A Phase II study of ERK inhibition by ulixertinib (BVD-523) in Metastatic Uveal Melanoma

PURPOSE

Uveal melanoma is a rare and aggressive subset of melanoma that is minimally responsive to traditional therapies. Greater than 80% of uveal melanomas have a mutation in GNAQ or GNA11 which lead to downstream signaling through the MAPK pathway. Ulixertinib (BVD-523) is a potent and reversible small molecule ATP-competitive inhibitor of both ERK1 and ERK2 protein kinases.

PATIENTS AND METHODS

We performed a phase II study to determine the efficacy and safety of BVD-523 in patients with metastatic uveal melanoma. This was conducted as a Simon two-stage design with a sample size of 25 patients (pts) and an initial evaluation of efficacy after 13 pts.

RESULTS

From April 2018 to April 2019 thirteen pts were enrolled. Pts were predominantly female (69%) with a median age of 64 years (34 -76). Sites of metastases included liver (84.6%) and lung (30.8%). Grade 3 and 4 toxicities associated with therapy were consistent with ERK inhibitors and included LFT elevation, hyponatremia, pruritis, amylase elevation, anemia and rash. The best response, per RECIST 1.1, was stable disease in 4 pts, and disease progression in 7 patients. Two patients were unevaluable for response due to withdrawal from study. Median time to progression was 2.0 months. There were eight deaths due to disease progression with a median overall survival of 6.9 months.

CONCLUSIONS

ERK inhibition with ulixertinib (BVD-523) did not demonstrate activity in patients with metastatic uveal melanoma. The toxicities observed were consistent with what would be expected with MAPK pathway inhibition.

C3d-Targeted factor H inhibits tissue complement in disease models and reduces glomerular injury without affecting circulating complement

Complement-mediated diseases can be treated using systemic inhibitors. However, complement components are abundant in circulation, affecting systemic inhibitors' exposure and efficacy. Furthermore, because of complement's essential role in immunity, systemic treatments raise infection risk in patients. To address these challenges, we developed antibody fusion proteins combining the alternative-pathway complement inhibitor factor H (fH1-5) with an anti-C3d monoclonal antibody (C3d-mAb-2fH). Because C3d is deposited at sites of complement activity, this molecule localizes to tissue complement while minimizing circulating complement engagement. These fusion proteins bind to deposited complement in diseased human skin sections and localize to activated complement in a primate skin injury model. We further explored the pharmacology of C3d-mAb-2fH proteins in rodent models with robust tissue complement activation. Doses of C3d-mAb-2fH >1 mg/kg achieved >75% tissue complement inhibition in mouse and rat injury models while avoiding circulating complement blockade. Glomerular-specific complement inhibition reduced proteinuria and preserved podocyte foot-process architecture in rat membranous nephropathy, indicating disease-modifying efficacy. These data indicate that targeting local tissue complement results in durable and efficacious complement blockade in skin and kidney while avoiding systemic inhibition, suggesting broad applicability of this approach in treating a range of complement-mediated diseases.

Lymphadenopathy and lymph node rejection following facial vascularized composite allotransplantation

BACKGROUND

Apart from the skin, little is known about the immunological processes in deeper tissues, which are typically not accessible to biopsy and inspection, of vascularized composite allografts (VCAs). Face transplant patients develop prominent adenopathy shortly after transplantation that resolves over time. The mechanisms underlying this process are not understood.

MATERIALS AND METHODS

A retrospective cohort study was conducted on 9 patients who underwent 10 facial VCAs at the Brigham and Women's Hospital, Boston, MA, between April 2009 and July 2019. Clinical, radiological, and histological data related to lymphadenopathy of the head and neck were reviewed.

RESULTS

Patients who received donor-derived lymph nodes (LNs) developed bilateral lymphadenopathy of the submental or submandibular superficial LNs. Median time of presentation was POD18 (range POD6-POM3). Notably, bilateral adenopathy of the neck was not observed in later stages of follow-up (mean follow-up, 115 months). Histology of 3 LNs showed increased histiocytes and apoptosis, with the features reminiscent of necrotizing histiocytic lymphadenitis, and B and T lymphocytes (mostly CD8 + T) admixed with CD163 + histiocytes and dendritic cells. Molecular chimerism analysis in one case showed the coexistence of donor (81%) and recipient (19%) derived lymphocytes. Granzyme B (GZMB) expression confirmed the presence of increased cytotoxic T cells in this LN sample.

CONCLUSION

Our data suggested the involvement of an immunological process within the donor-derived LNs after facial allotransplantation between the recipient and donor cells. GZMB expression suggested LN rejection that can occurred independently of skin rejection. This finding supports the need to better define the role of donor-derived immune cells in the context of allograft rejection.

Androgenic steroids induce pathologic scarring in a preclinical porcine model via dysfunctional extracellular matrix deposition

Hypertrophic scarring is a major source of morbidity. Sex hormones are not classically considered modulators of scarring. However, based on increased frequency of hypertrophic scarring in patients on testosterone, we hypothesized that androgenic steroids induce abnormal scarring and developed a preclinical porcine model to explore these effects. Mini-swine underwent castration, received no testosterone (noT) or biweekly testosterone therapy (+T), and underwent excisional wounding. To create a delayed wound healing model, a subset of wounds were re-excised at 2 weeks. Scars from postoperative day 42 (POD42) and delayed wounds (POD28) were harvested 6 weeks after initial wounding for analysis via histology, bulk RNA-seq, and mechanical testing. Histologic analysis of scars from +T animals showed increased mean fibrosis area (16 mm2noT, 28 mm2+T; p = .007) and thickness (0.246 mm2noT, 0.406 mm2+T; p < .001) compared to noT. XX+T and XY+T scars had greater tensile burst strength (p = .024 and p = .013, respectively) compared to noT swine. Color deconvolution analysis revealed greater deposition of type I and type III collagen as well as increased collagen type I:III ratio in +T scars. Dermatopathologist histology scoring showed that +T exposure was associated with worse overall scarring (p < .05). Gene ontology analysis found that testosterone exposure was associated with upregulation of cellular metabolism and immune response gene sets, while testosterone upregulated pathways related to keratinization and laminin formation on pathway analysis. In conclusion, we developed a preclinical porcine model to study the effects of the sex hormone testosterone on scarring. Testosterone induces increased scar tissue deposition and appears to increase physical strength of scars via supraphysiologic deposition of collagen and other ECM factors. The increased burst strength seen in both XX and XY animals suggests that hormone administration has a strong influence on scar mechanical properties independent of chromosomal sex. Anti-androgen topical therapies may be a promising future area of research.

