LAG3+ Regulatory T Cells Restrain Interleukin-23-Producing CX3CR1+ Gut-Resident Macrophages during Group 3 Innate Lymphoid Cell-Driven Colitis.

Interleukin-22 (IL-22)-producing group 3 innate lymphoid cells (ILC3) maintains gut homeostasis but can also promote inflammatory bowel disease (IBD). The regulation of ILC3-dependent colitis remains to be elucidated. Here we show that Foxp3+ regulatory T cells (Treg cells) prevented ILC3-mediated colitis in an IL-10-independent manner. Treg cells inhibited IL-23 and IL-1ß production from intestinal-resident CX3CR1+ macrophages but not CD103+ dendritic cells. Moreover, Treg cells restrained ILC3 production of IL-22 through suppression of CX3CR1+ macrophage production of IL-23 and IL-1ß. This suppression was contact dependent and was mediated by latent activation gene-3 (LAG-3)-an immune checkpoint receptor-expressed on Treg cells. Engagement of LAG-3 on MHC class II drove profound immunosuppression of CX3CR1+ tissue-resident macrophages. Our study reveals that the health of the intestinal mucosa is maintained by an axis driven by Treg cells communication with resident macrophages that withhold inflammatory stimuli required for ILC3 function.

Interleukin-23-Induced Transcription Factor Blimp-1 Promotes Pathogenicity of T Helper 17 Cells.

Interleukin-23 (IL-23) is a pro-inflammatory cytokine required for the pathogenicity of T helper 17 (Th17) cells but the molecular mechanisms governing this process remain unclear. We identified the transcription factor Blimp-1 (Prdm1) as a key IL-23-induced factor that drove the inflammatory function of Th17 cells. In contrast to thymic deletion of Blimp-1, which causes T cell development defects and spontaneous autoimmunity, peripheral deletion of this transcription factor resulted in reduced Th17 activation and reduced severity of autoimmune encephalomyelitis. Furthermore, genome-wide occupancy and overexpression studies in Th17 cells revealed that Blimp-1 co-localized with transcription factors RORγt, STAT-3, and p300 at the Il23r, Il17a/f, and Csf2 cytokine loci to enhance their expression. Blimp-1 also directly bound to and repressed cytokine loci Il2 and Bcl6. Taken together, our results demonstrate that Blimp-1 is an essential transcription factor downstream of IL-23 that acts in concert with RORγt to activate the Th17 inflammatory program.

Interleukin-23-Independent IL-17 Production Regulates Intestinal Epithelial Permeability.

Whether interleukin-17A (IL-17A) has pathogenic and/or protective roles in the gut mucosa is controversial and few studies have analyzed specific cell populations for protective functions within the inflamed colonic tissue. Here we have provided evidence for IL-17A-dependent regulation of the tight junction protein occludin during epithelial injury that limits excessive permeability and maintains barrier integrity. Analysis of epithelial cells showed that in the absence of signaling via the IL-17 receptor adaptor protein Act-1, the protective effect of IL-17A was abrogated and inflammation was enhanced. We have demonstrated that after acute intestinal injury, IL-23R(+) γδ T cells in the colonic lamina propria were the primary producers of early, gut-protective IL-17A, and this production of IL-17A was IL-23 independent, leaving protective IL-17 intact in the absence of IL-23. These results suggest that IL-17-producing γδ T cells are important for the maintenance and protection of epithelial barriers in the intestinal mucosa.

The interleukin 23 receptor is essential for the terminal differentiation of interleukin 17-producing effector T helper cells in vivo.

Interleukin 23 (IL-23) is required for autoimmune inflammation mediated by IL-17-producing helper T cells (T(H)-17 cells) and has been linked to many human immune disorders. Here we restricted deficiency in the IL-23 receptor to defined cell populations in vivo to investigate the requirement for IL-23 signaling in the development and function of T(H)-17 cells in autoimmunity, inflammation and infection. In the absence of IL-23, T(H)-17 development was stalled at the early activation stage. T(H)-17 cells failed to downregulate IL-2 and also failed to maintain IL-17 production or upregulate expression of the IL-7 receptor alpha-chain. These defects were associated with less proliferation; consequently, fewer effector T(H)-17 cells were produced in the lymph nodes and hence available to emigrate to the bloodstream and tissues.

