Thalidomide and analogues: potential for immunomodulation of inflammatory and neoplastic dermatologic disorders

Thalidomide and analogues are a class of immunomodulatory drugs or IMiDS. Thalidomide was initially approved by the U.S. Food and Drug Administation for treatment of erythema nodosum in leprosy and is now approved for multiple myeloma as well. A second generation IMiD, lenalidomide, is also approved for multiple myeloma and refractory myelodysplastic syndrome. Discovery of this class of drugs has been serendipitous and empirical, as the drug targets have been unknown. In this review, the authors integrate recent identification of drug targets of IMiDS, which include the inducible form of nitric oxide synthase (iNOS), Rho GTPase and caspase-1, with the developments in the understanding of the molecular biology of human inflammatory, infectious and neoplastic skin disorders. Because thalidomide reemerged through leprosy, the original disease classified by the T cell, the authors have also emphasized advances in the understanding of T-cell subsets in human skin disorders.

CD4 (+)CD25 (+)Foxp3 (+) regulatory T cells and hematologic malignancies

Regulatory T cells (Tregs) are an immunosuppressive T cell subset that functions to prevent autoimmunity and to regulate physiologic immune reactions. Tregs are also present in the tumor microenvironment and appear to play an important role in the pathophysiology of malignant processes. Available data suggests that this role is context-dependent, as a higher density of tumor infiltrating Tregs at diagnosis may be associated with either a positive or a negative clinical outcome. Negative prognostic associations are found primarily in solid tumors such as ovarian carcinoma, while positive associations have been reported in various lymphomas, most prominently in those of germinal center (GC) B cell derivation. Most of these observations are correlative, however, as mechanistic studies have lagged behind descriptive observations because of a lack of informative animal models. Nonetheless, the available data are intriguing and provide compelling support for the hypothesis that Tregs are pathobiologically relevant. This review focuses on studies of the role of CD4 (+)CD25 (+)FOXP3 (+) Tregs in hematopoietic malignancies and clonal myeloid neoplasms.

A case of CD4+/CD56+ hematodermic neoplasm (plasmacytoid dendritic cell neoplasm)

CD4+/CD56+ hematodermic neoplasm (blastic plasmacytoid dendritic cell neoplasm) involving the skin is relatively rare and has been of significant interest in the recent literature. We report here a 64-year-old male who presented with multiple purple-red nodules and plaques on his face, back, and chest. Histological examination of skin biopsies showed an intense hematolymphoid infiltration in the dermis and in the subcutaneous tissue. Stains were positive for CD4 (weak), CD56, and terminal deoxynucleotidyl transferase (TdT). These cells were negative for CD2, CD3, CD5, CD10, CD20, CD30, CD68, and T cell intracellular antigen (TIA). In situ hybridization (ISH) for Epstein-Barr virus was negative and the diagnosis was blastic NK cell lymphoma. The patient was treated with a hyper-CVAD regimen (cyclophosphamide, vincristine, doxorubicine, dexamethasone, methotrexate, and cytarabine).This treatment regimen achieved partial remission but the patient died eight months after the diagnosis. The patient presented with exclusively cutaneous involvement at the beginning but progressed rapidly and died shortly after despite aggressive chemotherapy. Due to its rarity, we present here a case of CD4+/CD56+ hematodermic neoplasm.

Leukaemic cutaneous T-cell lymphoma-manifesting papuloerythroderma with CD3(-) CD4(+) phenotype

The leukaemic form of cutaneous T-cell lymphoma, as represented by Sézary syndrome, exhibits erythroderma. We describe here an indolent leukaemic patient with cutaneous T-cell lymphoma, who initially had a nodulo-tumourous eruption with a crop of solid papules, but finally presented with papuloerythroderma. Histologically, the skin lesions showed non-epidermotropic dermal infiltration of atypical lymphocytes with lymphoid follicles and a granulomatous change. The circulating malignant CD4(+) CCR4(+) T cells lacked the expression of T-cell receptor and did not respond to concanavalin A. The unresponsiveness of T cells to the T-cell mitogen may be associated with the non-epidermotropic behaviour of the tumour cells and the initially non-erythrodermic eruption.

