Hodgkin/Reed-Sternberg Cells Induce Fibroblasts to Secrete Eotaxin, a Potent Chemoattractant for T Cells and Eosinophils

The biology of classical Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is distinguished by several important biological characteristics. The presence of Hodgkin Reed Sternberg (HRS) cells is a defining feature of this disease. The tumor microenvironment with relatively few HRS cells in an expansive infiltrate of immune cells is another key feature. Numerous cell-cell mediated interactions and a plethora of cytokines in the tumor microenvironment collectively work to promote HRS cell growth and survival. Aberrancy and constitutive activation of core signal transduction pathways are a hallmark trait of cHL. Genetic lesions contribute to these dysregulated pathways and evasion of the immune system through a variety of mechanisms is another notable feature of cHL. While substantial elucidation of the biology of cHL has enabled advancements in therapy, increased understanding in the future of additional mechanisms driving cHL may lead to new treatment opportunities.

The Medium Obtained from the Culture of Hodgkin Lymphoma Cells Affects the Biophysical Characteristics of a Fibroblast Cell Model

The neoplastic Hodgkin-Reed-Sternberg (HRS) cells in Hodgkin lymphoma (HL) represent only 1-10% of cells and are surrounded by an inflammatory microenvironment. The HL cytokine network is a key point for the proliferation of HRS cells and for the maintenance of an advantageous microenvironment for HRS survival. In the tumor microenvironment (TME), the fibroblasts are involved in crosstalk with HRS cells. The aim of this work was to study the effect of lymphoma cell conditioned medium on a fibroblast cell population and evaluate modifications of cell morphology and proliferation. Hodgkin lymphoma-derived medium was used to obtain a population of "conditioned" fibroblasts (WS-1 COND). Differences in biophysical parameters were detected by the innovative device Celector^®. Fibroblast-HL cells interactions were reproduced in 3D co-culture spheroids. WS-1 COND showed a different cellular morphology with an enlarged cytoplasm and enhanced metabolism. Area and diameter cell values obtained by Celector^® measurement were increased. Co-culture spheroids created with WS-1 COND showed a tighter aggregation than those with non-conditioned WS-1. The presence of soluble factors derived from HRS cells in the conditioned medium was adequate for the proliferation of fibroblasts and conditioned fibroblasts in a 3D HL model allowed to develop a representative model of the in vivo TME.

Filling the Gap: The Immune Therapeutic Armamentarium for Relapsed/Refractory Hodgkin Lymphoma

Despite years of clinical progress which made Hodgkin lymphoma (HL) one of the most curable malignancies with conventional chemotherapy, refractoriness and recurrence may still affect up to 20–30% of patients. The revolution brought by the advent of immunotherapy in all kinds of neoplastic disorders is more than evident in this disease because anti-CD30 antibodies and checkpoint inhibitors have been able to rescue patients previously remaining without therapeutic options. Autologous hematopoietic cell transplantation still represents a significant step in the treatment algorithm for chemosensitive HL; however, the possibility to induce complete responses after allogeneic transplant procedures in patients receiving reduced-intensity conditioning regimens informs on its sensitivity to immunological control. Furthermore, the investigational application of adoptive T cell transfer therapies paves the way for future indications in this setting. Here, we seek to provide a fresh and up-to-date overview of the new immunotherapeutic agents dominating the scene of relapsed/refractory HL. In this optic, we will also review all the potential molecular mechanisms of tumor resistance, theoretically responsible for treatment failures, and we will discuss the place of allogeneic stem cell transplantation in the era of novel therapies.

Eosinophils in skin diseases

Eosinophil infiltration is a common finding in a broad spectrum of skin diseases, despite the fact that the skin is devoid of eosinophils under physiologic conditions. Although cutaneous eosinophilia is reactive, cytokine-mediated in most cases, diseases with an intrinsic mutation-mediated clonal expansion of eosinophils can also manifest on the skin. As eosinophils are involved in host defense, regulate immune responses, generate pruritus, induce remodeling and fibrosis, and can cause tissue damage, they have the capacity to actively contribute to the pathogenesis of diseases. Recent research provided deeper insights in the mechanisms, e.g., bacterial and viral clearance, blister formation, recruitment of cytotoxic T cells, and generation of pruritus, by which eosinophils might come into action. This review aims at providing an overview on the clinical presentations of eosinophil-associated dermatoses and the current understanding of their pathogenic role in these diseases. Further, we discuss the effects of therapies targeting eosinophils.

IL-10, IL-13, Eotaxin and IL-10/IL-6 ratio distinguish breast implant-associated anaplastic large-cell lymphoma from all types of benign late seromas

Breast implant-associated anaplastic large-cell lymphoma (BI-ALCL) is an uncommon peripheral T cell lymphoma usually presenting as a delayed peri-implant effusion. Chronic inflammation elicited by the implant has been implicated in its pathogenesis. Infection or implant rupture may also be responsible for late seromas. Cytomorphological examination coupled with CD30 immunostaining and eventual T-cell clonality assessment are essential for BI-ALCL diagnosis. However, some benign effusions may also contain an oligo/monoclonal expansion of CD30 + cells that can make the diagnosis challenging. Since cytokines are key mediators of inflammation, we applied a multiplexed immuno-based assay to BI-ALCL seromas and to different types of reactive seromas to look for a potential diagnostic BI-ALCL-associated cytokine profile. We found that BI-ALCL is characterized by a Th2-type cytokine milieu associated with significant high levels of IL-10, IL-13 and Eotaxin which discriminate BI-ALCL from all types of reactive seroma. Moreover, we found a cutoff of IL10/IL-6 ratio of 0.104 is associated with specificity of 100% and sensitivity of 83% in recognizing BI-ALCL effusions. This study identifies promising biomarkers for initial screening of late seromas that can facilitate early diagnosis of BI-ALCL.

SNPs in genes encoding for IL-10, TNF-α, and NFκB p105/p50 are associated with clinical prognostic factors for patients with Hodgkin lymphoma

Classical Hodgkin lymphoma (cHL) is a B-cell-derived malignant neoplasia that has a unique histological distribution, in which the scarce malignant Hodgkin and Reed-Sternberg cells are surrounded by nonmalignant inflammatory cells. The interactions between the malignant and inflammatory cells are mediated by aberrantly produced cytokines, which play an important role in tumor immunopathogenesis. Single nucleotide polymorphisms (SNPs) in genes encoding cytokines and their regulatory proteins may influence the peripheral levels of these molecules and affect disease’s pathobiology. In this study, we evaluate SNPs in the promoter regions of the genes encoding for two key cytokines in Hodgkin lymphoma: IL-10 (SNP/pIL10–592, rs1800872; and SNP/pIL10–1082, rs1800896) and TNF-α (SNP/pTNF -238, rs361525; and SNP/pTNF -862, rs1800630), as well as an SNP in the intronic region of the NFκB1 gene (SNP/iNFKB1, rs1585215), an important regulator of cytokine gene expression. We then look to their possible association with clinical and laboratory features in cHL patients. Seventy-three patients with cHL are genotyped by qPCR-high resolution melting. The SNPs’ genotypes are analyzed individually for each SNP, and when more than two allelic combinations are identified, the genotypes are also divided into two groups according to proposed biological relevance. By univariate analysis, patients harboring SNP/pTNF -238 AG genotype more frequently have EBV-associated cHL compared to homozygous GG, whereas the presence of mediastinal disease (bulky and nonbulky) is more common in the pIL10–592 AC/CC group compared to the AA homozygous group. Patients with SNP/iNFKB1 AA genotype more frequently have stage IV and extranodal disease at diagnosis. These results indicate that some SNPs’ genotypes for IL-10 and TNF-α genes are associated with prognostic parameters in cHL. For the first time, the SNP/iNFKB1 is described in association with clinical features of the disease.

