Deciphering Tumor Cell Evolution in Cutaneous T-Cell Lymphomas: Distinct Differentiation Trajectories in Mycosis Fungoides and Sézary Syndrome

Cutaneous T-cell lymphomas are a heterogeneous group of neoplasms originating in the skin, with mycosis fungoides (MF) and Sézary syndrome (SS) representing the most common variants. The cellular origin of cutaneous lymphomas has remained controversial owing to their immense phenotypic heterogeneity that obfuscates lineage reconstruction on the basis of classical surface biomarkers. To overcome this heterogeneity and reconstruct the differentiation trajectory of malignant cells in MF and SS, TCR sequencing was performed in parallel with targeted transcriptomics at the single-cell resolution among cutaneous samples in MF and SS. Unsupervised lineage reconstruction showed that Sézary cells exist as a population of CD4+ T cells distinct from those in patch, plaque, and tumor MF. Further investigation of malignant cell heterogeneity in SS showed that Sézary cells phenotypically comprised at least 3 subsets on the basis of differential proliferation potentials and expression of exhaustion markers. A T helper 1-polarized cell type, intermediate cell type, and exhausted T helper 2-polarized cell type were identified, with T helper 1- and T helper 2-polarized cells displaying divergent proliferation potentials. Collectively, these findings provide evidence to clarify the relationship between MF and SS and reveal cell subsets in SS that suggest a possible mechanism for therapeutic resistance.

The Role of Cytokines in Cutaneous T Cell Lymphoma: A Focus on the State of the Art and Possible Therapeutic Targets

Cutaneous T cell lymphomas (CTCLs), encompassing mycosis fungoides (MF) and Sézary syndrome (SS), present a complex landscape influenced by cytokines and cellular responses. In this work, the intricate relationship between these inflammatory proteins and disease pathogenesis is examined, focusing on what is known at the clinical and therapeutic levels regarding the most well-known inflammatory mediators. An in-depth look is given to their possible alterations caused by novel immunomodulatory drugs and how they may alter disease progression. From this narrative review of the actual scientific landscape, Interferon-gamma (IFN-γ) emerges as a central player, demonstrating a dual role in both promoting and inhibiting cancer immunity, but the work navigates through all the major interleukins known in inflammatory environments. Immunotherapeutic perspectives are elucidated, highlighting the crucial role of the cutaneous microenvironment in shaping dysfunctional cell trafficking, antitumor immunity, and angiogenesis in MF, showcasing advancements in understanding and targeting the immune phenotype in CTCL. In summary, this manuscript aims to comprehensively explore the multifaceted aspects of CTCL, from the immunopathogenesis and cytokine dynamics centred around TNF-α and IFN-γ to evolving therapeutic modalities. Including all the major known and studied cytokines in this analysis broadens our understanding of the intricate interplay influencing CTCL, paving the way for improved management of this complex lymphoma.

High-throughput RNA sequencing of the T cell receptor alpha and beta chains for simultaneous clonality and biological analyses in Sezary syndrome

BACKGROUND

Previous investigations pointed out a role for antigen stimulation in Sezary syndrome (SS). High-throughput sequencing of the T cell receptor (TR) offers several applications beyond diagnostic purposes, including the study of T cell pathogenesis.

METHODS

We performed high-throughput RNA sequencing of the TR alpha (TRA) and beta (TRB) genes focusing on the complementarity-determining region 3 (CDR3) in 11 SS and one erythrodermic mycosis fungoides (MF) patients. Five psoriasis patients were employed as controls. Peripheral blood CD4+ cells were isolated and RNA sequenced (HiSeq2500). High-resolution HLA typing was performed in neoplastic patients.

RESULTS

Highly expanded predominant TRA and TRB CDR3 were only found in SS patients (median frequency: 94.4% and 93.7%). No remarkable CDR3 expansions were observed in psoriasis patients (median frequency of predominant TRA and TRB CDR3: 0.87% and 0.69%, p < 0.001 compared to SS). CDR3 almost identical to the predominant were identified within each SS patient and were exponentially correlated with frequencies of the predominant CDR3 (R2  = 0.918, p < 0.001). Forty-six different CDR3 were shared between SS patients displaying HLA similarities, including predominant TRA and TRB CDR3 in one patient that were found in other three patients. Additionally, 351 antigen matches were detected (Cytomegalovirus, Epstein-Barr, Influenza virus, and self-antigens), and the predominant CDR3 of two different SS patients matched CDR3 with specificity for Influenza and Epstein-Barr viruses.

CONCLUSIONS

Besides detecting clonality, these findings shed light on the nature of SS-related antigens, pointing to RNA sequencing as a useful tool for simultaneous clonality and biological analysis in SS.

New JAK3-INSL3 Fusion Transcript-An Oncogenic Event in Cutaneous T-Cell Lymphoma

Constitutively activated tyrosine kinase JAK3 is implicated in the pathogenesis of cutaneous T-cell lymphomas (CTCL). The mechanisms of constitutive JAK3 activation are unknown although a JAK3 mutation was reported in a small portion of CTCL patients. In this study, we assessed the oncogenic roles of a newly identified JAK3-INSL3 fusion transcript in CTCL. Total RNA from malignant T-cells in 33 patients with Sézary syndrome (SS), a leukemic form of CTCL, was examined for the new JAK3-INSL3 fusion transcript by RT-PCR followed by Sanger sequencing. The expression levels were assessed by qPCR and correlated with patient survivals. Knockdown and/or knockout assays were conducted in two CTCL cell lines (MJ cells and HH cells) by RNA interference and/or CRISPR/Cas9 gene editing. SS patients expressed heterogeneous levels of a new JAK3-INSL3 fusion transcript. Patients with high-level expression of JAK3-INSL3 showed poorer 5-year survival (n = 19, 42.1%) than patients with low-level expression (n = 14, 78.6%). CTCL cells transduced with specific shRNAs or sgRNAs had decreased new JAK3-INSL3 fusion transcript expression, reduced cell proliferation, and decreased colony formation. In NSG xenograft mice, smaller tumor sizes were observed in MJ cells transduced with specific shRNAs than cells transduced with controls. Our results suggest that the newly identified JAK3-INSL3 fusion transcript confers an oncogenic event in CTCL.

Sézary syndrome originates from heavily mutated hematopoietic progenitors

The pathogenesis of cutaneous T-cell lymphoma (CTCL) remains unclear. Using single-cell RNA or T-cell receptor (TCR) sequencing of 32 619 CD3+CD4+ and CD26+/CD7+ and 29 932 CD3+CD4+ and CD26-/CD7- lymphocytes from the peripheral blood of 7 patients with CTCL, coupled to single-cell ATAC-sequencing of 26,411 CD3+CD4+ and CD26+/CD7+ and 33 841 CD3+CD4+ and CD26-/CD7- lymphocytes, we show that tumor cells in Sézary syndrome and mycosis fungoides (MF) exhibit different phenotypes and trajectories of differentiation. When compared to MF, Sézary cells exhibit narrower repertoires of TCRs and exhibit clonal enrichment. Surprisingly, we identified ≥200 mutations in hematopoietic stem cells from multiple patients with Sézary syndrome. Mutations in key oncogenes were also present in peripheral Sézary cells, which also showed the hallmarks of recent thymic egression. Together our data suggest that CTCL arises from mutated lymphocyte progenitors that acquire TCRs in the thymus, which complete their malignant transformation in the periphery.

