Hodgkin's disease: a tumor with disturbed immunological pathways

The Relationship Between Thrombo-Inflammatory Biomarkers and Cellular Indices of Inflammation in Lymphoma Patients

Introduction

Thrombo-inflammatory biomarkers play an important role in the pathogenesis of lymphoma. We aimed to characterize the interrelationship of thrombo-inflammatory biomarkers and blood cellular indices in lymphoma patients.

Materials and Methods

Ninety-eight lymphoma patient samples were collected from Lymphoma Center of Clinic of Hematology, University of Belgrade, Serbia. Normal controls (n = 50) represented plasma from healthy individuals. Plasminogen activator inhibitor (PAI-1), D-Dimer, factor XIII, C-reactive protein (CRP), microparticles (Mp), Von Willebrand factor (vWF), total protein S, urokinase-type plasminogen activator (uPA), tumor necrosis factor (TNFα), β2-glycoprotein I (β2GPI), and fibronectin levels were measured utilizing commercially-available ELISA methods. Thrombin generation profile (TGA) was measured using a fluorometric kinetic assay. Platelets, leukocytes, lymphocytes, and neutrophils were measured in conjunction with the complete blood profile.

Results

Statistically significant differences were noted in levels of PAI-1, D-Dimer, factor XIII, CRP, microparticles, vWF, uPA, TNFα, β2GPI, fibronectin, and TGA when compared to normal (all P values < .001). Platelet to leukocyte ratio (PLA) correlated to TNFα and fibronectin (R = −0.31 and −0.53, respectively) and the platelet to neutrophil ratio (PNR) correlated to factor XIII and β2GPI (R = 0.40 and 0.40, respectively).

Conclusion

Plasma samples from lymphoma patients demonstrated a significantly altered thrombo-inflammatory biomarker profile that has notable correlations to blood cellular indices.

Role of mast cells in fibrosis of classical Hodgkin lymphoma

The underlying mechanism of fibrosis in classical Hodgkin lymphoma (CHL) remains uncertain. This study aimed to investigate the association of fibrosis in the lymph nodes of patients with CHL through histological examination of the expression of cytokines associated with fibrosis and mast cell proliferation. Additionally, we sought to determine the degree of mast cell infiltration in a nodular sclerosis subtype of CHL (NSCHL) compared with that in non-NSCHL. We analyzed lymph nodes from 22 patients with CHL, of which eight were of the NSCHL and 14 of the non-NSCHL subtype, using immunohistochemical staining of forkhead box P3 (FOXP3), transforming growth factor (TGF)-β, interleukin (IL)-3, IL-13, and stem cell factor (SCF). Mast cells were positive for TGF-β and IL-13, and FOXP3-positive cells were negative for TGF-β. Only the expression of IL-13 in Hodgkin and Reed-Sternberg (HRS) cells was significantly more frequently observed in NSCHL than that in non-NSCHL (P = 0.0028) and was associated with a higher rate of fibrosis (P = 0.0097). The number of mast cells was significantly higher in NSCHL than that in non-NSCHL (P = 0.0001). A significantly positive correlation was observed between the rate of fibrosis and the number of mast cells (correlation coefficient, 0.8524; 95% CI, 0.6725-0.9372) (P <0.0001). The number of mast cells was significantly higher in the group with IL-13-positive HRS cells than that in the group with IL-13-negative HRS cells (P = 0.0157). Based on these findings, we hypothesize that IL-13 production by HRS cells may lead to fibrosis, and furthermore, promote mast cell proliferation and infiltration. This in turn might further produce the fibrotic cytokines IL-13 and TGF-β, resulting in fibrosis typical of NSCHL.

Difference in cytokine production and cell cycle progression induced by Epstein-Barr virus Lmp1 deletion variants in Kmh2, a Hodgkin lymphoma cell line

Background

Epstein-Barr virus (EBV) is associated with 20-40% of Hodgkin’s Lymphoma (HL) cases. EBV-encoded latent membrane protein 1 (LMP1) is a well-known oncogenic protein and two C-terminal deletion variants, del30-LMP1 and del69-LMP1, have been described in animal models to be more tumorigenic than the wild-type form. This work aims to detail the implication of LMP1 in the development of HL and to characterize the particular effects of these variants.

Methods

We established HL-derived cell lines stably transfected with the pRT-LMP1 vector coding for the EBNA1 gene and allowing expression of the different LMP1 variants under the control of a doxycyclin-inducible promoter. Communication between cells was assessed by measuring the expression of various pro-inflammatory cytokines by flow cytometry after intracellular LMP1 and cytokine double staining. Proliferative properties of LMP1 variants were also compared by studying the repartition of cells in the different phases of the cell cycle after EdU incorporation combined to LMP1 and DAPI staining.