Multiplexed 3D Analysis of Immune States and Niches in Human Tissue

Tissue homeostasis and the emergence of disease are controlled by changes in the proportions of resident and recruited cells, their organization into cellular neighbourhoods, and their interactions with acellular tissue components. Highly multiplexed tissue profiling (spatial omics)1 makes it possible to study this microenvironment in situ, usually in 4-5 micron thick sections (the standard histopathology format)2. Microscopy-based tissue profiling is commonly performed at a resolution sufficient to determine cell types but not to detect subtle morphological features associated with cytoskeletal reorganisation, juxtracrine signalling, or membrane trafficking3. Here we describe a high-resolution 3D imaging approach able to characterize a wide variety of organelles and structures at sub-micron scale while simultaneously quantifying millimetre-scale spatial features. This approach combines cyclic immunofluorescence (CyCIF) imaging4 of over 50 markers with confocal microscopy of archival human tissue thick enough (30-40 microns) to fully encompass two or more layers of intact cells. 3D imaging of entire cell volumes substantially improves the accuracy of cell phenotyping and allows cell proximity to be scored using plasma membrane apposition, not just nuclear position. In pre-invasive melanoma in situ5, precise phenotyping shows that adjacent melanocytic cells are plastic in state and participate in tightly localised niches of interferon signalling near sites of initial invasion into the underlying dermis. In this and metastatic melanoma, mature and precursor T cells engage in an unexpectedly diverse array of juxtracrine and membrane-membrane interactions as well as looser "neighbourhood" associations6 whose morphologies reveal functional states. These data provide new insight into the transitions occurring during early tumour formation and immunoediting and demonstrate the potential for phenotyping of tissues at a level of detail previously restricted to cultured cells and organoids.

SpatialCells: automated profiling of tumor microenvironments with spatially resolved multiplexed single-cell data

Cancer is a complex cellular ecosystem where malignant cells coexist and interact with immune, stromal and other cells within the tumor microenvironment (TME). Recent technological advancements in spatially resolved multiplexed imaging at single-cell resolution have led to the generation of large-scale and high-dimensional datasets from biological specimens. This underscores the necessity for automated methodologies that can effectively characterize molecular, cellular and spatial properties of TMEs for various malignancies. This study introduces SpatialCells, an open-source software package designed for region-based exploratory analysis and comprehensive characterization of TMEs using multiplexed single-cell data. The source code and tutorials are available at https://semenovlab.github.io/SpatialCells. SpatialCells efficiently streamlines the automated extraction of features from multiplexed single-cell data and can process samples containing millions of cells. Thus, SpatialCells facilitates subsequent association analyses and machine learning predictions, making it an essential tool in advancing our understanding of tumor growth, invasion and metastasis.

Development and validation of time-to-event models to predict metastatic recurrence of localized cutaneous melanoma

BACKGROUND

The recent expansion of immunotherapy for stage IIB/IIC melanoma highlights a growing clinical need to identify patients at high risk of metastatic recurrence and, therefore, most likely to benefit from this therapeutic modality.

OBJECTIVE

To develop time-to-event risk prediction models for melanoma metastatic recurrence.

METHODS

Patients diagnosed with stage I/II primary cutaneous melanoma between 2000 and 2020 at Mass General Brigham and Dana-Farber Cancer Institute were included. Melanoma recurrence date and type were determined by chart review. Thirty clinicopathologic factors were extracted from electronic health records. Three types of time-to-event machine-learning models were evaluated internally and externally in the distant versus locoregional/nonrecurrence prediction.

RESULTS

This study included 954 melanomas (155 distant, 163 locoregional, and 636 1:2 matched nonrecurrences). Distant recurrences were associated with worse survival compared to locoregional/nonrecurrences (HR: 6.21, P < .001) and to locoregional recurrences only (HR: 5.79, P < .001). The Gradient Boosting Survival model achieved the best performance (concordance index: 0.816; time-dependent AUC: 0.842; Brier score: 0.103) in the external validation.

LIMITATIONS

Retrospective nature and cohort from one geography.

CONCLUSIONS

These results suggest that time-to-event machine-learning models can reliably predict the metastatic recurrence from localized melanoma and help identify high-risk patients who are most likely to benefit from immunotherapy.

SpatialCells: Automated Profiling of Tumor Microenvironments with Spatially Resolved Multiplexed Single-Cell Data

Background

Cancer is a complex cellular ecosystem where malignant cells coexist and interact with immune, stromal, and other cells within the tumor microenvironment. Recent technological advancements in spatially resolved multiplexed imaging at single-cell resolution have led to the generation of large-scale and high-dimensional datasets from biological specimens. This underscores the necessity for automated methodologies that can effectively characterize the molecular, cellular, and spatial properties of tumor microenvironments for various malignancies.

Results

This study introduces SpatialCells, an open-source software package designed for region-based exploratory analysis and comprehensive characterization of tumor microenvironments using multiplexed single-cell data.

Conclusions

SpatialCells efficiently streamlines the automated extraction of features from multiplexed single-cell data and can process samples containing millions of cells. Thus, SpatialCells facilitates subsequent association analyses and machine learning predictions, making it an essential tool in advancing our understanding of tumor growth, invasion, and metastasis.