Cutaneous T-Cell Lymphoma: A Paradigm for Biological Therapies

Mycosis Fungoides and Sézary Syndrome are the most common types of cutaneous T-cell lymphomas. There is no current standard of care for Mycosis Fungoides/Sézary Syndrome, with a general tendency to rely on topical interventions for early disease delaying systemic, more toxic therapy until the development of extensive symptoms. Knowledge of the biological characteristics of this disease has allowed for the development of rational interventions and a significant advance in its treatment. Retinoids are active in Mycosis Fungoides/Sézary Syndrome with the newer rexinoids being available in topical and systemic forms. Interferon alpha remains one of the most active therapeutic agents for Mycosis Fungoides/Sézary Syndrome, especially in combination with other agents such as PUVA. The monoclonal antibody alemtuzumab leads to responses in at least half of patients with advanced disease with its side effect profile consisting mainly of immunosupression and infusion reactions. The recombinant IL2-diphteria toxin denileukin diftitox (Ontak) is active in this disease and appears to have a beneficial effect in symptoms relief and quality of life. Extracorporeal photochemotherapy as an immunostimulating intervention seems to be very effective in a subset of patients, but its availability is limited to less than a hundred centers worldwide. Experimental and less studied interventions include autologous and allogeneic peripheral stem cell transplantation, Interleukin-12, the histone-deacetylator depsipeptide and the synthetic deoxynucleotide CpG7909. Cutaneous T-cell lymphoma has served as a paradigm for the development of biological agents. Further knowledge of the signaling pathways in Mycosis Fungoides/Sézary Syndrome will allow for the development of more effective treatment strategies.

Defucosylated anti-CCR4 monoclonal antibody exercises potent ADCC-mediated antitumor effect in the novel tumor-bearing humanized NOD/Shi-scid, IL-2Rgamma(null) mouse model

PURPOSE

There are no suitable small animal models to evaluate human antibody-dependent cellular cytotoxicity (ADCC) in vivo, due to species incompatibilities. Thus, the first aim of this study was to establish a human tumor-bearing mouse model in which human immune cells can engraft and mediate ADCC, but where the endogenous mouse immune cells cannot mediate ADCC. The second aim was to evaluate ADCC mediated in these humanized mice by the defucosylated anti-CC chemokine receptor 4 (CCR4) monoclonal antibody (mAb) which we have developed and which is now in phase I clinical trials.

EXPERIMENTAL DESIGN

NOD/Shi-scid, IL-2Rgamma(null) (NOG) mice were the recipients of human immune cells, and CCR4-expressing Hodgkin lymphoma (HL) and cutaneous T-cell lymphoma (CTCL) cell lines were used as target tumors.

RESULTS

Humanized mice have been established using NOG mice. The chimeric defucosylated anti-CCR4 mAb KM2760 showed potent antitumor activity mediated by robust ADCC in these humanized mice bearing the HL or CTCL cell lines. KM2760 significantly increased the number of tumor-infiltrating CD56-positive NK cells which mediate ADCC, and reduced the number of tumor-infiltrating FOXP3-positive regulatory T (Treg) cells in HL-bearing humanized mice.

CONCLUSIONS

Anti-CCR4 mAb could be an ideal treatment modality for many different cancers, not only to directly kill CCR4-expressing tumor cells, but also to overcome the suppressive effect of Treg cells on the host immune response to tumor cells. In addition, using our humanized mice, we can perform the appropriate preclinical evaluation of many types of antibody based immunotherapy.

Increased percentage of CD8+CD28- suppressor lymphocytes in peripheral blood and skin infiltrates correlates with advanced disease in patients with cutaneous T-cell lymphomas

INTRODUCTION

T cells with the CD8+CD28- phenotype are CD8+ lymphocytes with regulatory function. Their increased numbers were observed in infections, autoimmune and neoplastic diseases, and in elderly healthy individuals. CD8+CD28- lymphocyte levels in patients with cutaneous T-cell lymphoma (CTCL) has not yet been described. The aim of the study was to determine their levels in these patients' peripheral blood and cutaneous infiltrates and their relation to the clinical stage of disease.

MATERIAL/METHODS

Forty-one untreated patients, 26 males and 15 females, with CTCL were enrolled in the study. CD8+CD28- lymphocyte levels were determined by flow cytometry in peripheral blood and by immunochemistry in skin infiltrates.