Single-cell analysis of Sézary syndrome reveals novel markers and shifting gene profiles associated with treatment

Cutaneous T-cell lymphomas (CTCLs) are a spectrum of diseases with varied clinical courses caused by malignant clonal proliferation of skin-tropic T cells. Most patients have an indolent disease course managed with skin-directed therapies. In contrast, others, especially in advanced stages of disease or with specific forms, have aggressive progression and poor median survival. Sézary syndrome (SS), a leukemic variant of CTCL, lacks highly consistent phenotypic and genetic markers that may be leveraged to prevent the delay in diagnosis experienced by most patients with CTCL and could be useful for optimal treatment selection. Using single-cell mRNA and T-cell receptor sequencing of peripheral blood immune cells in SS, we extensively mapped the transcriptomic variations of nearly 50 000 T cells of both malignant and nonmalignant origins. We identified potential diverging SS cell populations, including quiescent and proliferative populations shared across multiple patients. In particular, the expression of AIRE was the most highly upregulated gene in our analysis, and AIRE protein expression could be observed over a variety of CTCLs. Furthermore, within a single patient, we were able to characterize differences in cell populations by comparing malignant T cells over the course of treatment with histone deacetylase inhibition and photopheresis. New cellular clusters after progression of the therapy notably exhibited increased expression of the transcriptional factor FOXP3, a master regulator of regulatory T-cell function, raising the potential implication of an evolving mechanism of immune evasion.

Epigenetics of Cutaneous T-Cell Lymphomas

Epigenetic modifications rarely occur in isolation (as single “epigenetic modifications”). They usually appear together and form a network to control the epigenetic system. Cutaneous malignancies are usually affected by epigenetic changes. However, there is limited knowledge regarding the epigenetic changes associated with cutaneous lymphomas. In this review, we focused on cutaneous T-cell lymphomas such as mycosis fungoides, Sézary syndrome, and anaplastic large cell lymphoma. With regard to epigenetic changes, we summarize the detailed chemical modifications categorized into DNA methylation and histone acetylation and methylation. We also summarize the epigenetic modifications and characteristics of the drug for cutaneous T-cell lymphoma (CTCL). Furthermore, we discuss current research on epigenetic-targeted therapy against cutaneous T-cell lymphomas. Although the current method of treatment with histone deacetylase inhibitors does not exhibit sufficient therapeutic benefits in all cases of CTCL, epigenetic-targeted combination therapy might overcome this limitation for patients with CTCL.

Frequent and Persistent PLCG1 Mutations in Sézary Cells Directly Enhance PLCγ1 Activity and Stimulate NFκB, AP-1, and NFAT Signaling

Phospholipase C Gamma 1 (PLCG1) is frequently mutated in primary cutaneous T-cell lymphoma (CTCL). This study functionally interrogated nine PLCG1 mutations (p.R48W, p.S312L, p.D342N, p.S345F, p.S520F, p.R1158H, p.E1163K, p.D1165H, and the in-frame indel p.VYEEDM1161V) identified in Sézary Syndrome, the leukemic variant of CTCL. The mutations were demonstrated in diagnostic samples and persisted in multiple tumor compartments over time, except in patients who achieved a complete clinical remission. In basal conditions, the majority of the mutations confer PLCγ1 gain-of-function activity through increased inositol phosphate production and the downstream activation of NFκB, AP-1, and NFAT transcriptional activity. Phosphorylation of the p.Y783 residue is essential for the proximal activity of wild-type PLCγ1, but we provide evidence that activating mutations do not require p.Y783 phosphorylation to stimulate downstream NFκB, NFAT, and AP-1 transcriptional activity. Finally, the gain-of-function effects associated with the p.VYEEDM1161V indel suggest that the C2 domain may have a role in regulating PLCγ1 activity. These data provide compelling evidence to support the development of therapeutic strategies targeting mutant PLCγ1.

The MicroRNA Expression Profile Differs Between Erythrodermic Mycosis Fungoides and Sézary Syndrome

It is difficult to distinguish erythrodermic mycosis fungoides from Sézary syndrome due to their similar clinical and histological features. The main purpose of this study was to investigate whether microRNA expression profiles in lesional skin could discriminate patients with erythrodermic mycosis fungoides from those with Sézary syndrome. A further aim was to assess whether the microRNA expression profiles in erythrodermic mycosis fungoides skin was more comparable to microRNA expression profiles of Sézary syndrome or early-stage mycosis fungoides. RNA was extracted from diagnostic skin biopsies, followed by quantitative reverse transcription polymerase chain reaction analysis of 383 microRNAs. Twenty-seven microRNAs were significantly differentially expressed between erythro-dermic mycosis fungoides and Sézary syndrome. More-over, erythrodermic mycosis fungoides showed microRNA features overlapping with Sézary syndrome and early-stage mycosis fungoides, although hierarchical cluster analysis co-clustered erythrodermic mycosis fungoides with early-stage mycosis fungoides rather than with Sézary syndrome. These findings underscore that erythrodermic mycosis fungoides and Sézary syndrome are different diseases.

Role of Dysregulated Cytokine Signaling and Bacterial Triggers in the Pathogenesis of Cutaneous T-Cell Lymphoma

Cutaneous T-cell lymphoma is a heterogeneous group of lymphomas characterized by the accumulation of malignant T cells in the skin. The molecular and cellular etiology of this malignancy remains enigmatic, and what role antigenic stimulation plays in the initiation and/or progression of the disease remains to be elucidated. Deep sequencing of the tumor genome showed a highly heterogeneous landscape of genetic perturbations, and transcriptome analysis of transformed T cells further highlighted the heterogeneity of this disease. Nonetheless, using data harvested from high-throughput transcriptional profiling allowed us to develop a reliable signature of this malignancy. Focusing on a key cytokine signaling pathway previously implicated in cutaneous T-cell lymphoma pathogenesis, JAK/STAT signaling, we used conditional gene targeting to develop a fully penetrant small animal model of this disease that recapitulates many key features of mycosis fungoides, a common variant of cutaneous T-cell lymphoma. Using this mouse model, we show that T-cell receptor engagement is critical for malignant transformation of the T lymphocytes and that progression of the disease is dependent on microbiota.

Placental Growth Factor and Vascular Endothelial Growth Factor Together Regulate Tumour Progression via Increased Vasculature in Cutaneous T-cell Lymphoma

Angiogenesis is regarded as an essential step in supporting tumour growth and metastasis. In haematological malignancies, including cutaneous T-cell lymphoma (CTCL), angiogenesis is increased and serum levels of some pro-angiogenic markers are elevated. The aim of this study was to investigate expression levels of placental growth factor (PlGF) and vascular endothelial growth factor (VEGF)-A in lesional skin and sera in patients with CTCL, and to assess the association of these factors with development of CTCL. A further aim was to investigate the effect of PlGF on lymphoma cell growth in vivo using a tumour inoculation model. Expression of PlGF and VEGF-A were significantly elevated in CTCL skin. Tumour cells expressed PlGF in some cases. Serum PlGF levels were increased in patients with advanced CTCL and correlated with disease markers. Moreover, PlGF enhanced lymphoma cell growth in vivo through increasing tumour vasculature. These findings suggest that angiogenesis plays a role in the progression of CTCL and raises the possibility of using inhibitors of PlGF in CTCL therapy.

