ERG Functionally Overlaps with Other Ets Proteins in Promoting TH9 Cell Expression of Il9 during Allergic Lung Inflammation.

CD4+ TH cells develop into subsets that are specialized in the secretion of particular cytokines to mediate restricted types of inflammation and immune responses. Among the subsets that promote development of allergic inflammatory responses, IL-9-producing TH9 cells are regulated by a number of transcription factors. We have previously shown that the E26 transformation-specific (Ets) family members PU.1 and Ets translocation variant 5 (ETV5) function in parallel to regulate IL-9. In this study we identified a third member of the Ets family of transcription factors, Ets-related gene (ERG), that mediates IL-9 production in TH9 cells in the absence of PU.1 and ETV5. Chromatin immunoprecipitation assays revealed that ERG interaction at the Il9 promoter region is restricted to the TH9 lineage and is sustained during murine TH9 polarization. Knockdown or knockout of ERG during murine or human TH9 polarization in vitro led to a decrease in IL-9 production in TH9 cells. Deletion of ERG in vivo had modest effects on IL-9 production in vitro or in vivo. However, in the absence of PU.1 and ETV5, ERG was required for residual IL-9 production in vitro and for IL-9 production by lung-derived CD4 T cells in a mouse model of chronic allergic airway disease. Thus, ERG contributes to IL-9 regulation in TH9 cells.

Withdrawing Ixekizumab in Patients With Psoriatic Arthritis Who Achieved Minimal Disease Activity: Results From a Randomized, Double-Blind Withdrawal Study.

OBJECTIVE: To evaluate the effect of withdrawing ixekizumab in patients with psoriatic arthritis (PsA) in whom minimal disease activity (MDA) has been achieved after open-label ixekizumab treatment. METHODS: SPIRIT-P3 was a multicenter, randomized, double-blind withdrawal study of biologic treatment-naive adult patients with PsA who were treated with open-label ixekizumab for 36 weeks (160 mg at week 0, then 80 mg every 2 weeks). Patients in whom MDA was sustained for >3 consecutive months were randomized 1:1, between weeks 36 and 64, to undergo blinded withdrawal of ixekizumab treatment (placebo) or to continue ixekizumab treatment every 2 weeks up to week 104. The primary efficacy end point was time to relapse (loss of MDA) for randomized patients. Patients who experienced a relapse were re-treated with ixekizumab every 2 weeks up to week 104. RESULTS: A total of 394 patients were enrolled and received open-label ixekizumab every 2 weeks. Of those patients, 158 (40%) achieved sustained MDA and were randomized to undergo withdrawal of ixekizumab treatment (placebo every 2 weeks; n = 79) or to continue ixekizumab treatment every 2 weeks (n = 79). Disease relapse occurred more rapidly with treatment withdrawal (median 22.3 weeks [95% confidence interval (95% CI) 16.1-28.3]) compared to those who continued treatment with ixekizumab (median not estimable; P < 0.0001). Sixty-seven patients (85%) compared to 30 patients (38%) experienced relapse in the placebo group and the continued treatment group, respectively. Median time to achieving MDA again with re-treatment was 4.1 weeks (95% CI 4.1-4.3); in 64 of 67 patients (96%) who experienced relapse with treatment withdrawal, MDA was achieved again with re-treatment. Safety was consistent with the known safety profile for ixekizumab. CONCLUSION: Continued ixekizumab therapy is superior to ixekizumab withdrawal in maintaining low disease activity in biologic treatment-naive patients with PsA. Re-treatment with ixekizumab following a relapse may restore disease control in cases of treatment interruption.

Ixekizumab, with or without concomitant methotrexate, improves signs and symptoms of PsA: week 52 results from Spirit-P1 and Spirit-P2 studies.

