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Dermatomyositis is a chronic autoimmune disease with distinctive cutaneous eruptions and muscle weakness, and the pathophysiology is characterised by type I interferon (IFN) dysregulation. This study aims to assess the efficacy, safety, and target engagement of dazukibart, a potent, selective, humanised IgG1 neutralising monoclonal antibody directed against IFNβ, in adults with moderate-to-severe dermatomyositis. This multicentre, double-blind, randomised, placebo-controlled, phase 2 trial was conducted at 25 university-based hospitals and outpatient sites in Germany, Hungary, Poland, Spain, and the USA. Adults aged 18–80 years with skin-predominant dermatomyositis were enrolled during stages 1, 2, and 2a, and had to have a Cutaneous Dermatomyositis Disease Area and Severity Index-Activity (CDASI-A) score of 14 or more and at least one unsuccessful systemic treatment with standard of care; whereas those with muscle-predominant dermatomyositis were enrolled in stage 3 and had to have active moderate muscle involvement. Patients were randomly assigned using an interactive response technology system to dazukibart 600 mg or placebo in stage 1; dazukibart 600 mg, dazukibart 150 mg, or placebo in stage 2; dazukibart 600 mg then placebo, dazukibart 150 mg then placebo, placebo then dazukibart 600 mg, or placebo then dazukibart 150 mg in stage 2a; and dazukibart 600 mg then placebo or placebo then dazukibart 600 mg in stage 3. For stage 2a and stage 3, treatments were switched at week 12. Patients, investigators, outcome assessors, and funders were masked to the treatment assignment. Dazukibart and placebo were administered intravenously on day 1 every 4 weeks, up to and including week 8 (stages 1 and 2, and stages 2a and 3 for patients starting dazukibart), or on week 12 every 4 weeks, up to and including week 20 (stages 2a and 3 for patients who started placebo and switched to dazukibart). The primary outcome for the skin-predominant cohorts was the change from baseline in CDASI-A score at week 12 assessed in the full analysis set (FAS; stage 1) and the pooled skin FAS (stages 1, 2, and 2a), and safety in the muscle-predominant cohort. This study is registered with ClinicalTrials.gov, NCT03181893. Between Jan 23, 2018, and Feb 23, 2022, 125 adults were assessed and 50 were excluded. 75 patients were randomly assigned and treated (15 to dazukibart 150 mg, 37 to dazukibart 600 mg, and 23 to placebo). Most patients were female (53 [93%] of 57 in the skin-predominant cohort vs 13 [72%] of 18 in the muscle-predominant cohort and four [7%] vs five [28%] were male). In the FAS in stage 1 at week 12, the mean change from baseline in CDASI-A for dazukibart 600 mg was –18·8 (90% CI –21·8 to –15·8; placebo-adjusted difference –14·8 [–20·3 to –9·4]; p<0·0001). In the pooled skin FAS at week 12, the mean change from baseline in CDASI-A for the dazukibart 600 mg group was –19·2 (–21·5 to –16·8; placebo-adjusted difference –16·3 [–20·4 to –12·1]; p<0·0001), whereas the dazukibart 150 mg group was –16·6 (–19·8 to –13·4; placebo-adjusted difference –13·7 [–18·3 to –9·0]; p<0·0001). Treatment-emergent adverse events occurred in 12 (80%) of 15 patients in the dazukibart 150 mg group versus 30 (81%) of 37 in the dazukibart 600 mg group versus 18 (78%) of 23 in the placebo group, with the most common being infections and infestations (two [13%] vs 12 [32%] vs seven [30%]). Four (11%) patients in the dazukibart 150 mg group and one (4%) in the placebo group reported serious adverse events. One patient in stage 3 received dazukibart 600 mg then placebo and died during follow-up due to haemophagocytic lymphohistiocytosis and macrophage activation syndrome. Dazukibart resulted in a pronounced reduction in disease activity and was generally well tolerated, supporting IFNβ inhibition as a highly promising therapeutic strategy in adults with dermatomyositis. Pfizer.

