Validation of the Delphi Consensus Diagnostic Criteria for Necrobiotic Xanthogranuloma.

This diagnostic study validates the Delphi consensus diagnostic criteria for necrobiotic xanthogranuloma compared with its mimics.

Spatial transcriptomics reveals organized and distinct immune activation in cutaneous granulomatous disorders.

BACKGROUND: Noninfectious (inflammatory) cutaneous granulomatous disorders include cutaneous sarcoidosis (CS), granuloma annulare (GA), necrobiosis lipoidica (NL), and necrobiotic xanthogranuloma (NXG). These disorders share macrophage-predominant inflammation histologically, but the inflammatory architecture and the pattern of extracellular matrix alteration varies. The underlying molecular explanations for these differences remain unclear. OBJECTIVE: We sought to understand spatial gene expression characteristics in these disorders. METHODS: We performed spatial transcriptomics in cases of CS, GA, NL, and NXG to compare patterns of immune activation and other molecular features in a spatially resolved fashion. RESULTS: CS is characterized by a polarized, spatially organized type 1-predominant response with classical macrophage activation. GA is characterized by a mixed but spatially organized pattern of type 1 and type 2 polarization with both classical and alternative macrophage activation. NL showed concomitant activation of type 1, type 2, and type 3 immunity with a mixed pattern of macrophage activation. Activation of type 1 immunity was shared among, CS, GA, and NL and included upregulation of IL-32. NXG showed upregulation of CXCR4-CXCL12/14 chemokine signaling and exaggerated alternative macrophage polarization. Histologic alteration of extracellular matrix correlated with hypoxia and glycolysis programs and type 2 immune activation. CONCLUSIONS: Inflammatory cutaneous granulomatous disorders show distinct and spatially organized immune activation that correlate with hallmark histologic changes.

Enhanced Intratumoral Delivery of Immunomodulator Monophosphoryl Lipid A through Hyperbranched Polyglycerol-Coated Biodegradable Nanoparticles.

Immunomodulatory agents have significant potential to enhance cancer treatment but have demonstrated limited efficacy beyond the preclinical setting owing to poor pharmacokinetics and toxicity associated with systemic administration. Conversely, when locally delivered, immunomodulatory agents require repeated administration to optimize immune stimulation. To overcome these challenges, we encapsulated the toll-like receptor 4 agonist monophosphoryl lipid A (MPLA) within hyperbranched polyglycerol-coated biodegradable nanoparticles (NPs) engineered for gradual drug release from the NP core, resulting in a more persistent stimulation of antitumor immune responses while minimizing systemic side effects. In a model of malignant melanoma, we demonstrate that hyperbranched polyglycerol-NP encapsulation significantly improves the antitumor efficacy of MPLA by enhancing its ability to remodel the tumor microenvironment. Relative to free MPLA, hyperbranched polyglycerol-coated NP-encapsulated MPLA significantly increased the NK cell- and cytotoxic T-cell-mediated antitumor immune response and tuned the tumor-draining lymph nodes toward a T helper 1 response. Furthermore, when combined with local delivery of a chemotherapeutic agent, hyperbranched polyglycerol-NP-MPLA induces the conversion of an immunosuppressive tumor microenvironment to immunogenic tumor microenvironment and significantly improves survival.

Pediatric cutaneous Crohn disease: A case series of 89 patients and review.