Clinical improvement in psoriasis with specific targeting of interleukin-23.

Psoriasis is a chronic inflammatory skin disorder that affects approximately 2-3% of the population worldwide and has severe effects on patients' physical and psychological well-being. The discovery that psoriasis is an immune-mediated disease has led to more targeted, effective therapies; recent advances have focused on the interleukin (IL)-12/23p40 subunit shared by IL-12 and IL-23. Evidence suggests that specific inhibition of IL-23 would result in improvement in psoriasis. Here we evaluate tildrakizumab, a monoclonal antibody that targets the IL-23p19 subunit, in a three-part, randomized, placebo-controlled, sequential, rising multiple-dose phase I study in patients with moderate-to-severe psoriasis to provide clinical proof that specific targeting of IL-23p19 results in symptomatic improvement of disease severity in human subjects. A 75% reduction in the psoriasis area and severity index (PASI) score (PASI75) was achieved by all subjects in parts 1 and 3 (pooled) in the 3 and 10 mg kg(-1) groups by day 196. In part 2, 10 out of 15 subjects in the 3 mg kg(-1) group and 13 out of 14 subjects in the 10 mg kg(-1) group achieved a PASI75 by day 112. Tildrakizumab demonstrated important clinical improvement in moderate-to-severe psoriasis patients as demonstrated by improvements in PASI scores and histological samples.

Foxp3(+) regulatory T cells promote T helper 17 cell development in vivo through regulation of interleukin-2.

T helper 17 (Th17) cell development is driven by cytokines including transforming growth factor-ß (TGF-ß), interleukin-6 (IL-6), IL-1, and IL-23. Regulatory T (Treg) cells can provide the TGF-ß in vitro, but their role in vivo remains unclear, particularly because Treg cells inhibit inflammation in many models of Th17 cell-associated autoimmunity. We used mice expressing Diphtheria toxin receptor under control of the Foxp3 promoter to deplete Foxp3(+) Treg cells in adult mice during in vivo Th17 cell priming. Treg cell depletion resulted in a reduced frequency of antigen-specific IL-17 producers in draining lymph nodes and blood, correlating with reduced inflammatory skin responses. In contrast, Treg cells did not promote IL-17 secretion after initial activation stages. Treg cell production of TGF-ß was not required for Th17 cell promotion, and neither was suppression of Th1 cell-associated cytokines. Rather, regulation of IL-2 availability and resultant signaling through CD25 by Treg cells was found to play an important role.

TGF-beta and IL-6 drive the production of IL-17 and IL-10 by T cells and restrain T(H)-17 cell-mediated pathology.

Studies have shown that transforming growth factor-beta (TGF-beta) and interleukin 6 (IL-6) are required for the lineage commitment of pathogenic IL-17-producing T helper cells (T(H)-17 cells). Unexpectedly, here we found that stimulation of myelin-reactive T cells with TGF-beta plus IL-6 completely abrogated their pathogenic function despite upregulation of IL-17 production. Cells stimulated with TGF-beta plus IL-6 were present in the spleen as well as the central nervous system, but they failed to upregulate the proinflammatory chemokines crucial for central nervous system inflammation. In addition, these cells produced IL-10, which has potent anti-inflammatory activities. In contrast, stimulation with IL-23 promoted expression of IL-17 and proinflammatory chemokines but not IL-10. Hence, TGF-beta and IL-6 'drive' initial lineage commitment but also 'restrain' the pathogenic potential of T(H)-17 cells. Our findings suggest that full acquisition of pathogenic function by effector T(H)-17 cells is mediated by IL-23 rather than by TGF-beta and IL-6.

T-cell infiltration and clonality correlate with programmed cell death protein 1 and programmed death-ligand 1 expression in patients with soft tissue sarcomas.