Modified vaccinia virus Ankara (MVA) is an attenuated poxvirus that has been engineered as a vaccine against infectious agents and cancers. Our goal is to understand how MVA modulates innate immunity in dendritic cells (DCs), which can provide insights to vaccine design. In this study, using murine bone marrow-derived dendritic cells, we assessed type I interferon (IFN) gene induction and protein secretion in response to MVA infection. We report that MVA infection elicits the production of type I IFN in murine conventional dendritic cells (cDCs), but not in plasmacytoid dendritic cells (pDCs). Transcription factors IRF3 (IFN regulatory factor 3) and IRF7, and the positive feedback loop mediated by IFNAR1 (IFN alpha/beta receptor 1), are required for the induction. MVA induction of type I IFN is fully dependent on STING (stimulator of IFN genes) and the newly discovered cytosolic DNA sensor cGAS (cyclic guanosine monophosphate-adenosine monophosphate synthase). MVA infection of cDCs triggers phosphorylation of TBK1 (Tank-binding kinase 1) and IRF3, which is abolished in the absence of cGAS and STING. Furthermore, intravenous delivery of MVA induces type I IFN in wild-type mice, but not in mice lacking STING or IRF3. Treatment of cDCs with inhibitors of endosomal and lysosomal acidification or the lysosomal enzyme Cathepsin B attenuated MVA-induced type I IFN production, indicating that lysosomal enzymatic processing of virions is important for MVA sensing. Taken together, our results demonstrate a critical role of the cGAS/STING-mediated cytosolic DNA-sensing pathway for type I IFN induction in cDCs by MVA. We present evidence that vaccinia virulence factors E3 and N1 inhibit the activation of IRF3 and the induction of IFNB gene in MVA-infected cDCs.

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. 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. 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. 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.

Macrophages respond to cytosolic nucleic acids by activating cysteine protease caspase-1 within a complex called the inflammasome. Subsequent cleavage and secretion of proinflammatory cytokines IL-1β and IL-18 are critical for innate immunity. Here, we show that macrophages from mice lacking absent in melanoma 2 (AIM2) cannot sense cytosolic double-stranded DNA and fail to trigger inflammasome assembly. Caspase-1 activation in response to intracellular pathogen Francisella tularensis also required AIM2. Immunofluorescence microscopy of macrophages infected with F. tularensis revealed striking colocalization of bacterial DNA with endogenous AIM2 and inflammasome adaptor ASC. By contrast, type I IFN (IFN-α and -β) secretion in response to F. tularensis did not require AIM2. IFN-I did, however, boost AIM2-dependent caspase-1 activation by increasing AIM2 protein levels. Thus, inflammasome activation was reduced in infected macrophages lacking either the IFN-I receptor or stimulator of interferon genes (STING). Finally, AIM2-deficient mice displayed increased susceptibility to F. tularensis infection compared with wild-type mice. Their increased bacterial burden in vivo confirmed that AIM2 is essential for an effective innate immune response.

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. 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. 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. 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.

Despite early reports to the contrary, there is increasing evidence that patients with severe COVID-19 have a robust type I interferon response, which contrasts with the delayed, possibly suppressed, interferon response seen early in infection. A robust type I interferon response could exacerbate hyperinflammation in the progression to severe COVID-19 through diverse mechanisms. Further understanding of the roles of type I interferon at different stages of infection and in patients with mild versus severe COVID-19 will provide insights for the therapeutic use of interferon administration or JAK inhibitors in patients with COVID-19.In this Comment, Jeong Seok Lee and Eui-Cheol Shin discuss contradictory results regarding the downregulation or upregulation of type I interferon responses in patients with COVID-19 and the implications for therapies that target this pathway.

In clinical practice natalizumab is typically used in patients who have experienced breakthrough disease during treatment with interferon beta (IFNβ) or glatiramer acetate. In these patients it is important to reduce disease activity as quickly as possible. In a phase II study, differences between natalizumab and placebo in MRI outcomes reflecting inflammatory activity were evident after the first infusion and maintained through a 6-month period, suggesting a rapid onset of natalizumab treatment effects. To explore how soon after natalizumab initiation clinical effects become apparent, annualized relapse rates per 3-month period and time to first relapse were analyzed in the phase III AFFIRM study (natalizumab vs. placebo) and in the multinational Tysabri ® Observational Program (TOP). In AFFIRM, natalizumab reduced the annualized relapse rate within 3 months of treatment initiation compared with placebo in the overall population (0.30 vs. 0.71; p  < 0.0001) and in patients with highly active disease (0.30 vs. 0.94; p  = 0.0039). The low annualized relapse rate was maintained throughout the 2-year study period, and the risk of relapse in AFFIRM patients treated with natalizumab was reduced [hazard ratio against placebo 0.42 (95 % CI 0.34–0.52); p  < 0.0001]. Rapid reductions in annualized relapse rate also occurred in TOP (baseline 1.99 vs. 0–3 months 0.26; p  < 0.0001). Natalizumab resulted in rapid, sustained reductions in disease activity in both AFFIRM and in clinical practice. This decrease in disease activity occurred within the first 3 months of treatment even in patients with more active disease.