Nodal histiocytic sarcoma with prominent eosinophilic infiltration: expression of eotaxin-2 on tumor cells

Background

Histiocytic sarcoma (HS) is a rare neoplasm showing morphological and immunophenotypic features of mature tissue histiocytes. We report a patient with nodal HS exhibiting prominent reactive eosinophilic infiltration.

Case presentation

A 68-year-old man presented with intermittent left lower abdominal pain and weight loss over 3 months. A computed tomography scan revealed multiple abdominal nodules. Open biopsy of the mesenteric tumors was performed for definitive diagnosis. Histologically, the tumor was comprised of a diffuse noncohesive proliferation of pleomorphic large cells, including multinucleated cells. Neoplastic cells were positive for histiocytic markers (CD68, CD163, and LIGHT) and PD-L1 but lacked markers of Langerhans cells, follicular dendritic cells, and epithelial cells. Frequent reactive inflammatory cells were intermingled in the background. Interestingly, prominent eosinophilic infiltration was also noted. Spindle neoplastic cells were prone to be present around areas with little to no eosinophilic infiltration and exhibiting fibrosis and lymphatic vessel proliferation. Conversely, polygonal neoplastic cells were prone to be present around areas with relatively large amounts of eosinophilic infiltration without fibrosis or lymphatic vessel proliferation. Immunohistochemically, the tumor cells and reactive eosinophils expressed eotaxin-2 and eotaxin-3, respectively.

Conclusion

We revealed that eotaxins induced the selective migration of eosinophils into tissues in this case. These eosinophils may affect the tumor remodeling and tumor biology characteristics of HS, such as fibrosis and lymphatic vessel proliferation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13000-020-01061-4.

The Evolving Knowledge on T and NK Cells in Classic Hodgkin Lymphoma: Insights into Novel Subsets Populating the Immune Microenvironment

Simple Summary

In classic Hodgkin lymphoma, T and NK cells constitute a significant fraction of the reactive microenvironment established by malignant Hodgkin Reed–Sternberg cells. Despite their abundance, T and NK cells remain largely ineffective because of two coordinated levels of immune evasion. The first is based on the acquisition of regulatory properties or exhausted phenotypes that cripple their antitumor activity. The second is represented by their peculiar spatial distribution, with the most immunosuppressive subpopulations lying in close proximity of neoplastic cells. Recent discoveries about the functional role and the spatial orientation of T and NK cells in classic Hodgkin lymphoma are the focus of this review.

Abstract

Classic Hodgkin lymphoma (cHL) is a unique lymphoid neoplasm characterized by extensive immune infiltrates surrounding rare malignant Hodgkin Reed–Sternberg (HRS) cells. Different subsets of T and NK cells have long been recognized in the cHL microenvironment, yet their distinct contribution to disease pathogenesis has remained enigmatic. Very recently, novel platforms for high dimensional analysis of immune cells, such as single-cell RNA sequencing and mass cytometry, have revealed unanticipated insights into the composition of T- and NK-cell compartments in cHL. Advances in imaging techniques have better defined specific T-helper subpopulations physically interacting with neoplastic cells. In addition, the identification of novel cytotoxic subsets with an exhausted phenotype, typically enriched in cHL milieu, is shedding light on previously unrecognized immune evasion mechanisms. This review examines the immunological features and the functional properties of T and NK subsets recently identified in the cHL microenvironment, highlighting their pathological interplay with HRS cells. We also discuss how this knowledge can be exploited to predict response to immunotherapy and to design novel strategies to improve PD-1 blockade efficacy.

A new dawn for eosinophils in the tumour microenvironment

Eosinophils are evolutionarily conserved, pleotropic cells that display key effector functions in allergic diseases, such as asthma. Nonetheless, eosinophils infiltrate multiple tumours and are equipped to regulate tumour progression either directly by interacting with tumour cells or indirectly by shaping the tumour microenvironment (TME). Eosinophils can readily respond to diverse stimuli and are capable of synthesizing and secreting a large range of molecules, including unique granule proteins that can potentially kill tumour cells. Alternatively, they can secrete pro-angiogenic and matrix-remodelling soluble mediators that could promote tumour growth. Herein, we aim to comprehensively outline basic eosinophil biology that is directly related to their activity in the TME. We discuss the mechanisms of eosinophil homing to the TME and examine their diverse pro-tumorigenic and antitumorigenic functions. Finally, we present emerging data regarding eosinophils as predictive biomarkers and effector cells in immunotherapy, especially in response to immune checkpoint blockade therapy, and highlight outstanding questions for future basic and clinical cancer research.

Formation of the Immunosuppressive Microenvironment of Classic Hodgkin Lymphoma and Therapeutic Approaches to Counter It

Classic Hodgkin lymphoma (cHL) is characterized by a few tumor cells surrounded by a protective, immunosuppressive tumor microenvironment composed of normal cells that are an active part of the disease. Hodgkin and Reed-Sternberg (HRS) cells evade the immune system through a variety of different mechanisms. They evade antitumor effector T cells and natural killer cells and promote T cell exhaustion. Using cytokines and extracellular vesicles, they recruit normal cells, induce their proliferation and "educate" (i.e. reprogram) them to become immunosuppressive and protumorigenic. Therefore, alternative treatment strategies are being developed to target not only tumor cells but also the tumor microenvironment. Here we summarize current knowledge on the ability of HRS cells to build their microenvironment and to educate normal cells to become immunosuppressive. We also describe therapeutic strategies to counteract formation of the tumor microenvironment and related processes leading to T cell exhaustion and repolarization of immunosuppressive tumor-associated macrophages.