BACKGROUND: Patients with metastatic sarcomas have poor outcomes and although the disease may be amenable to immunotherapies, information regarding the immunologic profiles of soft tissue sarcoma (STS) subtypes is limited. METHODS: The authors identified patients with the common STS subtypes: leiomyosarcoma, undifferentiated pleomorphic sarcoma (UPS), synovial sarcoma (SS), well-differentiated/dedifferentiated liposarcoma, and myxoid/round cell liposarcoma. Gene expression, immunohistochemistry for programmed cell death protein (PD-1) and programmed death-ligand 1 (PD-L1), and T-cell receptor Vß gene sequencing were performed on formalin-fixed, paraffin-embedded tumors from 81 patients. Differences in liposarcoma subsets also were evaluated. RESULTS: UPS and leiomyosarcoma had high expression levels of genes related to antigen presentation and T-cell infiltration. UPS were found to have higher levels of PD-L1 (P≤.001) and PD-1 (P≤.05) on immunohistochemistry and had the highest T-cell infiltration based on T-cell receptor sequencing, significantly more than SS, which had the lowest (P≤.05). T-cell infiltrates in UPS also were more oligoclonal compared with SS and liposarcoma (P≤.05). A model adjusted for STS histologic subtype found that for all sarcomas, T-cell infiltration and clonality were highly correlated with PD-1 and PD-L1 expression levels (P≤.01). CONCLUSIONS: In the current study, the authors provide the most detailed overview of the immune microenvironment in sarcoma subtypes to date. UPS, which is a more highly mutated STS subtype, provokes a substantial immune response, suggesting that it may be well suited to treatment with immune checkpoint inhibitors. The SS and liposarcoma subsets are less mutated but do express immunogenic self-antigens, and therefore strategies to improve antigen presentation and T-cell infiltration may allow for successful immunotherapy in patients with these diagnoses. Cancer 2017;123:3291-304. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Safety and clinical activity of pembrolizumab for treatment of recurrent or metastatic squamous cell carcinoma of the head and neck (KEYNOTE-012): an open-label, multicentre, phase 1b trial.

BACKGROUND: Patients with recurrent or metastatic squamous cell carcinoma of the head and neck have few treatment options. We aimed to assess the safety, tolerability, and antitumour activity of pembrolizumab, a humanised anti-programmed death receptor 1 (PD-1) antibody, in patients with PD-L1-positive recurrent or metastatic squamous cell carcinoma of the head and neck. METHODS: This study was an open-label, multicentre, phase 1b trial of patients with recurrent or metastatic squamous cell carcinoma of the head and neck. Patients were eligible for enrolment if they were aged 18 years or older, had a confirmed diagnosis of recurrent or metastatic squamous cell carcinoma of the head and neck, and had any level of PD-L1 expression (ie, at least 1% of tumour cells or stroma that were PD-L1-positive by immunohistochemistry). Patients received pembrolizumab 10 mg/kg intravenously every 2 weeks. Primary outcomes were safety in the per-protocol population and the proportion of patients with centrally reviewed overall response per Response Evaluation Criteria In Solid Tumors (RECIST, version 1.1). Overall response was analysed in the full analysis set, which was defined as all patients who had received at least one dose of pembrolizumab, had measurable disease at baseline, and one post-baseline scan or patients without a post-baseline scan who discontinued therapy because of disease progression or a drug-related adverse event. The study is registered with ClinicalTrials.gov, number NCT01848834 and is ongoing, but no longer enrolling patients. FINDINGS: Of the 104 patients screened between June 7, 2013, and Oct 3, 2013, 81 (78%) were PD-L1-positive. Of these, 60 patients with PD-L1-positive squamous cell carcinoma of the head and neck were enrolled and treated: 23 (38%) were HPV-positive and 37 (62%) were HPV-negative. Pembrolizumab was well tolerated, with 10 (17%) of 60 patients having grade 3-4 drug-related adverse events, the most common of which were increases in alanine aminotransferase and in aspartate aminotransferase, and hyponatraemia, each occurring in two of 60 patients; one patient developed a grade 3 drug-related rash. 27 (45%) of 60 patients experienced a serious adverse event. There were no drug-related deaths. The proportion of patients with an overall response by central imaging review was 18% (eight of 45 patients; 95% CI 8-32) in all patients and was 25% (four of 16 patients; 7-52) in HPV-positive patients and 14% (four of 29 patients; 4-32) in HPV-negative patients. INTERPRETATION: Pembrolizumab was well tolerated and demonstrated clinically meaningful antitumour activity in recurrent or metastatic squamous cell carcinoma of the head and neck, supporting further study of pembrolizumab as anticancer therapy for advanced head and neck cancers. FUNDING: Merck & Co.