Results

All LMP1 proteins induced the expression of several pro-inflammatory cytokines such as TNF-α, TNF-β, IL-6, RANTES/CCL5 and IFN-γ. However, the del30-LMP1 variant induced cytokine expression at a lower level than the other variants, especially IFN-γ, while the del69-LMP1 variant stimulated greater cytokine expression. In addition, we measured that all LMP1 proteins greatly impacted the cell cycle progression, triggering a reduction in the number of cells in S-phase and an accumulation of cells in the G2/M phase compared to the HL-non induced cells. Interestingly, the del30-LMP1 variant reduced the number of cells in S-phase in a significantly greater manner and also increased the number of cells in the G0/G1 phase of the cell cycle.

Conclusion

Weak IFN-γ expression and specific alteration of the cell cycle might be a way for del30-LMP1 infected cells to escape the immune anti-viral response and to promote the development of cancer. The differences observed between the LMP1 variants reflect their own oncogenic properties and eventually impact the development of HL.

Utility of LRF/Pokemon and NOTCH1 protein expression in the distinction between nodular lymphocyte-predominant Hodgkin lymphoma and classical Hodgkin lymphoma

Classical Hodgkin lymphoma (CHL) and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) are considered separate entities with different prognosis and treatment. However, morphologic features can be similar and immunohistochemical studies are essential in the distinction; thus, determination of additional biomarkers is of utmost importance. LRF/Pokemon is a proto-oncogene, an interacting partner co-expressed with BCL6 in germinal centers and highly expressed in diffuse large B-cell lymphoma and follicular lymphoma. Conversely, loss of the LRF gene in mouse hematopoietic stem cells results in complete block of early B cell development with concomitant Notch de-repression, indicating its critical role in B versus T cell fate decision at the hematopoietic stem cell stage. For the first time, we show that LRF/Pokemon is predominantly expressed in NLPHL cases as is BCL6 with low to absent NOTCH1 protein expression; while Hodgkin Reed-Sternberg (HRS) cells in CHL show low to absent BCL6 and LRF/Pokemon expression with higher NOTCH1 expression. We illustrate a potential functional interaction between LRF and BCL6 in NLPHL pathogenesis, and differential expression of LRF/Pokemon and NOTCH1 proteins in CHL thus showing differential expression, making for an additional diagnostic marker and therapeutic target.

Defining characteristics of classical Hodgkin lymphoma microenvironment T-helper cells

CD4(+) T-helper cells (THs) dominate the classical Hodgkin lymphoma (CHL) microenvironment, but their role is poorly understood. Advances in flow cytometry and immunohistochemistry permit more detailed investigation of this aspect of CHL pathophysiology. To address the hypothesis that the TH-infiltrate, rather than being TH2-enriched, senescent and hypofunctional, is TH1 and activation marker-rich, cytokine-secretory and proliferative, we applied comprehensive flow cytometric immunophenotyping and functional assays of cytokine secretion/proliferation to TH cells from 18 CHL-derived single-cell suspensions (SCSs) compared to reactive lymph nodes (RLNs). CHL-derived TH cells express TH1-associated CXCR3/CCR5 and TNFα/IFNγ/interleukin-2 (IL-2) and less TH2-associated CCR3/CCR4, with no IL-4/IL-13. They lack exhaustion-/suppression-associated PD1, CD57 and terminally differentiated effector memory cells, with more central memory cells, activation-associated partners of Hodgkin Reed Sternberg (HRS) cell-expressed CD30/OX40-L/ICOS-L, and other activation markers. TH cell lines established from CHL and RLN-derived SCSs remain cytokine-secretory. We confirmed and extended these studies using tissue microarray immunohistochemistry (TMA-IHC) from a large CHL tissue bank (n = 122) and demonstrate TH1-associated TBET is abundant in CHL, and TH2-associated CMAF/GATA3 and exhaustion-associated PD1 expressed at significantly lower levels. These molecular insights into the CHL-associated TH offer potential diagnostic, prognostic and pharmacologically modifiable therapeutic targets and do not support the established view of a TH2-enriched, senescent/exhausted, hypofunctional, hypoproliferative infiltrate.