BACKGROUND: Cutaneous (or "Metastatic") Crohn disease (CCD) is a rare and underrecognized disease characterized by cutaneous granulomatous inflammation. We describe patient demographics, clinical characteristics, histology, and treatment of 89 pediatric cases of CCD, including 78 previously reported and 11 new cases seen at four academic institutions. We emphasize the efficacy of biologic mono- and dual therapy. METHODS: PubMed identified cases using keywords including "metastatic Crohn disease" and "cutaneous Crohn disease". Patients were identified by retrospective review of the electronic health record including histopathologic diagnosis consistent with CCD. Chart review collected demographic, clinical, and histologic data. RESULTS: Most pediatric patients with CCD are male 55% (49/89), present with edema (73/89, 82%) and erythema (47/89, 53%) of the genitals (33/49, 67%), and have intestinal Crohn disease (69/89, 78%). Oral corticosteroids (53/75, 71%) and metronidazole (29/75, 39%) are the most frequently prescribed medications. Of the 17 patients treated with tumor necrosis factor (TNF)-blockade, 94% (16/17) had partial or total clearance. Ustekinumab resulted in clearance of cutaneous disease in two patients (2/3, 67%) and partial clearance in one patient (1/3, 33%). Two cases achieved total clearance with the use of dual biologic therapy defined as the use of two biologic therapies with differing mechanisms of action or the use of a biologic therapy and small molecule inhibitor. CONCLUSIONS: TNF blockade is an effective treatment for pediatric CCD, and interleukin-12/23 inhibitors may be similarly effective. Consideration of dual biologic therapy may be useful in pediatric patients requiring discordant therapies for their intestinal and cutaneous CD.

Granuloma Annulare Exhibits Mixed Immune and Macrophage Polarization Profiles with Spatial Transcriptomics.

Granuloma annulare (GA) is an idiopathic condition characterized by granulomatous inflammation in the skin. Prior studies have suggested that GA develops from various triggers, leading to a complex interplay involving innate and adaptive immunity, tissue remodeling, and fibrosis. Macrophages are the major immune cells comprising GA granulomas; however, the molecular drivers and inflammatory signaling cascade behind macrophage activation are poorly understood. Histologically, GA exhibits both palisaded and interstitial patterns on histology; however, the molecular composition of GA at the spatial level remains unexplored. GA is a condition without Food and Drug Administration-approved therapies despite the significant impact of GA on QOL. Spatial transcriptomics is a valuable tool for profiling localized, genome-wide gene expression changes across tissues, with emerging applications in clinical medicine. To improve our understanding of the spatially localized gene expression patterns underlying GA, we profiled the spatial gene expression landscape from 6 patients with GA. Our findings revealed mixed T helper 1 and T helper 2 signals comprising the GA microenvironment and spatially distinct M1 and M2 macrophage polarization characteristics. IFN-γ and TNF signals emerged as important regulators of GA granulomatous inflammation, and IL-32 emerged as a key driver of granulomatous inflammation. Overall, our spatial transcriptomics data indicate that GA exhibits mixed immune and macrophage polarization.

Paradoxical Psoriasis.

Cytokine blocking therapies have revolutionized the management of psoriasis and atopic dermatitis but can lead to the development of paradoxic psoriasis (PP). Patients treated with biologics should be closely monitored for the development of PP and other paradoxical eruptions (including inflammatory joint disease, inflammatory bowel disease, eczematous eruptions, lupus like eruptions, sarcoidal eruptions, and others) and occasionally the development of cutaneous T-cell lymphoma. Further understanding the immunologic mechanism of these processes will ultimately drive our understanding of and ability to predict and manage PPs.

A TCF4-dependent gene regulatory network confers resistance to immunotherapy in melanoma.

To better understand intrinsic resistance to immune checkpoint blockade (ICB), we established a comprehensive view of the cellular architecture of the treatment-naive melanoma ecosystem and studied its evolution under ICB. Using single-cell, spatial multi-omics, we showed that the tumor microenvironment promotes the emergence of a complex melanoma transcriptomic landscape. Melanoma cells harboring a mesenchymal-like (MES) state, a population known to confer resistance to targeted therapy, were significantly enriched in early on-treatment biopsies from non-responders to ICB. TCF4 serves as the hub of this landscape by being a master regulator of the MES signature and a suppressor of the melanocytic and antigen presentation transcriptional programs. Targeting TCF4 genetically or pharmacologically, using a bromodomain inhibitor, increased immunogenicity and sensitivity of MES cells to ICB and targeted therapy. We thereby uncovered a TCF4-dependent regulatory network that orchestrates multiple transcriptional programs and contributes to resistance to both targeted therapy and ICB in melanoma.

