Mycosis fungoides and Sézary syndrome

Small bowel obstruction due to mycosis fungoides: an unusual presentation

Visceral involvement usually occurs in the late stages of mycosis fungoides (MF). Small bowel involvement in MF is uncommon. When involved, it could cause significant morbidity and mortality. In this study, the authors present an 89-year-old woman diagnosed with T1, N0, B1, M0; stage 1A MF, treated with topical temovate with good response who presented 3 months later with small bowel obstruction due to biopsy-proven localization of MF in the gastrointestinal tract.

Oncogenic tyrosine kinase NPM-ALK induces expression of the growth-promoting receptor ICOS

Here we report that T-cell lymphoma cells carrying the NPM-ALK fusion protein (ALK(+) TCL) frequently express the cell-stimulatory receptor ICOS. ICOS expression in ALK(+) TCL is moderate and strictly dependent on the expression and enzymatic activity of NPM-ALK. NPM-ALK induces ICOS expression via STAT3, which triggers the transcriptional activity of the ICOS gene promoter. In addition, STAT3 suppresses the expression of miR-219 that, in turn, selectively inhibits ICOS expression. ALK(+) TCL cell lines display extensive DNA methylation of the CpG island located within intron 1, the putative enhancer region, of the ICOS gene, whereas cutaneous T-cell lymphoma cell lines, which strongly express ICOS, show no methylation of the island. Treatment of the ALK(+) TCL cell lines with DNA methyltransferase inhibitor reversed the CpG island methylation and augmented the expression of ICOS mRNA and protein. Stimulation of the ICOS receptor with anti-ICOS antibody or ICOS ligand-expressing B cells markedly enhanced proliferation of the ALK(+) TCL cells. These results demonstrate that NPM-ALK, acting through STAT3 as the gene transcriptional activator, induces the expression of ICOS, a cell growth promoting receptor. These data also show that the DNA methylation status of the intronic CpG island affects transcriptional activity of the ICOS gene and, consequently, modulates the concentration of the expressed ICOS protein.

Malignant cutaneous T-cell lymphoma cells express IL-17 utilizing the Jak3/Stat3 signaling pathway

IL-17 is a proinflammatory cytokine that is crucial for the host's protection against a range of extracellular pathogens. However, inappropriately regulated expression of IL-17 is associated with the development of inflammatory diseases and cancer. In cutaneous T-cell lymphoma (CTCL), malignant T cells gradually accumulate in skin lesions characterized by massive chronic inflammation, suggesting that IL-17 could be involved in the pathogenesis. In this study we show that IL-17 protein is present in 10 of 13 examined skin lesions but not in sera from 28 CTCL patients. Importantly, IL-17 expression is primarily observed in atypical lymphocytes with characteristic neoplastic cell morphology. In accordance, malignant T-cell lines from CTCL patients produce IL-17 and the synthesis is selectively increased by IL-2 receptor β chain cytokines. Small-molecule inhibitors or small interfering RNA against Jak3 and signal transducer and activator of transcription 3 (Stat3) reduce the production of IL-17, showing that the Jak3/Stat3 pathway promotes the expression of the cytokine. In summary, our findings indicate that the malignant T cells in CTCL lesions express IL-17 and that this expression is promoted by the Jak3/Stat3 pathway.

Genetic alterations in Sezary syndrome

Sezary syndrome (SS) is a rare form of cutaneous T-cell lymphoma characterized by erythroderma and the presence of Sezary cells in the skin, lymph nodes, and peripheral blood. Over the past few decades, cytogenetic and molecular cytogenetic findings have revealed many genetic alterations in patients with SS. The most frequent genetic lesions include monosomy 10, losses of 10q and 17p, gains of 8q24 and 17q, and diverse structural alterations involving these regions. Expression patterns in regions of genomic imbalance show that a large number of genes in SS are deregulated, and this might have a causative role in oncogenesis. Overall, chromosomal instability is characteristic of this lymphoma and related to a poor prognosis, but no specific abnormalities that may be directly involved in development of the disease have yet been found.

Interleukin-16 as a marker of Sézary syndrome onset and stage

INTRODUCTION

Sézary syndrome is one of the most common forms of cutaneous T cell lymphoma (CTCL). It is characterized by skin infiltration of malignant T cells. We examined interleukin-16, a potent T cell chemoattractant and cell-cycle regulator, as a prospective marker of disease onset and stage.