Severe infusion reactions to brentuximab vedotin in two patients with Hodgkin lymphoma previously treated with allogeneic stem cell transplantation

Brentuximab vendotin is a monoclonal antibody approved in August 2011 for use in patients with Hodgkin disease and a rare systemic lymphoma known as anaplastic large cell lymphoma. Brentuximab is approved in patients with Hodgkin disease who have failed autologous transplantation or after failure of at least two prior multi-agent chemotherapy regimens but has not been studied following allogeneic transplantation. Four patients with relapsed Hodgkin disease have been treated at our institution with at least two doses of brentuximab vendotin. Two patients have experienced significant infusion reactions on multiple occasions, and two patients have tolerated the infusions well. During phase 2 trials, there were no reports of Grade 3 or 4 infusion-related reactions. Both patients with reactions had relapsed following allogeneic stem cell transplants, while neither of the patients who tolerated the infusions had undergone transplantation. We report our experience with brentuximab vendotin-treated patients at our institution, focusing on the two post-allogeneic patients who experienced multiple significant infusion reactions. This report evaluates possible mechanisms behind their reactions, including previous allogeneic stem cell transplantation as a likely precipitating factor.

Alloantigen-stimulated induction and release of CD30 in patients with end-stage renal failure

High serum levels of soluble CD30 (sCD30) are associated with poor renal allograft survival, and regulatory T cells (Tregs) influence allograft survival depending on CD30 signaling. However, how sCD30 modulates alloimmune responses remains poorly understood. We measured the level of Tregs and sCD30 in patients with end-stage renal failure (ESRF) and analyzed whether allo- or polyclonal stimulation of the patients' T cells results in the expression and release of CD30. ESRF patients showed increased serum sCD30 levels and lower percentages of circulating Tregs as compared to healthy controls (HC) (p<0.001 and 0.024). Polyclonal and allogeneic stimulation resulted in higher expression of CD30, and after polyclonal stimulation, ESRF patients showed higher percentages of CD30-expressing T cells than HC (p<0.001). Compared to autologous stimulation, allogeneic stimulation induced significantly higher expression of CD30 on T cells of ESRF patients only. After polyclonal as well as allogeneic stimulation, an increased sCD30 content was found in culture supernatants of both ESRF patients and HC (p<0.001). Together with decreased Tregs, high serum sCD30 and increased induction of CD30 on T cells after polyclonal stimulation may explain exacerbated alloimmune responses and poor allograft survival in ESRF patients in whom immunosuppression is not able to control the alloimmune response.

Serum levels of interleukins 6, 10, and 13 before and after treatment of classic Hodgkin lymphoma

CONTEXT

Interleukins (ILs) 6, 10, and 13 seem to be important in the pathogenesis of Hodgkin lymphoma (HL), but there is insufficient data on the serum levels of these cytokines in patients with HL.

OBJECTIVES

To evaluate serum levels of IL-6, IL-10, and IL-13 before and after HL treatment and to determine their potential association with clinical and laboratory parameters.

DESIGN

Serum IL-6, IL-10, and IL-13 levels were quantified in the serum of 27 patients with HL by enzyme-linked immunosorbent assay. Results were evaluated against clinical and laboratory parameters, response to treatment, and presence of infection by the Epstein-Barr virus. As a control group, serum samples from 26 healthy blood donors were evaluated the same way.

RESULTS

Pretreatment serum levels of IL-6 and IL-10 were significantly higher in patients with HL (P < .001), and a significant decrease was observed after treatment (P < .001). Serum IL-13 was undetectable in both patient and control groups. Serum IL-6 was higher in patients with abdominal involvement (P  =  .02), hepatomegaly (P  =  .03), B symptoms (P  =  .02), and anemia (P  =  .02). Serum IL-10 levels were higher in patients with hypoalbuminemia (P  =  .04). No association with EBV status was observed. Lymphocytopenia and B symptoms were accurate predictors of IL-6 serum levels before treatment, and higher pretreatment levels of IL-6 were observed in patients with treatment failure (P  =  .03).

CONCLUSIONS

Serum levels of IL-6 and IL-10 were frequently elevated in patients with HL and decreased substantially after conventional chemotherapy. The association of elevated IL-6 and IL-10 levels in serum with some clinical and laboratory features suggests those ILs may be useful biomarkers for monitoring the HL disease and its response to chemotherapy.

Hodgkin disease and the role of the immune system

Hodgkin disease (HD) is a malignancy of primarily B lymphocytes that has the unique ability to cause immunodeficiency, as well as provide immune evasion mechanisms to avoid self-destruction. In this review, the authors discuss Hodgkin disease, its association with Epstein-Barr virus (EBV), the immune deficiency caused by HD, and tumor immune evasion mechanisms. Specifically, the authors closely evaluate the roles of regulatory T cells in HD, cytotoxic T cells, cytokine and chemokine secretion, down-regulation of Fas ligand, and indoleamine 2,3-dioxygenase (IDO) secretion.