RESULTS

The percentage of CD8+CD28- lymphocytes in the peripheral blood of the patients was significantly higher than in the controls. Patients with advanced disease displayed a higher percentage of CD8+CD28- lymphocytes in the peripheral blood and skin than did the individuals with early stages of the disease. Moreover, positive correlations between CD8+CD28- lymphocyte level in peripheral blood and age, clinical stage, and the levels in the skin infiltrates was revealed. Additionally, the percentage of CD8+CD28- T cells in the skin infiltrates correlated positively with age and clinical stage of the disease.

CONCLUSIONS

These data suggest that CD8+CD28- lymphocytes play an important role in the development of immunotolerance in the progression of cutaneous T-cell lymphoma.

[Hydroa vacciniforme-like cutaneous T cell lymphoma: a case report and literature review]

OBJECTIVE

To study the clinical features, diagnosis and therapy of hydroa vacciniforme-like cutaneous T cell lymphoma.

METHODS

The clinical presentations and the findings of laboratory examinations and skin biopsy of affected tissue in a child with hydroa vacciniforme-like cutaneous T cell lymphoma were retrospectively reviewed.

RESULTS

The child manifested as rash, fever and lymph node intumesce. Rash was pantomorphia, including edematous erythema, vesicles, crusts, necrosis and depressed scar, and it was mild in winter and severe in summer, mainly involving in the face and extremities. Epstein-Barre virus (EBV)-IgM was positive. Histopathological findings revealed focal lymphocyte invasion in subcutaneous panniculus adiposus, mainly surrounding the blood vessels. Immunohistochemistry showed CD3 (+), CD43 (+), CD20 (-), pax-5 (-), TIA (+), CD5 (+), CD8 (+), Granmye (+) and CD4 (-). The clinical symptoms were improved after glucocorticoid treatment in this child.

CONCLUSIONS

Hydroa vacciniforme-like cutaneous T cell lymphoma has special clinical manifestations. This disorder may be definitely diagnosed by skin biopsy of affected tissue and immunohistochemistry assay. Glucocorticoid treatment is effective. EBV infection may be related to the development of this disorder.

Current Concepts of the Immunobiology and Immunotherapy of Cutaneous T Cell Lymphoma: Insights Gained through Cross-talk between the Clinic and the Bench

An understanding of the immunologic features of cutaneous T cell lymphoma (CTCL) has led to insights into the life cycle of the malignancy. The identification of the T cell lineage of the neoplastic CTCL cells has allowed unification of diverse clinical presentations under a single entity. The CD4 inducer T cell phenotype of the malignant cells has provided an understanding of the patient's ability to resist infection with certain bacteria. The clonality of the tumor cells, beyond its diagnostic implications, has made them a valuable resource for studying both normal and neoplastic T cell biology. The recently identified immunosuppressive features of the malignant T cells and their dependency for survival on an interaction with immature dendritic cells have explained previously cryptic clinical observations and identified new targets for immunotherapy. Future insights gained both from the bedside and the bench will provide not only an understanding of the immunobiology of the malignancy but also open new avenues for therapeutic intervention.

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.

Gamma c-signaling cytokines induce a regulatory T cell phenotype in malignant CD4+ T lymphocytes

In this study, we demonstrate that malignant mature CD4(+) T lymphocytes derived from cutaneous T cell lymphomas (CTCL) variably display some aspects of the T regulatory phenotype. Whereas seven cell lines representing a spectrum of primary cutaneous T cell lymphoproliferative disorders expressed CD25 and TGF-beta, the expression of FOXP3 and, to a lesser degree, IL-10 was restricted to two CTCL cell lines that are dependent on exogenous IL-2. IL-2, IL-15, and IL-21, all of which signals through receptors containing the common gamma chain, induced expression of IL-10 in the IL-2-dependent cell lines as well as primary leukemic CTCL cells. However, only IL-2 and IL-15, but not IL-21, induced expression of FOXP3. The IL-2-triggered induction of IL-10 and FOXP3 expression occurred by signaling through STAT3 and STAT5, respectively. Immunohistochemical analysis of the CTCL tissues revealed that FOXP3-expressing cells were common among the CD7-negative enlarged atypical and small lymphocytes at the early skin patch and plaque stages. Their frequency was profoundly diminished at the tumor stage and in the CTCL lymph node lesions with or without large cell transformation. These results indicate that the T regulatory cell features are induced in CTCL T cells by common gamma chain signaling cytokines such as IL-2 and do not represent a fully predetermined, constitutive phenotype independent of the local environmental stimuli to which these malignant mature CD4(+) T cells become exposed.