CD164 identifies CD4+ T cells highly expressing genes associated with malignancy in Sézary syndrome: the Sézary signature genes, FCRL3, Tox, and miR-214

Sézary syndrome (SS), a leukemic variant of cutaneous T-cell lymphoma (CTCL), is associated with a significantly shorter life expectancy compared to skin-restricted mycosis fungoides. Early diagnosis of SS is, therefore, key to achieving enhanced therapeutic responses. However, the lack of a biomarker(s) highly specific for malignant CD4+ T cells in SS patients has been a serious obstacle in making an early diagnosis. We recently demonstrated the high expression of CD164 on CD4+ T cells from Sézary syndrome patients with a wide range of circulating tumor burdens. To further characterize CD164 as a potential biomarker for malignant CD4+ T cells, CD164+ and CD164-CD4+ T cells isolated from patients with high-circulating tumor burden, B2 stage, and medium/low tumor burden, B1-B0 stage, were assessed for the expression of genes reported to differentiate SS from normal controls, and associated with malignancy and poor prognosis. The expression of Sézary signature genes: T plastin, GATA-3, along with FCRL3, Tox, and miR-214, was significantly higher, whereas STAT-4 was lower, in CD164+ compared with CD164-CD4+ T cells. While Tox was highly expressed in both B2 and B1-B0 patients, the expression of Sézary signature genes, FCRL3, and miR-214 was associated predominantly with advanced B2 disease. High expression of CD164 mRNA and protein was also detected in skin from CTCL patients. CD164 was co-expressed with KIR3DL2 on circulating CD4+ T cells from high tumor burden SS patients, further providing strong support for CD164 as a disease relevant surface biomarker.

Genomic profiling of Sézary syndrome identifies alterations of key T cell signaling and differentiation genes

Sézary syndrome is a rare leukemic form of cutaneous T cell lymphoma characterized by generalized redness, scaling, itching and increased numbers of circulating atypical T lymphocytes. It is rarely curable, with poor prognosis. Here we present a multiplatform genomic analysis of 37 patients with Sézary syndrome that implicates dysregulation of cell cycle checkpoint and T cell signaling. Frequent somatic alterations were identified in TP53, CARD11, CCR4, PLCG1, CDKN2A, ARID1A, RPS6KA1 and ZEB1. Activating CCR4 and CARD11 mutations were detected in nearly one-third of patients. ZEB1, encoding a transcription repressor essential for T cell differentiation, was deleted in over one-half of patients. IL32 and IL2RG were overexpressed in nearly all cases. Our results demonstrate profound disruption of key signaling pathways in Sézary syndrome and suggest potential targets for new therapies.

Novel biomarkers, dysregulated epigenetics, and therapy in cutaneous T-cell lymphoma

Cutaneous T cell lymphomas (CTCL) are a diverse group of lymphoid malignancies that develop in the skin. The most common variants are mycosis fungoides (MF) and Sezary syndrome (SS). These skin lymphomas can be challenging to differentiate from non-malignant inflammatory skin disorders such as psoriasis or nummular eczema, thus the identification of biomarkers is important in early diagnosis and treatment. Gene expression analysis has identified novel genes that are expressed in MF/SS that may improve diagnosis of MF/SS. Although the catalog of biomarker genes remains incomplete, a mechanism playing a role in the increased expression of biomarkers in MF/SS includes epigenetic changes. This is supported by the efficacy of evolving therapeutic strategies that modulate gene regulation, such as HDAC inhibitors and methylation inhibitors in the treatment of this group of cancers.

The role of microRNAs in the biology of rare diseases

Rare diseases (RD) are characterized by low prevalence and affect not more than five individuals per 10,000 in the European population; they are a large and heterogeneous group of disorders including more than 7,000 conditions and often involve all organs and tissues, with several clinical subtypes within the same disease. Very often information concerning either diagnosis and/or prognosis on many RD is insufficient. microRNAs are a class of small non-coding RNAs that regulate gene expression at the posttranscriptional level by either degrading or blocking translation of messenger RNA targets. Recently, microRNA expression patterns of body fluids underscored their potential as noninvasive biomarkers for various diseases. The role of microRNAs as potential biomarkers has become particularly attractive. The identification of disease-related microRNAs is essential for understanding the pathogenesis of diseases at the molecular level, and is critical for designing specific molecular tools for diagnosis, treatment and prevention. Computational analysis of microRNA-disease associations is an important complementary means for prioritizing microRNAs for further experimental examination. In this article, we explored the added value of miRs as biomarkers in a selected panel of RD hitting different tissues/systems at different life stages, but sharing the need of better biomarkers for diagnostic and prognostic purposes.

Diagnostic tools in Sezary syndrome

Primary cutaneous T-cell lymphomas (CTCL) mycosis fungoides (Mf) and Sézary syndrome (SS) belong to the group of non-Hodgkin lymphomas which are characterized by clonally proliferating CD4+ cells localized in the skin. SS is a leukemic variant of CTCL and is characterized by erythroderma, generalized lymphadenopathy, and circulating atypical T-cells with cerebriform nuclei, so-called Sézary cells. Palmoplantar hyperkeratosis, generalized alopecia, and severe pruritus are additional symptoms that are associated with SS. Patients have a poor prognosis with an estimated five year survival of 12.5 to 27 percent and estimated median survival of 14.5 to 18 months. The incidence of MF and also SS has increased with time and may be in part due to improved clinical awareness and especially advances in diagnostic testing.

Twist2 regulates CD7 expression and galectin-1-induced apoptosis in mature T-cells

In the periphery, a galectin-1 receptor, CD7, plays crucial roles in galectin-1-mediated apoptosis of activated T-cells as well as progression of T-lymphoma. Previously, we demonstrated that NF-kappaB downregulated CD7 gene expression through the p38 MAPK pathway in developing immature thymocytes. However, its regulatory pathway is not well understood in functional mature T-cells. Here, we show that CD7 expression was downregulated by Twist2 in Jurkat cells, a human acute T-cell lymphoma cell line, and in EL4 cells, a mature murine T-cell lymphoma cell line. Furthermore, ectopic expression of Twist2 in Jurkat cells reduced galectin-1-induced apoptosis. While full-length Twist2 decreased CD7 promoter activity, a C-terminal deletion form of Twist2 reversed its inhibition, suggesting an important role of the C-terminus in CD7 regulation. In addition, CD7 expression was enhanced by histone deacetylase inhibitors such as trichostatin A and sodium butyrate, which indicates that Twist2 might be one of candidate factors involved in histone deacetylation. Based on these results, we conclude that upregulation of Twist2 increases the resistance to galectin-1-mediated-apoptosis, which may have significant implications for the progression of some T-cells into tumors such as Sezary cells.

