Type I interferons inhibit interleukin-10 production in activated human monocytes and stimulate IL-10 in T cells: implications for Th1-mediated diseases

Adaptive and innate immune responses in multiple sclerosis with anti-CD20 therapy: Gene expression and protein profiles

Background

Anti-CD20 is a highly effective therapy for multiple sclerosis (MS), a disease with multiple abnormalities in function of B and T cells and innate immune cells. Anti-CD20 therapy depletes B cells, which alters antibody production and has diverse effects on B cell immunity. These changes potentially affect immunity beyond B cells in MS.

Objective

Determine if anti-CD20 therapy effects non-B cell, as well as B cell, gene expression, and serum protein levels.

Methods

Samples were collected from 10 healthy controls and from clinically stable relapsing-remitting MS - 10 untreated, 9 interferon-β-treated, and 15 ocrelizumab-treated patients were studied before, and 2  weeks and 6  months after, the first anti-CD20 infusion. Peripheral blood mononuclear cells (PBMC) were analyzed with sensitive, 135,000-transcript RNA expression microarrays, using stringent criteria. Gene expression was compared to 43 MS-relevant serum immune and neurotrophic proteins, using multiplex protein assays.

Results

Anti-CD20 therapy reduced expression of 413 total genes and 185 B-cell-regulated genes at 2  weeks vs. pre-therapy. Expression of 19 (15%) of these B cell genes returned toward baseline by 6  months, including genes for the B cell activation protein, CD79A, and for immunoglobulin A, D, and G heavy chains. Expression pathways for Th17 and CD4 regulatory T-cell (Treg) development, differentiation, and proliferation also quieted. In contrast, expression increased in Th1 and myeloid cell antiviral, pro-inflammatory, and toll-like receptor (TLR) gene pathways.

Conclusion

These findings have clinical implications. B cell gene expression diminishes 2  weeks after anti-CD20 antibody infusion, but begins to rebound by 6  months. This suggests that the optimum time for vaccination is soon before reinfusion of anti-CD20 therapy. In addition, at 6  months, there is enhanced Th1 cell gene expression and induction of innate immune response genes and TLR expression, which can enhance anti-viral and anti-tumor immunity. This may compensate for diminished B cell gene expression after therapy. These data suggest that anti-CD20 therapy has dynamic effect on B cells and causes a compensatory rise in Th1 and myeloid immunity.

Prolonged Interferon-Stimulated Gene and Protein Signatures in Multiple Sclerosis Induced by PEGylated IFN-β-1a Compared to Non-PEGylated IFN-β-1a

Interferon (IFN)-β-1a (Avonex) and longer half-life, polyethylene glycol-conjugated IFN-β-1a (PEG-IFN-β-1a, Plegridy), may generate different molecular responses. We identified different short-term and long-term in vivo global RNA signatures of IFN-stimulated genes in multiple sclerosis (MS) peripheral blood mononuclear cells and in selected paired serum immune proteins. At 6 h, non-PEGylated IFN-β-1a injection upregulated expression of 136 genes and PEG-IFN-β-1a upregulated 85. At 24 h, induction was maximal; IFN-β-1a upregulated 476 genes and PEG-IFN-β-1a now upregulated 598. Long-term PEG-IFN-β-1a therapy increased expression of antiviral and immune-regulatory genes (IFIH1, TLR8, IRF5, TNFSF10 [TRAIL], STAT3, JAK2, IL15, and RB1) and IFN signaling pathways (IFNB1, IFNA2, IFNG, IRF7), but downregulated expression of inflammatory genes (TNF, IL1B, and SMAD7). Long-term PEG-IFN-β-1a induced longer and stronger expression of Th1, Th2, Th17, chemokine, and antiviral proteins than long-term IFN-β-1a. Long-term therapy also primed the immune system, evoking higher gene and protein induction after IFN reinjection at 7 months than at 1 month of PEG-IFN-β-1a treatment. Both forms of IFN-β balanced correlations of expression among these genes and proteins, with positive correlations between Th1 and Th2 families, quelling the "cytokine storm" of untreated MS. Both IFNs induced long-term, potentially beneficial, molecular effects on immune and possibly neuroprotective pathways in MS.

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

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

Vitamin D enhances responses to interferon-β in MS

Objective

To determine the effect of vitamin D3 on interferon-β (IFN-β) response and immune regulation in MS mononuclear cells (MNCs).