METHODS

The correlation of total intracellular interleukin-16 and surface CD26 was studied by flow cytometry. Confocal microscopy was performed to determine localization of interleukin-16 at different stages of the disease. The levels of interleukin-16 in plasma and culture supernatants were examined by enzyme-linked immunoassay. Additionally, lymphocytes from stage IB patients were cultured in the presence of interleukin-16 alone and in combination with interleukin-15, and their ability to survive and proliferate was determined by cell counts and [3H]TdR incorporation.

RESULTS

The data indicate that loss of both nuclear and intracellular pro-interleukin-16 highly correspond to disease stage, with a concomitant increase in secreted mature interleukin-16 in both culture supernatants and patients' plasma that peaks at stage IB. Loss of intracellular interleukin-16 strongly corresponded to loss of surface CD26, which has been shown to occur with more advanced stage of CTCL. Nuclear translocation of pro-interleukin-16 was not observed in late stages of Sézary syndrome, indicating this loss is not reversible.

CONCLUSIONS

We propose that it is feasible to use plasma levels of IL-16 as a potential diagnostic marker of Sézary syndrome and to use loss of intracellular IL-16 as a prognostic indicator of disease severity and stage.

Deficiency of SATB1 expression in Sezary cells causes apoptosis resistance by regulating FasL/CD95L transcription

Sézary syndrome (SS) is an aggressive subtype of cutaneous T-cell lymphoma that is characterized by circulating leukemic Sézary cells. The accumulation of these malignant cells has been shown to be the result of the resistance to apoptosis, in particular, activation-induced cell death. However, the mechanism of apoptosis resistance remains unknown. By characterizing the gene transcription profiles of purified CD4(+)CD7(-) Sézary cells from patients with SS and cultured Sézary cells, it was found that Sézary cells are deficient in the expression of special AT-rich region binding protein 1 (SATB1), a key regulator of T-cell development and maturation. Retrovirus-mediated gene transduction revealed that SATB1 restoration in cultured Sézary cells (Hut78) triggered spontaneous cell death and sensitized Hut78 cells to activation-induced cell death, with associated activation of caspase 8 and caspase 3. Furthermore, endogenous expression of FasL in Sézary cells was increased in transcriptional and translational levels on restoration of SATB1 expression in cultured Sézary cells. These results suggest that deficiency in SATB1 expression in Sézary cells plays an important role in SS pathogenesis by causing apoptosis resistance. Thus, restoration of SATB1 expression may represent a potential molecular targeted therapy for SS, which does not have a cure at present.

Absence of modulation of CD4+CD25 regulatory T cells in CTCL patients treated with bexarotene

Cutaneous T-cell lymphoma (CTCL) are a heterogeneous group of lymphoproliferative disorders, characterized by the infiltration of the epidermis by mature and activated malignant CD4+ T-lymphocytes. Retinoids such as retinoic acid and synthetic analogues have long been used alone or in combination with other therapies for CTCL. Bexarotene, the first synthetic highly selective RXR retinoid, was approved for the treatment of all stages of CTCL in patients refractory to at least one systemic therapy. Recently, six cases in which the initiation of bexarotene therapy for CTCL was associated with the progression of internal disease despite improvement of cutaneous signs and symptoms were reported. Moreover, it has been established that retinoids promote the generation of CD4+ Foxp3+ regulatory T cells, raising the question of an induction of regulatory T-cells by bexarotene. The aim of this work was to determine if bexarotene induces an increase of functional regulatory T cells which could play a role in the development of secondary extra-cutaneous lymphomas. Regulatory T cells were studied both in cutaneous biopsy specimens using an immunohistochemical analysis of CD4, CD25 and Foxp3 and in blood where proportion and functionality of circulating CD4+CD25(high) T-cells were determined. The study was performed in 10 patients [five patients with Sézary syndrome (SS) and five mycosis fungoïdes (MF)], treated for 6 months with bexarotene. Four healthy donors were used as controls for phenotypic and functional analysis on PBL. We found that the frequency of CD4+CD25(high) Treg cells was not significantly different before starting bexarotene and after 6 months of treatment in CTCL patients. However, we observed that the frequency of CD4+CD25(high) Treg cells before the beginning of the treatment was significantly increased compared to healthy donors. In addition, functional assays demonstrated that Foxp3 expressing CD4+CD25(high) T-cells were capable of suppressing autologous CD4 + CD25- T-cell proliferation. In the present work, we detected the presence of functional circulating CD4+CD25(high) Foxp3+ regulatory T-cells in CTCL patients, with an increased frequency compared to healthy donors. The treatment with bexarotene does not seem to affect the regulatory T-cell compartment.