Single-cell profiling reveals unique features of diabetogenic T cells in anti-PD-1-induced type 1 diabetes mice

Immune-related adverse events (irAEs) are a notable complication of PD-1 cancer immunotherapy. A better understanding of how these iatrogenic diseases compare with naturally arising autoimmune diseases is needed for treatment and monitoring of irAEs. We identified differences in anti-PD-1-induced type 1 diabetes (T1D) and spontaneous T1D in non-obese diabetic (NOD) mice by performing single-cell RNA-seq and TCR-seq on T cells from the pancreas, pancreas-draining lymph node (pLN), and blood of mice with PD-1-induced T1D or spontaneous T1D. In the pancreas, anti-PD-1 resulted in expansion of terminally exhausted/effector-like CD8+ T cells, an increase in T-bethi CD4+FoxP3- T cells, and a decrease in memory CD4+FoxP3- and CD8+ T cells in contrast to spontaneous T1D. Notably, anti-PD-1 caused increased TCR sharing between the pancreas and the periphery. Moreover, T cells in the blood of anti-PD-1-treated mice expressed markers that differed from spontaneous T1D, suggesting that the blood may provide a window to monitor irAEs rather than relying exclusively on the autoimmune target organ.

Development of a Patient-Derived 3D Immuno-Oncology Platform to Potentiate Immunotherapy Responses in Ascites-Derived Circulating Tumor Cells

High-grade serous ovarian cancer (HGSOC) is responsible for the majority of gynecology cancer-related deaths. Patients in remission often relapse with more aggressive forms of disease within 2 years post-treatment. Alternative immuno-oncology (IO) strategies, such as immune checkpoint blockade (ICB) targeting the PD-(L)1 signaling axis, have proven inefficient so far. Our aim is to utilize epigenetic modulators to maximize the benefit of personalized IO combinations in ex vivo 3D patient-derived platforms and in vivo syngeneic models. Using patient-derived tumor ascites, we optimized an ex vivo 3D screening platform (PDOTS), which employs autologous immune cells and circulating ascites-derived tumor cells, to rapidly test personalized IO combinations. Most importantly, patient responses to platinum chemotherapy and poly-ADP ribose polymerase inhibitors in 3D platforms recapitulate clinical responses. Furthermore, similar to clinical trial results, responses to ICB in PDOTS tend to be low and positively correlated with the frequency of CD3+ immune cells and EPCAM+/PD-L1+ tumor cells. Thus, the greatest response observed with anti-PD-1/anti-PD-L1 immunotherapy alone is seen in patient-derived HGSOC ascites, which present with high levels of systemic CD3+ and PD-L1+ expression in immune and tumor cells, respectively. In addition, priming with epigenetic adjuvants greatly potentiates ICB in ex vivo 3D testing platforms and in vivo tumor models. We further find that epigenetic priming induces increased tumor secretion of several key cytokines known to augment T and NK cell activation and cytotoxicity, including IL-6, IP-10 (CXCL10), KC (CXCL1), and RANTES (CCL5). Moreover, epigenetic priming alone and in combination with ICB immunotherapy in patient-derived PDOTS induces rapid upregulation of CD69, a reliable early activation of immune markers in both CD4+ and CD8+ T cells. Consequently, this functional precision medicine approach could rapidly identify personalized therapeutic combinations able to potentiate ICB, which is a great advantage, especially given the current clinical difficulty of testing a high number of potential combinations in patients.

Cellular activation pathways and interaction networks in vascularized composite allotransplantation

Vascularized composite allotransplantation (VCA) is an evolving field of reconstructive surgery that has revolutionized the treatment of patients with devastating injuries, including those with limb losses or facial disfigurement. The transplanted units are typically comprised of different tissue types, including skin, mucosa, blood and lymphatic vasculature, muscle, and bone. It is widely accepted that the antigenicity of some VCA components, such as skin, is particularly potent in eliciting a strong recipient rejection response following transplantation. The fine line between tolerance and rejection of the graft is orchestrated by different cell types, including both donor and recipient-derived lymphocytes, macrophages, and other immune and donor-derived tissue cells (e.g., endothelium). Here, we delineate the role of different cell and tissue types during VCA rejection. Rejection of VCA grafts and the necessity of life-long multidrug immunosuppression remains one of the major challenges in this field. This review sheds light on recent developments in decoding the cellular signature of graft rejection in VCA and how these may, ultimately, influence the clinical management of VCA patients by way of novel therapies that target specific cellular processes.

Insights from Immunoproteomic Profiling of a Rejected Full Face Transplant

Vascularized composite allografts (VCAs) of faces and extremities are subject to chronic rejection that is incompletely understood. Here we report on immunoproteomic evaluation of a full facial VCA removed 88 months after transplantation due to chronic rejection. CD8-positive T cells of donor (graft) origin infiltrating deep intragraft arteries in apposition to degenerating endothelium of chimeric recipient origin in association with arteriosclerotic alterations. Digital spatial proteomic profiling highlighted proteins expressed by activated cytotoxic T cells and macrophages as well as pathway components involved in atherogenic responses, including IDO1 and STING. Chronic facial VCA rejection thus involves T cell/macrophage-mediated accelerated arteriosclerosis not normally represented in punch biopsies and potentially driven by persistent graft-resident effector T cells and recipient target endothelium that chimerically repopulates graft arteries.

Immune Profiling of Dermatologic Adverse Events from Checkpoint Blockade using Tissue Cyclic Immunofluorescence

In this study, we demonstrate the utility of whole-slide CyCIF (tissue-based cyclic immunofluorescence) imaging for characterizing immune cell infiltrates in immune checkpoint inhibitor (ICI)-induced dermatologic adverse events (dAEs). We analyzed six cases of ICI-induced dAEs, including lichenoid, bullous pemphigoid, psoriasis, and eczematous eruptions, comparing immune profiling results obtained using both standard immunohistochemistry (IHC) and CyCIF. Our findings indicate that CyCIF provides more detailed and precise single-cell characterization of immune cell infiltrates than IHC, which relies on semi-quantitative scoring by pathologists. This pilot study highlights the potential of CyCIF to advance our understanding of the immune environment in dAEs by revealing tissue-level spatial patterns of immune cell infiltrates, allowing for more precise phenotypic distinctions and deeper exploration of disease mechanisms. By demonstrating that CyCIF can be performed on friable tissues, such as bullous pemphigoid, we provide a foundation for future studies to examine the drivers of specific dAEs using larger cohorts of phenotyped toxicity and suggest a broader role for highly multiplexed tissue imaging in phenotyping the immune mediated disease that they resemble.