Methods

MNCs from 126 subjects, including therapy-naive patients with different forms of MS, plus patients with MS receiving IFN-β or glatiramer treatment, plus healthy controls were incubated in vitro with IFN-β-1b ± vitamin D3 (calcitriol). Activation of the IFN-β–induced transcription factor, p-Y-STAT1, and antiviral myxovirus A (MxA) protein was measured with flow cytometry and Western blots; serum proteins were measured with a customized 31-protein multiplex assay.

Results

Vitamin D enhanced in vitro IFN responses, as measured by induction of p-Y-STAT1 and MxA in MNCs, T cells, and monocytes. Vitamin D augmentation of IFN responses was seen in untreated and in IFN-β-1b–treated MS. The combination of vitamin D plus IFN-β reduced Th1 and Th17 cytokines, and increased Th2 responses, reversing the effect of IFN-β alone. Exacerbations and progression in untreated patients reduced the vitamin D enhancement of IFN responses. Vitamin D had less effect on IFN response in clinically stable glatiramer-treated than in IFN-β–treated patients.

Conclusion

Vitamin D enhances IFN-β induction of multiple proteins and also reverses the Th1/Th2 bias in MS seen with IFN-β alone. The combination of vitamin D and IFN-β has potential benefit in ameliorating MS.

Restoration of the type I IFN-IL-1 balance through targeted blockade of PTGER4 inhibits autoimmunity in NOD mice

Type I IFN (IFN-I) dysregulation contributes to type 1 diabetes (T1D) development, and although increased IFN-I signals are pathogenic at the initiation of autoimmune diabetes, IFN-I dysregulation at later pathogenic stages more relevant for therapeutic intervention is not well understood. We discovered that 5 key antigen-presenting cell subsets from adult prediabetic NOD mice have reduced responsiveness to IFN-I that is dominated by a decrease in the tonic-sensitive subset of IFN-I response genes. Blockade of IFNAR1 in prediabetic NOD mice accelerated diabetes and increased Th1 responses. Therefore, IFN-I responses shift from pathogenic to protective as autoimmunity progresses, consistent with chronic IFN-I exposure. In contrast, IL-1-associated inflammatory pathways were elevated in prediabetic mice. These changes correlated with human T1D onset-associated gene expression. Prostaglandin E2 (PGE2) and prostaglandin receptor 4 (PTGER4), a receptor for PGE2 that mediates both inflammatory and regulatory eicosanoid signaling, were higher in NOD mice and drive innate immune dysregulation. Treating prediabetic NOD mice with a PTGER4 antagonist restored IFNAR signaling, decreased IL-1 signaling, and decreased infiltration of leukocytes into the islets. Therefore, innate cytokine alterations contribute to both T1D-associated inflammation and autoimmune pathogenesis. Modulating innate immune balance via signals such as PTGER4 may contribute to treatments for autoimmunity.

Interferon-Alpha Reduces Human Hippocampal Neurogenesis and Increases Apoptosis via Activation of Distinct STAT1-Dependent Mechanisms

BACKGROUND

In humans, interferon-α treatment for chronic viral hepatitis is a well-recognized clinical model for inflammation-induced depression, but the molecular mechanisms underlying these effects are not clear. Following peripheral administration in rodents, interferon-α induces signal transducer and activator of transcription-1 (STAT1) within the hippocampus and disrupts hippocampal neurogenesis.

METHODS

We used the human hippocampal progenitor cell line HPC0A07/03C to evaluate the effects of 2 concentrations of interferon-α, similar to those observed in human serum during its therapeutic use (500 pg/mL and 5000 pg/mL), on neurogenesis and apoptosis.

RESULTS

Both concentrations of interferon-α decreased hippocampal neurogenesis, with the high concentration also increasing apoptosis. Moreover, interferon-α increased the expression of interferon-stimulated gene 15 (ISG15), ubiquitin-specific peptidase 18 (USP18), and interleukin-6 (IL-6) via activation of STAT1. Like interferon-α, co-treatment with a combination of ISG15, USP18, and IL-6 was able to reduce neurogenesis and enhance apoptosis via further downstream activation of STAT1. Further experiments showed that ISG15 and USP18 mediated the interferon-α-induced reduction in neurogenesis (potentially through upregulation of the ISGylation-related proteins UBA7, UBE2L6, and HERC5), while IL-6 mediated the interferon-α-induced increase in apoptosis (potentially through downregulation of aquaporin 4). Using transcriptomic analyses, we showed that interferon-α regulated pathways involved in oxidative stress and immune response (e.g., Nuclear Factor (erythroid-derived 2)-like 2 [Nrf2] and interferon regulatory factor [IRF] signaling pathway), neuronal formation (e.g., CAMP response element-binding protein [CREB] signaling), and cell death regulation (e.g., tumor protein(p)53 signaling).