BACKGROUND: The efficacy and safety of ixekizumab (IXE) with and without continuous concomitant methotrexate (MTX), for up to 52 weeks of treatment, were evaluated in patients with active psoriatic arthritis (PsA). METHODS: Patients with active PsA who were biologic-naive (SPIRIT-P1) or had prior inadequate response to tumor necrosis factor inhibitors (SPIRIT-P2) were randomized to 80 mg IXE every 4 (IXE Q4W) or 2 weeks (IXE Q2W), after a 160-mg initial dose. In this post hoc analysis, efficacy and safety were assessed up to week 52 in the subgroups of patients who received (i) IXE as monotherapy and (ii) IXE along with a stable dose of MTX (no dose tapering or increase). Efficacy outcomes included, but were not limited to, the percentage of patients achieving the American College of Rheumatology (ACR) responses. RESULTS: Out of 455 patients initially randomized to IXE, 177 (38.9%) received monotherapy, 230 (50.5%) had concomitant MTX use, and 48 (10.5%) had other concomitant medication. Overall, 183 (40.2%) received IXE with a stable dose of concomitant MTX for 1 year. At week 52, the percentage of patients achieving ACR20/50/70 responses in IXE Q4W monotherapy versus concomitant MTX groups were 66.3% versus 55.3%, 48.4% versus 38.8%, and 35.8% versus 27.1%, respectively; these responses were generally similar with IXE Q2W. The safety profiles were similar between patients receiving IXE with or without concomitant MTX. CONCLUSIONS: In this post hoc analysis, treatment with IXE demonstrated sustained efficacy in patients with PsA up to 1 year of treatment, with or without concomitant MTX therapy. TRIAL REGISTRATION: ClinicalTrials.gov NCT01695239 and NCT02349295 .

Disease Characteristics and the Burden of Joint and Skin Involvement Amongst People With Psoriatic Arthritis: A Population Survey.

INTRODUCTION: Psoriatic arthritis (PsA) is a chronic, systemic, inflammatory disease where disease burden and quality of life (QoL) are affected by both joint and skin manifestations. METHODS: Patient and physician reported data were collected about 3200 patients in a cross-sectional survey of patients from nine countries. Patient-reported outcomes (PROs) included perceptions of symptom importance, EuroQol questionnaire (EQ-5D), Psoriatic Arthritis Impact of Disease (PsAID12), and Work Productivity and Activity Impairment (WPAI) Index. Outcomes were compared in patients with 'joint-only' and 'joint and skin' disease symptoms. RESULTS: Of the 3200 patients, 2703 had complete information for 'joint-only' or 'joint and skin' involvement and were included in the analysis. Patients had a mean age of 49.2 years, 45.2% were female, and 64.5% had 'joint and skin' involvement. Patients with 'joint and skin' involvement had higher mean tender and swollen joint counts (5.2 and 4.8) than patients who were 'joint-only' (2.0 and 1.5). Significantly more patients with active 'joint and skin' symptoms experienced a flare (currently or within the last 12 months) compared with 'joint-only' patients (34.9 vs. 23.2%, p < 0.001). When asked to prioritize the burden of symptoms, 61.6% of patients prioritized joints, 38.4% prioritized skin. Anxiety/depression was experienced by 41.4% of patients, 62.4% of whom indicated that both joint and skin symptoms were the cause. Patients with 'joint and skin' involvement reported significantly worse QoL, work productivity and activity impairment than 'joint-only' patients (EQ-5D index 0.79 vs. 0.85, p < 0.001; EQ-5D VAS 71.98 vs. 77.68, p < 0.001; PsAID12 2.91 vs. 1.66, p < 0.001; WPAI overall work impairment 25.61 vs. 16.32, p < 0.001). CONCLUSIONS: PsA patients who experience 'joint and skin' symptoms had significantly worse clinical outcomes, health-related QoL, and work productivity compared with patients with 'joint-only' symptoms.

The contribution of joint and skin improvements to the health-related quality of life of patients with psoriatic arthritis: a post hoc analysis of two randomised controlled studies.