Background: The frequency and impact of neutralizing antibodies (NAbs) to interferon beta-1b (IFNβ-1b) on clinical and radiographic outcomes is controversial. Objective: To assess NAb impact in the BEYOND study. Methods: 2244 patients were randomized (2:2:1) to receive IFNβ-1b, either 250 or 500 µg, or glatiramer acetate, 20 mg, and observed for 2–3.5 years. NAb titers were determined every 6 months. A titer ≥20 NU/ml was considered NAb positive. Efficacy was compared between NAb-positive and NAb-negative patients, using comprehensive statistical analyses, taking into account the delayed appearance of NAbs, the time-dependent changes in the relapse rate, spontaneous reversions to NAb-negative status, NAb-titer level, and also adjusting for baseline factors. Results: In the IFNβ-1b 250 µg group, NAb-positive titers were detected (≥ once) in 319 patients (37.0%); of these, 112 (35.1%) reverted to NAb-negative status. In the IFNβ-1b 500 µg group, 340 patients (40.7%) became NAb-positive and 119 (35.0%) reverted to NAb-negative status. In both IFNβ groups, especially the 250 µg arm, NAb-positive status was not associated with a convincing impact on any clinical outcome measure by any statistical analysis. By contrast, in both IFNβ groups, NAbs were associated with a very consistent deleterious impact on most MRI outcomes. Conclusion: There was a notable dissociation between the impact of NAbs on MRI and clinical outcomes. On MRI measures, the impact was consistent and convincing, whereas on clinical measures a negative impact of NAbs was not found. The basis for this clinico-radiographic paradox is unknown but it suggests that the relationship between NAbs and the therapeutic effects of IFNβ-1b is complex.

The uptake of apoptotic polymorphonuclear cells (PMN) by macrophages is critical for timely resolution of inflammation. High-burden uptake of apoptotic cells is associated with loss of phagocytosis in resolution phase macrophages. Here, using a transcriptomic analysis of macrophage subsets, we show that non-phagocytic resolution phase macrophages express a distinct IFN-β-related gene signature in mice. We also report elevated levels of IFN-β in peritoneal and broncho-alveolar exudates in mice during the resolution of peritonitis and pneumonia, respectively. Elimination of endogenous IFN-β impairs, whereas treatment with exogenous IFN-β enhances, bacterial clearance, PMN apoptosis, efferocytosis and macrophage reprogramming. STAT3 signalling in response to IFN-β promotes apoptosis of human PMNs. Finally, uptake of apoptotic cells promotes loss of phagocytic capacity in macrophages alongside decreased surface expression of efferocytic receptors in vivo. Collectively, these results identify IFN-β produced by resolution phase macrophages as an effector cytokine in resolving bacterial inflammation. Clearance of apoptotic neutrophils by macrophages is important for the resolution of inflammation. Here, the authors show that interferon-β produced by resolution phase macrophages promotes neutrophil apoptosis and efferocytosis and induces macrophage reprogramming to a pro-resolving phenotype, thereby identifying IFN-β as a multi-pronged pro-resolution cytokine.

WebTreatment of lipopolysaccharide-activated macrophages with the cell-permeable itaconate derivative 4-octyl itaconate activates the anti-inflammatory transcription factor Nrf2 by alkylating key cysteine residues on the KEAP1 protein. Anti-inflammatory effects of itaconate Macrophages are white blood cells that recognize and destroy invading bacterial pathogens, and later tone down inflammation to enable tissue repair. The endogenous metabolite itaconate inhibits a number of inflammatory cytokines during macrophage activation. Luke O'Neill and colleagues investigate the mechanism underlying this process. Treatment of lipopolysaccharide (LPS)-activated macrophages with the cell-permeable itaconate derivative 4-octyl itaconate activates the anti-oxidant and anti-inflammatory transcription factor Nrf2. This activation occurs via alkylation of key cysteine residues on the KEAP1 protein, which blocks KEAP1-dependent proteolysis of Nrf2. Pre-treating mouse models of LPS with the itaconate derivative activates Nrf2 and prolongs the survival of the animals after a lethal dose of LPS. The authors suggest that itaconate derivatives may prove useful in the treatment of inflammatory diseases. The endogenous metabolite itaconate has recently emerged as a regulator of macrophage function, but its precise mechanism of action remains poorly understood 1 , 2 , 3 . Here we show that itaconate is required for the activation of the anti-inflammatory transcription factor Nrf2 (also known as NFE2L2) by lipopolysaccharide in mouse and human macrophages. We find that itaconate directly modifies proteins via alkylation of cysteine residues. Itaconate alkylates cysteine residues 151, 257, 288, 273 and 297 on the protein KEAP1, enabling Nrf2 to increase the expression of downstream genes with anti-oxidant and anti-inflammatory capacities. The activation of Nrf2 is required for the anti-inflammatory action of itaconate. We describe the use of a new cell-permeable itaconate derivative, 4-octyl itaconate, which is protective against lipopolysaccharide-induced lethality in vivo and decreases cytokine production. We show that type I interferons boost the expression of Irg1 (also known as Acod1 ) and itaconate production. Furthermore, we find that itaconate production limits the type I interferon response, indicating a negative feedback loop that involves interferons and itaconate. Our findings demonstrate that itaconate is a crucial anti-inflammatory metabolite that acts via Nrf2 to limit inflammation and modulate type I interferons.