CONCLUSIONS

We identify novel molecular mechanisms mediating the effects of interferon-α on the human hippocampus potentially involved in inflammation-induced neuropsychiatric symptoms.

How type I interferons work in multiple sclerosis and other diseases: some unexpected mechanisms

Type I interferons (IFNs) are important in innate and adaptive immunity. They are used to treat virus infections, cancer, and multiple sclerosis (MS). There are 5 type I IFN families in humans-IFN-α with 13 subtypes, plus IFN-β, ɛ, κ, and ω. Because their receptor binding affinities vary, these IFNs have different gene induction profiles and quite variable therapeutic effects. IFN-α subtypes may each be specific for certain viruses, but can be neurotoxic. IFN-β induces IFN-α, plus has additional direct effects on target cells. IFN-β was the first therapy approved that could change the course of MS. It has broader specificity than IFN-α, enhances cognition in MS, and may be neuroprotective and can potentially enhance fertility in women. Priming the IFN signaling system with an injection of IFN-β can enhance subnormal type I IFN signals in MS. Many other commonly used drugs and vitamins may potentiate clinical benefits of IFN-β.

Immunomodulatory activity of interferon-beta

Multiple sclerosis (MS) is a complex disorder of the central nervous system that appears to be driven by a shift in immune functioning toward excess inflammation that results in demyelination and axonal loss. Beta interferons were the first class of disease-modifying therapies to be approved for patients with MS after treatment with this type I interferon improved the course of MS on both clinical and radiological measures in clinical trials. The mechanism of action of interferon-beta appears to be driven by influencing the immune system at many levels, including antigen-presenting cells, T cells, and B cells. One effect of these interactions is to shift cytokine networks in favor of an anti-inflammatory effect. The pleiotropic mechanism of action may be a critical factor in determining the efficacy of interferon-beta in MS. This review will focus on select immunological mechanisms that are influenced by this type I cytokine.

Subtypes of type I IFN differentially enhance cytokine expression by suboptimally stimulated CD4(+) T cells

Human type I interferons (IFNs) include IFN-β and 12 subtypes of IFN-α. During viral infection, infiltrating memory CD4(+) T cells are exposed to IFNs, but their impact on memory T-cell function is poorly understood. To address this, we pretreated PBMCs with different IFNs for 16 h before stimulation with Staphylococcus aureus enterotoxin B and measured cytokine expression by flow cytometry. IFN-α8 and -α10 most potently enhanced expression of IFN-γ, IL-2, and IL-4. Potency among the subtypes differed most at doses between 10 and 100 U/mL. While enhancement of IL-2 and IL-4 correlated with the time of preincubation with type I IFN, IFN-γ production was enhanced best when IFN-α was added immediately preceding or simultaneously with T-cell stimulation. Comparison of T-cell responses to multiple doses of Staphylococcus aureus enterotoxin B and to peptide libraries from RSV or CMV demonstrated that IFN-α best enhanced cytokine expression when CD4(+) T cells were suboptimally stimulated. We conclude that type I IFNs enhance Th1 and Th2 function with dose dependency and subtype specificity, and best when T-cell stimulation is suboptimal. While type I IFNs may beneficially enhance CD4(+) T-cell memory responses to vaccines or viral pathogens, they may also enhance the function of resident Th2 cells and exacerbate allergic inflammation.

Aberrant Type I Interferon Regulation in Autoimmunity: Opposite Directions in MS and SLE, Shaped by Evolution and Body Ecology

Studying the action of mechanisms of type I interferon (IFN) provides the insight to elucidate the cause and therapy for autoimmune diseases. There are high IFN responses in some diseases such as connective tissue diseases, but low responses in multiple sclerosis. Distinct IFN features lead us to understand pathology of a spectrum of autoimmune diseases and help us to search genetic changes, gene expression, and biomarkers for diagnosis, disease progression, and treatment response.