IL-17A gene transfer induces bone loss and epidermal hyperplasia associated with psoriatic arthritis.

BACKGROUND: Psoriatic arthritis (PsA) is a chronic inflammatory disease characterised by clinical features that include bone loss and epidermal hyperplasia. Aberrant cytokine expression has been linked to joint and skin pathology; however, it is unclear which cytokines are critical for disease initiation. Interleukin 17A (IL-17A) participates in many pathological immune responses; however, its role in PsA has not been fully elucidated. OBJECTIVE: To determine the role of IL-17A in epidermal hyperplasia and bone destruction associated with psoriatic arthritis. DESIGN: An in vivo gene transfer approach was used to investigate the role of IL-17A in animal models of inflammatory (collagen-induced arthritis) and non-inflammatory (receptor activator of NF-κB ligand (RANKL)-gene transfer) bone loss. RESULTS: IL-17A gene transfer induced the expansion of IL-17RA(+)CD11b(+)Gr1(low) osteoclast precursors and a concomitant elevation of biomarkers indicative of bone resorption. This occurred at a time preceding noticeable joint inflammation, suggesting that IL-17A is critical for the induction of pathological bone resorption through direct activation of osteoclast precursors. Moreover, IL-17A induced a second myeloid population CD11b(+)Gr1(high) neutrophil-like cells, which was associated with cutaneous pathology including epidermal hyperplasia, parakeratosis and Munro's microabscesses formation. CONCLUSIONS: Collectively, these data support that IL-17A can play a key role in the pathogenesis of inflammation-associated arthritis and/or skin disease, as observed in PsA.

IL-25 regulates Th17 function in autoimmune inflammation.

Interleukin (IL)-25 is a member of the IL-17 family of cytokines. However, unlike the other members of this family, IL-25 promotes T helper (Th) 2 responses. We now show that IL-25 also regulates the development of autoimmune inflammation mediated by IL-17-producing T cells. We have generated IL-25-deficient (il25-/-) mice and found that they are highly susceptible to experimental autoimmune encephalomyelitis (EAE). The accelerated disease in the il25-/- mice is associated with an increase of IL-23 in the periphery and a subsequent increase in the number of inflammatory IL-17-, IFNgamma-, and TNF-producing T cells that invade the central nervous system. Neutralization of IL-17 but not IFNgamma in il25-/- mice prevented EAE, suggesting that IL-17 is a major disease-promoting factor. IL-25 treatment at several time points during a relapse-remitting model or chronic model of EAE completely suppressed disease. IL-25 treatment induced elevated production of IL-13, which is required for suppression of Th17 responses by direct inhibition of IL-23, IL-1beta, and IL-6 expression in activated dendritic cells. Thus, IL-25 and IL-17, being members of the same cytokine family, play opposing roles in the pathogenesis of organ-specific autoimmunity.

Interleukin 25 regulates type 2 cytokine-dependent immunity and limits chronic inflammation in the gastrointestinal tract.

The cytokine interleukin (IL) 25 has been implicated in the initiation of type 2 immunity by driving the expression of type 2 cytokines such as IL-5 and IL-13, although its role in the regulation of immunity and infection-induced inflammation is unknown. Here, we identify a dual function for IL-25: first, in promoting type 2 cytokine-dependent immunity to gastrointestinal helminth infection and, second, in limiting proinflammatory cytokine production and chronic intestinal inflammation. Treatment of genetically susceptible mice with exogenous IL-25 promoted type 2 cytokine responses and immunity to Trichuris. IL-25 was constitutively expressed by CD4+ and CD8+ T cells in the gut of mouse strains that are resistant to Trichuris, and IL-25-deficient mice on a genetically resistant background failed to develop a type 2 immune response or eradicate infection. Furthermore, chronically infected IL-25(-/-) mice developed severe infection-induced intestinal inflammation associated with heightened expression of interferon-gamma and IL-17, identifying a role for IL-25 in limiting pathologic inflammation at mucosal sites. Therefore, IL-25 is not only a critical mediator of type 2 immunity, but is also required for the regulation of inflammation in the gastrointestinal tract.