Extracellular Vesicles: New Players in Lymphomas

Lymphomas are heterogeneous diseases, and the term includes a number of histological subtypes that are characterized by different clinical behavior and molecular phenotypes. Valuable information on the presence of lymphoma cell-derived extracellular vesicles (LCEVs) in the bloodstream of patients suffering from this hematological cancer has recently been provided. In particular, it has been reported that the number and phenotype of LCEVs can both change as the disease progresses, as well as after treatment. Moreover, the role that LCEVs play in driving tumor immune escape has been reported. This makes LCEVs potential novel clinical tools for diagnosis, disease progression, and chemoresistance. LCEVs express surface markers and convey specific molecules in accordance with their cell of origin, which can be used as targets and thus lead to the development of specific therapeutics. This may be particularly relevant since circulating LCEVs are known to save lymphoma cells from anti-cluster of differentiation (CD)20-induced complement-dependent cytotoxicity. Therefore, effort should be directed toward investigating the feasibility of using LCEVs as predictive biomarkers of disease progression and/or response to treatment that can be translated to clinical use. The use of liquid biopsies in combination with serum EV quantification and cargo analysis have been also considered as potential approaches that can be pursued in the future. Upcoming research will also focus on the identification of specific molecular targets in order to generate vaccines and/or antibodies against LCEVs. Finally, the removal of circulating LCEVs has been proposed as a simple and non-invasive treatment approach. We herein provide an overview of the role of LCEVs in lymphoma diagnosis, immune tolerance, and drug resistance. In addition, alternative protocols that utilize LCEVs as therapeutic targets are discussed.

Microenvironment Cell Contribution to Lymphoma Immunity

Lymphoma microenvironment is a complex system composed of stromal cells, blood vessels, immune cells as well as extracellular matrix, cytokines, exosomes, and chemokines. In this review, we describe the function, localization, and interactions between various cellular components. We also summarize their contribution to lymphoma immunity in the era of immunotherapy. Publications were identified from searching Pubmed. Primary literature was carefully evaluated for replicability before incorporating into the review. We describe the roles of mesenchymal stem/stromal cells (MSCs), lymphoma-associated macrophages (LAMs), dendritic cells, cytotoxic T cells, PD-1 expressing CD4+ tumor infiltrating lymphocytes (TILs), T-cells expressing markers of exhaustion such as TIM-3 and LAG-3, regulatory T cells, and natural killer cells. While it is not in itself a cell, we also include a brief overview of the lymphoma exosome and how it contributes to anti-tumor effect as well as immune dysfunction. Understanding the cellular players that comprise the lymphoma microenvironment is critical to developing novel therapeutics that can help block the signals for immune escape and promote tumor surveillance. It may also be the key to understanding mechanisms of resistance to immune checkpoint blockade and immune-related adverse events due to certain types of immunotherapy.

Hodgkin Lymphoma-Derived Extracellular Vesicles Change the Secretome of Fibroblasts Toward a CAF Phenotype

Secretion of extracellular vesicles (EVs) is a ubiquitous mechanism of intercellular communication based on the exchange of effector molecules, such as growth factors, cytokines, and nucleic acids. Recent studies identified tumor-derived EVs as central players in tumor progression and the establishment of the tumor microenvironment (TME). However, studies on EVs from classical Hodgkin lymphoma (cHL) are limited. The growth of malignant Hodgkin and Reed–Sternberg (HRS) cells depends on the TME, which is actively shaped by a complex interaction of HRS cells and stromal cells, such as fibroblasts and immune cells. HRS cells secrete cytokines and angiogenic factors thus recruiting and inducing the proliferation of surrounding cells to finally deploy an immunosuppressive TME. In this study, we aimed to investigate the role of tumor cell-derived EVs within this complex scenario. We observed that EVs collected from Hodgkin lymphoma (HL) cells were internalized by fibroblasts and triggered their migration capacity. EV-treated fibroblasts were characterized by an inflammatory phenotype and an upregulation of alpha-smooth muscle actin (α-SMA), a marker of cancer-associated fibroblasts. Analysis of the secretome of EV-treated fibroblast revealed an enhanced release of pro-inflammatory cytokines (e.g., IL-1α, IL-6, and TNF-α), growth factors (G-CSF and GM-CSF), and pro-angiogenic factors such as VEGF. These soluble factors are known to promote HL progression. In line, ingenuity pathway analysis identified inflammatory pathways, including TNF-α/NF-κB-signaling, as key factors directing the EV-dependent phenotype changes in fibroblasts. Confirming the in vitro data, we demonstrated that EVs promote α-SMA expression in fibroblasts and the expression of proangiogenic factors using a xenograft HL model. Collectively, we demonstrate that HL EVs alter the phenotype of fibroblasts to support tumor growth, and thus shed light on the role of EVs for the establishment of the tumor-promoting TME in HL.

Associations between elevated pre-treatment serum cytokines and peripheral blood cellular markers of immunosuppression in patients with lymphoma

Higher ratios of the pre-treatment peripheral blood absolute lymphocyte (ALC) to absolute monocyte counts (AMC) are associated with improved outcomes in lymphoma. Conversely, elevated pre-treatment serum cytokines are associated with inferior outcomes. The relationship between pre-treatment serum cytokines and ALC/AMC ratios remains unknown. We studied twelve serum cytokines and the ALC/AMC ratios in 390 patients with untreated diffuse large B-cell, follicular, mantle cell, T-cell, and Hodgkin lymphoma. Different pre-treatment serum cytokine concentrations correlated with ALC, AMC, and ALC/AMC ratios depending on the lymphoma type. In the entire cohort (n = 390) lower ALC/AMC ratios modestly correlated with higher IL-2R (r = -0.36), IL-12 (r = -0.17), IP-10 (r = -0.23), and MIG (r = -0.32) concentrations (p < 0.001). Elevated IL-2R was independently associated with suppressed ALC (OR 2.69, 95% CI 1.77-4.07, p < 0.001), elevated AMC (OR 2.05, 95% CI 1.34-3.14, p < 0.001), and suppressed ALC/AMC ratios (OR 3.51, 95% CI 2.31-5.34, p < 0.001). Both elevated IL-2R (HR 2.27, 95% CI 1.48-3.49, p < 0.001) and suppressed ALC/AMC ratios (HR 1.53, 95% CI 1.03-2.28, p = 0.037) were independently associated with inferior overall survival. These data support the notion that elevated serum cytokines are immunosuppressive and provide further rationale to target the tumor microenvironment for therapeutic benefit.

Undifferentiated Nasopharyngeal Carcinoma Mimicking Hodgkin Lymphoma With CD30 Expression

The presence of CD30-expressing Hodgkin-like cells with a background of inflammation and eosinophils in a young adolescent is usually diagnostic of classical Hodgkin lymphoma. Herein we present the case of a 12-year-old boy presenting with enlarged cervical lymph node characterized by the presence of Hodgkin-like cells expressing CD30 and EBV-LMP1 with a Hodgkin-like background. The Hodgkin-like cells were negative for CD15, CD20, CD45, and Pax-5. The tumor cells, however, expressed several cytokeratins, confirming the diagnosis of an undifferentiated carcinoma nasopharyngeal type. This case highlights the importance of possessing a high index of suspicion when encountering lymph nodes with Hodgkin-like cells and a Hodgkin-like background, even with CD30 expression, as the differential can include undifferentiated carcinoma nasopharyngeal type.