Increase of Ki-67+ natural killer cells in multiple sclerosis patients treated with interferon-β and interferon-β combined with low-dose oral steroids

Interferon-β (IFN-β) is known to expand regulatory CD56(bright) natural killer (NK) cells in multiple sclerosis (MS). In this cross-sectional study we show that MS patients treated with IFN-β alone or in combination with low-dose prednisolone displayed increased proportion of all NK cell subsets in the active phase of the cell cycle (Ki-67+). There was no difference in NK cell apoptosis markers. In vitro experiments showed that both IFN-β and IFN-β in combination with corticosteroids increased the proportion of Ki-67(+) NK cells. This study, although limited, shows that treatment with IFN-β affects NK cell cycle without altering NK cell apoptosis in MS patients.

The association of cryoglobulinaemia with sustained virological response in patients with chronic hepatitis C

Previous reports suggest cryoglobulinemia might influence the hepatitis C virus (HCV) infection clinical course and treatment response but this association has not been thoroughly evaluated. We aimed to assess the relationship between cryoglobulinemia and sustained viral response (SVR) in patients treated for HCV infection. We included patients with HCV infection treated from January 2003 through December 2006. Biochemical analyses, detection cryoglobulinemia, and liver biopsies were performed prior to treatment. Genotype 1 or 4 infections received Peg-interferon (IFN) alpha-2a or -2b for 48 weeks; genotypes 2 or 3 received IFN alpha for 24 weeks. All patients also received ribavirin. Of 329 enrolled patients, 242 (73%) were male and the median age was 43 years. Cryoglobulinemia was detected in 196 (59.6%) patients; liver biopsy was performed in 301. Multivariate analysis showed an association of cryoglobulinemia with severe active necroinflammation (A3) (adjusted odds ratio [AOR] = 9.48; 95% confidence interval [CI]: 1.50-59.92) and rheumatoid factor (RF) level (AOR = 1.01; 95% CI: 1.00-1.02). Variables associated with advanced fibrosis were age, aspartate aminotransferase and alkaline phosphatase levels, alcohol use, and presence of diabetes. Variables independently associated with SVR were cryoglobulinemia (AOR = 2.33, 95% CI: 1.26-4.32), absence of cirrhosis (AOR = 4.5, 95% CI: 1.4-14.80), and RF level (AOR = 1.008, 95% CI: 1.001-1.014). Our findings suggest cryoglobulinemia is associated with severe necroinflammatory activity in HCV-infected patients. We also provide the first evidence for an association between cryoglobulinemia and higher SVR rates, highlighting its potential role as a prognostic factor for treatment response.

Interferon-beta increases systemic BAFF levels in multiple sclerosis without increasing autoantibody production

BACKGROUND

Treatment with interferon-beta (IFN-beta) increases B-cell activating factor of the TNF family (BAFF) expression in multiple sclerosis (MS), raising the concern that treatment of MS patients with IFN-beta may activate autoimmune B cells and stimulate the production of MS-associated autoantibodies.

OBJECTIVE

To investigate whether BAFF levels are associated with disease severity/activity in untreated MS patients, and to assess the effect of IFN-beta therapy on circulating BAFF and anti-myelin basic protein (MBP) autoantibody levels.

RESULTS

Twenty-three patients with relapsing-remitting MS (RRMS) were followed longitudinally from initiation of IFN-beta therapy. Their blood levels of BAFF correlated positively at baseline with the expanded disability status scale (p<0.009) and MS severity score (p<0.05), but not with disease activity as determined by the number of gadolinium-enhanced lesions. The patients were followed for up to 26 months, during which the BAFF levels remained elevated without association to increased disease activity. IFN-beta therapy caused an increase in plasma BAFF levels after both 3 and 6 months of therapy (p<0.002). However, an 11% decrease in IgM and a 33% decrease in IgG anti-MBP autoantibodies (p<0.09 and p<0.009, respectively) was observed after 6 months.

CONCLUSION

Pre-treatment BAFF levels correlate with high disability scores in MS, suggesting that high BAFF expression is a negative prognostic marker. Despite its known beneficial effects, IFN-beta therapy causes a sustained increase in plasma BAFF levels, which does not translate into increased levels of anti-MBP autoantibodies.