Low-dose interleukin-2 promotes immune regulation in face transplantation: A pilot study

Face transplantation is a life-changing procedure for patients with severe composite facial defects. However, it is hampered by high acute rejection rates due to the immunogenicity of skin allograft and toxicity linked to high doses of immunosuppression. To reduce immunosuppression-associated complications, we, for the first time in face transplant recipients, used low-dose interleukin 2 (IL-2) therapy to expand regulatory T cells (Tregs) in vivo and to enhance immune modulation, under close immunological monitoring of peripheral blood and skin allograft. Low-dose IL-2 achieved a sustained expansion (∼4-fold to 5-fold) of circulating Tregs and a reduction (∼3.5-fold) of B cells. Post-IL-2 Tregs exhibited greater suppressive function, characterized by higher expression of TIM-3 and LAG3co-inhibitory molecules. In the skin allograft, Tregs increased after low-dose IL-2 therapy. IL-2 induced a distinct molecular signature in the allograft with reduced cytotoxicity-associated genes (granzyme B and perforin). Two complications were observed during the trial: one rejection event and an episode of autoimmune hemolytic anemia. In summary, this initial experience demonstrated that low-dose IL-2 therapy was not only able to promote immune regulation in face transplant recipients but also highlighted challenges related to its narrow therapeutic window. More specific targeted Treg expansion strategies are needed to translate this approach to the clinic.

PRMT1 Inhibition Selectively Targets BNC1-Dependent Proliferation, but not Migration in Squamous Cell Carcinoma

Squamous Cell Carcinoma (SCC) develops in stratified epithelial tissues and demonstrates frequent alterations in transcriptional regulators. We sought to discover SCC-specific transcriptional programs and identified the transcription factor Basonuclin 1 (BNC1) as highly expressed in SCC compared to other tumor types. RNA-seq and ChIP-seq analysis identified pro-proliferative genes activated by BNC1 in SCC cells and keratinocytes. Inhibition of BNC1 in SCC cells suppressed proliferation and increased migration via FRA1. In contrast, BNC1 reduction in keratinocytes caused differentiation, which was abrogated by IRF6 knockdown, leading to increased migration. Protein interactome analysis identified PRMT1 as a co-activator of BNC1-dependent proliferative genes. Inhibition of PRMT1 resulted in a dose-dependent reduction in SCC cell proliferation without increasing migration. Importantly, therapeutic inhibition of PRMT1 in SCC xenografts significantly reduced tumor size, resembling functional effects of BNC1 knockdown. Together, we identify BNC1-PRMT1 as an SCC-lineage specific transcriptional axis that promotes cancer growth, which can be therapeutically targeted to inhibit SCC tumorigenesis.

Inhibition of melanoma cell-intrinsic Tim-3 stimulates MAPK-dependent tumorigenesis

T-cell immunoglobulin and mucin domain 3 (Tim-3) is an immune checkpoint receptor that dampens effector functions and causes terminal exhaustion of cytotoxic T-cells. Tim-3 inhibitors are under investigation in immuno-oncology (IO) trials, because blockade of T-cell-Tim-3 enhances antitumor immunity. Here, we identify an additional role for Tim-3 as a growth-suppressive receptor intrinsic to melanoma cells. Inhibition of melanoma cell-Tim-3 promoted tumor growth in both immunocompetent and immunocompromised mice, while melanoma-specific Tim-3 overexpression attenuated tumorigenesis. Antibody (Ab)-mediated Tim-3 blockade inhibited growth of immunogenic murine melanomas in T-cell-competent hosts, consistent with established antitumor effects of T-cell Tim-3 inhibition. In contrast, Tim-3 Ab administration stimulated tumorigenesis of both highly and lesser immunogenic murine and human melanomas in T-cell-deficient mice, confirming growth-promoting effects of melanoma-Tim-3 antagonism. Melanoma-Tim-3 activation suppressed, while its blockade enhanced, phosphorylation of pro-proliferative downstream mitogen-activated protein kinase (MAPK) signaling mediators. Finally, pharmacologic MAPK inhibition reversed unwanted Tim-3 Ab-mediated tumorigenesis in T-cell-deficient mice and promoted desired antitumor activity of Tim-3 interference in T-cell-competent hosts. These results identify melanoma-Tim-3 blockade as a mechanism that antagonizes T-cell-Tim-3-directed IO therapeutic efficacy. They further reveal MAPK targeting as a combination strategy for circumventing adverse consequences of unintended melanoma-Tim-3 inhibition.

Limbal BCAM expression identifies a proliferative progenitor population capable of holoclone formation and corneal differentiation

The corneal epithelium is renowned for high regenerative potential, which is dependent on the coordinated function of its diverse progenitor subpopulations. However, the molecular pathways governing corneal epithelial progenitor differentiation are incompletely understood. Here, we identify a highly proliferative limbal epithelial progenitor subpopulation characterized by expression of basal cell adhesion molecule (BCAM) that is capable of holocone formation and corneal epithelial sheet generation. BCAM-positive cells can be found among ABCB5-positive limbal stem cells (LSCs) as well as among ABCB5-negative limbal epithelial cell populations. Mechanistically, we show that BCAM is functionally required for cellular migration and differentiation and that its expression is regulated by the transcription factor p63. In aggregate, our study identifies limbal BCAM expression as a marker of highly proliferative corneal epithelial progenitor cells and defines the role of BCAM as a critical molecular mediator of corneal epithelial differentiation.

Using scRNA sequencing of ABCB5-positive human limbal stem cells, Sasamoto et al. identify a BCAM-positive highly proliferative limbal epithelial progenitor subpopulation that is capable of holocone formation and corneal epithelial sheet generation. BCAM regulated by the stem cell transcription factor p63 is functionally required for corneal cell migration and differentiation.