Cutaneous Sarcoidosis.

Sarcoidosis is a multisystem disease that most commonly affects the lungs, lymphatic system, eyes, and skin but any organ may be involved. Cutaneous sarcoidosis most commonly presents as pink-red to red-brown papules and plaques that commonly affect the head and neck. With the skin being readily accessible for evaluation and biopsy, when sarcoidosis is suspected, dermatologic evaluation may be helpful for establishing a definitive diagnosis. Treatment strategy depends on the severity and distribution of skin lesions and should incorporate patient preference and treatment considerations for other organs that may be involved.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part II diagnosis and management.

Drug-induced hypersensitivity syndrome, also known as drug reaction with eosinophilia and systemic symptoms, is a severe cutaneous adverse reaction characterized by an exanthem, fever, and hematologic and visceral organ involvement. The differential diagnosis includes other cutaneous adverse reactions, infections, inflammatory and autoimmune diseases, and neoplastic disorders. Three sets of diagnostic criteria have been proposed; however, consensus is lacking. The cornerstone of management is immediate discontinuation of the suspected drug culprit. Systemic corticosteroids remain first-line therapy, but the literature on steroid-sparing agents is expanding. Longitudinal evaluation for sequelae is recommended. Adjunctive tests for risk stratification and drug culprit identification remain under investigation. Part II of this continuing medical education activity begins by exploring the differential diagnosis and diagnosis of drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms and concludes with an evidence-based overview of evaluation and treatment.

Retrospective assessment of immunologic and histologic heterogeneity in granuloma annulare by cytokine staining.

BACKGROUND: Type 1 (Th1) and Type 2 (Th2) immunity have both been implicated in granuloma annulare (GA). To what extent these pathways contribute to clinical/histologic heterogeneity and/or distinct disease endotypes remains unexplored. METHODS: We retrospectively analyzed 30 GA biopsies with either palisaded or interstitial histology with and without eosinophils. We performed RNA in situ hybridization to assess how markers of Type 1 (interferon gamma), Type 2 (interleukin [IL]4, IL13, IL5), and Type 3 (IL17A) immunity in GA compared with canonical inflammatory disorders and whether markers correlated with histology. We analyzed another cohort of 14 patients who had multiple biopsies across anatomic space and time for individual conservation of histologic features. RESULTS: Interferon (IFN)G staining is highest in GA relative to other cytokines. Type 2 cytokine staining is less prominent, with IL4 increased in interstitial pattern cases. Eosinophils did not correlate with Type 2 markers. Patients with multiple biopsies display intrapatient variability in histology. CONCLUSION: Type 1 inflammation predominates over Type 2 inflammation in GA irrespective of histologic pattern. Distinct disease endotypes were not detected.

A bedside to bench study of anti-PD-1, anti-CD40, and anti-CSF1R indicates that more is not necessarily better.

BACKGROUND: Stimulating inflammatory tumor associated macrophages can overcome resistance to PD-(L)1 blockade. We previously conducted a phase I trial of cabiralizumab (anti-CSF1R), sotigalimab (CD40-agonist) and nivolumab. Our current purpose was to study the activity and cellular effects of this three-drug regimen in anti-PD-1-resistant melanoma. METHODS: We employed a Simon's two-stage design and analyzed circulating immune cells from patients treated with this regimen for treatment-related changes. We assessed various dose levels of anti-CSF1R in murine melanoma models and studied the cellular and molecular effects. RESULTS: Thirteen patients were enrolled in the first stage. We observed one (7.7%) confirmed and one (7.7%) unconfirmed partial response, 5 patients had stable disease (38.5%) and 6 disease progression (42.6%). We elected not to proceed to the second stage. CyTOF analysis revealed a reduction in non-classical monocytes. Patients with prolonged stable disease or partial response who remained on study for longer had increased markers of antigen presentation after treatment compared to patients whose disease progressed rapidly. In a murine model, higher anti-CSF1R doses resulted in increased tumor growth and worse survival. Using single-cell RNA-sequencing, we identified a suppressive monocyte/macrophage population in murine tumors exposed to higher doses. CONCLUSIONS: Higher anti-CSF1R doses are inferior to lower doses in a preclinical model, inducing a suppressive macrophage population, and potentially explaining the disappointing results observed in patients. While it is impossible to directly infer human doses from murine studies, careful intra-species evaluation can provide important insight. Cabiralizumab dose optimization is necessary for this patient population with limited treatment options. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03502330.