About the cutaneous targets of bexarotene in CTCL patients

There are several approved therapies for cutaneous T-cell lymphoma (CTCL). The retinoids are one of the major biologic response modifiers used in CTCL, producing good response rates but few complete responses. Bexarotene has been demonstrated to act on malignant T-cells by inducing their apoptosis, but nothing is known about its role on keratinocytes and Langerhans cells. Immunohistochemical analysis using CD1a, HLA-DR, ICAM-1 (activation markers), CD95 and CD40 (apoptosis markers) was conducted on frozen sections of bexarotene-exposed cutaneous explants and skin biopsy specimens from patients treated with bexarotene. None of the studied markers was significantly modulated both on cutaneous explants and on skin biopsy specimens after treatment with bexarotene, compared to controls. Langerhans cells and keratinocytes do not appear to play a central role in the therapeutic control of CTCL by bexarotene therapy. The main bexarotene's target thus remains T-cells by inducing their apoptosis, a mechanism that is different from the other retinoids used in CTCL.

Predictors of response to extracorporeal photopheresis in advanced mycosis fungoides and Sézary syndrome

BACKGROUND

Extracorporeal photopheresis (ECP) has been utilized for more than 20 years to treat cutaneous T-cell lymphoma (CTCL), but a clinical response can take up to 9 months to manifest. This study was undertaken to determine whether clinical features, laboratory values, cytokine levels, or gene expression levels of tumor markers are useful to predict the subsequent response to ECP in CTCL patients with blood involvement.

METHODS

Twenty-one patients with CTCL treated with ECP as monotherapy for at least 6 months were retrospectively identified. Laboratory and clinical data and blood obtained at baseline, 3, and 6 months of treatment were used for analysis.

RESULTS

In pretreatment blood specimens, a lower percentage of Sézary cells and a higher absolute eosinophil count were associated with a favorable clinical response. Clinical evidence of an early response after 3 months of ECP did not reliably predict a favorable response at 6 months or beyond. Comparison of cytokines, gene transcripts, and other laboratory measures of disease did not correlate with the subsequent clinical response, although lactate dehydrogenase levels tended to decrease progressively in ECP-responsive cases and increase progressively in ECP-non-responsive cases. Additionally, serum levels of TNF-alpha significantly increased from baseline to 6 months of ECP, but was not found to correlate with the clinical response.

CONCLUSIONS

Although we found that increased eosinophils and decreased percentage of Sézary cells were associated with a favorable clinical response to ECP, we were not able to identify the predictors of ECP response within the first 3 months of treatment.

The role of toll-like receptors in host defenses and their relevance to dermatologic diseases

The family of toll-like receptors (TLRs) plays a central role in the cutaneous immune defense system. To date, different TLRs have been found on several major cell populations of the skin, such as keratinocytes, fibroblasts, antigen-presenting cells, and melanocytes. Activation of TLRs leads, via different intracellular signaling pathways, to the production of pro-inflammatory stimuli, and is considered a danger signal that should transform the skin in to the functional state of defense. However, TLRs have also been implicated in tissue homeostasis and renewal. Within the group of TLRs, two types have been identified: surface-expressed TLRs, which are predominantly active against bacterial cell wall compounds; and intracellular receptors, which preferentially recognize virus-associated pattern molecules. In addition, surface-expressed receptors trigger phagocytotic and maturation signals, while the intracellular TLRs lead to the induction of antiviral genes. Our review aims to outline the importance of TLRs in the pathogenesis of numerous skin diseases and the potential of TLR agonists as a treatment option for various skin diseases.

Chronic vulvar fissure--a rare manifestation of mycosis fungoides

BACKGROUND

Vulvar fissures are a common cause of vulvar pain and discomfort. The differential diagnosis of the underlying process is broad, and some cases remain undiagnosed. Mycosis fungoides, the dominant component of cutaneous T-cell lymphoma, rarely present as fissures. We report a case of a chronic vulvar fissure due to mycosis fungoides.