T-Cell Traffic Jam in Hodgkin's Lymphoma: Pathogenetic and Therapeutic Implications

In hematologic malignancies, the microenvironment is often characterized by nonneoplastic cells with peculiar phenotypic and functional features. This is particularly true in Hodgkin's lymphoma (HL), in which T lymphocytes surrounding Hodgkin's Reed-Sternberg cells are essentially polarized towards a memory T-helper type 2 phenotype. In this paper we will first evaluate the main processes modulating T-cell recruitment towards the lymph node microenvironment in HL, especially focusing on the role played by cytokines. We will then consider the most relevant mechanisms of immune escape exerted by neoplastic cells in order to evade antitumor immunity. The potential pathogenetic and prognostic impact of regulatory T cells in such a context will be also described. We will finally overview some of the strategies of cellular immunotherapy applied in patients with HL.

On the origin of serum CD26 and its altered concentration in cancer patients

Dipeptidyl peptidase IV (DPP-IV), assigned to the CD26 cluster, is expressed on epithelial cells and lymphocytes and is a multifunctional or pleiotropic protein. Its peptidase activity causes degradation of many biologically active peptides, e.g. some incretins secreted by the enteroendocrine system. DPP-IV has, therefore, become a novel therapeutic target for inhibitors that extend endogenously produced insulin half-life in diabetics, and several reviews have appeared in recent months concerning the clinical significance of CD26/DPP-IV. Biological fluids contain relatively high levels of soluble CD26 (sCD26). The physiological role of sCD26 and its relation, if any, to CD26 functions, remain poorly understood because whether the process for CD26 secretion and/or shedding from cell membranes is regulated or not is not known. Liver epithelium and lymphocytes are often cited as the most likely source of sCD26. It is important to establish which tissue or organ is the protein source as well as the circumstances that can provoke an abnormal presence/absence or altered levels in many diseases including cancer, so that sCD26 can be validated as a clinical marker or a therapeutic target. For example, we have previously reported low levels of sCD26 in the blood of colorectal cancer patients, which indicated the potential usefulness of the protein as a biomarker for this cancer in early diagnosis, monitoring and prognosis. Through this review, we envisage a role for sCD26 and the alteration of normal peptidase capacity (in clipping enteroendocrine or other peptides) in the complex crosstalk between the lymphoid lineage and, at least, some malignant tumours.

Different role of CD30 in the development of acute and chronic airway inflammation in a murine asthma model

CD30 is a costimulatory molecule of the TNF receptor superfamily, expressed on activated T and B cells. Previously, we have shown in a murine asthma model the crucial role of CD30 signaling for the development of this Th2-cell-mediated disease. In the present study, we investigated the role of CD30 in the maintenance of the immune response. In contrast to the acute model, in the chronic model CD30(-/-) mice developed a severe asthma-like phenotype with eosinophilic inflammation and high serum IgE levels. Collagen content, ECM protein deposition and proliferation of smooth muscle cells as signs for airway remodeling were equally increased in both CD30(-/-) and WT mice. Reduced expression of the costimulatory molecule OX40 on CD3(+) T cells in the acute and up-regulation in the chronic model indirectly supported a compensatory role of OX40 for CD30 signaling. In accordance, application of agonistic OX40 antibody restored the asthma phenotype in CD30(-/-) mice in the acute model, whereas chronic airway inflammation was reduced in the presence of an inhibitory anti-OX40 ligand antibody. These data demonstrate that the crucial role of CD30 signaling in the development of acute asthma may be taken over by other costimulatory molecules like OX40 after long-term exposure to the antigen.

Hodgkin lymphoma: an update on its biology with new insights into classification

In the past few years, there has been a greater understanding of the spectrum and biology of Hodgkin lymphoma (HL). In standard texts, HL is classified as 2 distinct entities, namely nodular lymphocyte-predominant HL and classical HL (CHL). However, recent evidence suggests that CHL is not a single disease. Although the mixed cellularity and lymphocyte-depleted subtypes might be part of a biologic continuum, the nodular sclerosis subtype has a distinct epidemiology, clinical presentation, and histology. Nodular sclerosis HL might also be related to primary mediastinal B-cell lymphoma and mediastinal gray-zone lymphomas. We present an update on the pathobiology of HL and discuss these biologic and clinical differences in this review.