Molecularly Targeted Therapies for Inflammatory Cutaneous Granulomatous Disorders: A Review of the Evidence and Implications for Understanding Disease Pathogenesis.

Inflammatory cutaneous granulomatous diseases, including granuloma annulare, cutaneous sarcoidosis, and necrobiosis lipoidica, are distinct diseases unified by the hallmark of macrophage accumulation and activation in the skin. There are currently no Food and Drug Administration-approved therapies for these conditions except prednisone and repository corticotropin injection for pulmonary sarcoidosis. Treatment of these diseases has generally been guided by low-quality evidence and may involve broadly immunomodulatory medications. Development of new treatments has in part been limited by an incomplete understanding of disease pathogenesis. Recently, there has been substantial progress in better understanding the molecular pathogenesis of these disorders, opening the door for therapeutic innovation. Likewise, reported outcomes of treatment with immunologically targeted therapies may offer insights into disease pathogenesis. In this systematic review, we summarize progress in deciphering the pathomechanisms of these disorders and discuss this in the context of emerging evidence on the use of molecularly targeted therapies in treatment of these diseases.

Combinatorial Immunotherapy with Agonistic CD40 Activates Dendritic Cells to Express IL12 and Overcomes PD-1 Resistance.

Checkpoint inhibitors have revolutionized cancer treatment, but resistance remains a significant clinical challenge. Myeloid cells within the tumor microenvironment can modulate checkpoint resistance by either supporting or suppressing adaptive immune responses. Using an anti-PD-1-resistant mouse melanoma model, we show that targeting the myeloid compartment via CD40 activation and CSF1R blockade in combination with anti-PD-1 results in complete tumor regression in a majority of mice. This triple therapy combination was primarily CD40 agonist-driven in the first 24 hours after therapy and showed a similar systemic cytokine profile in human patients as was seen in mice. Functional single-cell cytokine secretion profiling of dendritic cells (DC) using a novel microwell assay identified a CCL22+CCL5+ IL12-secreting DC subset as important early-stage effectors of triple therapy. CD4+ and CD8+ T cells are both critical effectors of treatment, and systems analysis of single-cell RNA sequencing data supported a role for DC-secreted IL12 in priming T-cell activation and recruitment. Finally, we showed that treatment with a novel IL12 mRNA therapeutic alone was sufficient to overcome PD-1 resistance and cause tumor regression. Overall, we conclude that combining myeloid-based innate immune activation and enhancement of adaptive immunity is a viable strategy to overcome anti-PD-1 resistance.

PD-1 maintains CD8 T cell tolerance towards cutaneous neoantigens.

The peripheral T cell repertoire of healthy individuals contains self-reactive T cells1,2. Checkpoint receptors such as PD-1 are thought to enable the induction of peripheral tolerance by deletion or anergy of self-reactive CD8 T cells3-10. However, this model is challenged by the high frequency of immune-related adverse events in patients with cancer who have been treated with checkpoint inhibitors11. Here we developed a mouse model in which skin-specific expression of T cell antigens in the epidermis caused local infiltration of antigen-specific CD8 T cells with an effector gene-expression profile. In this setting, PD-1 enabled the maintenance of skin tolerance by preventing tissue-infiltrating antigen-specific effector CD8 T cells from (1) acquiring a fully functional, pathogenic differentiation state, (2) secreting significant amounts of effector molecules, and (3) gaining access to epidermal antigen-expressing cells. In the absence of PD-1, epidermal antigen-expressing cells were eliminated by antigen-specific CD8 T cells, resulting in local pathology. Transcriptomic analysis of skin biopsies from two patients with cutaneous lichenoid immune-related adverse events showed the presence of clonally expanded effector CD8 T cells in both lesional and non-lesional skin. Thus, our data support a model of peripheral T cell tolerance in which PD-1 allows antigen-specific effector CD8 T cells to co-exist with antigen-expressing cells in tissues without immunopathology.