Immunopathogenesis of mycosis fungoides/Sézary syndrome (cutaneous T-cell lymphoma)

T cells are critical effectors of the adaptive immune response and play an important role in cutaneous immunity. In the skin, various cell types cooperate together, from components of both the innate immunity and adaptive immunity, provide sentinel function to mediate the immune response. However, when T cell function becomes abnormal, there is a loss of normal effector immune function, and the abnormal T cells become a cause of disease as well. Mycosis fungoides (MF) is a cutaneous T cell lymphoma (CTCL) that preferentially travels to the epidermis. When skin homing T cells become malignant, the clinical consequences reflect not only the presence of the malignant cells, but likely from a complex reaction of the immune response to the malignant cell. The clinical presentation is the evolving manifestation of the steps in cancer immunosurveillance. Analysis of gene expression in MF/CTCL patients has provided support for the role of the immune response in the early phase of the disease and a loss of immune response in advance stages of MF/CTCL. This review will focus on cytokine gene expression abnormalities in the clinical stages of the disease and discuss the relationship between the clinical and immunologic abnormalities to gain a better understanding of mechanisms important in the evolution of this disease. A better understanding of the immunopathogenesis of MF/CTCL would support innovative strategies for the development of novel therapies to treat this T cell malignancy.

The molecular pathogenesis of mycosis fungoides and Sézary syndrome

Mycosis fungoides (MF) and the Sézary syndrome (Sz) are the two most frequent forms of cutaneous T cell lymphomas (CTCL). Generally the Sz is regarded as a leukemic variant of MF. They are caused by malignant CD4+ T cells, which infiltrate the skin and both diseases proceed in different stages. It has been found in colon carcinoma that cancerogenesis is a sequence of activation of different oncogenes and inactivation of tumor suppressor genes. This finding has initiated efforts to identify the genes that are responsible for the progression of MF and Sz. The development of new screening methods has strongly accelerated this search and many oncogenes and tumor suppressor genes have been identified that may play a role in the progression of both diseases. Changes in the expression of some of these genes are already found at early stages, whereas others become active or inactivated only in later stages. These results will help to search for more specific drugs and lead to a more exact staging that will help to develop effective and personalized treatments of these diseases.

Mycosis fungoides and Sézary syndrome

Mycosis fungoides and Sézary syndrome are the most common of the cutaneous T-cell lymphomas, which are a heterogeneous group of neoplasms that affect the skin as a primary site. Although the aetiologies of mycosis fungoides and Sézary syndrome are unknown, important insights have been gained in the immunological and genetic perturbations that are associated with these diseases. Unlike some B-cell lymphomas, cutaneous T-cell lymphomas as a group are rarely if ever curable and hence need chronic-disease management. New approaches to treatments are being investigated and include biological and cytotoxic drugs, phototherapy, and monoclonal antibodies that are directed towards novel molecular targets. New molecular technologies such as complementary-DNA microarray have the potential to increase the accuracy of diagnosis and provide important prognostic information. Treatments can be combined to greatly improve clinical outcome without substantially increasing toxic effects in advanced disease that is otherwise difficult to treat. Although present treatment strategies are generally not curative, there is hope that experimental treatments, particularly immunotherapy, might eventually reverse or suppress the abnormalities of mycosis fungoides and Sézary syndrome to the point at which they become non-life-threatening, chronic diseases.

Identification of a novel e8/a4 BCR/ABL fusion transcript in a case of a transformed Sézary syndrome

This report deals with a case of Sézary syndrome, a rare peripheral T-cell lymphoproliferative disorder, in which cytogenetic analysis performed during the disease transformation revealed the presence of a t(9;22) (q34;q11.2) translocation. Molecular analyses identified a new transcript, an e8a4 BCR-ABL fusion mRNA which could be responsible for the disease transformation.

Consequences of p16 tumor suppressor gene inactivation in mycosis fungoides and Sézary syndrome and role of the bmi-1 and ras oncogenes in disease progression

In examining the expression of oncogenes and tumor suppressor genes in mycosis fungoides and Sézary syndrome, we found the cell cycle-regulating protein p16 to be absent in T cells. Immunohistochemical staining with p16-specific antibodies showed that the number of p16-expressing cells in cutaneous lesions decreases in late stages. The repression of p16 was not attributable to deletion or methylation of this gene; however, the Bmi-1 oncogene, a known suppressor of p16, was present in mycosis fungoides and Sézary syndrome cell lines and skin lesions. The absence of p16 correlated with the phosphorylation of the retinoblastoma protein on cyclin D/CDK4- or cyclin D/CDK6-specific sites. Ki-ras, which stimulates phosphorylation of retinoblastoma via cyclin-dependent kinases, was found in all tested cutaneous T-cell lymphoma samples; and its expression generally was stronger in advanced stages. Thus, cutaneous T-cell lymphoma cells show changes in oncogene and tumor suppressor gene expression that increase proliferation.

Chemokine receptor expression by leukemic T cells of cutaneous T-cell lymphoma: clinical and histopathological correlations

Chemokine receptors expressed by normal and neoplastic lymphocytes provide an important mechanism for cells to traffic into the skin and skin-associated lymph nodes. The goal of this study was to correlate chemokine receptor and CD62L expression by circulating neoplastic T cells with the clinical and pathological findings of the leukemic phase of cutaneous T-cell lymphoma, primarily Sézary syndrome (SS). Chemokine receptor mRNA transcripts were found in the majority of leukemic cells for CCR1, CCR4, CCR7, CCR10, CXCR3, and CD62L and in 20-50% of the samples for CXCR5. In patients with SS, relatively high expression levels of CCR7 and CCR10 by circulating neoplastic T cells correlated with epidermotropism, CXCR5 expression correlated with density of the dermal infiltrate, and CD62L correlated with extent of lymphadenopathy. Of note, CXCR5 expression and a dense dermal infiltrate correlated with a poor prognosis. The chemokine receptor profile supports the concept that neoplastic T cells are central memory T cells, and that CCR10 and CD62L play a fundamental role respectively in epidermotropism and lymphadenopathy that is observed in SS.

Mature T-cell leukemias including T-prolymphocytic leukemia, adult T-cell leukemia/lymphoma, and Sézary syndrome

The 2005 Society for Hematopathology/European Association for Haematopathology Workshop Session 1 was devoted to case presentations with discussions of 3 types of mature T-cell leukemias--T-cell prolymphocytic leukemia, adult T-cell leukemia/lymphoma, and Sézary syndrome. These 3 disorders are clonal proliferations of postthymic alphabeta T cells that are often characterized by systemic manifestations and a leukemic blood picture. The application of clinical, morphologic, immunophenotypic, and genetic studies to the assessment and characterization of these 3 disorders is presented, along with specific diagnostic recommendations and differential diagnostic considerations.