Extracorporeal photopheresis: Lighting the way to immunomodulation

Photopheresis, initially established as an effective treatment of cutaneous T-cell lymphoma, has in recent years also been used to treat chronic graft vs. host disease, heart transplant rejection, and several other conditions requiring immunosuppression. Despite reported beneficial results of this procedure in treatment of various conditions, randomized controlled clinical trials are lacking for the majority of suggested indications. Furthermore, the mechanisms of action of this procedure are still unclear. Deeper understanding of the molecular basis of photopheresis-based immunomodulation will allow better selection of patients to be treated and will facilitate development of novel, minimally toxic immunomodulatory treatments.

[Diagnostic significance of immunophenotyping and detection of gene rearrangement in subcutaneous panniculitis-like T-cell lymphoma]

OBJECTIVE

To explore the diagnostic implication of immunophenotyping and gene rearrangement in subcutaneous panniculitis-like T-cell lymphoma (SPTL).

METHODS

According to the selection criteria of 2005 WHO-EORTC classification for cutaneous lymphomas, 20 SPTL patients were enrolled in this study. A 10-antibody panel was used for immunophenotyping and in addition, polymerase chain reaction for TCR gamma and IgH gene rearrangement and in situ hybridization for EBER1/2 were also employed.

RESULTS

There were 9 males and 11 female with a mean age of 29.5 years. Immunophenotypic study showed that all the patients expressed one to three T-cell associated antigens (CD2, CD3 or CD45RO), 18 patients were positive for beta F1, 18 for CD8, 20 for TIA-1 and 16 for granzyme B. None of the patients expressed CD4, CD20 and CD56. TCR gamma gene rearrangement was found in 16 of 20 cases (80.0%) and none for IgH gene rearrangement. The positive rate of EBER1/2 was 25.0% (5/20).

CONCLUSIONS

Since the majority of SPTL patients show clonal TCR gene rearrangements, correlations among clinical presentation, histological features, immunophenotype and gene rearrangement data are considered important in confirming a diagnosis of SPTL.

Cutaneous T cell lymphoma: translating immunobiology into therapeutic opportunities

Cutaneous T cell lymphoma (CTCL) has always served as a proving ground where conceptual advances in immunology can be tested and the results translated into clinical practice. From the earliest studies that used sheep red blood cells to identify the malignant cell as a T lymphocyte to molecular demonstration of the clonalilty of the disease, basic science techniques have provided sign posts that allow us to understand the clinical features seen in the patients. We continue to apply this paradigm to develop new insights into the role of the immune system in CTCL with the goal of using this knowledge to enhance the therapeutic options available to the patient. This article will review the studies that have led to our current understanding of the immunobiology of CTCL and the new therapeutic approaches that are being tested in this disease.

A human CD4 monoclonal antibody for the treatment of T-cell lymphoma combines inhibition of T-cell signaling by a dual mechanism with potent Fc-dependent effector activity

Zanolimumab is a human IgG1 antibody against CD4, which is in clinical development for the treatment of cutaneous and nodal T-cell lymphomas. Here, we report on its mechanisms of action. Zanolimumab was found to inhibit CD4+ T cells by combining signaling inhibition with the induction of Fc-dependent effector mechanisms. First, T-cell receptor (TCR) signal transduction is inhibited by zanolimumab through a fast, dual mechanism, which is activated within minutes. Ligation of CD4 by zanolimumab effectively inhibits early TCR signaling events but, interestingly, activates signaling through the CD4-associated tyrosine kinase p56lck. An uncoupling of p56lck from the TCR by anti-CD4 allows the kinase to transmit direct inhibitory signals via the inhibitory adaptor molecules Dok-1 and SHIP-1. Second, CD4+ T cells are killed by induction of antibody-dependent cell-mediated cytotoxicity, to which CD45RO+ cells are more sensitive than CD45RA+ cells. Finally, zanolimumab induces down-modulation of CD4 from cell surfaces via a slow Fc-dependent mechanism. In conclusion, zanolimumab rapidly inhibits T-cell signaling via a dual mechanism of action combined with potent Fc-dependent lysis of CD4+ T cells and may act long-term by down-regulating CD4.