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.

Micro-vessel density and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PdEGF) in classical Hodgkin lymphoma (HL)

There is little information to date regarding the role of angiogenesis in Hodgkin lymphoma (HL). The present study examines micro-vessel density and the expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial growth factor (PdEGF) in lymph node biopsies of patients with HL at presentation and relapse. Using immunohistochemistry, the degree of new blood vessel formation and the expression of VEGF and PdEGF was assessed in Hodgkin-rich tissue. The micro-vessel density (MVD) increased with disease progression in seven out of 11 cases. Expression of VEGF was observed in endothelial cells (EC) of some micro-vessels and also in follicular dendritic cells. The Hodgkin/Reed-Sternberg (H-RS) cells as well as the inflammatory lymphocytes were negative for VEGF. Cytoplasmic or cytoplasmic and nuclear expression of PdEGF by the H-RS cells was observed in five of the 11 presentation cases. The expression of PdEGF increased with disease progression in seven cases. In conclusion, Hodgkin tissue shows prominent vascularization. The increased MVD and PdEGF expression with disease progression merits further investigation.

Inflammatory cells and immune microenvironment in malignant lymphoma

It has become clear that the biological and clinical behaviour of malignant lymphoma is not only determined by the properties of the tumour cells themselves but are also largely by the interaction of the tumour cells with their nonmalignant microenvironment. The composition and functional status of the tumour microenvironment is highly variable between different classes of malignant lymphoma and may provide both growth-supportive and growth suppressive signals via components of the adaptive and innate immune response. In this review, the functional interactions and clinical consequences of these insights are discussed in indolent and aggressive B-cell lymphomas and in classical Hodgkin's lymphoma.

HLA-G protein expression as a potential immune escape mechanism in classical Hodgkin's lymphoma

Classical Hodgkin's lymphoma (cHL) is characterized by the presence of an abundant reactive infiltrate, lacking effective cytotoxic responses. Especially in Epstein-Barr virus (EBV)-negative cHL, the neoplastic Hodgkin-Reed-Sternberg (HRS) cells have lost protein expression of major histocompatibility complex (MHC) class I, enabling escape from cytotoxic T lymphocyte (CTL) responses. However, downregulation of MHC class I generally induces natural killer (NK) cell activation. The paucity of NK cells in the reactive infiltrate of cHL and the systemic NK cell deficiency observed in cHL patients led us to investigate the expression of human leukocyte antigen (HLA)-G, which is known to inhibit NK-cell- and CTL-mediated cytotoxicity. By immunohistochemistry, HLA-G protein was expressed by HRS cells in 54% (95/175) of cHL cases. This expression was associated with absence of MHC class I on the cell surface of HRS cells (P < 0.001) and EBV-negative status (P < 0.001). Previously, genetic markers located in the proximity of the HLA-A and HLA-G genes had been shown to be associated with susceptibility to EBV-positive cHL. In the present study, these markers associated with MHC class I protein expression but not with presence of HLA-G. Our results suggest that induction of HLA-G protein expression in HRS cells contributes to the modulation of immune responses observed in cHL.

The CD4+CD26- T-cell population in classical Hodgkin's lymphoma displays a distinctive regulatory T-cell profile

Little is known about the gene expression profile and significance of the rosetting CD4+CD26- T cells in classical Hodgkin's lymphoma (cHL). To characterize these T cells, CD4+CD26- and CD4+CD26+ T-cell populations were sorted from lymph node (LN) cell suspensions from nodular sclerosis HL (NSHL) and reactive LNs. mRNA profiles of stimulated and resting cell subsets were evaluated with quantitative RT-PCR for 46 genes. We observed a higher percentage of CD4+CD26- T cells in NSHL than in reactive LNs. The resting CD4+CD26- T cells in NSHL showed higher mRNA levels of CD25, CTLA4, OX40 and CCR4 compared with in LNs, supporting a regulatory T-cell (Treg) type, and this was validated by immunohistochemistry. Moreover, these cells showed low or no expression of the Th1- or Th2-related cytokines IL-2, IFN-gamma, IL-13, IL-12B, IL-4, and IL-5, and the chemoattractant receptor CRTH2. Besides Tregs, Th17 cells may exist in NSHL based on the significantly higher IL-17 mRNA level for both T-cell populations in NSHL. Upon stimulation in vitro, lack of upregulation of mRNA levels of most cytokine genes indicated an anergic character for the CD4+CD26- T-cell subset. Anergy fits with the Treg profile of these cells, probably explaining the immunosuppressive mechanism involved in NSHL.