Setdb1 -loss induces type-I interferons and immune clearance of melanoma.

Despite recent advances in the treatment of melanoma, many patients with metastatic disease still succumb to their disease. To identify tumor-intrinsic modulators of immunity to melanoma, we performed a whole-genome CRISPR screen in melanoma and identified multiple components of the HUSH complex, including Setdb1 , as hits. We found that loss of Setdb1 leads to increased immunogenicity and complete tumor clearance in a CD8+ T-cell dependent manner. Mechanistically, loss of Setdb1 causes de-repression of endogenous retroviruses (ERVs) in melanoma cells and triggers tumor-cell intrinsic type-I interferon signaling, upregulation of MHC-I expression, and increased CD8+ T-cell infiltration. Furthermore, spontaneous immune clearance observed in Setdb1 -/- tumors results in subsequent protection from other ERV-expressing tumor lines, supporting the functional anti-tumor role of ERV-specific CD8+ T-cells found in the Setdb1 -/- microenvironment. Blocking the type-I interferon receptor in mice grafted with Setdb1 -/- tumors decreases immunogenicity by decreasing MHC-I expression, leading to decreased T-cell infiltration and increased melanoma growth comparable to Setdb1 wt tumors. Together, these results indicate a critical role for Setdb1 and type-I interferons in generating an inflamed tumor microenvironment, and potentiating tumor-cell intrinsic immunogenicity in melanoma. This study further emphasizes regulators of ERV expression and type-I interferon expression as potential therapeutic targets for augmenting anti-cancer immune responses.

Subsets of IFN Signaling Predict Response to Immune Checkpoint Blockade in Patients with Melanoma.

PURPOSE: IFN signaling in the tumor microenvironment is a critical determinant of both response and resistance of cancer to immune checkpoint inhibitors (ICI). We hypothesized that distinct patterns of IFN signaling in melanoma are associated with clinical response or resistance to ICIs. EXPERIMENTAL DESIGN: Two tissue microarrays containing samples from 97 patients with metastatic melanoma who received nivolumab, pembrolizumab, or a combination of ipilimumab and nivolumab at Yale New Haven Hospital between 2011 and 2017 were randomized into discovery and validation cohorts. Samples were stained and visualized using multiplexed immunofluorescence microscopy for STAT1, STAT1 phosphorylated at Y701 (pSTAT1Y701), and PD-L1, and signals were quantified using the automated quantitative analysis method of quantitative immunofluorescence. Treatment response was assessed using RECIST, and overall survival was analyzed. For in vitro studies, human melanoma cell lines were stimulated with IFNγ and IFNß, and Western blotting was performed. RESULTS: Pretreatment STAT1 levels were higher in responders to ICIs [complete response/partial response/stable disease (SD) for > 6 months] than in nonresponders (SD < 6 months/progressive disease). Higher pretreatment STAT1 levels were associated with improved survival after ICIs in both the discovery and validation cohorts. Western blot analysis of human melanoma cell lines stimulated with IFN demonstrated distinct patterns of upregulation of STAT1 compared with pSTAT1Y701 and PD-L1. When combining STAT1 and PD-L1 markers, patients with STAT1highPD-L1low tumors had improved survival compared with those with STAT1lowPD-L1high tumors. CONCLUSIONS: STAT1 may better predict melanoma response to ICIs than current strategies, and combined STAT1 and PD-L1 biomarkers may provide insight into IFN-responsive versus IFN-resistant states.