The Spatial Landscape of Progression and Immunoediting in Primary Melanoma at Single-Cell Resolution

Cutaneous melanoma is a highly immunogenic malignancy that is surgically curable at early stages but life-threatening when metastatic. Here we integrate high-plex imaging, 3D high-resolution microscopy, and spatially resolved microregion transcriptomics to study immune evasion and immunoediting in primary melanoma. We find that recurrent cellular neighborhoods involving tumor, immune, and stromal cells change significantly along a progression axis involving precursor states, melanoma in situ, and invasive tumor. Hallmarks of immunosuppression are already detectable in precursor regions. When tumors become locally invasive, a consolidated and spatially restricted suppressive environment forms along the tumor-stromal boundary. This environment is established by cytokine gradients that promote expression of MHC-II and IDO1, and by PD1-PDL1-mediated cell contacts involving macrophages, dendritic cells, and T cells. A few millimeters away, cytotoxic T cells synapse with melanoma cells in fields of tumor regression. Thus, invasion and immunoediting can coexist within a few millimeters of each other in a single specimen.

SIGNIFICANCE

The reorganization of the tumor ecosystem in primary melanoma is an excellent setting in which to study immunoediting and immune evasion. Guided by classic histopathology, spatial profiling of proteins and mRNA reveals recurrent morphologic and molecular features of tumor evolution that involve localized paracrine cytokine signaling and direct cell-cell contact. This article is highlighted in the In This Issue feature, p. 1397.

Autoreactive CD8+ T cells are restrained by an exhaustion-like program that is maintained by LAG3

Impaired chronic viral and tumor clearance has been attributed to CD8⁺ T cell exhaustion, a differentiation state in which T cells have reduced and altered effector function that can be partially reversed upon blockade of inhibitory receptors. The role of the exhaustion program and transcriptional networks that control CD8⁺ T cell function and fate in autoimmunity is not clear. Here we show that intra-islet CD8⁺ T cells phenotypically, transcriptionally, epigenetically and metabolically possess features of canonically exhausted T cells, yet maintain important differences. This 'restrained' phenotype can be perturbed and disease accelerated by CD8⁺ T cell-restricted deletion of the inhibitory receptor lymphocyte activating gene 3 (LAG3). Mechanistically, LAG3-deficient CD8⁺ T cells have enhanced effector-like functions, trafficking to the islets, and have a diminished exhausted phenotype, highlighting a physiological role for an exhaustion program in limiting autoimmunity and implicating LAG3 as a target for autoimmune therapy.

T cell-attracting CCL18 chemokine is a dominant rejection signal during limb transplantation

Limb transplantation is a life-changing procedure for amputees. However, limb recipients have a 6-fold greater rejection rate than solid organ transplant recipients, related in part to greater immunogenicity of the skin. Here, we report a detailed immunological and molecular characterization of individuals who underwent bilateral limb transplantation at our institution. Circulating Th17 cells are increased in limb transplant recipients over time. Molecular characterization of 770 genes in skin biopsies reveals upregulation of T cell effector immune molecules and chemokines, particularly CCL18. Skin antigen-presenting cells primarily express the chemokine CCL18, which binds to the CCR8 receptor. CCL18 treatment recruits more allo-T cells to the skin xenograft in a humanized skin transplantation model, leading to signs of accelerated graft rejection. Blockade of CCR8 remarkedly decreases CCL18-induced allo-T cell infiltration. Our results suggest that targeting the CCL18:CCR8 pathway could be a promising immunosuppressive approach in transplantation.

Regulation of 5-hydroxymethylcytosine by TET2 contributes to Squamous Cell Carcinoma tumorigenesis

DNA methylation is a key regulatory event controlling a variety of physiological processes and can have dramatic effects on gene transcription. Methylated Cytosine (5mC) can be oxidized by the TET family of enzymes to 5-hydroxymethylcytosine (5-hmC), a key intermediate in the de-methylation cycle, and 5-hmC levels are reduced in malignancies such as AML and melanoma. We constructed a tissue microarray of human cutaneous Squamous Cell Carcinoma (SCC) tumors and found a global reduction in 5-hmC levels compared to adjacent skin. Using a murine K14-CreER system, we have found that loss of Tet2 promotes carcinogen-induced SCC and cooperates with loss of Tp53 to drive spontaneous SCC tumors in epithelial tissues. Analysis of changes in 5-hmC and gene expression following loss of Tet2 in the epidermis revealed focal alterations in 5-hmC levels and an increase in Hair Follicle Transient Amplifying Cell (HF-TAC) genes along with a reduction in epidermal differentiation genes. These results demonstrate a role for Tet2 in epidermal lineage specification, consistent with reported roles for Tet enzymes in controlling lineage commitment in hematopoietic stem cells and ES cells and establish Tet2 as a bone fide tumor suppressor in SCC.

Full facial retransplantation in a female patient-Technical, immunologic, and clinical considerations

There is limited experience with facial retransplantation (fRT). We report on the management of facial retransplantation in a facial vascularized composite allotransplant recipient following irreversible allograft loss 88 months after the first transplant. Chronic antibody-mediated rejection and recurrent cellular rejection resulted in a deteriorated first allograft and the patient underwent retransplantation. We summarize the events between the two transplantations, focusing on the final rejection episode. We describe the surgical technique of facial retransplantation, the immunological and psychosocial management, and the 6-month postoperative outcomes. Removal of the old allograft and inset of the new transplant were done in one operation. The donor and recipient were a good immunological match. The procedure was technically complex, requiring more proximal arterial anastomoses and an interposition vein graft. During the first and second transplantation, the facial nerve was coapted at the level of the branches. There was no hyperacute rejection in the immediate postoperative phase. Outcomes 6 months postoperatively are promising. We provide proof-of-concept that facial retransplantation is a viable option for patients who suffer irreversible facial vascularized composite allograft loss.