Lipopolysaccharide-mediated IL-10 transcriptional regulation requires sequential induction of type I IFNs and IL-27 in macrophages

IL-10 is a potent anti-inflammatory molecule that regulates excessive production of inflammatory cytokines during an infection or tissue damage. Dysregulation of IL-10 is associated with a number of autoimmune diseases, and so, understanding the mechanisms by which IL-10 gene expression is regulated remains an important area of study. Macrophages represent a major source of IL-10, which is generated in response to TLR signaling as a feedback mechanism to curtail inflammatory response. In this study, we identify a signaling pathway in murine bone marrow-derived macrophages in which activation of TLR4 by LPS induces the expression of IL-10 through the sequential induction of type I IFNs followed by induction and signaling through IL-27. We demonstrate that IL-27 signaling is required for robust IL-10 induction by LPS and type I IFNs. IL-27 leads directly to transcription of IL-10 through the activation of two required transcription factors, STAT1 and STAT3, which are recruited to the IL-10 promoter. Finally, through systematic functional promoter-reporter analysis, we identify three cis elements within the proximal IL-10 promoter that play an important role in regulating transcription of IL-10 in response to IL-27.

Autoantibodies to myelin basic protein (MBP) in healthy individuals and in patients with multiple sclerosis: a role in regulating cytokine responses to MBP

Anti-myelin basic protein (-MBP) autoantibodies have generally been considered to be absent from sera from healthy individuals, but to be detectable in sera from some patients with multiple sclerosis (MS). However, their pathogenic role is uncertain. We demonstrate the presence of MBP-reactive autoantibodies in sera from 17 healthy individuals and 17 MS patients. The addition of MBP to the sera caused a dose-dependent deposition of MBP and co-deposition of immunoglobulin M (IgM) and fragments of complement component 3 (C3) on allogeneic monocytes. Calcium chelation abrogated the immunoglobulin deposition, indicating that formation of complement-activating immune complexes played a role in the binding process. Furthermore, MBP elicited tumour necrosis factor (TNF)-alpha and interleukin (IL)-10 production by normal mononuclear cells in the presence of serum from both patients and controls. Mononuclear cells from MS patients responded to MBP with the production of interferon (IFN)-gamma, IL-4 and IL-5, in addition to TNF-alpha and IL-10. The production of IFN-gamma and IL-5 was increased when MS serum was added rather than normal serum. Denaturation of MBP strongly inhibited MBP deposition and the MBP-induced IgM deposition and cytokine production, indicating that these events were facilitated by autoantibodies recognizing conformational epitopes on MBP. We infer that MBP-elicited TNF-alpha and IL-10 responses are promoted to equal extents by naturally occurring MBP autoantibodies and autoantibodies contained in MS sera. However, the latter seem to be more efficient in facilitating the production of IFN-gamma and IL-5.

The effect of beta-interferon therapy on myelin basic protein-elicited CD4+ T cell proliferation and cytokine production in multiple sclerosis

Interferon (IFN)-beta therapy has well-established clinical benefits in multiple sclerosis (MS), but the underlying modulation of cytokine responses to myelin self-antigens remains poorly understood. We analysed the CD4+ T cell proliferation and cytokine responses elicited by myelin basic protein (MBP) and a foreign recall antigen, tetanus toxoid (TT), in mononuclear cell cultures from fourteen MS patients undergoing IFN-beta therapy. The MBP-elicited IFN-gamma-, TNF-alpha- and IL-10 production decreased during therapy (p<0.007-0.03), while the IL-6 production increased (p<0.03). No significant change was observed in the MBP-induced CD4+ T cell proliferation, or in the production of IL-4, IL-5 and brain-derived neurotrophic factor. In comparison, IFN-beta therapy reduced IFN-gamma and IL-4 responses to TT (p<0.003 and p<0.04). Thus, IFN-beta inhibits IFN-gamma production in general, presumably alleviating the detrimental influence of IFN-gamma in MS. However, the increase in proinflammatory IL-6 and the decrease in anti-inflammatory IL-10 responses suggest that IFN-beta has more diverse effects than previously assumed.

Increased IL-10 mRNA and IL-23 mRNA expression in multiple sclerosis: interferon-beta treatment increases IL-10 mRNA expression while reducing IL-23 mRNA expression

BACKGROUND

Interferon (IFN)-beta therapy in multiple sclerosis (MS) has been suggested to promote a deviation from T lymphocyte production of pathogenic Th1 cytokines to less detrimental Th2 cytokines, but this is still controversial. We studied patterns of in vivo blood mononuclear cell (MNC) and whole blood cytokine and transcription factor mRNA expression before and during IFN-beta therapy in MS.

METHODS

Twenty patients with relapsing-remitting MS were sampled before and after 3 months of treatment with IFN-beta along with 15 healthy volunteers. An additional 39 patients and 50 healthy volunteers served to confirm initial findings. mRNA was analyzed by real-time reverse transcriptase polymerase chain reaction (PCR).

