosphorylation of the STAT1 transcription factor was markedly reduced, suggesting a mechanism for the low levels of IFN-induced genes. Secondly, in untreated patients with stable MS, culture with IFN-beta induced excessive tyrosine phosphorylation of STAT1, and this correlated with low SHP1 tyrosine phosphatase levels. Excessive P-Tyr-STAT1 responses could induce inflammatory cytokines and demyelination in MS, as in motheaten mice, which have defects in SHP-1 function. Abnormal IFN signaling may predict the course of MS and responses to therapy.
[Show abstract] [Hide abstract] ABSTRACT: There is increasing scientific and clinical interest in elucidating the biology of type I Interferons, which began approximately 60years ago with the concept of "viral interference", a property that reduces the ability of a virus to infect cells. Although our understanding of the multiple cellular and molecular functions of interferons has advanced significantly, much remains to be learned and type I Interferons remain an active and fascinating area of inquiry. In this review, we cover some general aspects of type I interferon genes, with emphasis on interferon-alpha, and various aspects of molecular mechanisms triggered by type I interferons and toll-like receptor signaling by the Janus activated kinase/signal transducer activation of transcription (JAK-STAT) pathway and interferon regulatory factor pathway. We will also describe the role of type I interferons in autoimmune and inflammatory diseases, and its potential use as therapeutic agent.0Comments 2Citations
- "In the above-mentioned study in untreated relapsing-remitting MS patients (Feng et al., 2002), blood mononuclear cells also showed downregulation of IRF1 and IRF2 genes, two key transcription factors that regulate many type I IFN-regulated genes and IFNα-induced expression of the antiviral proteins 2′,5′-OAS and MxA. Nevertheless , the IRF1 and IRF2 expression levels only increased slightly above the baseline levels in response to IFN-β-1b therapy (Feng et al., 2002), suggesting that MS patients may have a defect in IFN signaling which is only partially reversed by therapy. Although most MS patients display low levels of type I IFN-regulated genes, a subset of MS patients has a high IFN signature as well as more clinical and MRI disease activity before therapy, and these patients often do not respond to IFN-β treatment (Comabella et al., 2009; Hundeshagen et al., 2012; Matas et al., 2014), suggesting that MS immunopathogenesis may differ between patients. "
[Show abstract] [Hide abstract] ABSTRACT: Background Myxovirus resistance protein A (MxA) is a molecule induced after interferon-beta injection, mostly used to evaluate its bioactivity. There is little available data on clinical utility of baseline MxA mRNA status. The objective of the study is to investigate whether baseline MxA mRNA expression can predict relapse and disease progression in multiple sclerosis patients treated with interferon-beta. Methods Baseline blood samples were obtained before the first interferon-beta dose was administered to evaluate MxA mRNA expression using real-time polymerase chain reaction (PCR). Demographic and clinical variables were prospectively recorded to define treatment responder and non responder groups. Results 104 patients were included in the study. Baseline MxA mRNA expression was significantly lower in the group of patients who met the definition of responders (1.07 vs 1.95, Student t test, p<0.0001). A threshold of 1.096 was established using Receiver Operating Characteristic analysis to differentiate between responders and non-responders (sensitivity 73.9%, specificity 69.0%). Survival analysis using this threshold showed that time to next relapse (p<0.0001) and to EDSS progression (p = 0.01) were significantly higher in patients with lower MxA titers. Conclusion The results suggest that baseline MxA mRNA levels may be useful for predicting whether multiple sclerosis patients will respond or not to interferon-beta treatment.0Comments 4Citations
- "Baseline MxA expression has been evaluated in several studies. Some authors have suggested that spontaneous MxA mRNA levels in MS patients may be useful to identify patients with active disease forms  and those experiencing a relapse .They found that higher baseline MxA mRNA levels are related to a longer time to a new relapse. Essential differences were found between these studies and the present. "
[Show abstract] [Hide abstract] ABSTRACT: Autoantibodies against CD28 have been found in patients with autoimmune and atopic diseases. These antibodies may act as superagonists and activate T cells but may also be antagonistic or induce immunosuppressive effects by activating regulatory T cells. Autoimmunity in melanoma patients has been discussed controversially. We investigated 230 melanoma patients for the occurrence of CD28 antibodies and the effect of the latter on overall and progress-free survival. We constructed an ELISA assay to measure CD28 serum antibodies. 230 patients with melanoma and a control-group of 625 patients consistent of 212 patients with virus hepatitis b or c, 149 patients with allergies, 78 patients with psoriasis, 46 patients with plasmocytoma and 140 healthy blood donors were investigated for the occurrence of CD28 antibodies. CD28 abs occur at a higher percentage in patients with melanoma and in patients with viral hepatitis than in other groups investigated (p<0.001). Occurrence of CD28 abs is significantly higher in patients receiving interferons independent from the underlying disease (p<0.001). In vitro CD28 serum antibodies have an inhibitory effect on the CD28 receptor as they lead to reduced stimulation of Jurkat cells. Presence of CD28 was correlated with a higher risk of dying from melanoma (p = 0.043), but not with a significantly shortened overall survival or progression-free survival. Interferon therapy appears to induce the production of CD28 abs. In light of reports that these CD28 abs induce immunosuppressive Tregs and - as our data show - that they are inhibitors of CD28 receptor mediated stimulation, the continuation of therapies with interferons in melanoma patients developing CD28 antibodies should be critically reconsidered, since our data indicate a worse outcome of patients with CD28 abs.0Comments 0Citations
- "biological meaning anti-CD28 could become a valuable adjunct marker of progression. Impaired IFN signalling has been observed in multiple sclerosis and chronic hepatitis C infection [14,15]. Critchley-Thorne et al. identified defects in IFN signalling as a dominant mechanism of immune dysfunction in cancer patients [7,8]. "