Sporadic superficial angiomyxomas demonstrate loss of PRKAR1A expression

Superficial angiomyxomas are cutaneous mesenchymal tumors that typically present clinically as slow-growing, solitary, asymptomatic nodules that can occur at any age. Histopathologically, these dermal and subcutaneous tumors are characterized by abundant myxoid stroma, numerous thin-walled and often arborizing blood vessels, and spindled to stellate fibroblast-like cells. While usually sporadic, superficial angiomyxomas can occasionally be associated with Carney complex (CNC), an autosomal dominant disorder characterized by inactivating germline mutations in the 1-alpha regulatory subunit of protein kinase A (PRKAR1A) and various clinical manifestations, including: cardiac myxomas, facial lentigines, epithelioid blue nevi, endocrinopathies, and psammomatous melanotic schwannomas. In this study, we sought to characterize the presence or absence of PRKAR1A expression by immunohistochemistry (IHC) in sporadic superficial angiomyxomas based on our observations in an index case. In total, PRKAR1A immunohistochemical expression was determined in 15 sporadic superficial angiomyxoma cases retrieved from the surgical pathology archives. IHC demonstrated that the lesional cells in 12 cases (80%) were non-reactive to antibodies against PRKAR1A. This study provides evidence in support of a role for PRKAR1A in the development of clinically non-syndromic superficial angiomyxomas. Along with previous studies, this report demonstrates that PRKAR1A may play an important role in the development of a variety of myxomatous mesenchymal tumors.

Evolution of delayed resistance to immunotherapy in a melanoma responder

Despite initial responses1-3, most melanoma patients develop resistance4 to immune checkpoint blockade (ICB). To understand the evolution of resistance, we studied 37 tumor samples over 9 years from a patient with metastatic melanoma with complete clinical response to ICB followed by delayed recurrence and death. Phylogenetic analysis revealed co-evolution of seven lineages with multiple convergent, but independent resistance-associated alterations. All recurrent tumors emerged from a lineage characterized by loss of chromosome 15q, with post-treatment clones acquiring additional genomic driver events. Deconvolution of bulk RNA sequencing and highly multiplexed immunofluorescence (t-CyCIF) revealed differences in immune composition among different lineages. Imaging revealed a vasculogenic mimicry phenotype in NGFRhi tumor cells with high PD-L1 expression in close proximity to immune cells. Rapid autopsy demonstrated two distinct NGFR spatial patterns with high polarity and proximity to immune cells in subcutaneous tumors versus a diffuse spatial pattern in lung tumors, suggesting different roles of this neural-crest-like program in different tumor microenvironments. Broadly, this study establishes a high-resolution map of the evolutionary dynamics of resistance to ICB, characterizes a de-differentiated neural-crest tumor population in melanoma immunotherapy resistance and describes site-specific differences in tumor-immune interactions via longitudinal analysis of a patient with melanoma with an unusual clinical course.

Rejection of benign melanocytic nevi by nevus-resident CD4+ T cells

Melanoma and melanocytic nevi harbor shared lineage-specific antigens and oncogenic mutations. Yet, the relationship between the immune system and melanocytic nevi is unclear. Using a patient-derived xenograft (PDX) model, we found that 81.8% of the transplanted nevi underwent spontaneous regression, while peripheral skin remained intact. Nevus-resident CD4⁺ T helper 1 cells, which exhibited a massive clonal expansion to melanocyte-specific antigens, were responsible for nevus rejection. Boosting regulatory T cell suppressive function with low-dose exogenous human interleukin-2 injection or treatment with a human leukocyte antigen (HLA) class II-blocking antibody prevented nevus rejection. Notably, mice with rejected nevus PDXs were protected from melanoma tumor growth. We detected a parallel CD4⁺ T cell-dominant immunity in clinically regressing melanocytic nevi. These findings reveal a mechanistic explanation for spontaneous nevus regression in humans and posit the activation of nevus-resident CD4⁺ effector T cells as a novel strategy for melanoma immunoprevention and treatment.

ATF-3 expression inhibits melanoma growth by downregulating ERK and AKT pathways

Activating transcription factor 3 (ATF-3), a cyclic AMP-dependent transcription factor, has been shown to play a regulatory role in melanoma, although its function during tumor progression remains unclear. Here, we demonstrate that ATF-3 exhibits tumor suppressive function in melanoma. Specifically, ATF-3 nuclear expression was significantly diminished with melanoma progression from nevi to primary to metastatic patient melanomas, correlating low expression with poor prognosis. Significantly low expression of ATF-3 was also found in cultured human metastatic melanoma cell lines. Importantly, overexpression of ATF-3 in metastatic melanoma cell lines significantly inhibited cell growth, migration, and invasion in vitro; as well as abrogated tumor growth in a human melanoma xenograft mouse model in vivo. RNA sequencing analysis revealed downregulation of ERK and AKT pathways and upregulation in apoptotic-related genes in ATF-3 overexpressed melanoma cell lines, which was further validated by Western-blot analysis. In summary, this study demonstrated that diminished ATF-3 expression is associated with melanoma virulence and thus provides a potential target for novel therapies and prognostic biomarker applications.

Comparison of Shave and Punch Biopsy Utilization Among Dermatology Practices

In 2019, the 2 Current Procedural Terminology (CPT) codes for skin biopsies were replaced with 6 new CPT codes to allow for technique specification and differential reimbursement. We sought to evaluate whether the concurrent decrease in reimbursement for shave biopsies and increase in reimbursement for punch biopsies led to utilization changes. We examined shave and punch biopsies submitted for pathologic examination at 3 academic centers in May 2018 and May 2019. We performed χ² tests to evaluate for changes in the ratio of biopsy utilization over time, with subgroup analyses by practice setting and provider type. Totals included 11,785 (12.11% punch) and 11,291 (12.08% punch) biopsies submitted in May 2018 and May 2019, respectively. Our results demonstrate small yet important changes in biopsy use patterns within the context of recent reimbursement changes when analyzing academic and private practices separately. Although small in magnitude, this change in behavior may have a substantial impact when extrapolated to behavior across the nation.