Tumor-Infiltrating Macrophages in Post-Transplant, Relapsed Classical Hodgkin Lymphoma Are Donor-Derived

Tumor-associated inflammatory cells in classical Hodgkin lymphoma (CHL) typically outnumber the neoplastic Hodgkin/Reed-Sternberg (H/RS) cells. The composition of the inflammatory infiltrate, particularly the fraction of macrophages, has been associated with clinical behavior. Emerging work from animal models demonstrates that most tissue macrophages are maintained by a process of self-renewal under physiologic circumstances and certain inflammatory states, but the contribution from circulating monocytes may be increased in some disease states. This raises the question of the source of macrophages involved in human disease, particularly that of CHL. Patients with relapsed CHL following allogeneic bone marrow transplant (BMT) provide a unique opportunity to begin to address this issue. We identified 4 such patients in our archives. Through molecular chimerism and/or XY FISH studies, we demonstrated the DNA content in the post-BMT recurrent CHL was predominantly donor-derived, while the H/RS cells were derived from the patient. Where possible to evaluate, the cellular composition of the inflammatory infiltrate, including the percentage of macrophages, was similar to that of the original tumor. Our findings suggest that the H/RS cells themselves define the inflammatory environment. In addition, our results demonstrate that tumor-associated macrophages in CHL are predominantly derived from circulating monocytes rather than resident tissue macrophages. Given the association between tumor microenvironment and disease progression, a better understanding of macrophage recruitment to CHL may open new strategies for therapeutic intervention.

Mechanisms underlying the association between obesity and Hodgkin lymphoma

A solid body of knowledge indicates that overweight and obese subjects are prone to develop cancer, aggressive disease, and death more than their lean counterparts. While obesity has been causally associated with various cancers, only a limited number of studies beheld the link with classical Hodgkin lymphoma (HL). Contemporary meta-analysis and prospective studies confirmed the association of body mass index with HL. Besides epidemiological evidence, excess adiposity is known to influence tumor behavior through adipokines, adipose-derived stem cell migration, and metabolism regulation, and by modulating immunoinflammatory response. Nevertheless, the obesity paradox has been described in few cancers. Considering that adipose tissue is an immunomodulatory organ, and that inflammation is the cornerstone of HL pathophysiology, the rationale for being causally related due to endocrine/paracrine interactions cannot be negligible. In this hypothesis-generating review, we explore the biologically plausible links between excess adiposity and HL in light of recent basic and clinical data, in order to create a basis for understanding the underlying mechanisms and foster applied research. The establishment of an association of excess adiposity with HL will determine public health preventive measures to fight obesity and eventually novel therapeutic approaches in HL patients.

Role of the tumor microenvironment in regulating apoptosis and cancer progression

Apoptosis is a gene-directed program that is engaged to efficiently eliminate dysfunctional cells. Evasion of apoptosis may be an important gate to tumor initiation and therapy resistance. Like any other developmental program, apoptosis can be disrupted by several genetic aberrations driving malignant cells into an uncontrolled progression and survival. For its sustained growth, cancer develops in a complex environment, which provides survival signals and rescues malignant cells from apoptosis. Recent studies have clearly shown a wide interaction between tumor cells and their microenvironment, confirming the influence of the surrounding cells on tumor expansion and invasion. These non-malignant cells not only intensify tumor cells growth but also upgrade the process of metastasis. The strong crosstalk between malignant cells and a reactive microenvironment is mediated by soluble chemokines and cytokines, which act on tumor cells through surface receptors. Disturbing the microenvironment signaling might be an encouraging approach for patient's treatment. Therefore, the ultimate knowledge of "tumor-microenvironment" interactions facilitates the identification of novel therapeutic procedures that mobilize cancer cells from their supportive cells. This review focuses on cancer progression mediated by the dysfunction of apoptosis and by the fundamental relationship between tumor and reactive cells. New insights and valuable targets for cancer prevention and therapy are also presented.

Hodgkin lymphoma: Pathology and biology

The Hodgkin and Reed-Sternberg (HRS) tumor cells of classical Hodgkin lymphoma (HL), as well as the lymphocyte predominant (LP) cells of nodular lymphocyte predominant HL (NLPHL), are derived from mature B cells. However, HRS cells have largely lost their B-cell phenotype and show a very unusual expression of many markers of other hematopoietic cell lineages, which aids in the differential diagnosis between classical HL (cHL) and NLPHL and distinguishes cHL from all other hematopoietic malignancies. The bi- or multinucleated Reed-Sternberg cells most likely derive from the mononuclear Hodgkin cells through a process of incomplete cytokinesis. HRS cells show a deregulated activation of numerous signaling pathways, which is partly mediated by cellular interactions in the lymphoma microenvironment and partly by genetic lesions. In a fraction of cases, Epstein-Barr virus contributes to the pathogenesis of cHL. Recurrent genetic lesions in HRS cells identified so far often involve members of the nuclear factor-κB (NF-κB) and JAK/STAT pathways and genes involved in major histocompatibility complex expression. However, further lead transforming events likely remain to be identified. We here discuss the current knowledge on HL pathology and biology.

Cancer associated fibroblasts in hematological malignancies

Tumor microenvironment plays an important role in cancer initiation and progression. In hematological malignancies, the bone marrow represents the paradigmatic anatomical site in which tumor microenvironment expresses its morphofunctional features. Among the cells participating in the composition of this microenvironment, cancer associated fibrobasts (CAFs) have received less attention in hematopoietic tumors compared to solid cancers. In this review article, we discuss the involvement of CAFs in progression of hematological malignancies and the potential targeting of CAFs in a therapeutic perspective.

Expression of Interleukin-1 and Interleukin-1 Receptors Type 1 and Type 2 in Hodgkin Lymphoma

Signaling through the IL-1-receptor type 1 (IL-1R1), IL-1 is required for initiation and maintenance of diverse activities of the immune system. A second receptor, IL-1R2, blocks IL-1 signal transduction. We studied expression of IL-1beta, IL-1R1, and IL-1R2 in 17 Hodgkin lymphomas (HL) by in situ hybridization (ISH). IL-1beta expressing cells, morphologically consistent with endothelial cells and fibroblasts, occurred in all HL tissues with elevated transcript levels in areas of active fibrosis. Hodgkin and Reed-Sternberg (HRS) cells of all cases expressed low IL-1R1 transcript levels in some tumor cells, and high levels of IL-1R2 in large proportions of HRS cells. Only few bystander cells showed low levels of IL-1R1 and IL-1R2 RNA. Supernatants of 4 out of 7 HL-derived cell lines contained soluble IL-1R2 protein at high levels. HL patient sera carried variably amounts of IL-1R2 protein with significantly increased titers in patients with active disease compared to patients in complete remission and control individuals without HL. Western blots and co-immunoprecipitations showed binding of the IL-1R2 to the intracellular IL-1R-accessory protein (IL-1IRAcP). These data suggest functions of the IL-1R2 as a „decoy-receptor” sequestrating paracrine IL-1 extracellularly and intracellularly by engaging IL-1IRAcP, thus depriving IL1-R1 molecules of their extracellular and intracellular ligands. Expression of IL1-R2 by HRS cells seems to contribute to local and systemic modulation of immune function in HL.