Abnormal expression of interleukin-23 in mycosis fungoides/Sézary syndrome lesions

Progression of mycosis fungoides (MF) to Sézary syndrome (SS) is accompanied by a shift from a T(H)1 to a T(H)2 cytokine profile. Interleukin (IL)-23 is a novel cytokine that shares a common p40 subunit with the T(H)1 inducer, IL-12. IL-23 induces a third profile, T(H)IL-17, that is dominant in inflammation and autoimmunity. Although IL-23 induces an eczematous-like skin reaction in mice, and is expressed in T(H)1-mediated skin disorders such as psoriasis, it has not been evaluated in MF/SS. To study the role of IL-23 in MF/SS development, 40 MF/SS lesions of all stages were immunohistochemically analyzed with a novel anti-human IL-23 antibody raised against full-length human IL-23. IL-23 was detected with the catalyzed signal amplification system. The intensity and frequency of IL-23 staining were semi-quantitatively graded in both the dermal infiltrate and the epidermis. Increased expression of IL-23 was observed throughout the epidermal keratinocytes and in dermal lymphocytes compared to normal skin. IL-23 intensity did not differ significantly among the stages of MF/SS; however, in stage IVB patients, we observed lower frequency of IL-23 expression in dermal lymphocytes than in other stage patients [P = 0.13, analysis of variance (ANOVA)]. Interestingly, clusters of atypical lymphocytes, especially the epidermotropic tumor cells, demonstrated weak or absent IL-23 staining in 18 of 40 (45%) lesions. This finding was present in 4 of 5 (80%) of the stage IVB lesions and 7 of 11 (64%) of the lesions from Sézary patients. These findings indicate that abnormal IL-23 expression may play a role in the pathogenesis and progression of MF/SS.

Th1 Response and Cytotoxicity Genes Are Down-Regulated in Cutaneous T-Cell Lymphoma

PURPOSE

Increased production of Th2 cytokines characterizes Sezary syndrome, the leukemic form of cutaneous T-cell lymphomas (CTCL). To identify the molecular background and to study whether shared by the most common CTCL subtype, mycosis fungoides, we analyzed the gene expression profiles in both subtypes.

EXPERIMENTAL DESIGN

Freshly isolated cells from 30 samples, representing skin, blood, and enriched CD4(+) cell populations of mycosis fungoides and Sezary syndrome, were analyzed with Affymetrix (Santa Clara, CA) oligonucleotide microarrays, quantitative PCR, or immunohistochemistry. The gene expression profiles were combined with findings of comparative genomic hybridization of the same samples to identify chromosomal changes affecting the aberrant gene expression.

RESULTS

We identified a set of Th1-specific genes [e.g., TBX21 (T-bet), NKG7, and SCYA5 (RANTES)] to be down-regulated in Sezary syndrome as well as in a proportion of mycosis fungoides samples. In both Sezary syndrome and mycosis fungoides blood samples, the S100P and LIR9 gene expression was up-regulated. In lesional skin, IL7R and CD52 were up-regulated. Integration of comparative genomic hybridization and transcriptomic data identified chromosome arms 1q, 3p, 3q, 4q, 12q, 16p, and 16q as likely targets for new CTCL-associated gene aberrations.

CONCLUSIONS

Our findings revealed several new genes involved in CTCL pathogenesis and potential therapeutic targets. Down-regulation of a set of genes involved in Th1 polarization, including the major Th1-polarizing factor, TBX21, was for the first time associated with CTCL. In addition, a plausible explanation for the proliferative response of CTCL cells to locally produced interleukin-7 was revealed.

Molecular Analysis of T-Cell Receptor β Genes in Cutaneous T-Cell Lymphoma Reveals Jβ1 Bias

Molecular characterization of T-cell receptor junctional region sequences in cutaneous T-cell lymphoma had not been previously reported. We have examined in detail the features of the T-cell receptor beta (TCRB) gene rearrangements in 20 individuals with well-defined stages of cutaneous T-cell lymphoma (CTCL) comprising 10 cases with early-stage mycosis fungoides (MF) and 10 cases with late-stage MF or Sezary syndrome. Using BIOMED-2 PCR primers, we detected a high frequency of clonally rearranged TCR gamma and TCRB genes (17/20 and 15/20 cases, respectively). We carried out sequencing analysis of each complete clonal variable (V)beta-diversity (D)beta-joining(J)beta fingerprint generated by PCR amplification, and determined the primary structure of the Vbeta-Dbeta-Jbeta junctional regions. We observed considerable diversity in the T-cell receptor Vbeta gene usage and complementarity-determining region 3 loops. Although we found that TCRB gene usage in CTCL and normal individuals share common features, our analysis also revealed preferential usage of Jbeta1 genes in all cases with advanced stages of disease.

Molecular staging of lymph nodes from 60 patients with mycosis fungoides and Sézary syndrome: correlation with histopathology and outcome suggests prognostic relevance in mycosis fungoides

BACKGROUND

Histological evidence of lymph node involvement is associated with a poor prognosis in patients with cutaneous T-cell lymphoma (CTCL).

OBJECTIVES

To determine whether T-cell receptor (TCR) gene analysis is of prognostic relevance in CTCL.

METHODS

TCR gene analysis was performed on lymph node specimens from 60 patients with mycosis fungoides (MF) and Sézary syndrome (SS) using a highly sensitive polymerase chain reaction (PCR)/single-strand conformational polymorphism analysis and results were correlated with skin, overall clinical and histological lymph node stages.

RESULTS

The frequency with which a T-cell clone was detected in lymph node samples from patients with MF increased with skin stage, overall clinical stage and with the degree of histological involvement: six of 19 patients with uninvolved lymph nodes or limited histological involvement (LN0-2) and 13 of 14 patients with advanced histological involvement (LN3-4) had a detectable T-cell clone. In SS, 22 of 27 patients had a detectable lymph node T-cell clone. The clonal patients had a poorer prognosis than nonclonal patients (median survival from biopsy of > 72 months vs. 16 months for MF and 41.5 vs. 16.5 months for SS). Regression analysis confirmed that TCR gene analysis identifies a group of MF patients with a worse prognosis (P = 0.013). However, the molecular lymph node stage did not provide independent prognostic information in this cohort of patients in multivariate analysis.

CONCLUSIONS

Molecular staging in MF and SS using a PCR-based method for TCR gene analysis provides additional information to histological examination. Specifically, this study identified a group of MF patients with early lymph node involvement with a poorer prognosis. However, a larger prospective study of patients with MF and early histological lymph node involvement is required to confirm whether molecular staging of lymph nodes provides independent prognostic information in a multivariate model.