IL-23 stimulates epidermal hyperplasia via TNF and IL-20R2-dependent mechanisms with implications for psoriasis pathogenesis.

Aberrant cytokine expression has been proposed as an underlying cause of psoriasis, although it is unclear which cytokines play critical roles. Interleukin (IL)-23 is expressed in human psoriasis and may be a master regulator cytokine. Direct intradermal administration of IL-23 in mouse skin, but not IL-12, initiates a tumor necrosis factor-dependent, but IL-17A-independent, cascade of events resulting in erythema, mixed dermal infiltrate, and epidermal hyperplasia associated with parakeratosis. IL-23 induced IL-19 and IL-24 expression in mouse skin, and both genes were also elevated in human psoriasis. IL-23-dependent epidermal hyperplasia was observed in IL-19-/- and IL-24-/- mice, but was inhibited in IL-20R2-/- mice. These data implicate IL-23 in the pathogenesis of psoriasis and support IL-20R2 as a novel therapeutic target.

Endogenous IL-33 enhances Th2 cytokine production and T-cell responses during allergic airway inflammation.

IL-33 is an IL-1-related cytokine which has been implicated in T(h)2-associated biology and allergic diseases in humans and mice. IL-33 stimulates T(h)2 cells, mast cells, eosinophils, basophils, iNKT cells and circulating CD34(+) stem cells to proliferate and produce pro-allergic cytokines such as IL-5 and IL-13. IL-33 mediates its cytokine effects through a receptor consisting of ST2 and IL-1RAcP. Whereas IL-1RAcP is ubiquitously expressed, ST2 expression is cell-type restricted and determines responsiveness to IL-33. Studies employing ST2-deficient mice have reported variable results on the role of this receptor, and consequently IL-33, with regards to allergic lung inflammation. In this study, we demonstrate that IL-33 is important for allergic lung inflammation. Intra-nasal administration of IL-33 triggered an immediate allergic response in the airways, and more importantly, we show that endogenous IL-33 contributes to airway inflammation and peripheral antigen-specific responses in ovalbumin-induced acute allergic lung inflammation using IL-33-deficient mice. Our results suggest that IL-33 is sufficient and required for severe allergic inflammation in the lung and support the concept of IL-33 as a therapeutic target in allergic lung inflammation.

Human Th17 cells comprise heterogeneous subsets including IFN-gamma-producing cells with distinct properties from the Th1 lineage.

Th17 cells have been named after their signature cytokine IL-17 and accumulating evidence indicates their involvement in the induction and progression of inflammatory diseases. In addition to IL-17 single-producing T cells, IL-17/IFN-gamma double-positive T cells are found in significantly elevated numbers in inflamed tissues or blood from patients with chronic inflammatory disorders. Because IFN-gamma is the classical Th1-associated cytokine, the origin and roles of these subsets remain elusive. In this paper, we show that not only IL-17(+)/IFN-gamma(+) but also IFN-gamma(+) (IL-17(-)) cells arise under Th17-inducing condition and have distinct properties from the Th1 lineage. In fact, these populations displayed characteristics reminiscent to IL-17 single-producing cells, including production of IL-22, CCL20, and induction of antimicrobial gene expression from epithelial cells. Live sorted IL-17(+) and Th17-IFN-gamma(+) cells retained expression of IL-17 or IFN-gamma after culture, respectively, whereas the IL-17(+)/IFN-gamma(+) population was less stable and could also become IL-17 or IFN-gamma single-producing cells. Interestingly, these Th17 subsets became "Th1-like" cells in the presence of IL-12. These results provide novel insights into the relationship and functionality of the Th17 and Th1 subsets and have direct implications for the analysis and relevance of IL-17 and/or IFN-gamma-producing T cells present in patients' peripheral blood and inflamed tissues.