The role of T cells in the microenvironment of Hodgkin lymphoma

The cellular microenvironment in HL is dominated by a mixed infiltrate of inflammatory cells with typically only 1 or a few percent of HRS tumor cells. HRS cells orchestrate this infiltrate by the secretion of a multitude of chemokines. T cells are usually the largest population of cells in the HL tissue, encompassing Th cells, T(regs), and CTLs. Th cells and T(regs) presumably provide essential survival signals for the HRS cells, and the T(regs) also play an important role in rescuing HRS cells from an attack by CTLs and NK cells. The interference with this complex interplay of HRS cells with other immune cells in the microenvironment may provide novel strategies for targeted immunotherapies.

Microenvironment-related biomarkers and novel targets in classical Hodgkin's lymphoma

Classical Hodgkin's lymphoma accounts for approximately 10% of all malignant lymphomas. Although most patients can be cured with modern treatment strategies, approximately 25% of them experience either primary or secondary chemorefractoriness or disease relapse, thus requiring novel treatments. Increasing preclinical and clinical evidences have demonstrated the role of microenvironment in the molecular pathogenesis of classical Hodgkin's lymphoma and elucidated the complex cross-talk between the malignant Hodgkin Reed–Sternberg cells and the nonmalignant, reactive cells of the microenvironment, strongly supporting novel therapeutic approaches aimed at targeting Hodgkin's Reed–Sternberg cells along with reactive cells in order to overcome chemorefractoriness. In the near future, these novel therapies will also be tested in chemosensitive patients to reduce long-term toxicities of chemo-radiotherapy.

Eosinophilia in Dermatologic Disorders

Eosinophil infiltration can be observed in skin disorders, such as allergic/immunologic, autoimmune, infectious, and neoplastic diseases. Clinical presentations are variable and include eczematous, papular, urticarial, bullous, nodular, and fibrotic lesions; pruritus is a common symptom in all. In this review, we present representative eosinophilic skin diseases according to their clinical pattern, together with histologic findings and diagnostic procedures. We also discuss the potential roles of eosinophils in the pathogenesis of dermatologic disorder. Current pathogenesis-based diagnostic and therapeutic approaches are outlined.

Lymphomagenesis in Hodgkin lymphoma

Hodgkin lymphoma (HL) accounts for approximately 0.6% of all new cancer cases, 10% of all lymphomas in the USA, leading to an approximate 9000 new cases per year. It is very unique in that the neoplastic Hodgkin and Reed-Sternberg (HRS) cells of classical HL account for only 1% of the tumor tissue in most cases, with various inflammatory cells including B-cells, T-cells, mast cells, macrophages, eosinophils, neutrophils, and plasma cells comprising the tumor microenvironment. Recent research has identified germinal center B-cells to be the cellular origin of HRS cells. Various transcription factor dysregulation in these neoplastic cells that explains for the loss of B-cell phenotype as well as acquisition of survival and anti-apoptotic features of HRS cells has been identified. Aberrant activation of nuclear factor-kappa B (NF-κB), Janus kinase (JAK)/signal transducer and activator of transcription (STAT), and phosphoinositide 3-kinase (PI3K) pathways play a central role in HL pathogenesis. Both intrinsic genetic mechanisms as well as extrinsic signals have been identified to account for the constitutive activation of these pathways. The extrinsic factors that regulate the activation of transcription pathways in HRS cells have also been studied in detail. Cytokines and chemokines produced both by the HRS cells as well as cells of the microenvironment of HL work in an autocrine and/or paracrine manner to promote survival of HRS cells as well as providing mechanisms for immune escape from the body's antitumor immunity. The understanding of various mechanisms involved in the lymphomagenesis of HL including the importance of its microenvironment has gained much interest in the use of these microenvironmental features as prognostic markers as well as potential treatment targets. In this article, we will review the pathogenesis of HL starting with the cellular origin of neoplastic cells and the mechanisms supporting its pathogenesis, especially focusing on the microenvironment of HL and its associated cytokines.

The Epstein-Barr virus and the pathogenesis of lymphoma

Since the discovery in 1964 of the Epstein-Barr virus (EBV) in African Burkitt lymphoma, this virus has been associated with a remarkably diverse range of cancer types. Because EBV persists in the B cells of the asymptomatic host, it can easily be envisaged how it contributes to the development of B-cell lymphomas. However, EBV is also found in other cancers, including T-cell/natural killer cell lymphomas and several epithelial malignancies. Explaining the aetiological role of EBV is challenging, partly because the virus probably contributes differently to each tumour and partly because the available disease models cannot adequately recapitulate the subtle variations in the virus-host balance that exist between the different EBV-associated cancers. A further challenge is to identify the co-factors involved; because most persistently infected individuals will never develop an EBV-associated cancer, the virus cannot be working alone. This article will review what is known about the contribution of EBV to lymphoma development.

Contribution of the Epstein-Barr Virus to the Pathogenesis of Hodgkin Lymphoma

The morphology of the pathognomonic Hodgkin and Reed-Sternberg cells (HRS) of Hodgkin lymphoma was described over a century ago, yet it was only relatively recently that the B-cell origin of these cells was identified. In a proportion of cases, HRS cells harbour monoclonal forms of the B lymphotropic Epstein-Barr virus (EBV). This review summarises current knowledge of the pathogenesis of Hodgkin lymphoma with a particular emphasis on the contribution of EBV.

Control of the inflammatory response mechanisms mediated by natural and induced regulatory T-cells in HCV-, HTLV-1-, and EBV-associated cancers

Virus infections are involved in chronic inflammation and, in some cases, cancer development. Although a viral infection activates the immune system's response that eradicates the pathogen mainly through inflammatory mechanisms, it is now recognized that this inflammatory condition is also favorable to the development of tumors. Indeed, it is well described that viruses, such as hepatitis C virus (HCV), Epstein Barr virus (EBV), human papillomavirus (HPV) or human T-cell lymphotropic virus type-1 (HTLV-1), are important risk factors for tumor malignancies. The inflammatory response is a fundamental immune mechanism which involves several molecular and cellular components consisting of cytokines and chemokines that are released by various proinflammatory cells. In parallel to this process, some endogenous recruited components release anti-inflammatory mediators to restore homeostasis. The development of tools and strategies using viruses to hijack the immune response is mostly linked to the presence of regulatory T-cells (Treg) that can inhibit inflammation and antiviral responses of other effector cells. In this review, we will focus on current understanding of the role of natural and induced Treg in the control and the resolution of inflammatory response in HCV-, HTLV-1-, and EBV-associated cancers.