OBJECTIVE: Determine the contribution of joint and skin improvements to health-related quality of life (HRQoL) in patients with psoriatic arthritis (PsA). METHODS: SPIRIT-P1 and SPIRIT-P2 are phase 3 trials investigating ixekizumab, an interleukin-17A antagonist, in the treatment of patients with active PsA. Patients were randomised to ixekizumab or placebo. Outcomes included the Disease Activity Index for Psoriatic Arthritis (DAPSA), the Psoriasis Area and Severity Index (PASI), the European Quality of Life-Five Dimensions (EQ-5D) Visual Analogue Score (VAS), the 36-Item Short-Form Health Survey (SF-36) and the Work Productivity and Activity Impairment (WPAI) Questionnaire. The contribution of joint and skin improvements to HRQoL was modelled using a smoothing spline method and depicted with response surface graphics. RESULTS: In this integrated analysis, 402 patients with PsA had baseline psoriasis of ≥3% of body surface area. We applied response surface modelling to this patient data set to investigate the relationship between DAPSA, PASI and HRQoL improvements at week 24. The greatest improvement in EQ-5D VAS was associated with the largest per cent improvements in both DAPSA and PASI together, rather than DAPSA or PASI alone. Similar observations were made in domains of SF-36 and WPAI. CONCLUSION: Optimal improvements in patients' HRQoL were dependent on successful treatment of both joint and skin symptoms.

The ETS Family Transcription Factors Etv5 and PU.1 Function in Parallel To Promote Th9 Cell Development.

The IL-9-secreting Th9 subset of CD4 Th cells develop in response to an environment containing IL-4 and TGF-ß, promoting allergic disease, autoimmunity, and resistance to pathogens. We previously identified a requirement for the ETS family transcription factor PU.1 in Th9 development. In this report, we demonstrate that the ETS transcription factor ETS variant 5 (ETV5) promotes IL-9 production in Th9 cells by binding and recruiting histone acetyltransferases to the Il9 locus at sites distinct from PU.1. In cells that are deficient in both PU.1 and ETV5 there is lower IL-9 production than in cells lacking either factor alone. In vivo loss of PU.1 and ETV5 in T cells results in distinct effects on allergic inflammation in the lung, suggesting that these factors function in parallel. Together, these data define a role for ETV5 in Th9 development and extend the paradigm of related transcription factors having complementary functions during differentiation.

STAT3 Impairs STAT5 Activation in the Development of IL-9-Secreting T Cells.

Th cell subsets develop in response to multiple activating signals, including the cytokine environment. IL-9-secreting T cells develop in response to the combination of IL-4 and TGF-ß, although they clearly require other cytokine signals, leading to the activation of transcription factors including STAT5. In Th17 cells, there is a molecular antagonism of STAT5 with STAT3 signaling, although whether this paradigm exists in other Th subsets is not clear. In this paper, we demonstrate that STAT3 attenuates the ability of STAT5 to promote the development of IL-9-secreting T cells. We demonstrate that production of IL-9 is increased in the absence of STAT3 and cytokines that result in a sustained activation of STAT3, including IL-6, have the greatest potency in repressing IL-9 production in a STAT3-dependent manner. Increased IL-9 production in the absence of STAT3 correlates with increased endogenous IL-2 production and STAT5 activation, and blocking IL-2 responses eliminates the difference in IL-9 production between wild-type and STAT3-deficient T cells. Moreover, transduction of developing Th9 cells with a constitutively active STAT5 eliminates the ability of IL-6 to reduce IL-9 production. Thus, STAT3 functions as a negative regulator of IL-9 production through attenuation of STAT5 activation and function.

PU.1 Expression in T Follicular Helper Cells Limits CD40L-Dependent Germinal Center B Cell Development.

