The mycosis fungoides cutaneous microenvironment shapes dysfunctional cell trafficking, antitumor immunity, matrix interactions, and angiogenesis.

Malignant T lymphocyte proliferation in mycosis fungoides (MF) is largely restricted to the skin, implying that malignant cells are dependent on their specific cutaneous tumor microenvironment (TME), including interactions with non-malignant immune and stromal cells, cytokines, and other immunomodulatory factors. To explore these interactions, we performed a comprehensive transcriptome analysis of the TME in advanced-stage MF skin tumors by single-cell RNA sequencing. Our analysis identified cell-type compositions, cellular functions, and cell-to-cell interactions in the MF TME that were distinct from those from healthy skin and benign dermatoses.

Cell Type-Specific Biomarkers of Systemic Sclerosis Disease Severity Capture Cell-Intrinsic and Cell-Extrinsic Circuits.

Objective: Systemic sclerosis (SSc) is a multifactorial autoimmune fibrotic disorder involving complex rewiring of cell-intrinsic and cell-extrinsic signaling coexpression networks involving a range of cell types. However, the rewired circuits as well as corresponding cell-cell interactions remain poorly understood. To address this, we used a predictive machine learning framework to analyze single-cell RNA-sequencing data from 24 SSc patients across the severity spectrum as quantified by the modified Rodnan skin score (MRSS).

Single-Cell RNA Sequencing Unveils the Clonal and Transcriptional Landscape of Cutaneous T-Cell Lymphomas.

Purpose: Clonal malignant T lymphocytes constitute only a fraction of T cells in mycosis fungoides skin tumors and in the leukemic blood of Sézary syndrome, the classic types of cutaneous T-cell lymphomas. However, lack of markers specific for malignant lymphocytes prevents distinguishing them from benign T cells, thus delaying diagnosis and the development of targeted treatments. Here we applied single-cell methods to assess the transcriptional profiles of both malignant T-cell clones and reactive T lymphocytes directly in mycosis fungoides/Sézary syndrome patient samples.

Single-cell transcriptome analysis identifies skin-specific T-cell responses in systemic sclerosis.

Objectives: Although T cells have been implicated in the pathogenesis of systemic sclerosis (SSc), a comprehensive study of T-cell-mediated immune responses in the affected skin of patients with progressive SSc is lacking. Droplet-based single-cell transcriptome analysis of SSc skin biopsies opens avenues for dissecting patient-specific T-cell heterogeneity, providing a basis for identifying novel gene expression related to functional pathways associated with severity of SSc skin disease.

Methods: Single-cell RNA sequencing was performed by droplet-based sequencing (10x Genomics), focusing on 3729 CD3 lymphocytes (867 cells from normal and 2862 cells from SSc skin samples) from skin biopsies of 27 patients with active SSc and 10 healthy donors.

Genome-wide transcriptome analysis of the STAT6-regulated genes in advanced-stage cutaneous T-cell lymphoma.

The signal transducer and activator of transcription 6 (STAT6) is a critical up-stream mediator of interleukin-13 (IL-13) and IL-4 signaling and is constitutively activated in malignant lymphocytes from Sezary syndrome (SS) and mycosis fungoides (MF), the most common subtypes of cutaneous T-cell lymphomas. By combining genome-wide expression profiling with pharmacological STAT6 inhibition, we have identified the genes regulated by STAT6 in MF/SS tumors. We found that STAT6 regulates several common pathways in MF/SS malignant lymphocytes that are associated with control of cell-cycle progression and genomic stability as well as production of Th2 cytokines.

Single-Cell Lymphocyte Heterogeneity in Advanced Cutaneous T-cell Lymphoma Skin Tumors.

Purpose: The heterogeneity of tumor cells presents a major challenge to cancer diagnosis and therapy. Cutaneous T-cell lymphomas (CTCL) are a group of T lymphocyte malignancies that primarily affect skin. Lack of highly specific markers for malignant lymphocytes prevents early diagnosis, while only limited treatment options are available for patients with advanced stage CTCL.

T cells and cytokines in systemic sclerosis.

Purpose Of Review: Dysregulation of both the innate and the adaptive immune systems has been identified in systemic sclerosis (SSc). However, the mechanisms underlying aberrant immune cell function remain poorly understood. T cells represent a predominant cell type in the affected tissues of patients, particularly in the early inflammatory stage of the disease.

14-3-3z sequesters cytosolic T-bet, upregulating IL-13 levels in T2 and CD8 lymphocytes from patients with scleroderma.

Background: IL-13-producing CD8 T cells have been implicated in the pathogenesis of type 2-driven inflammatory human conditions. We have shown that CD8IL-13 cells play a critical role in cutaneous fibrosis, the most characteristic feature of systemic sclerosis (SSc; scleroderma). However, the molecular mechanisms underlying production of IL-13 and other type 2 cytokines by CD8 T cells remain unclear.

Current perspectives on the role of CD8+ T cells in systemic sclerosis.

Despite long-standing recognition of the importance of T cells in systemic sclerosis (SSc; scleroderma), the role of CD8 T cells in disease pathogenesis has not been well studied. Our work has shown that over-production of the pro-fibrotic cytokine IL-13 by peripheral blood effector/memory CD8 T cells is critical for predisposing patients to more severe forms of cutaneous fibrosis. Moreover, IL-13-producing CD8 T cells induce a pro-fibrotic phenotype in normal and SSc dermal fibroblasts, and exhibit a strong cytotoxic activity ex vivo.