Creation and Validation of Classification Criteria for Discoid Lupus Erythematosus

Importance

Classification criteria are the standardized definitions that are used to enroll uniform cohorts for research studies. They emphasize high specificity and are distinct from diagnostic criteria. No universally recognized classification criteria currently exist for discoid lupus erythematosus (DLE), which has led to problematic heterogeneity in observational and interventional clinical studies across the field.

Objective

To create and validate classification criteria for DLE using 12 previously defined candidate criteria items.

Design, Setting, and Participants

For this diagnostic study, candidate criteria items were prospectively applied by dermatologists and dermatopathologists at clinical visits of patients with DLE or a condition that could be confused for DLE, termed a DLE mimicker, at academic dermatology practices across the United States, Poland, Japan, and South Korea. Data were collected from December 1, 2017, to February 1, 2019, and analyzed from March 1 to September 19, 2019.

Main Outcomes and Measures

Clinical features among these 2 groups were calculated and compared with χ2 or Fisher exact tests. Candidate models were identified using best subsets logistic regression analysis. Improvement tests, fit statistics, and discrimination were considered to choose a final model.

Results

Nine sites contributed 215 patients, 15 of whom had missing or incomplete data. The final model for DLE classification criteria includes only clinical variables: atrophic scarring (3 points), location in the conchal bowl (2 points), preference for the head and neck (2 points), dyspigmentation (1 point), follicular hyperkeratosis and/or plugging (1 point), and erythematous to violaceous in color (1 point), with an area under the receiving operating characteristic curve of 0.91 (95% CI, 0.87-0.95). A score of at least 5 points yields a sensitivity of 84.1% and a specificity of 75.9% in the classification of DLE, with increasing scores yielding higher specificity.

Conclusions and Relevance

These findings provide the initial validation of classification criteria for DLE for use in observational and clinical trials.

Mucosa and Rejection in Facial Vascularized Composite Allotransplantation: A Systematic Review

BACKGROUND

Facial vascularized composite allotransplantation (fVCA) presents an established approach to restore form and function of patients with catastrophic facial defects. Skin is one of the target tissues of the rejection process, and due to its easy accessibility has become the gold standard in the diagnosis of rejection. Mucosal rejection frequently occurs; however, the added value of mucosal rejection assessment for patient management is unknown.

METHODS

We conducted a systematic review of manuscripts listed in the MEDLINE/PubMed and GoogleScholar databases to identify articles that provide data on mucosal rejection following fVCA. For inclusion, papers had to be available as full-text and written in English. Non-VCA studies and animal studies were excluded. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

We included 17 articles that described changes in allotransplanted mucosa of fVCAs. These articles yielded data on 168 BANFF graded biopsies of corresponding skin and mucosa biopsies. Rejection grades were consistently higher in mucosal biopsies. Concordance between allograft skin and mucosa biopsy grades increased with an increasing skin-BANFF grade. Mucosa rejection grades were on average lower in the early stages of the posttransplant period (<postoperative mo 12, time of motor, and sensory recovery) when compared to the later stages (>postoperative mo 12).

CONCLUSIONS

The mucosa of facial allotransplants is one of the primary targets of rejection. The data indicates that higher-grade skin rejection does not occur in absence of mucosal rejection. Further investigations are needed to elucidate the exact role of mucosal biopsies for fVCA patient management.

Pathologies of oral and sinonasal mucosa following facial vascularized composite allotransplantation

BACKGROUND

Cutaneous changes of facial vascularized composite allotransplants (fVCAs) are extensively described in the literature. Parts of the nose, nasal, and oral cavities are included in most fVCAs. Distinctively, the nose and mouth are lined by mucosa. Little is known about the histopathology and complications of the mucosa involved in fVCA patients.

METHODS

The study constitutes a retrospective cohort study of nine fVCA patients. Medical records were reviewed for information about changes of oral and nasal mucous membranes. Types of mucosal lesions were recorded and analyzed. Uni- and multivariate generalized estimating equation (GEE) models were used to assess the odds of developing mucosal inflammation in the presence of clinico-pathologic variables.

RESULTS

A total of 186 clinical encounters with examination of oral and nasal mucous membranes were included. Membranes were devoid of clinical pathology in 101 instances (53% of all clinical assessments). Ulcerations/erosions (27%), edema (18%), and erythema (14%) were the most common lesions. Oral lesions affected the lips (58%), buccal mucosa (38%), and palate (5%). Sinonasal processes predominantly affected nasal vestibules and septae. In univariate analysis, sirolimus, skin rejection, and skin Banff grade were associated with the presence of an acute inflammatory mucosal lesion (p<0.05). In multivariate analysis, skin Banff grade and sirolimus were independent predictors of mucosal inflammation.

CONCLUSION

Pathologies of fVCA mucous membranes are more common than previously reported. Mucosal assessment plays an important role in the pleomorphic allograft rejection process evaluation rather than diagnosis and treatment based on cutaneous pathology.  A closer look at the pathophysiology of fVCA mucosal rejection and inflammation is warranted.

De novo subacute cutaneous lupus erythematosus-like eruptions in the setting of programmed death-1 or programmed death ligand-1 inhibitor therapy: clinicopathological correlation

Immune checkpoint inhibitors (ICI) may cause eruptions resembling cutaneous autoimmune diseases. There are six cases of immunotherapy-associated subacute cutaneous lupus erythematosus (SCLE) in the literature. We present details of five patients referred to the Skin Toxicity Program at the Dana-Farber Cancer Institute/Brigham and Women's Cancer Center who developed de novo immunotherapy-associated SCLE-like eruptions, along with clinicopathological correlation and highlight potential mechanistic features and important diagnostic points. Two patients were maintained on topical corticosteroids, antihistamines and photoprotection. One had complete clearance and two had improvement with addition of hydroxychloroquine. Four patients continued their immunotherapy uninterrupted, while one had immunotherapy suspended for a month before restarting at full dose. Histopathologically, this series illustrates the temporal evolution of ICI-induced immune cutaneous reactions with SCLE subtype. Looking beyond the universally present lichenoid infiltrate, features of evolving SCLE were evident. We hypothesize that programmed death-1 blockade may induce immunological recognition of previously immunologically tolerated drug antigens, leading to epitope spreading and the SCLE phenotype.