Cutting edge: A critical functional role for IL-23 in psoriasis.

Interleukin-23 is a key cytokine involved in the generation of Th17 effector cells. Clinical efficacy of an anti-p40 mAb blocking both IL-12 and IL-23 and disease association with single nucleotide polymorphisms in the IL23R gene raise the question of a functional role of IL-23 in psoriasis. In this study, we provide a comprehensive analysis of IL-23 and its receptor in psoriasis and demonstrate its functional importance in a disease-relevant model system. The expression of IL-23 and its receptor was increased in the tissues of patients with psoriasis. Injection of a mAb specifically neutralizing human IL-23 showed IL-23-dependent inhibition of psoriasis development comparable to the use of anti-TNF blockers in a clinically relevant xenotransplant mouse model of psoriasis. Together, our results identify a critical functional role for IL-23 in psoriasis and provide the rationale for new treatment strategies in chronic epithelial inflammatory disorders.

IL-33 induces IL-13-dependent cutaneous fibrosis.

IL-33 is constitutively expressed in epithelial barrier tissues, such as skin. Although increased expression of IL-33/IL-33R has been correlated with fibrotic disorders, such as scleroderma and progressive systemic sclerosis, the direct consequences of IL-33 release in skin has not been reported. To determine the effects of dysregulated IL-33 signaling in skin, we administered IL-33 s.c. and monitored its effects at the injection site. Administration of IL-33 resulted in IL-33R-dependent accumulation of eosinophils, CD3(+) lymphocytes, F4/80(+) mononuclear cells, increased expression of IL-13 mRNA, and the development of cutaneous fibrosis. Consistent with extensive cutaneous tissue remodeling, IL-33 resulted in significant modulation of a number of extracellular matrix-associated genes, including collagen VI, collagen III, and tissue inhibitor of metalloproteases-1. We establish that IL-33-induced fibrosis requires IL-13 using IL-13 knockout mice and eosinophils using Delta dblGATA mice. We show that bone marrow-derived eosinophils secrete IL-13 in response to IL-33 stimulation, suggesting that eosinophil-derived IL-13 may promote IL-33-induced cutaneous fibrosis. Collectively, our results identify IL-33 as a previously unrecognized profibrotic mediator in skin and highlight the cellular and molecular pathways by which this pathology develops.

IL-23 promotes tumour incidence and growth.

Chronic inflammation has long been associated with increased incidence of malignancy and similarities in the regulatory mechanisms have been suggested for more than a century. Infiltration of innate immune cells, elevated activities of matrix metalloproteases and increased angiogenesis and vasculature density are a few examples of the similarities between chronic and tumour-associated inflammation. Conversely, the elimination of early malignant lesions by immune surveillance, which relies on the cytotoxic activity of tumour-infiltrating T cells or intra-epithelial lymphocytes, is thought to be rate-limiting for the risk to develop cancer. Here we show a molecular connection between the rise in tumour-associated inflammation and a lack of tumour immune surveillance. Expression of the heterodimeric cytokine interleukin (IL)-23, but not of its close relative IL-12, is increased in human tumours. Expression of these cytokines antagonistically regulates local inflammatory responses in the tumour microenvironment and infiltration of intra-epithelial lymphocytes. Whereas IL-12 promotes infiltration of cytotoxic T cells, IL-23 promotes inflammatory responses such as upregulation of the matrix metalloprotease MMP9, and increases angiogenesis but reduces CD8 T-cell infiltration. Genetic deletion or antibody-mediated elimination of IL-23 leads to increased infiltration of cytotoxic T cells into the transformed tissue, rendering a protective effect against chemically induced carcinogenesis. Finally, transplanted tumours are growth-restricted in hosts depleted for IL-23 or in IL-23-receptor-deficient mice. Although many strategies for immune therapy of cancer attempt to stimulate an immune response against solid tumours, infiltration of effector cells into the tumour tissue often appears to be a critical hurdle. We show that IL-23 is an important molecular link between tumour-promoting pro-inflammatory processes and the failure of the adaptive immune surveillance to infiltrate tumours.