Multicolor fluorescence in situ hybridization (SKY) in mycosis fungoides and Sézary syndrome: search for recurrent chromosome abnormalities

Cutaneous T-cell lymphoma (CTCL) is a clonally derived lymphoproliferative disorder that preferentially involves the skin. The two major clinical expressions of CTCL, mycosis fungoides (MF) and Sézary syndrome (SS), have poorly understood pathogenesis. Chromosome abnormalities, mostly complex karyotypes, are seen in about 50% of patients with MF/SS, and there have only been a few instances of recurrent rearrangements. We analyzed 19 blood samples from patients with MF/SS with cytogenetics and multicolor FISH (SKY) to better describe the complex karyotypes and search for recurrent abnormalities or breakpoints. Comparison of phytohemagglutinin (PHA)-stimulated cultures versus a combination of interleukin 2 plus interleukin 7 showed similar efficiency in detecting abnormal clones; however, the PHA cultures yielded more analyzable metaphases. Nine of 19 patients (47%) had an abnormal karyotype. The most frequent abnormalities, in 7 of 9 cases, involved chromosome 10; followed by chromosome 6, in 6 of 9 cases; chromosomes 3, 7, 9, 17, and 19, in 5 of 9 cases; chromosomes 1 and 12, in 4 of 9 cases; and chromosomes 8, 11, and 13, in 3 of 9 cases. Most abnormalities were structural. Recurrent rearrangements included deleted chromosomes 6 and 13, in three cases each, and recurrent breakpoints at 1p32-36, 6q22-25, 17p11.2-13, 10q23-26, and 19p13.3, occurring in three or more cases. One patient had a pseudodicentric translocation between the short arms of chromosomes 8 and 17, confirmed by dual-color FISH and interpreted as psu dic(17;8)(p11.2;p11.2). Two patients with SS reported in the literature seem to have a similar translocation. If confirmed, a psu dic(17;8) could be the first recurring translocation detected in at least three patients with MF/SS.

Heterogeneous Abnormalities of CCND1 and RB1 in Primary Cutaneous T-Cell Lymphomas Suggesting Impaired Cell Cycle Control in Disease Pathogenesis

Upregulation of cyclin D1/B-cell leukemia/lymphoma 1 (CCND1/BCL1) is present in most mantle cell lymphomas with the t(11;14)(q13;q32) translocation. However, little is known about the abnormalities of CCND1 and its regulator RB1 in primary cutaneous T-cell lymphomas (CTCL). We analyzed CCND and RB status in CTCL using fluorescent in situ hybridization (FISH), immunohistochemistry (IHC), and Affymetrix expression microarray. FISH revealed loss of CCND1/BCL1 in five of nine Sézary syndrome (SS) cases but gain in two cases, and RB1 loss in four of seven SS cases. IHC showed absent CCND1/BCL1 expression in 18 of 30 SS, 10 of 23 mycosis fungoides (MF), and three of 10 primary cutaneous CD30+ anaplastic large-cell lymphoma (C-ALCL). Increased CCND1/BCL1 expression was seen in nine MF, seven C-ALCL, and six SS cases. Absent RB1 expression was detected in 8 of 12 MF and 7 of 9 SS cases, and raised RB1 expression in 7 of 8 C-ALCL. Affymetrix revealed increased gene expression of CCND2 in four of eight CTCL cases, CCND3 in three cases, and CDKN2C in two cases with a normal expression of CCND1 and RB1. These findings suggest heterogeneous abnormalities of CCND and RB in CTCL, in which dysregulated CCND and RB1 may lead to impaired cell cycle control.

Paucity of FOXP3+ cells in skin and peripheral blood distinguishes Sézary syndrome from other cutaneous T-cell lymphomas

Cutaneous T-cell lymphomas (CTCL) are mainly comprised of two variants: mycosis fungoides (MF) with CD4(+) tumor cells confined to the skin and the leukemic Sézary syndrome with tumor cell spread to the blood. In this study, we investigated cutaneous expression of the regulatory T-cell (T(reg)) marker FOXP3 in 30 CTCL patients. Immunohistochemical analysis revealed significantly lower numbers of CD4(+)FOXP3(+) cells within the dermal lymphomononuclear infiltrate of Sézary patients (16% FOXP3(+) cells of CD4(+) cells) in contrast to MF (43% FOXP3(+) cells (P<0.05)) and rare types of CTCL (45% FOXP3(+) cells). Furthermore, CD4(+)FOXP3(+) T cells were also markedly reduced in the CD4(+) population within the peripheral blood of Sézary patients compared to controls as determined by fluorescence-activated cell sorter, quantitative PCR and functional analyses. The data support the conclusion that the neoplastic cells in CTCL do not express the T(reg) marker FOXP3. Our data also identify Sézary syndrome as, to our knowledge, the first reported neoplastic disease with a clear reduction in T(reg) numbers within the CD4(+) population. This lack of T(reg) might account for the more aggressive nature of Sézary syndrome compared with other CTCL.

A comparison of morphologic features, flow cytometry, TCR-Vbeta analysis, and TCR-PCR in qualitative and quantitative assessment of peripheral blood involvement by Sézary syndrome

The strengths and weaknesses of various laboratory methods for peripheral blood (PB) Sézary cell quantitation have not been compared rigorously. In this study, manual Sézary cell counting, qualitative and quantitative flow cytometry, T-cell receptor (TCR) Vbeta flow cytometry, and TCR polymerase chain reaction were performed on PB specimens from 11 patients with Sézary syndrome (SS), 9 with reactive erythroderma, 6 with mycosis fungoides, and 11 healthy control subjects. These methods identified neoplastic cells in more than 90% of SS cases. The diagnostic specificities of these tests varied; they were enhanced by applying criteria proposed by the International Society for Cutaneous Lymphoma. Comparison of sequentially analyzed specimens from 6 patients with SS revealed that although the absolute number of clonal cells was reduced, in some cases, these cells still constituted the vast majority of the CD4+ T-cell subset, suggesting that quantitative subset analysis might be sufficient to monitor changes in the PB tumor burden.

Significance of circulating T-cell clones in Sezary syndrome

Identification of malignant Sézary cells by T-cell receptor (TCR) clonality studies is routinely used for the diagnosis of Sézary syndrome, but T-cell clones expressed in a single patient have never been accurately characterized. We previously reported that CD158k expression delineates Sézary syndrome malignant cells, and, more recently, we identified vimentin at the surface membranes of Sézary cells and normal activated lymphocytes. In the present study, T-cell clones from 13 patients with Sézary syndrome were identified by immunoscopy and further characterized in the blood according to their TCR Vbeta, CD158k, and vimentin cell-surface expression. We found in most patients a unique malignant T-cell clone that coexpressed CD158k and vimentin and that, when patients were tested, was also present in the skin. However, in some patients we detected the presence of a nonmalignant circulating clone expressing high amounts of vimentin and lacking CD158k. These results indicate that clonal expansion may originate from circulating malignant and nonmalignant CD4(+) T cell populations in patients with Sézary syndrome. Identification of the malignant cells in Sézary syndrome cannot be achieved by T-cell clonality studies or by TCR Vbeta monoclonal antibody (mAb) analysis alone; it also relies on CD158k phenotyping.

Quantitative PCR on 5 genes reliably identifies CTCL patients with 5% to 99% circulating tumor cells with 90% accuracy

We previously identified a small number of genes using cDNA arrays that accurately diagnosed patients with Sézary Syndrome (SS), the erythrodermic and leukemic form of cutaneous T-cell lymphoma (CTCL). We now report the development of a quantitative real-time polymerase chain reaction (qRT-PCR) assay that uses expression values for just 5 of those genes: STAT4, GATA-3, PLS3, CD1D, and TRAIL. qRT-PCR data from peripheral blood mononuclear cells (PBMCs) accurately classified 88% of 17 patients with high blood tumor burden and 100% of 12 healthy controls in the training set using Fisher linear discriminant analysis (FLDA). The same 5 genes were then assayed on 56 new samples from 49 SS patients with blood tumor burdens of 5% to 99% and 69 samples from 65 new healthy controls. The average accuracy over 1000 resamplings was 90% using FLDA and 88% using support vector machine (SVM). We also tested the classifier on 14 samples from patients with CTCL with no detectable peripheral involvement and 3 patients with atopic dermatitis with severe erythroderma. The accuracy was 100% in identifying these samples as non-SS patients. These results are the first to demonstrate that gene expression profiling by quantitative PCR on a selected number of critical genes can be employed to molecularly diagnosis SS.