Proteomics analysis of Hodgkin lymphoma: identification of new players involved in the cross-talk between HRS cells and infiltrating lymphocytes

Hodgkin and Reed-Sternberg (HRS) cells in Hodgkin lymphoma (HL) secrete factors that interact with inflammatory background cells and may serve as biomarkers for disease activity. To detect new proteins related to pathogenesis, we analyzed the secretome of HRS cells. Proteins in cell culture supernatant of 4 HL cell lines were identified using 1DGE followed by in-gel trypsin digestion and LC-MS/MS. In total, 1290 proteins, including 368 secreted proteins, were identified. Functional grouping of secreted proteins revealed 37 proteins involved in immune response. Sixteen of the 37 proteins (ie, ALCAM, Cathepsin C, Cathepsin S, CD100, CD150, CD26, CD44, CD63, CD71, Fractal-kine, IL1R2, IL25, IP-10, MIF, RANTES, and TARC) were validated in HL cell lines and patient material using immunohistochemistry and/or ELISA. Expression of all 16 proteins was confirmed in HL cell lines, and 15 were also confirmed in HL tissues. Seven proteins (ALCAM, cathepsin S, CD26, CD44, IL1R2, MIF, and TARC) revealed significantly elevated levels in patient plasma compared with healthy controls. Proteomics analyses of HL cell line supernatant allowed detection of new secreted proteins, which may add to our insights in the interaction between HRS cells and infiltrating lymphocytes and in some instances might serve as biomarkers.

RNA fingerprints provide direct evidence for the inhibitory role of TGFβ and PD-1 on CD4+ T cells in Hodgkin lymphoma

A hallmark of various human malignancies is the expression of immunoinhibitory factors within the tumor microenvironment. There is indirect evidence based on in vitro experiments that tumor-infiltrating T cells in human malignancies are suppressed by such factors. Still, direct evidence of the influence of individual inhibitory factors on immune cells in human cancer in vivo is lacking. To address this question, we used Hodgkin lymphoma (HL) as a model because histopathological characteristics of HL are thought to be due mostly to the effects of a wide variety of cytokines, including TGFβ or membrane-bound receptors such as PD-1 that are suspected to contribute to immune evasion of tumor cells. Using a genome-wide transcriptional approach, we established specific RNA fingerprints of TGFβ and PD-1 signaling in human T cells in vitro. Applying these specific fingerprints, we directly demonstrate that CD4+ T cells in HL—but not in follicular lymphoma (FL)—are under the inhibitory influence of both TGFβ and PD-1 in vivo. This approach can be easily generalized to provide direct evidence of the impact of any given soluble or cell-bound factor on any cell type within diseased tissue.

Glycogen synthase kinase 3beta inhibition reduces the development of nonseptic shock induced by zymosan in mice

Glycogen synthase kinase 3 has recently been identified as a ubiquitous serine-threonine protein kinase that participates in a multitude of cellular processes and plays an important role in the pathophysiology of a number of diseases. In the present study, we have investigated the effects of 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8), a glycogen synthase kinase 3beta inhibitor, on the development of nonseptic shock caused by zymosan (dose, 500 mg/kg i.p. suspension in saline) in mice. Organ failure and systemic inflammation in mice was assessed 18 h after administration of zymosan and/or TDZD-8; another group of mice was monitored for 12 days (for clinical score and mortality). Treatment of mice with TDZD-8 (dose, 10 mg/kg i.p., 1 and 6 h after zymosan administration) attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan. TDZD-8 also attenuated the lung, liver, and pancreatic injury, the renal dysfunction caused by zymosan, and the increase in myeloperoxidase activity caused by zymosan in the lung and in the intestine. Immunohistochemical analysis for inducible nitric oxide synthase, nitrotyrosine, poly(ADP-ribose), CD30, CD30 ligand, and Fas ligand revealed positive staining in lung and intestinal tissues obtained from zymosan-injected mice. The degree of staining for inducible nitric oxide synthase, nitrotyrosine, poly(ADP-ribose), CD30, CD30 ligand, and Fas ligand were markedly reduced in tissue sections obtained from zymosan-injected mice that had received TDZD-8. This study provides the first evidence that TDZD-8 attenuates the degree of zymosan-induced, nonseptic shock in mice.