From airway inflammation to inflammatory bowel disease: eotaxin-1, a key regulator of intestinal inflammation

Eotaxin-1 (CCL-11) is a potent eosinophil chemoattractant that is considered a major contributor to tissue eosinophilia. Elevated eotaxin-1 levels have been described in various pathologic conditions, ranging from airway inflammation, to Hodgkin lymphoma, obesity and coronary artery disease. The main receptor for eotaxin-1 is CCR3; however, recent evidence indicates that eotaxin-1 may also bind to other receptors expressed by various cell types, suggesting a more widespread regulatory role for eotaxin-1 beyond the recruitment of eosinophils. Eotaxin-1 is also strongly associated with various gastrointestinal (GI) disorders. Although the etiology of inflammatory bowel disease (IBD) is still unknown, eotaxin-1 may play a key role in the development of mucosal inflammation. In this review, we summarize the biological context and effects of eotaxin-1, as well as its potential role as a therapeutic target, with a special focus on gastrointestinal inflammation.

5-lipoxygenase-dependent recruitment of neutrophils and macrophages by eotaxin-stimulated murine eosinophils

The roles of eosinophils in antimicrobial defense remain incompletely understood. In ovalbumin-sensitized mice, eosinophils are selectively recruited to the peritoneal cavity by antigen, eotaxin, or leukotriene(LT)B4, a 5-lipoxygenase (5-LO) metabolite. 5-LO blockade prevents responses to both antigen and eotaxin. We examined responses to eotaxin in the absence of sensitization and their dependence on 5-LO. BALB/c or PAS mice and their mutants (5-LO-deficient ALOX; eosinophil-deficient GATA-1) were injected i.p. with eotaxin, eosinophils, or both, and leukocyte accumulation was quantified up to 24 h. Significant recruitment of eosinophils by eotaxin in BALB/c, up to 24 h, was accompanied by much larger numbers of recruited neutrophils and monocytes/macrophages. These effects were abolished by eotaxin neutralization and 5-LO-activating protein inhibitor MK886. In ALOX (but not PAS) mice, eotaxin recruitment was abolished for eosinophils and halved for neutrophils. In GATA-1 mutants, eotaxin recruited neither neutrophils nor macrophages. Transfer of eosinophils cultured from bone-marrow of BALB/c donors, or from ALOX donors, into GATA-1 mutant recipients, i.p., restored eotaxin recruitment of neutrophils and showed that the critical step dependent on 5-LO is the initial recruitment of eosinophils by eotaxin, not the secondary neutrophil accumulation. Eosinophil-dependent recruitment of neutrophils in naive BALB/c mice was associated with increased binding of bacteria.

The inflammatory chemokine CCL5 and cancer progression

Until recently, inflammatory chemokines were viewed mainly as indispensable “gate keepers” of immunity and inflammation. However, updated research indicates that cancer cells subvert the normal chemokine system and these molecules and their receptors become important constituents of the tumor microenvironment with very different ways to exert tumor-promoting roles. The CCR5 and the CCL5 ligand have been detected in some hematological malignancies, lymphomas, and a great number of solid tumors, but extensive studies on the role of the CCL5/CCR axis were performed only in a limited number of cancers. This review summarizes updated information on the role of CCL5 and its receptor CCR5 in cancer cell proliferation, metastasis, and the formation of an immunosuppressive microenvironment and highlights the development of newer therapeutic strategies aimed to inhibit the binding of CCL5 to CCR5, to inhibit CCL5 secretion, or to inhibit the interactions among tumor cells and the microenvironment leading to CCL5 secretion.

The microenvironment in classical Hodgkin lymphoma: an actively shaped and essential tumor component

Classical Hodgkin lymphoma (cHL) is characterized by a minority of tumor cells derived from germinal center B-cells and a vast majority of non-malignant reactive cells. The tumor cells show a loss of B-cell phenotype including lack of the B-cell receptor, which makes the tumor cells vulnerable to apoptosis. To overcome this threat, tumor cells and their precursors depend on anti-apoptotic and growth stimulating factors that are obtained via triggering of multiple membrane receptors. In addition, tumor cells shape the environment by producing a wide variety of chemokines and cytokines. These factors alter the composition of the microenvironment and modulate the nature and effectiveness of the infiltrating cells. The attracted cells enhance the pro-survival and growth stimulating signals for the tumor cells. To escape from an effective anti-tumor response tumor cells avoid recognition by T and NK cells, by downregulation of HLA molecules and modulating NK and T-cell receptors. In addition, the tumor cells produce immune suppressive cytokines that inhibit cytotoxic responses. In this review the relevance of the microenvironment in the pathogenesis of cHL will be discussed.

Role of immune escape mechanisms in Hodgkin's lymphoma development and progression: a whole new world with therapeutic implications

Hodgkin's lymphoma represents one of the most frequent lymphoproliferative syndromes, especially in young population. Although HL is considered one of the most curable tumors, a sizeable fraction of patients recur after successful upfront treatment or, less commonly, are primarily resistant. This work tries to summarize the data on clinical, histological, pathological, and biological factors in HL, with special emphasis on the improvement of prognosis and their impact on therapeutical strategies. The recent advances in our understanding of HL biology and immunology show that infiltrated immune cells and cytokines in the tumoral microenvironment may play different functions that seem tightly related with clinical outcomes. Strategies aimed at interfering with the crosstalk between tumoral Reed-Sternberg cells and their cellular partners have been taken into account in the development of new immunotherapies that target different cell components of HL microenvironment. This new knowledge will probably translate into a change in the antineoplastic treatments in HL in the next future and hopefully will increase the curability rates of this disease.

Nuclear factor-κB2 represses Sp1-mediated transcription at the CD99 promoter

Downregulation of the CD99 antigen on the surface of Hodgkin's lymphoma (HL) cells via EBV LMP1-mediated NF-κB suppression of Sp1 transcriptional activity is known to be associated with the appearance of pathogenic Reed-Sternberg cells. Here, we show that in addition, EBV LMP1 heterologous NF-κB activators such as CD30 and CD40 repress the CD99 promoter, which contains multiple Sp1-binding sites but no NF-κB binding sites. In addition, NF-κB-inducing kinase (NIK) repressed the CD99 promoter while NIK kinase mutants and JNK inhibitory protein failed to do so. Of the NF-κB subunits, NF-κB2 (p52) alone or in combination with other Rel subunits consistently inhibited the CD99, while NF-κB1 (p50) showed a marginal repressive effect. Furthermore, while transfection of LMP1 repressed the CD99 promoter in wild-type or NF-κB1 deficient MEFs, the same repression was not observed in NF-κB2 (p52)-deficient MEFs, indicating that NF-κB2 (p52) is required for LMP1-mediated repression of the CD99 promoter. Consistently, basal activity of the CD99 promoter was significantly higher in IKKα(-/-) and IKKβ(-/-) MEFs, but not in IKKΓ(-/-) MEFs compared to the wild-type control MEFs. Sp1-binding sites were directly used in the repression, because a synthetic Sp1 reporter with 10 Sp1-binding sites from the CD99 promoter was repressed by LMP1 or p52 transfection. These data indicate that LMP1-mediated NF-κB2 exhibits the major inhibitory role in the transcription at the CD99 promoter.