RESULTS

We found elevated expression of interleukin (IL)-23 and IL-10 in untreated MS patients. IFN-beta therapy increased IL-10 and decreased IL-23 expression independently of any Th1 or Th2 cytokines. The largest changes in cytokine mRNA levels occurred early (~9-12 h) after an IFN-beta injection.

CONCLUSION

We found no evidence of a Th1- or Th2-mRNA-promoting effect of IFN-beta therapy. The therapeutic effect of IFN-beta is more likely attributable to the induction of the regulatory cytokine IL-10. The elevated IL-23 mRNA levels in MS patients are noteworthy in view of the newly discovered IL-23-driven Th17 T-cell subset, which is crucial in animal models of MS. Since IFN-beta therapy resulted in decreased IL-23 mRNA levels, the Th17 axis could be another target of IFN-beta therapy.

Impaired ability of interferon-alpha-primed dendritic cells to stimulate Th1-type CD4 T-cell response in chronic hepatitis C virus infection

In interferon-alpha (IFN-alpha)/ribavirin combination therapy for chronic hepatitis C (CHC), an enhanced T helper 1 (Th1) response is essential for the eradication of hepatitis C virus (HCV). We aimed to elucidate the role of IFN-alpha or IFN-alpha/ribavirin in dendritic cell (DC) ability to induce Th1 response in HCV infection. We generated monocyte-derived DC from 20 CHC patients and 15 normal subjects driven by granulocyte-macrophage colony-stimulating factor and interleukin 4 (IL-4) without IFN-alpha (GM/4-DC), with IFN-alpha (IFN-DC), with ribavirin (R-DC) or with IFN-alpha/ribavirin (IFN/R-DC) and compared their phenotypes and functions between the groups. We also compared them in 14 CHC patients between who subsequently attained sustained virological response (SVR) and who did not (non-SVR) by 24 weeks of IFN-alpha/ribavirin therapy. Compared with GM/4-DC, IFN-DC displayed higher CD86 expression, but lesser ability to secrete IL-10 and were more potent to prime CD4(+) T cells to secrete IFN-gamma and IL-2. Such differences were more significant in healthy subjects than in CHC patients. No additive effect of ribavirin was observed in DC phenotypes and functions in vitro either which was used alone or in combined with IFN-alpha. However, in the SVR patients, an ability of IFN/R-DC to prime T cells to secrete IFN-gamma and IL-2 was higher than those of IFN-DC and those of IFN/R-DC in the non-SVR group, respectively. In conclusion, DC from CHC patients are impaired in the ability to drive Th1 in response to IFN-alpha. Such DC impairment is restored in vitro by the addition of ribavirin in not all but some patients who cleared HCV by the combination therapy.

Cutting Edge: Involvement of the Type I IFN Production and Signaling Pathway in Lipopolysaccharide-Induced IL-10 Production

Macrophages respond to LPS by the rapid activation of proinflammatory cytokines that serve to initiate host defense against microbial invasion. To prevent injury to the host from excess production of these cytokines, IL-10 is up-regulated to feedback inhibit the proinflammatory response. However, the molecular events responsible for LPS-induced up-regulation of IL-10 remain to be elucidated. In this study, we provide evidence that production of and signaling by type I IFN is required for LPS-induced IL-10 up-regulation. In addition, we demonstrate that defect in type I IFN production and signaling results in a trend toward LPS-mediated superinduction of proinflammatory genes and cytokines in bone marrow-derived macrophages. Our findings suggest a novel anti-inflammatory role for the type I IFN production and signaling pathway in regulating LPS response in bone marrow-derived macrophages.

Interferon-β regulates cytokines and BDNF: greater effect in relapsing than in progressive multiple sclerosis