Skin-Resident Effector Memory CD8CD28 T Cells Exhibit a Profibrotic Phenotype in Patients with Systemic Sclerosis.

Loss of CD28 expression by CD8 T cells occurs with age and during chronic inflammatory conditions. CD8CD28 T cells are a heterogeneous cell subpopulation whose function ranges from immunosuppressive to effector. Here we analyzed the role of CD8CD28 T cells in the pathogenesis of systemic sclerosis (SSc), a connective tissue disorder characterized by autoimmunity, vasculopathy, and extensive cutaneous and visceral fibrosis.

Current perspectives on the immunopathogenesis of systemic sclerosis.

Systemic sclerosis (SSc or scleroderma) is a progressive and highly debilitating autoimmune disorder characterized by inflammation, vasculopathy, and extensive fibrosis. SSc is highly heterogeneous in its clinical presentation, extent and severity of skin and internal organ involvement, and clinical course and has the highest fatality rate among connective tissue diseases. While clinical outcomes have improved in recent years, no current therapy is able to reverse or slow the natural progression of SSc, a reflection of its complex pathogenesis.

Interleukin-13 is overexpressed in cutaneous T-cell lymphoma cells and regulates their proliferation.

Cutaneous T-cell lymphomas (CTCLs) primarily affect skin and are characterized by proliferation of mature CD4(+) T-helper cells. The pattern of cytokine production in the skin and blood is considered to be of major importance for the pathogenesis of CTCLs. Abnormal cytokine expression in CTCLs may be responsible for enhanced proliferation of the malignant cells and/or depression of the antitumor immune response.

Interleukin-13-producing CD8+ T cells mediate dermal fibrosis in patients with systemic sclerosis.

Objective: Fibrosis is a major contributor to morbidity and mortality in systemic sclerosis (SSc). T cells are the predominant inflammatory infiltrate in affected tissue and are thought to produce cytokines that drive the synthesis of extracellular matrix (ECM) proteins by fibroblasts, resulting in excessive fibrosis. We have previously shown that aberrant interleukin-13 (IL-13) production by peripheral blood effector CD8+ T cells from SSc patients correlates with the extent of skin fibrosis.

Role of IL-13 in systemic sclerosis.

Systemic sclerosis (SSc) has the highest fatality rate among connective tissue diseases and is characterized by vascular damage, inflammation and fibrosis. Currently, no therapy has proven effective in modifying the course of SSc, a reflection of its complex pathogenesis. T cell-derived cytokines have been implicated in the induction of fibrosis.

CD8+ T cells in systemic sclerosis.

Systemic sclerosis (SSc) is a progressive and highly debilitating autoimmune disorder characterized by inflammation, fibrosis, and vascular damage of the connective tissue. T cell-derived cytokines have been implicated in the induction of fibrosis. We found that high levels of the profibrotic type-2 cytokine IL-13 are produced by peripheral blood effector CD8(+) T cells from SSc patients compared to normal controls.

GATA-3 up-regulation in CD8+ T cells as a biomarker of immune dysfunction in systemic sclerosis, resulting in excessive interleukin-13 production.

Objective: Despite the importance of interleukin-13 (IL-13) in systemic sclerosis (SSc) and other fibrotic diseases, its mechanisms of action are not understood. We have reported that excessive amounts of IL-13 are produced by peripheral blood effector CD8+ T cells from patients with diffuse cutaneous SSc (dcSSc). The aim of the present study was to establish the molecular basis of IL-13 dysregulation in the pathogenesis of SSc.

Gene expression analysis of dendritic cells that prevent diabetes in NOD mice: analysis of chemokines and costimulatory molecules.

We have demonstrated previously that BM-derived DCs can prevent diabetes development and halt progression of insulitis in NOD mice, the mouse model of type 1 diabetes. The DC population that was most effective in this therapy had a mature phenotype, expressed high levels of costimulatory molecules, and secreted low levels of IL-12p70. The protective DC therapy induced Treg and Th2 cells in vitro and in vivo.

Dynamic aspects of TCRalpha gene recombination: qualitative and quantitative assessments of the TCRalpha chain repertoire in man and mouse.

Most T-lymphocytes express a highly specific antigen receptor (TCR) on their cell surface, consisting of a clonotypic alphabeta-heterodimer. Both alpha- and beta chains are products of somatic rearrangements of V, (D) and J gene segments encoded on the respective loci. The qualitative, quantitative and dynamic aspects of the TCRalpha chain repertoire of humans and mice have been difficult to estimate, mainly due to locus complexity.

Effector CD8+ T cells in systemic sclerosis patients produce abnormally high levels of interleukin-13 associated with increased skin fibrosis.

Objective: T lymphocytes play an important role in systemic sclerosis (SSc), a connective tissue disease characterized by inflammation, fibrosis, and vascular damage. While their precise role and antigen specificity are unclear, T cell-derived cytokines likely contribute to the induction of fibrosis. The aim of this study was to establish the role of cytokine dysregulation by T cells in the pathogenesis of SSc.

Analysis of the TCR alpha-chain rearrangement profile in human T lymphocytes.

The size of the available human alphabeta T cell repertoire is difficult to determine and is open to debate. Empirical analysis of TCR beta-chain diversity reveals approximately 10(6) different beta chains in peripheral blood. Due in part to locus complexity, comparable information for TCR alpha is lacking.