Distinct eosinophil cytokine expression patterns in skin diseases - the possible existence of functionally different eosinophil subpopulations

BACKGROUND

The function of eosinophils has been attributed to host defense, immunomodulation, and fibrosis. Although eosinophils are found among infiltrating cells in a broad spectrum of skin diseases, their pathogenic role remains uncertain. This study aimed to analyze the cytokine expression by eosinophils in different skin diseases.

METHODS

Skin specimens from different skin diseases [allergic/reactive, infectious, autoimmune, and tumors/lymphomas (LY)] were stained by antibodies directed to eosinophil cationic protein, cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-5, IL-6, IL-10, IL-11, IL-13, IL-17, IL-25, IL-33, interferon-γ, transforming growth factor (TGF)-β, and thymic stromal lymphopoietin], eotaxins (CCL11, CCL24, and CCL26), metalloproteinase (MMP)-9 as well as extracellular matrix proteins (tenascin-C and procollagen-3) and then analyzed by laser scanning microscopy.

RESULTS

The number of eosinophils varied considerably in and between disease groups and did not correlate with the numbers of accompanying inflammatory cells. The expression of IL-5, IL-6, IL-11, TGF-β, CCL24, and MMP-9 by eosinophils significantly differed between disease groups. Eosinophils in tumors/LY predominantly expressed IL-6, TGF-β, and CCL24, but not IL-11. On the other hand, in autoimmune diseases, eosinophils largely contributed to MMP-9 production. IL-5-generating eosinophils were particularly obvious in allergic and infectious diseases.

CONCLUSION

In skin diseases, eosinophil expresses a broad spectrum of cytokines. The different cytokine expression patterns suggest distinct functional roles of eosinophils in these diseases that might be related to host defense, immunomodulation, fibrosis, and/or tumor development.

The molecular pathogenesis of Hodgkin lymphoma

Hodgkin lymphoma (HL) is an unusual malignancy in that the tumour cells, the Hodgkin and Reed-Sternberg (HRS) cells, are a minor component of the tumour mass, the bulk of which is a mixed cellular infiltrate. There is compelling evidence that HRS cells are clonal B cells that have lost their B cell phenotype. Mature B cells lacking B cell receptors would normally die by apoptosis, and therefore HRS cells must have developed mechanisms to facilitate survival. The escape from apoptosis and transcriptional reprogramming of HRS cells are interlinked and appear central to disease pathogenesis. Epstein-Barr virus (EBV) is present in the HRS cells of a proportion of cases and expresses genes with a plausible oncogenic function. It is likely that EBV plays a role in reprogramming and survival through dysregulation of several signalling networks and transcription factors, including nuclear factor (NF)-κB. Activation of NF-κB is a feature of all HRS cells and gene mutations affecting this pathway appear common in EBV-negative HL. The HRS cell furthers its own survival by attracting a supportive microenvironment of immune and stromal cells, and suppressing local immune responsiveness. Although many questions remain unanswered, the last two decades have witnessed a considerable increase in our knowledge of this complex disease.

[Cutaneous lymphoma and chemokine]

The expression pattern of chemokines and chemokine receptors is specific to certain organs and cells. Therefore, chemokines are important to elucidate the mechanism of organ-specific human diseases such as cutaneous lymphoma, characterized by proliferation of clonally expanded lymphocytes in skin without detectable systemic involvement. The most popular type of cutaneous lymphoma is T cell lymphoma, including mycosis fungoides and Sezary syndrome. We have reported that CCL17, CCL27, CCL11, and CCL26 are involved in progression of these diseases. The above chemokines are highly expressed in the lesional skin and serum levels of the chemokines are elevated as the disease progressed. Moreover, CXCL9 and CXCL10 are associated with epidermotropism of tumor cells, CCL21 is important for tumor invasion to lymph nodes, and CXCL12 may explain downregulation of CD26 on the cell surface. CXCL13 expression in lymphoid follicular formation in skin and CCR3 expression on tumor cells in CD30(+) lymphoproliferative disorders are also discussed. Biologics targeting chemokines and their receptors are promising strategies for cutaneous lymphoma. Indeed, humanized anti-CCR4 monoclonal antibody showed potent antitumor activity against CCR4(+) lymphoma cells both in vitro and ex vivo. This antibody may also be useful for allergic diseases such as hay fever. Further study on chemokines and chemokine receptors will be helpful for new classification of cutaneous lymphoma, elucidation of pathogenesis, and development of new therapeutic strategies.

Molecular Pathogenesis of Hodgkin's Lymphoma: Increasing Evidence of the Importance of the Microenvironment

Hodgkin's lymphoma (HL) represents the most common subtype of malignant lymphoma in young people in the Western world. Most patients can be cured with modern treatment strategies, although approximately 20% will die after relapse or progressive disease. The histologic hallmark of the disease is the presence of the characteristic Hodgkin Reed-Sternberg (HRS) cells in classical HL and so-called lymphocyte-predominant (LP) cells in nodular lymphocyte-predominant HL. HL is unique among all cancers because malignant cells are greatly outnumbered by reactive cells in the tumor microenvironment and make up only approximately 1% of the tumor. Expression of a variety of cytokines and chemokines by the HRS and LP cells is believed to be the driving force for an abnormal immune response, perpetuated by additional factors secreted by reactive cells in the microenvironment that help maintain the inflammatory milieu. The malignant HRS and LP cells manipulate the microenvironment, permitting them to develop their malignant phenotype fully and evade host immune attack. Gene expression signatures derived from non-neoplastic cells correlate well with response to initial and subsequent therapies, reflecting their functional relevance. Recent biomarker studies have added texture to clinical outcome predictors, and their incorporation into prognostic models may improve our understanding of the biologic correlates of treatment failure. Moreover, recent preclinical and clinical studies have demonstrated that the tumor microenvironment represents a promising therapeutic target, raising hope that novel treatment strategies focused on the interface between malignant and reactive cells will soon emerge.

Organ-specific eosinophilic disorders of the skin, lung, and gastrointestinal tract

Eosinophils are multifunctional leukocytes that increase in various tissues in patients with a variety of disorders. Locally, they can be involved in the initiation and propagation of diverse inflammatory responses. In this review the clinical association of eosinophils with diseases of the skin, lung, and gastrointestinal tract is summarized. An approach to determining the causal role of eosinophils in these diseases is presented. Recent findings concerning molecular diagnosis, cause, and treatment are discussed.