The Potential Role of Innate Immunity in the Pathogenesis of Hodgkin's Lymphoma

The innate immune system is our first line of defense against danger signals but in Hodgkin's lymphoma the role seems opposite, favoring malignant development. In this article we describe interactions between Hodgkin's and Reed-Sternberg cells and the cells of the innate immune system: eosinophils, mast cells, neutrophils, and macrophages. These cells clearly contribute to the pathogenesis of this disease and to the prognosis. Cytokines and chemokines released from the activated immune cells probably promote tumor cell growth and survival along with angiogenesis. Mast cells and eosinophils seem also to contribute to the fibrosis that is so characteristic for nodular sclerosis.

Transactivation of the ICAM-1 gene by CD30 in Hodgkin's lymphoma

The ICAM-1/LFA-1 complex mediates cell-cell interaction. ICAM-1 is overexpressed in Hodgkin/Reed-Sternberg (H/RS) cells, and serum levels of its soluble form are higher in Hodgkin's lymphoma (HL) patients than in controls. There are no data, however, regarding the regulation of expression of ICAM-1 in H/RS cells. CD30 was identified in H/RS cells of HL and has attracted much interest as a molecular marker of HL. To analyze ICAM-1 expression in H/RS cells, we examined the expression of ICAM-1, LFA-1, CD30 and CD30L in HL-derived cell lines. All cell lines expressed ICAM-1 and CD30, but not LFA-1 or CD30L. CD30 induced ICAM-1 expression. Analysis of the ICAM-1 promoter showed the importance of NF-kappaB binding site for CD30-induced ICAM-1 gene expression. Coexpression of IkappaB, IKK, NIK and TRAF dominant-negative constructs with CD30 inhibited CD30-induced activation of ICAM-1 promoter, suggesting that CD30 induces ICAM-1 via NF-kappaB signalling. The ICAM-1 promoter was activated by the C-terminal region of CD30, which activated NF-kappaB signalling. A decoy CD30 lacking the cytoplasmic region inhibited ICAM-1 promoter activity in HL cell lines. Thus, in H/RS cells, ligand-independent activation of CD30 signalling activates NF-kappaB and this leads to constitutive ICAM-1 expression, suggesting a link between 2 well known phenotypic characteristics of HL, CD30 and ICAM-1 overexpression.

Genetic susceptibility to Hodgkin's lymphoma associated with the human leukocyte antigen region

Based on the presence of an abundant inflammatory infiltrate, expression of a broad spectrum of cytokines and the professional antigen presenting phenotype of Hodgkin Reed-Sternberg cells it can be anticipated that immunological mechanisms play a major role in the pathogenesis of Hodgkin's lymphoma (HL). Genetic susceptibility to HL probably relates to functionality of the immune system and the large number of associations with the human leukocyte antigen (HLA) region in family and population-based studies supports this relation. In Epstein-Barr virus (EBV) positive HL cases, which usually demonstrate HLA class I expression, HRS cells should be able to present EBV derived antigenic peptides and trigger the immune system. This process depends on the affinity of the HLA binding groove for binding immunogenic peptides and thus on the HLA alleles. It can be anticipated that certain combinations of alleles predispose to or protect from the development of EBV positive HL. In EBV negative HL cases other antigenic peptides, related to malignant transformation, in combination with other HLA alleles may be involved. In addition, differential attraction and activation of inflammatory cells may influence HL subtype. In this article, possible roles of HLA in HL pathogenesis are explored and genetic associations of HLA with HL are reviewed and commented on.

The role of interleukin-3 in classical Hodgkin's disease

Classical Hodgkin's disease (HD) is a peculiar form of lymphoma characterized by a low frequency of tumor cells, the so-called Hodgkin (H) and Reed/Sternberg (RS) cells, embedded in a background of non-neoplastic (reactive) cells believed to be recruited and activated by H-RS cell-derived cytokines/chemokines. How these tumor cells can survive in such a seemingly hostile environment has confused researchers. We have previously identified interleukin (IL)-3 receptor (R) expression as a common feature of classical HD and unveiled the potential role of IL-3 as a growth and anti-apoptotic factor for H-RS cells. More then 90% of malignant cells of classical HD usually express the alpha chain of the IL-3R (IL-3R(alpha)), as evidenced by immunostaining of frozen sections and cell suspensions from neoplastic lymph nodes. Consistently, HD-derived cell lines (L428, KMH2, HDLM2 and L1236) express the alpha and beta chains that form IL-3R, both at the mRNA and protein level, with a molecular size of IL-3R(alpha) identical (70 kDa) to that expressed by human myeloid cells. Exogenous IL-3 promotes the growth of cultured H-RS cells, such an effect being potentiated by IL-9 and stem cell factor (SCF) co-stimulation, and is able to partially rescue tumor cells from apoptosis induced by serum deprivation. Finally, cultured H-RS cells are able to increase the production of IL-3 by pre-activated T cells, suggesting an involvement of IL-3/IL-3R interactions in the cellular growth of HD through paracrine mechanisms. This review will outline the biological activity of IL-3 and summarize the evidence indicating IL-3 as a growth and anti-apoptotic factor for H-RS cells in classical HD.