CASE

A 55-year-old woman was referred to the vaginitis clinic for evaluation of a chronic vulvar fissure, 6 cm in length, located at the left interlabial sulcus. A detailed history and examination for other skin lesions revealed an erythematous pruritic patch on left breast that had been present for years. Repeat biopsies from both sites showed a dense dermal lymphocytic infiltrate composed predominantly of CD3- and CD4-positive T cell with minimal epidermotropism. A T-gamma polymerase chain reaction analysis demonstrated a clonal T-cell rearrangement. Based on a diagnostic algorithm that combines clinical features, histopathology, and molecular biology, a diagnosis of mycosis fungoides was confirmed.

CONCLUSIONS

Patients presenting with vulvar lesions should always be suspected of having an underlying dermatosis, and a detailed examination for other skin lesions should be performed. In the presented case, once both skin lesions were linked clinically, repeat biopsies of both sites led to a confirmed diagnosis of mycosis fungoides.

A Rare Presentation of Mycosis Fungoides Mimicking Psoriasis Vulgaris

Mycosis fungoides (MF) is an uncommon primary cutaneous lymphoma with a wide spectrum of clinicopathological manifestations. Diagnosis can be difficult in its early stages given the considerable overlap with more common benign dermatoses. We report an unusual case of MF in a 52-year-old male presenting with psoriasiform plaques on the palms and the soles who rapidly developed additional lesions on the scalp, limps and trunk. Punch biopsy of the face was obtained for routine histology and immunohistochemical stains. Chest X-ray, total body computed tomography scanning and excisional biopsy of the inguinal lymph node were performed. Review of the face biopsy revealed a diffuse dermal infiltrate containing a high number of atypical lymphocytes showing a CD3+, CD4+, CD45RO+, CD8-, CD20- immunophenotype and epidermotropism. Findings were consistent with tumor stage MF (stage IIB, T3 N1 M0). We report a rare presentation of MF mimicking psoriasis vulgaris.

Chemokine receptors in T-cell-mediated diseases of the skin

The chemokine/chemokine receptor network is an integral element of the complex system of homeostasis and immunosurveillance. Initially studied because of their role in coordinating tissue-specific migration and activation of leucocytes, chemokines have been implicated in the pathogenesis of various malignancies and diseases with strong inflammatory components. We discuss recent findings suggesting a critical involvement of chemokine receptor interactions in the immunopathogenesis of classical inflammatory skin disorders such as psoriasis and atopic dermatitis, as well as neoplastic diseases with a T-cell origin, such as mycosis fungoides. A deeper understanding of the underlying contribution of the chemokine network in the disease processes is key for the development of selective targeted immunotherapeutics that may meet the delicate balance between efficacy and safety.

Identification of tyrosine kinase, HCK, and tumor suppressor, BIN1, as potential mediators of AHI-1 oncogene in primary and transformed CTCL cells

AHI-1 is an oncogene often targeted by provirus insertional mutagenesis in murine leukemias and lymphomas. Aberrant expression of human AHI-1 occurs in cutaneous T-cell lymphoma (CTCL) cells and in CD4+CD7− Sezary cells from patients with Sezary syndrome. Stable knockdown of AHI-1 using retroviral-mediated RNA interference in CTCL cells inhibits their transforming activity in vitro and in vivo. To identify genes involved in AHI-1–mediated transformation, microarray analysis was performed to identify differentially expressed genes in AHI-1–suppressed CTCL cells. Fifteen up-regulated and 6 down-regulated genes were identified and confirmed by quantitative reverse transcription-polymerase chain reaction. Seven were further confirmed in a microarray analysis of CD4+CD7− Sezary cells from Sezary syndrome patients. HCK and BIN1 emerged as new candidate cooperative genes, with differential protein expression, which correlates with observed transcript changes. Interestingly, changes in HCK phosphorylation and biologic response to its inhibitor, dasatinib, were observed in AHI-1–suppressed or –overexpressed cells. The tumor suppressor BIN1 physically interacts with MYC in CTCL cells, which also exhibit differential MYC protein expression. In addition, aberrant expression of alternative splicing forms of BIN1 was observed in primary and transformed CTCL cells. These findings indicate that HCK and BIN1 may play critical roles in AHI-1–mediated leukemic transformation of human CTCL cells.