Transcriptomic Determinants of Response to Pembrolizumab Monotherapy across Solid Tumor Types.

PURPOSE: To explore relationships between biological gene expression signatures and pembrolizumab response. EXPERIMENTAL DESIGN: RNA-sequencing data on baseline tumor tissue from 1,188 patients across seven tumor types treated with pembrolizumab monotherapy in nine clinical trials were used. A total of 11 prespecified gene expression signatures [18-gene T-cell-inflamed gene expression profile (TcellinfGEP), angiogenesis, hypoxia, glycolysis, proliferation, MYC, RAS, granulocytic myeloid-derived suppressor cell (gMDSC), monocytic myeloid-derived suppressor cell (mMDSC), stroma/epithelial-to-mesenchymal transition (EMT)/TGFß, and WNT] were evaluated for their relationship to objective response rate (per RECIST, version 1.1). Logistic regression analysis of response for consensus signatures was adjusted for tumor type, Eastern Cooperative Oncology Group performance status, and TcellinfGEP, an approach equivalent to evaluating the association between response and the residuals of consensus signatures after detrending them for their relationship with the TcellinfGEP (previously identified as a determinant of pembrolizumab response) and tumor type. Testing of the 10 prespecified non-TcellinfGEP consensus signatures for negative association [except proliferation (hypothesized positive association)] with response was adjusted for multiplicity. RESULTS: Covariance patterns of the 11 signatures (including TcellinfGEP) identified in Merck-Moffitt and The Cancer Genome Atlas datasets showed highly concordant coexpression patterns in the RNA-sequencing data from pembrolizumab trials. TcellinfGEP was positively associated with response; signatures for angiogenesis, mMDSC, and stroma/EMT/TGFß were negatively associated with response to pembrolizumab monotherapy. CONCLUSIONS: These findings suggest that features beyond IFNγ-related T-cell inflammation may be relevant to anti-programmed death 1 monotherapy response and may define other axes of tumor biology as candidates for pembrolizumab combinations. See related commentary by Cho et al., p. 1479.

Neoadjuvant Therapy Induces a Potent Immune Response to Sarcoma, Dominated by Myeloid and B Cells.

PURPOSE: To characterize changes in the soft-tissue sarcoma (STS) tumor immune microenvironment induced by standard neoadjuvant therapy with the goal of informing neoadjuvant immunotherapy trial design. EXPERIMENTAL DESIGN: Paired pre- and postneoadjuvant therapy specimens were retrospectively identified for 32 patients with STSs and analyzed by three modalities: multiplexed IHC, NanoString, and RNA sequencing with ImmunoPrism analysis. RESULTS: All 32 patients, representing a variety of STS histologic subtypes, received neoadjuvant radiotherapy and 21 (66%) received chemotherapy prior to radiotherapy. The most prevalent immune cells in the tumor before neoadjuvant therapy were myeloid cells (45% of all immune cells) and B cells (37%), with T (13%) and natural killer (NK) cells (5%) also present. Neoadjuvant therapy significantly increased the total immune cells infiltrating the tumors across all histologic subtypes for patients receiving neoadjuvant radiotherapy with or without chemotherapy. An increase in the percentage of monocytes and macrophages, particularly M2 macrophages, B cells, and CD4+ T cells was observed postneoadjuvant therapy. Upregulation of genes and cytokines associated with antigen presentation was also observed, and a favorable pathologic response (≥90% necrosis postneoadjuvant therapy) was associated with an increase in monocytic infiltrate. Upregulation of the T-cell checkpoint TIM3 and downregulation of OX40 were observed posttreatment. CONCLUSIONS: Standard neoadjuvant therapy induces both immunostimulatory and immunosuppressive effects within a complex sarcoma microenvironment dominated by myeloid and B cells. This work informs ongoing efforts to incorporate immune checkpoint inhibitors and novel immunotherapies into the neoadjuvant setting for STSs.