Circulating Natural Killer Lymphocytes Are Potential Cytotoxic Effectors Against Autologous Malignant Cells in Sezary Syndrome Patients

Patients with advanced cutaneous T cell lymphoma (CTCL) exhibit profound defects in cell-mediated immunity. Although it has been suggested that Sezary syndrome (SS) patients have a decreased natural killer (NK) lymphocyte activity, nothing has been reported concerning the sensitivity of Sezary cells to NK lymphocyte-mediated cytotoxicity. Peripheral blood NK cells from healthy donors were tested against Sezary tumoral cell lines as well as against freshly isolated Sezary cells. Further, we studied their ability to exhibit antibody -dependent cell-mediated cytotoxicity using either the murine anti-CD158k/KIR3DL2 monoclonal antibody (moAb) AZ158 that specifically recognizes Sezary cells, or the anti-CD52 monoclonal antibody alemtuzumab. The results show that Sezary cell lines are susceptible to NK lymphocyte lysis. More importantly, we found that freshly isolated malignant cells are killed either by IL-2 activated allogeneic NK lymphocytes or when the tumor lymphocyte targets are incubated with an anti-MHC class I F(ab)'2 antibody. Further, anti-KIR3DL2 and anti-CD52 moAb can enhance the NK lysis. Finally, we report that NK lymphocytes isolated from SS patients are potentially cytotoxic lymphocytes against autologous malignant Sezary cells. These findings indicate that antitumor-mediated NK lymphocyte cytotoxic activity can be triggered in patients with CTCL and raise the possibility of developing novel therapeutic strategies by stimulating their innate immunity.

Additional Her 2/neu gene copies in patients with Sézary syndrome

BACKGROUND

Her 2/neu gene amplification has been reported in several types of cancer. Monoclonal antibodies against the Her 2/neu receptor are used as a treatment in e.g. metastatic breast cancer.

AIM

The aim of this study was to determine the frequency of additional Her 2/neu gene copies in relations to the number of chromosome 17 centromeres of patients with Sézary syndrome.

METHODS

Fluorescence in situ hybridization (FISH) with probes specific for the Her 2/neu gene locus and the centromere of chromosome 17 was performed on nuclei from peripheral blood cells of 9 patients with Sézary syndrome. For analysis of Her 2/neu protein expression immunostaining was performed. In addition, FISH was used to analyze distribution of typical lymphocytes on cryo-cut sections of affected skin of two patients.

RESULTS

7/9 cases showed additional Her 2/neu gene copies in relation to the number of chromosome 17 centromeres. 4/5 cases with additional Her 2/neu gene copies in which immunostaining was performed expressed Her 2/neu protein. On cryo-cut sections atypical lymphocytes with additional Her 2/neu gene copies were detected in the dermis as well as in the epidermis of affected skin.

DISCUSSION

These data suggest that Her 2/neu might be involved in the pathogenesis of Sézary syndrome and that Her 2/neu might be a promising target for antitumor therapy in a subgroup of patients.

Primary Cutaneous T-Cell Lymphomas Show a Deletion or Translocation AffectingNAV3, the HumanUNC-53Homologue

Multicolor fluorescent in situ hybridization (FISH) was used to identify acquired chromosomal aberrations in 12 patients with mycosis fungoides or Sézary syndrome, the most common forms of primary cutaneous T-cell lymphoma (CTCL). The most frequently affected chromosome was 12, which showed clonal deletions or translocations with a break point in 12q21 or 12q22 in five of seven consecutive Sézary syndrome patients and a clonal monosomy in the sixth patient. The break point of a balanced translocation t(12;18)(q21;q21.2), mapped in the minimal common region of two deletions, fine mapped to 12q2. By locus-specific FISH, the translocation disrupted one gene, NAV3 (POMFIL1), a human homologue of unc-53 in Caenorhabditis elegans. A missense mutation in the remaining NAV3 allele was found in one of six cases with a deletion or translocation. With locus-specific FISH, NAV3 deletions were found in the skin lesions of four of eight (50%) patients with early mycosis fungoides (stages IA-IIA) and in the skin or lymph node of 11 of 13 (85%) patients with advanced mycosis fungoides or Sézary syndrome. Preliminary functional studies with lentiviral small interfering RNA-based NAV3 silencing in Jurkat cells and in primary lymphocytes showed enhanced interleukin 2 expression (but not CD25 expression). Thus, NAV3 may contribute to the growth, differentiation, and apoptosis of CTCL cells as well as to the skewing from Th1-type to Th2-type phenotype during disease progression. NAV3, a novel putative haploinsufficient tumor suppressor gene, is disrupted in most cases of the commonest types of CTCL and may thus provide a new diagnostic tool.

Durable Clinical, Cytogenetic, and Molecular Remissions After Allogeneic Hematopoietic Cell Transplantation for Refractory Sezary Syndrome and Mycosis Fungoides

Purpose

Sezary syndrome (SS) and tumor-stage mycosis fungoides (MF) are generally incurable with currently available treatments. We conducted a retrospective study to evaluate the outcome of allogeneic hematopoietic stem-cell transplantation (HSCT) in this patient population.

Patient and Methods

From August 1996 through October 2002, eight patients with advanced MF/SS underwent allogeneic HSCT at our institution. All patients were heavily pretreated, having failed a median number of seven prior therapies (range, five to 12). Clonal T-cell populations in peripheral blood or bone marrow were detectable by polymerase chain reaction analyses of T-cell receptor γ-chain gene rearrangements in six patients and cytogenetics in three patients. The conditioning regimen included total-body irradiation and cyclophosphamide (n = 3), busulfan and cyclophosphamide (n = 1), and the reduced-intensity regimen of fludarabine and melphalan (n = 4). Allogeneic hematopoietic stem cells were obtained from HLA-matched siblings (n = 4) and unrelated donors (n = 4).

Results

All patients achieved complete clinical remission and resolution of molecular and cytogenetic markers of disease within 30 to 60 days after HSCT. Two patients died from transplantation-related complications; graft-versus-host disease (GVHD; n = 1) and respiratory syncytial virus pneumonia (n = 1). With a median follow-up of 56 months, six patients remain alive and without evidence of lymphoma.

Conclusion

Our results suggest that allogeneic HSCT from both HLA–matched sibling and unrelated donors can induce durable clinical, molecular, and cytogenetic remissions in patients with advanced cutaneous T-cell lymphoma that is refractory to standard therapies.