The mechanism of action of interferon (IFN)-β therapy in multiple sclerosis (MS) is only partially known, and its efficacy changes with disease stage. In different forms of MS, we determined how IFN-β regulates mononuclear cell production of the important anti-inflammatory Th2 cytokine - IL-10, the Th1 cytokine - IFN-γ, and the brain-derived neurotrophic protein - BDNF. Activated T cells and monocytes from therapy-naïve patients secreted more IL-10 than healthy controls. During IFN-β therapy, however, T cells produced less IL-10. In vitro, IFN-β stimulated IL-10 production by activated T cells, but inhibited IL-10 secretion by activated monocytes, a richer source of IL-10 than T cells. The form of MS also affected cytokine production. IL-10 and BDNF levels in MNC were high during relapsing/remitting (RR) MS, but low in progressive MS. Surprisingly, IFN-β therapy increased BDNF levels in antidepressant-naïve patients, but BDNF was lower during concurrent antidepressant drug therapy, suggesting an interaction between MS, depression, and neurodegeneration. IFN-β in vitro strongly induced IL-10 and IFN-γ in activated T cells in RRMS, but not in progressive MS, suggesting IFN resistance. IFN-β effects are specific for disease state and immune subsets, possibly explaining why IFN-β therapy is most effective in early T cell-regulated RRMS, but less beneficial in progressive MS, where chronic plaques contain few T cells and high numbers of monocytes. Multiple Sclerosis 2007; 13: 459-470. http://msj.sagepub.com

Therapeutic role of beta-interferons in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS). In the last 12 years, there has been a proliferation of studies elucidating the immune mechanisms that mediate tissue damage in MS. Interferons (IFNs) have an important role in regulating innate and adaptive immune responses. They decrease pro-inflammatory responses such as the autoimmunity in MS, but other autoimmune responses such as systemic lupus erythematosus (SLE) may be exacerbated. This review offers a general overview of the biological properties of IFNs, effects on immune cells, and clinical effectiveness in MS treatment. IFN signaling is complex, from receptor binding events to the generation of effector mechanisms that dampen inflammation. Immune cell function is altered in MS. IFN treatment of MS patients ameliorates immune dysfunction, but not completely. The incomplete resolution of immune dysfunction by IFNs partly explains their significant, but modest therapeutic effects. This observation also suggests that there are immune mechanisms in MS that are resistant to IFN therapy. In MS, abnormalities may exist at several points along the IFN signaling pathway, including molecular defects in the IFN second messenger system. Currently, several studies are ongoing evaluating ways of potentiating IFN effects. IFNs were the first agents to show clinical efficacy in treatment of MS. More than a decade of experience with IFNs has showed continued clinical efficacy over time. In the near future, IFNs will continue to play a major role in MS.

Ingested (Oral) IFN-α Represses TNF-α mRNA in Relapsing-Remitting Multiple Sclerosis

In a phase II trial in relapsing-remitting multiple sclerosis (RRMS), patients ingesting 10,000 IU, but not 30,000 IU, interferon-alpha (IFN-alpha) showed fewer gadolinium enhancements at months 5 and 6, along with decreased proinflammatory tumor necrosis factor-alpha (TNF-alpha) protein secretion. Therefore, we examined MxA mRNA induction and TNF-alpha mRNA repression after 100, 300, 1,000, 3,000, and 10,000 IU doses of ingested IFN-alpha in 24 RRMS patients to determine the optimal dose for future clinical trials in MS. Maximal TNF-alpha repression occurs at 100, 1,000, and 3,000 IU. These data provide new optimal doses for additional clinical studies using ingested IFN-alpha in MS.

Reduced nasal IL-10 and enhanced TNFalpha responses during rhinovirus and RSV-induced upper respiratory tract infection in atopic and non-atopic infants

Rhinovirus and respiratory syncytial virus (RSV) are the most prevalent inducers of upper respiratory tract infections (URTI) in infants and may stimulate immune maturation. To estimate the amount of immune stimulation, nasal immune responses were examined during rhinovirus and RSV‐induced URTI in infants. Nasal brush samples were taken from infants (2–26 months; 57% atopic family) with rhinovirus‐induced URTI (N = 20), with RSV‐induced URTI (N = 7), and with rhinovirus‐induced rhinitis (N = 11), from children with asymptomatic rhinovirus infection (N = 7) and from eight non‐infected children. Numbers of nasal brush cells positive for Th1‐, Th2‐, regulatory and proinflammatory cytokines were measured by immunohistochemistry or by measuring protein levels using a cytometric bead array analysis. During rhinovirus and RSV‐induced URTI, fewer regulatory cytokine IL‐10 positive cells were found compared to non‐infected children. This fall was accompanied by an increase in levels of the Th1 cytokine TNFα. IL‐10 responses were inversely related to TNFα responses. No enhanced responses were observed for IFNγ, IL‐12 and IL‐18. Cytokine responses were comparable in children with rhinovirus‐induced URTI and in children with rhinitis, while responses in asymptomatic rhinovirus‐infected children were located between those for symptomatic and asymptomatic rhinovirus‐infected children. Cytokine responses did not depend on the age of the child or atopy in the family. In conclusion, reduced nasal IL‐10 responses during URTI in infants could facilitate the induction of a TNFα response. TNFα in turn could replace the immature production of IL‐12, IL‐18 and IFNγ during URTI to induce an effective clearance of the viral infection and which could stimulate the maturation of Th1 cytokine production in infancy. J. Med. Virol. 75:348–357, 2005. © 2004 Wiley‐Liss, Inc.