Down-modulation of CXCR3 surface expression and function in CD8+ T cells from cutaneous T cell lymphoma patients

Viruses can escape destruction by the immune system by exploitation of the chemokine-chemokine receptor system. It is less established whether human cancers can adopt similar strategies to evade immunologic control. In this study, we show that advanced cutaneous T cell lymphoma (CTCL) is associated with selective and efficient inactivation of CXCR3-dependent T cell migration. Our studies demonstrate that this alteration is at least in part due to CXCR3 down-regulation in vivo by elevated serum levels of CXCR3 ligands. The T cell population most affected by this down-regulatory mechanism are CD8+ cytotoxic effector T cells. In CTCL patients, cytotoxic effector T cells have strongly reduced surface CXCR3 expression, accumulate in peripheral blood, but are virtually absent from CTCL tumor lesions, indicating an inability to extravasate into lymphoma tissue. CTCL-associated inactivation of effector cell recruitment may be a paradigmatic example of a new type of immune escape mechanisms shielding the neoplasm from a tumoricidal attack.

FOXP3+ regulatory T cells in cutaneous T-cell lymphomas: association with disease stage and survival

FOXP3 is a unique marker for CD4+CD25+ regulatory T cells (Tregs). In solid tumours, high numbers of Tregs are associated with a poor prognosis. Knowledge about the implications of Tregs for the behaviour of haematological malignancies is limited. In this study, skin biopsies from 86 patients with mycosis fungoides (MF) and cutaneous T-cell lymphoma (CTCL) unspecified were analysed for the expression of FOXP3 on tumour cells and tumour-infiltrating Tregs. Labelling of above 10% of the neoplastic cells was seen in one case classified as an aggressive epidermotropic CD8+ cytotoxic CTCL. In the remaining 85 cases, the atypical neoplastic infiltrate was either FOXP3 negative (n=80) or contained only very occasional weakly positive cells (n=5). By contrast, all biopsies showed varying numbers of strongly FOXP3+ tumour-infiltrating Tregs. MF with early or infiltrated plaques had significantly higher numbers of FOXP3+ Tregs than CTCL unspecified or advanced MF with tumours or transformation to large cell lymphoma. An analysis of all patients demonstrated that increasing numbers of FOXP3+ Tregs were associated with improved survival in both MF and CTCL unspecified. In conclusion, our data indicate that the presence of FOXP3+ Tregs in CTCL is associated with disease stage and patient survival.

CD13 and TCR clone: markers of early mycosis fungoides

Making a differential diagnosis between early mycosis fungoides and parapsoriasis is often difficult at the clinical and histological level. The aim of this study was to explore markers that could help in this process. A total of 88 patients were included in 2 categories: large plaque parapsoriasis and digitiform parapsoriasis. A histological examination was performed for each patient, and expression of the antigen My7 (CD13), which is lacking in cutaneous T-lymphomas (but not in inflammatory lesions) and rearrangement of the T-cell receptor gene were analysed. A histological aspect of epidermotropic cutaneous T-cell lymphoma was observed in 23.5% of cases of large plaque parapsoriasis and 15% of cases of digitiform parapsoriasis. A disappearance of My7 antigen was noted in the 2 forms of parapsoriasis, more frequently when there was cutaneous T-cell lymphoma histology. A cutaneous clone was observed in 10.3% of cases of large plaque parapsoriasis, but not of digitiform parapsoriasis. For 3 patients, a cutaneous clone and a disappearance of My7 were associated with a non-specific histology. Considering these histological, immunological and molecular biological data, it appears that My7 antigen combined with T-cell clone may help the dermatologist to confirm the diagnosis of early mycosis fungoides. Moreover, further studies will determine whether CD13 is an early prognostic marker of evolution of a parapsoriasis to mycosis fungoides. Finally, these results demonstrate that digitiform parapsoriasis can be an early stage of MF.