Cutaneous T-cell lymphoma: roles for chemokines and chemokine receptors

Chemokine receptors are G-protein-coupled, seven-transmembrane-spanning surface receptors that play key roles in cell trafficking, cell motility, and survival. These receptors are activated by small molecular weight chemotactic cytokines called chemokines. Chemokine receptors play roles in the migration and localization of normal T cells (and other leukocytes) during physiological responses in inflamed or infected skin. In cancer cells, these receptors may also facilitate tumorigenesis, metastasis, and resistance to immune-mediated killing. This review will focus on recent data that reveal potential roles of specific chemokine receptors, including CCR4, CXCR4, and CCR10, in the pathophysiology of cutaneous T-cell lymphoma, including mycosis fungoides and Sézary syndrome.

Epigenetics and dermatological disease

Epigenetics is the study of differences in phenotype, in the absence of variation in the genetic code. Epigenetics is relevant in the pathogenesis of many skin diseases. In the case of the common skin cancers, aberrant methylation of tumor suppressor gene promoters is associated with their transcriptional inactivation. Environmental carcinogens such as ultraviolet radiation and arsenic may act through epigenetic mechanisms. Hypomethylation is associated with activation of systemic autoimmune diseases, such as systemic lupus erythematosus, subacute cutaneous lupus erythematosus and scleroderma. This may be through a mechanism of immunological cross-reactivity with hypomethylated DNA from pathogenic bacteria. Epigenetic factors may also be relevant in the pathogenesis of psoriasis and other inflammatory skin diseases, as well as in the pathogenesis of the disorders of genomic imprinting with cutaneous features.

Array-based comparative genomic hybridization in early-stage mycosis fungoides: recurrent deletion of tumor suppressor genes BCL7A, SMAC/DIABLO, and RHOF

The etiology of mycosis fungoides (MF), the most frequent form of cutaneous T cell lymphoma (CTCL), is poorly understood. No specific genetic aberration has been detected, especially in early-stage disease, possibly due to the clinical and histological heterogeneity of patient series and to the different sources of malignant cells (skin, blood, or lymph node) included in most studies. Frozen skin biopsies from 16 patients with early-stage MF were studied using array-based comparative genomic hybridization. A DNA pool from healthy donors was used as the reference. Results demonstrated recurrent loss of 19, 7p22.1-p22.3, 7q11.1-q11.23, 9q34.12, 12q24.31, and 16q22.3-q23.1, and gain of 8q22.3-q23.1 and 21q22.12. The 12q24.31 region was recurrently deleted in 7/16 patients. Real-time PCR investigation for deletion of genes BCL7A, SMAC/DIABLO, and RHOF-three tumor suppressor genes with a putative role in hematological malignancies-demonstrated that they were deleted in 9, 10, and 13 cases, respectively. The identified genomic alterations and individual genes could yield important insights into the early steps of MF pathogenesis.

Oncogenomic analysis of mycosis fungoides reveals major differences with Sezary syndrome

Mycosis fungoides (MF), the most common cutaneous T-cell lymphoma, is a malignancy of mature, skin-homing T cells. Sézary syndrome (Sz) is often considered to represent a leukemic phase of MF. In this study, the pattern of numerical chromosomal alterations in MF tumor samples was defined using array-based comparative genomic hybridization (CGH); simultaneously, gene expression was analyzed using microarrays. Highly recurrent chromosomal alterations in MF include gain of 7q36, 7q21-7q22 and loss of 5q13 and 9p21. The pattern characteristic of MF differs markedly from chromosomal alterations observed in Sz. Integration of data from array-based CGH and gene-expression analysis yielded several candidate genes with potential relevance in the pathogenesis of MF. We confirmed that the FASTK and SKAP1 genes, residing in loci with recurrent gain, demonstrated increased expression. The RB1 and DLEU1 tumor suppressor genes showed diminished expression associated with loss. In addition, it was found that the presence of chromosomal alterations on 9p21, 8q24, and 1q21-1q22 was associated with poor prognosis in patients with MF. This study provides novel insight into genetic alterations underlying MF. Furthermore, our analysis uncovered genomic differences between MF and Sz, which suggest that the molecular pathogenesis and therefore therapeutic requirements of these cutaneous T-cell lymphomas may be distinct.