Overexpression of c-myb in Leukaemic and Non-Leukaemic Variants of Cutaneous T-Cell Lymphoma

BACKGROUND

The c-myb oncogene is a transcription factor that regulates proliferation, differentiation and apoptosis of haematopoietic cells and activated T cells by binding to promoter sequences of such genes as c-myc or bcl-2 that are expressed in cutaneous T-cell lymphoma (CTCL).

OBJECTIVE

Our study was performed in order to evaluate c-myb expression as a quantitative parameter for differential diagnosis in leukaemic and non-leukaemic variants of CTCL.

METHODS

c-myb expression was analysed in lesional skin and in the peripheral blood of 21 patients with mycosis fungoides (MF), 15 patients with Sézary syndrome (SS) and 15 patients with inflammatory skin diseases using immunohistochemistry and semiquantitative as well as quantitative RT-PCR.

RESULTS

Immunohistochemistry confirmed expression of c-myb in the lesional skin of the majority of CTCL patients with a tendency towards higher expression in SS (1.86 +/- 0.5) versus MF (1.2 +/- 0.7) while c-myb was absent from the lesional skin of patients with inflammatory skin diseases. c-myb was overexpressed in the peripheral blood in all SS patients (100% SS vs. 35.7% MF) at a high expression level (51,335.31 +/- 31,960.32 AU in SS vs. 1,226.35 +/- 1,258.29 AU in MF using semiquantitative RT-PCR, and 5.72 x 10(-2) +/- 2.27 x 10(-2) in SS vs. 0.91 x 10(-2) +/- 1.18 x 10(-2) in MF vs. 0.24 x 10(-2) +/- 0.11 x 10(-2) in inflammatory skin disease using quantitative RT-PCR). CD4+ cells from the peripheral blood of SS patients and cell lines in vitro showed the highest c-myb expression levels upon quantitative RT-PCR (23.27 x 10(-2) and 10.78 x 10(-2) +/- 7.24 x 10(-2)).

CONCLUSION

Overexpression of c-myb in skin lesions of both non-leukaemic and leukaemic CTCL independent of the stage of the disease indicates that it acts early in disease development. Nevertheless, if positive, c-myb expression in lesional skin is a clear-cut diagnostic marker for CTCL as compared to inflammatory skin diseases. High-level expression of c-myb in the peripheral blood as assessed by quantitative RT-PCR constitutes an additional diagnostic parameter for SS and may be especially useful in cases in which morphological determination of Sézary cells or FACS analysis of CD7 and CD26 remain inconclusive.

T-cell receptor γ gene rearrangement by multiplex polymerase chain reaction/heteroduplex analysis in patients with cutaneous T-cell lymphoma (mycosis fungoides/Sézary syndrome) and benign inflammatory disease: correlation with clinical, histological and i

BACKGROUND

A dominant T-cell clone can be detected by polymerase chain reaction (PCR) in 40-90% of cutaneous samples from patients with cutaneous T-cell lymphoma (CTCL).

MATERIALS AND METHODS

From 1996 to 2003 we analysed 547 cutaneous biopsies performed to exclude CTCL (mycosis fungoides, MF/Sézary syndrome, SS). The final diagnosis was benign inflammatory disease (BID) in 353 samples (64.5%) and CTCL in 194 (35.5%). T-cell receptor (TCR)-gamma gene rearrangement was studied by using a multiplex PCR/heteroduplex (HD) analysis. The PCR results were correlated with the clinical picture, the histological pattern and the presence of T-cell lineage antigen loss, using univariate and multivariate logistic regression analyses.

OBJECTIVE

To determine the sensitivity and specificity of the multiplex PCR/HD analysis and to identify which are the clinical, histopathological or immunophenotypical features significantly associated with a positive T-cell clonality.

RESULTS

A clonality was demonstrated in 83.5% of CTCL and in 2.3% of BID (P < 0.001). A significantly higher percentage of clonal cases was associated with the cutaneous T-score (71.4% in T1, 76.1% in T2 and 100% in nodular and erythrodermic MF samples) and with the presence of a T-cell lineage antigen loss (93.9% vs. 77.4%). Moreover, clonality was closely related to an increase in the histopathological score (51.3% in the samples with a score < 5, compared with 92% in the lesions with > or = 5). No significant difference in the percentage of clonal cases was found between T1/T2 and T3/T4 lesions with a histopathological score > or = 5. The multivariate logistic regression showed that the density and extent of the cell infiltrate, the degree of epidermotropism and the presence of cytological atypia share an independent predictive value for clonality in T1/T2 samples, even if the highest odds ratios (3.6) were associated with the density of the cell infiltrate. The disease course of T1/T2 patients was analysed according to the PCR findings. All the PCR-negative patients showed a long-standing stable disease course; on the other hand, a disease progression occurred in 12/87 (13.8%) positive patients.

CONCLUSIONS

The multiplex PCR/HD analysis is associated with a high diagnostic accuracy (92.7%) in CTCL patients. The finding of a clonal T-cell rearrangement is more closely associated with the histological pattern (in particular with the density and extent of the cell infiltrate) rather than with the MF cutaneous T-score or immunophenotype.

Fine mapping of chromosome 10q deletions in mycosis fungoides and sezary syndrome: Identification of two discrete regions of deletion at 10q23.33-24.1 and 10q24.33-25.1

Previous cytogenetic studies in mycosis fungoides (MF) and Sezary syndrome (SS) have identified a large and poorly defined area of chromosomal deletion on chromosome 10q. We report an extensive fine-mapping allelotyping study using 19 microsatellite markers in the region 10q22.3-10q26.13. Allelic loss was identified by loss of heterozygosity analysis in 26 of 60 (43%) cases: 15 of 45 (33%) with MF and 11 of 15 (73%) with SS. MF and SS samples showed similar patterns of allelic loss with the identification of two discrete regions of deletion which were mutually exclusive in all but two cases. Within the first region of deletion at 10q23.33-10q24.1, around microsatellite marker D10S185 (2.77 Mb), 23 genes were identified, including three (KIF11, HHEX, and HELLS) with functions that, if dysregulated, could be critical in MF and SS. The second region of deletion, 10q24.33-10q25.1, around microsatellite marker D10S530 (3.92 Mb), encodes 11 genes, the majority of which have poorly identified functions. This extensive allelotyping study provides the basis for future highly selective candidate gene analyses.

Transition of Sézary syndrome into mycosis fungoides after complete clinical and molecular remission under extracorporeal photophoresis

Mycosis fungoides (MF) and Sezary syndrome (SS) are the most common clinical variants of cutaneous T cell lymphoma. Although thought to be closely related to mature T helper cells, the relation between the neoplastic cells in MF and SS is still not fully clarified. This report describes a patient with complete remission of SS under treatment with extracorporeal photophoresis (ECP), who subsequently developed typical plaques of MF and large cell lymphoma (LCL). Serial polymerase chain reaction analyses confirmed identical T cell receptor beta and gamma gene rearrangements in SS, MF, and LCL, and complete disappearance of the circulating malignant T cell clone from the peripheral blood after ECP. These findings indicate that the neoplastic cells in SS, MF, and LCL are derived from a common precursor T cell, despite the change in clinical phenotype.