PU.1 is an ETS family transcription factor that is important for the development of multiple hematopoietic cell lineages. Previous work demonstrated a critical role for PU.1 in promoting Th9 development and in limiting Th2 cytokine production. Whether PU.1 has functions in other Th lineages is not clear. In this study, we examined the effects of ectopic expression of PU.1 in CD4(+) T cells and observed decreased expression of genes involved with the function of T follicular helper (Tfh) cells, including Il21 and Tnfsf5 (encoding CD40L). T cells from conditional mutant mice that lack expression of PU.1 in T cells (Sfpi1(lck-/-)) demonstrated increased production of CD40L and IL-21 in vitro. Following adjuvant-dependent or adjuvant-independent immunization, we observed that Sfpi1(lck-/-) mice had increased numbers of Tfh cells, increased germinal center B cells (GCB cells), and increased Ab production in vivo. This correlated with increased expression of IL-21 and CD40L in Tfh cells from Sfpi1(lck-/-) mice compared with control mice. Finally, although blockade of IL-21 did not affect GCB cells in Sfpi1(lck-/-) mice, anti-CD40L treatment of immunized Sfpi1(lck-/-) mice decreased GCB cell numbers and Ag-specific Ig concentrations. Together, these data indicate an inhibitory role for PU.1 in the function of Tfh cells, germinal centers, and Tfh-dependent humoral immunity.

Viral infection of the lung: host response and sequelae.

Because of its essential role in gas exchange and oxygen delivery, the lung has evolved a variety of strategies to control inflammation and maintain homeostasis. Invasion of the lung by pathogens (and in some instances exposure to certain noninfectious particulates) disrupts this equilibrium and triggers a cascade of events aimed at preventing or limiting colonization (and more importantly infection) by pathogenic microorganisms. In this review we focus on viral infection of the lung and summarize recent advances in our understanding of the triggering of innate and adaptive immune responses to viral respiratory tract infection, mechanisms of viral clearance, and the well-recognized consequences of acute viral infection complicating underlying lung diseases, such as asthma.

Influenza-infected neutrophils within the infected lungs act as antigen presenting cells for anti-viral CD8(+) T cells.

Influenza A virus (IAV) is a leading cause of respiratory tract disease worldwide. Anti-viral CD8(+) T lymphocytes responding to IAV infection are believed to eliminate virally infected cells by direct cytolysis but may also contribute to pulmonary inflammation and tissue damage via the release of pro-inflammatory mediators following recognition of viral antigen displaying cells. We have previously demonstrated that IAV antigen expressing inflammatory cells of hematopoietic origin within the infected lung interstitium serve as antigen presenting cells (APC) for infiltrating effector CD8(+) T lymphocytes; however, the spectrum of inflammatory cell types capable of serving as APC was not determined. Here, we demonstrate that viral antigen displaying neutrophils infiltrating the IAV infected lungs are an important cell type capable of acting as APC for effector CD8(+) T lymphocytes in the infected lungs and that neutrophils expressing viral antigen as a result of direct infection by IAV exhibit the most potent APC activity. Our findings suggest that in addition to their suggested role in induction of the innate immune responses to IAV, virus clearance, and the development of pulmonary injury, neutrophils can serve as APCs to anti-viral effector CD8(+) T cells within the infected lung interstitium.

Recent insights into pulmonary repair following virus-induced inflammation of the respiratory tract.

A hallmark of infection by respiratory viruses is productive infection of and the subsequent destruction of the airway epithelium. These viruses can also target other stromal cell types as well as in certain instances, CD45(+) hematopoietic cells either resident in the lungs or part of the inflammatory response to infection. The mechanisms by which the virus produces injury to these cell types include direct infection with cytopathic effects as a consequence of replication. Host mediated damage is also a culprit in pulmonary injury as both innate and adaptive immune cells produce soluble and cell-associated pro-inflammatory mediators. Recently, it has become increasingly clear that in addition to control of excess inflammation and virus elimination, the resolution of infection requires an active repair process, which is necessary to regain normal respiratory function and restore the lungs to homeostasis. The repair response must re-establish the epithelial barrier and regenerate the microarchitecture of the lung. Emerging areas of research have highlighted the importance of innate immune cells, particularly the newly described innate lymphoid cells, as well as alternatively activated macrophages and pulmonary stem cells in the repair process. The mechanisms by which respiratory viruses may impede or alter the repair response will be important areas of research for identifying therapeutic targets aimed at limiting virus and host mediated injury and expediting recovery.