Chemokines and cutaneous lymphoma

Chemokines are small molecules of 8-10kDa that induce chemotaxis and activation of certain subsets of leukocytes. It has been recently shown that chemokines have broader function such as inhibition of apoptosis of target cells. The expression patterns of chemokines and chemokine receptors are specific to certain organs and cells. Therefore, chemokines are important to elucidate the mechanism of organ-specific human diseases. Primary cutaneous lymphomas are characterized by proliferation of clonally expanded lymphocytes in skin, but without detectable systemic involvement at the first diagnosis. Many chemokines are reported to be expressed in lesional skin of cutaneous lymphoma. Moreover, tumor cells of a certain group of cutaneous lymphoma express limited numbers of chemokine receptors, suggesting that interactions between chemokines and their receptors may explain skin-tropism of these types of lymphoma. This article focuses on chemokines expressed in lesional skin of cutaneous lymphoma and discusses their possible roles in disease progression.

Eotaxins and CCR3 interaction regulates the Th2 environment of cutaneous T-cell lymphoma

CC chemokine receptor 3 (CCR3), the sole receptor for eotaxins, is expressed on eosinophils and T helper type 2 (Th2) cells. In Hodgkin's disease, eotaxin-1 secreted by fibroblasts collects Th2 cells and eosinophils within the tissue. Similarly, many Th2 cells infiltrate the lesional skin of cutaneous T-cell lymphoma (CTCL). In this study, we investigated the role of eotaxins in the development of the Th2 environment of CTCL. We revealed that fibroblasts from lesional skin of CTCL expressed higher amounts of eotaxin-3 messenger RNA (mRNA) compared with those from normal skin. Lesional skin of CTCL at advanced stages contained significantly higher levels of eotaxin-3 and CCR3 mRNA, compared with early stages of CTCL. IL-4 mRNA was expressed in some cases at advanced stages. Immunohistochemistry revealed that keratinocytes, endothelial cells, and dermal fibroblasts in lesional skin of CTCL showed a stronger expression of eotaxin-3 than did normal skin. CCR3(+) lymphocytes and IL-4 expression were observed in some cases of advanced CTCL. Furthermore, both serum eotaxin-3 and eotaxin-1 levels of CTCL patients at advanced stages were significantly higher than those of healthy individuals. The concentrations of these chemokines correlated with serum soluble IL-2 receptor levels. These results suggest that interaction of eotaxins and CCR3 regulates the Th2-dominant tumor environment, which is closely related to the development of CTCL.

Functional coexpression of Interleukin (IL)-7 and its receptor (IL-7R) on Hodgkin and Reed-Sternberg cells: Involvement of IL-7 in tumor cell growth and microenvironmental interactions of Hodgkin's lymphoma

The clinical and pathological features of classical Hodgkin lymphoma (cHL) mirror an abnormal tissue and systemic immune response due to the production of a variety of cytokines and chemokines by the malignant Hodgkin-Reed-Sternberg (H-RS) cells and/or surrounding reactive cells. Here, we demonstrate that HL-derived cell lines (L-428, KM-H2, HDLM-2, L-1236 and L-540) and primary H-RS cells from lymph node tissues of HL patients express the IL-7(R) receptor. IL-7 appears to be involved in autocrine circuitries of HL because L-1236, HDLM-2 and KM-H2 cells display the constitutive production of IL-7 and neutralizing anti-IL-7 antibodies induces a statistically significant inhibition of their basal proliferation. In addition, IL-7, either exogenous or fibroblasts-derived, promotes the clonogenic growth and reduces apoptosis of cultured H-RS cells, being also able to partially protect these cells from the cytotoxic effects of doxorubicin. We also provide evidence that IL-7 stimulates IL-6 secretion from IL-7R-expressing fibroblasts from HL-involved lymph nodes (HLFs), and that a striking increase in IL-6 secretion can be observed in cocultures of HLFs with L1236 cells. Finally, we show that L-1236 cells-derived IL-7 represents a costimulator for proliferation of purified CD4+CD25+CD127(dim/-) regulatory T cells (Tregs). Taken together, our data indicates that the IL-7/IL-7R axis constitutes an additional signaling pathway between H-RS cells and their reactive cellular background, thereby affecting proliferation and survival of tumor cells, acting as a cofactor for Tregs expansion and enhancing the microenviromental production of IL-6, a cytokine associated with the presence of "B" symptoms and a poor outcome in HL patients.

Pathogenesis of classical and lymphocyte-predominant Hodgkin lymphoma

Hodgkin and Reed-Sternberg (HRS) cells in classical Hodgkin lymphoma (HL) and lymphocytic and histiocytic (L&H) cells in nodular lymphocyte-predominant HL (NLPHL) are derived from germinal-center B cells. HRS cells have, however, largely lost their B cell phenotype and aberrantly express markers and transcriptional regulators of other hematolymphoid cell types. Deregulation of multiple signaling pathways and downstream transcription factors, including receptor tyrosine kinases, nuclear factor-kappa B (NF-kappaB), and Janus kinase/signal transducer and activator of transcription (JAK/STAT), is a further hallmark of HRS cells. These cells harbor genetic lesions that contribute to or cause increases in the activity of transcription factors of the NF-kappaB and STAT families. HRS cells are found within a mixed reactive cellular infiltrate and interact with these nonmalignant cells in a complex fashion that appears to be essential for HRS cell survival and proliferation. Less is known about the pathogenesis of L&H cells in NLPHL, but increases in the activity of receptor tyrosine kinases, NF-kappaB, and JAK/STAT have also been detected.

Elevated pretreatment interleukin-10 serum level is an International Prognostic Score (IPS)-independent risk factor for early treatment failure in advanced stage Hodgkin lymphoma

Early treatment failure is still a clinical challenge despite high cure rates in Hodgkin lymphoma (HL) patients. To identify the biological risk factors predicting early treatment failure, we performed a retrospective case-control study. Forty-seven pretherapeutic serum samples were available from 47 advanced stage HL patients with early treatment failure and from 47 matched controls in complete remission. All patients were treated within German Hodgkin Study Group phase 3 trials. Matching was done according to treatment, stage, age, gender, International Prognostic Score (IPS) and histological subtype. Pretreatment serum levels of 30 cytokines, chemokines and soluble receptors were determined using immunoassays and flow cytometer based cytometric bead arrays. Only interleukin-10 serum levels were significantly associated with early treatment failure after statistical correction for multitesting (paired-sign test, p = 0.0008). In summary, pretherapeutic interleukin-10 levels are associated with early treatment failure within 12 months after the end of treatment in advanced stage HL independently from known clinical factors such as age or IPS.

The biology of Hodgkin's lymphoma

Hodgkin's lymphoma was first described in 1832. The aetiology of this lymphoma, however, remained enigmatic for a long time. Only within the past 10 years has the B-cell nature of the pathognomonic Hodgkin and Reed-Sternberg (HRS) cells been revealed, along with several recurrent genetic lesions. The pathogenetic role for Epstein-Barr virus infection has also been substantiated. HRS cells in classical Hodgkin's lymphoma have several characteristics that are unusual for lymphoid tumour cells, and the Hodgkin's lymphoma microenvironment is dominated by an extensive mixed, potentially inflammatory cellular infiltrate. Understanding the contribution of all of these changes to the pathogenesis of this disease is essential for the development of novel therapies.