Subcutaneous Fat Reduction with Injected Ice Slurry

BACKGROUND

Cryolipolysis is a noninvasive method for removal of subcutaneous fat for body contouring. Conventional cryolipolysis with topical cooling requires extracting heat from subcutaneous fat by conduction across the skin, thus limiting the amount and the location of the fat removed. The authors hypothesized that local injection of a physiological ice slurry directly into target adipose tissue would lead to more efficient and effective cryolipolysis.

METHODS

Injectable slurries containing 20 percent and 40 percent ice content were made using common parenteral agents (normal saline and glycerol), then locally injected into the subcutaneous fat of swine. Ultrasound imaging, photography, histological, and gross tissue responses were monitored before and periodically up to 8 weeks after injection.

RESULTS

Fat loss occurred gradually over several weeks following a single ice slurry injection. There was an obvious and significant 55 ± 6 percent reduction in adipose tissue thickness compared with control sites injected with the same volume of melted slurry (p < 0.001, t test). The amount of fat loss correlated with the total volume of ice injected. There was no scarring or damage to surrounding tissue.

CONCLUSION

Physiological ice slurry injection is a promising new strategy for selective and nonsurgical fat removal.

X-linked dominant protoporphyria in a Chinese pedigree reveals a four-based deletion of ALAS2

Background

X-linked dominant protoporphyria (XLDPP) is a rare, hereditary disorder that leads to hepatobiliary and hematologic abnormalities including increased erythrocyte protoporphyrin, cutaneous photosensitivity, and decreased iron stores that is caused by a pathogenic mutation of ALAS2 gene.

Methods

This study aimed to confirm the existence of XLDPP in a Chinese pedigree. We observed and described the dermatoscopic findings of this disorder under dermoscopy, and assessed photo damage in XLDPP patients using the Fotofinder system and very high frequency (VHF) skin ultrasonic system. We performed next generation sequencing and Sanger sequencing to detect and confirm genetic variants in DNA samples from the XLDPP family. Moreover, we monitored the hepatobiliary function as well as hematologic changes in related family members.

Results

As compared to unaffected control subjects, patients exhibited evidence of severe cutaneous photodamage, causing photoaging, an increase in the size of the gallbladder, increased levels of protoporphyrin in red blood cells, an increase in blood levels of uroporphyrin and hematoporphyrin, and iron deficiency.

Conclusions

XLDPP was validated by the identification of a four-base-pair deletion (c.1706_1709delAGTG, p.E569fs) in ALAS2 (NM_000032.4) in the proband which segregated with the disease in an X-linked dominant pattern, with hemizygous males being more severely affected than heterozygous females. We also found a missense variant in GATA Binding Protein 1 (GATA1).

Accelerated chronic skin changes without allograft vasculopathy: A 10-year outcome report after face transplantation

BACKGROUND

Long-term outcomes after face transplantation are rarely reported in the scientific literature. Here we present outcome data of a partial face allograft recipient 10 years after transplantation.

METHODS

Medical records were reviewed for functional and psychosocial outcomes as well as complications. Histopathologic analyses of autopsy tissues and characterization of skin immune cells were performed.

RESULTS

The patient retained long-term motor and sensory function, though with a noticeable drop in sensory function after year 5. Social reintegration of the patient was marked by reconnection with his family and participation in public social activities. Immunosuppressive therapy consisted of tacrolimus (target levels 6-8 ng/mL after the first year), mycophenolate, and prednisone, while steroids were completely weaned between years 1 and 7. One acute cellular rejection episode of grade II or higher occurred on average per year and led to chronic skin changes (papillary dermal sclerosis with superficial hyalinization, epidermal thinning with loss of rete ridges, perieccrine fibrosis), but the allograft vessels, muscles, adipose tissue, and bone were spared. Allograft skin was characterized by increased number of CD4+ TNF-α/IL17A producing T-cells as compared with native skin. Long-term kidney function was maintained at 60 mL/min estimated glomerular filtration rate. Unfortunately, the preexisting hepatitis C virus infection with liver cirrhosis was resistant to 3 treatments with new direct-acting antivirals and eventually hepatocellular carcinoma developed, causing the patient's death 10 years after transplantation.

CONCLUSION

This report suggests that face transplants can maintain their function for at least 10 years. Chronic skin changes can occur independently of allograft vasculopathy.

Loss of the Epigenetic Mark 5-hmC in Psoriasis: Implications for Epidermal Stem Cell Dysregulation

Epigenetic regulation has a profound influence on stem cell fate during normal development in maintenance of physiologic tissue homeostasis. Here we report diminished ten-eleven translocation (TET) methylcytosine dioxygenase expression and loss of the DNA hydroxymethylation mark 5-hydroxymethylcytosine (5-hmC) in keratinocyte stem cells and transit amplifying cells in human psoriasis and in imiquimod-induced murine psoriasis. Loss of 5-hmC was associated with dysregulated keratinocyte stem cell kinetics, resulting in accumulation of nestin and FABP5-expressing transit amplifying cells to produce classic psoriatic epidermal architecture. Moreover, 5-hmC loss was accompanied by diminished TET1 and TET2 mRNA expression. Genome-wide mapping of epidermal 5-hmC in murine psoriasis revealed loci-specific loss of 5-hmC in genes regulating stem cell homeostasis, including MBD1, RTN1, STRN4, PRKD2, AKT1, and MAPKAP2, as well as those associated with RAR and Wnt/β-catenin signaling pathways. In vitro restoration of TET expression by ascorbic acid was accomplished in cultured human keratinocyte stem cells to show similar Ca⁺⁺-induced differentiation, resulting in increased 5-hmC levels and reduced nestin expression. To our knowledge, an epigenetic deficiency in psoriasis with relevance to stem cell dysregulation has not been previously reported. This observation raises the possibility that epigenetic modifiers that impact on the TET-5-hmC pathway may be a relevant approach of heretofore unappreciated therapeutic utility.