Timing of IFN-beta exposure during human dendritic cell maturation and naive Th cell stimulation has contrasting effects on Th1 subset generation: a role for IFN-beta-mediated regulation of IL-12 family cytokines and IL-18 in naive Th cell differentiation

Type I IFNs, IFN-alpha and IFN-beta, are early effectors of innate immune responses against microbes that can also regulate subsequent adaptive immunity by promoting antimicrobial Th1-type responses. In contrast, the ability of IFN-beta to inhibit autoimmune Th1 responses is thought to account for some of the beneficial effects of IFN-beta therapy in the treatment of relapsing remitting multiple sclerosis. To understand the basis of the paradoxical effects of IFN-beta on the expression of Th1-type immune responses, we developed an in vitro model of monocyte-derived dendritic cell (DC)-dependent, human naive Th cell differentiation, in which one can observe both positive and negative effects of IFN-beta on the generation of Th1 cells. In this model we found that the timing of IFN-beta exposure determines whether IFN-beta will have a positive or a negative effect on naive Th cell differentiation into Th1 cells. Specifically, the presence of IFN-beta during TNF-alpha-induced DC maturation strongly augments the capacity of DC to promote the generation of IFN-gamma-secreting Th1 cells. In contrast, exposure to IFN-beta during mature DC-mediated primary stimulation of naive Th cells has the opposite effect, in that it inhibits Th1 cell polarization and promotes the generation of an IL-10-secreting T cell subset. Studies with blocking mAbs and recombinant cytokines indicate that the mechanism by which IFN-beta mediates these contrasting effects on Th1 cell generation is at least in part by differentially regulating DC expression of IL-12 family cytokines (IL-12 and/or IL-23, and IL-27) and IL-18.

Immune complexes from SLE sera induce IL10 production from normal peripheral blood mononuclear cells by an FcgammaRII dependent mechanism: implications for a possible vicious cycle maintaining B cell hyperactivity in SLE

BACKGROUND

Raised interleukin (IL)6 and IL10 levels are thought to contribute to the pathogenesis of systemic lupus erythematosus (SLE) by enhancing autoantibody production and immune complex (IC) formation. These immune complexes can then stimulate cellular reactions through Fc and complement receptors.

OBJECTIVE

To investigate whether circulating SLE ICs stimulate type 2 cytokine production.

METHODS

Twenty serum samples from patients with active SLE were compared with sera from 18 healthy controls. Sera and polyethylene glycol (PEG) precipitates from sera were added to peripheral blood mononuclear cell (PBMC) cultures, and the production of IL10 and IL6 was investigated by enzyme linked immunospot assay (ELISPOT) and enzyme linked immunosorbent assay (ELISA). Fc gamma receptor (FcgammaR) antibodies were used in blocking experiments, and flow cytometry was used to assess the correlation between monocyte FcgammaR expression and IC-induced cytokine production.

RESULTS

Ten per cent dilutions of the SLE sera induced a significantly increased number of IL10-producing cells in comparison with control sera (median, 11.75 v 1.25 spot forming cells/50 000 PBMC; p<0.0001). PEG precipitates from SLE sera also induced significantly increased levels of IL10 (p=0.016) and IL6 (p=0.042) in comparison with control PEG precipitates. IL10 production induced by SLE PEG precipitates or by artificial ICs could be blocked by anti-FcgammaRII antibodies, and the FcgammaRII expression on CD14+ monocytes correlated with the IC-induced production of IL10 and IL6.

CONCLUSIONS

SLE sera stimulate IL10 and IL6 production from PBMC, and this effect is at least partly explained by precipitable ICs acting through FcgammaRII. This effect provides a possible mechanism for the enhanced production of IL10 in SLE, whereby B cell activation, antibody production, IC stimulated monocytes/macrophages, and type 2 cytokines create a vicious cycle that may help to maintain B cell hyperactivity in SLE.