Phenotype and frequency of Epstein-Barr virus-infected cells in pretreatment blood samples from patients with Hodgkin lymphoma

An accumulating body of data suggests that the Epstein-Barr virus (EBV), a lymphotropic herpesvirus, is involved in the pathogenesis of a proportion of cases of Hodgkin lymphoma (HL). In this study, we showed that the frequency of circulating EBV-infected cells was significantly higher (P < 0.001) in pretreatment blood samples from EBV-associated cases when compared with non-EBV-associated cases. We further showed that in patients with EBV-associated disease, the virus persisted in the peripheral blood in memory B cells. This phenotype is consistent with that seen in healthy seropositive controls, post-transplant patients and patients with acute infectious mononucleosis. The data suggest that an increased frequency of EBV carrying B cells in peripheral blood is associated with EBV-associated HL.

Expression of the T-cell transcription factors, GATA-3 and T-bet, in the neoplastic cells of Hodgkin lymphomas

Since Hodgkin and Reed-Sternberg (HRS) cells of Hodgkin lymphoma (HL) generally have immunoglobulin gene rearrangements, they are considered to be of B-cell origin. One of the characteristics of HRS cells is a prominent production of various cytokines and chemokines. Cytokine production is generally driven by expression of T-cell transcription factors (TFs). Only limited information is available on the expression of T-cell TFs in HL. Expression of four T-cell TFs and the target cytokine spectrum of these TFs were analyzed in six HL and three large B-cell lymphoma (LBCL) cell lines using quantitative PCR. ERM expression was observed in all HL and LBCL cell lines. Out of HL cell lines, T-bet was expressed in five, GATA-3 in four, and c-Maf in two cell lines. Immunohistochemistry in HL tissues revealed that in 11 of 12 (92%) of the classical HL cases HRS cells were GATA-3 and/or T-bet positive. In three of six cases of nodular lymphocyte predominance type of HL, the neoplastic cells were T-bet positive. Overall, the T-cell TF and cytokine profiles of the HL cell lines showed a considerable degree of consistency. The expression of T-cell TFs may explain the production of various cytokines by HL cell lines and HRS cells.

Interactions between tissue fibroblasts in lymph nodes and Hodgkin/Reed-Sternberg cells

Classic Hodgkin's Disease (cHD) is a lymphoid neoplasia characterized by a few malignant Hodgkin and Reed-Sternberg (H-RS) cells embedded in an abundant background of non-tumor cells. In this context, fibrosis is a common morphologic feature of HD lesions, being found more frequently in cHD subtypes. The clinical and histopathologic features of cHD are thought to be largely due to the effects of a wide variety of cytokines and chemokines primarily produced by H-RS cells, as well as by the surrounding reactive component. In the present review, first we propose three mechanisms putatively explaining fibroblast activation and fibrosis in HD: (1) unbalanced production of the pro-fibrogenic Th2 over Th1 cytokines; (2) production of TGF-beta, b-FGF and IL-13 by H-RS cells; (3) activation of fibroblasts by CD40L-expressing cells of the HD microenvironment. Second, we suggest some molecular pathways involving cytokines produced by HD-derived fibroblasts (SCF, IL-7, IL-6) supposedly responsible for H-RS proliferation and rescue from apoptosis. Finally, we describe the role of specific molecules produced by H-RS cells in the regulation of HD-derived fibroblast production of chemokines, in turn involved in T-lymphocytes and recruitment of eosinophils.

Lymphocyte populations in lymph nodes in different histological types of Hodgkin's disease in children

Proliferating Reed-Sternberg and Hodgkin's cells within the lymph node in Hodgkin's disease (HD) affect the surrounding cells, which results in alterations of the proportion between T and B lymphocytes and the activation of these cells. The purpose of this study was to assay the changes within lymphocyte populations in lymph nodes in different types of HD. The lymph nodes of 10 children with nonmalignant, reactive changes, and 31 children with HD of the following types: mixed cellularity (MC; 11 cases), nodular sclerosis (NS; 17 cases) and lymphocyte depletion (LD; 3 cases) were included in the study. The percentage of T lymphocytes (CD3+), B lymphocytes (CD22+), T cell (CD4+ and CD8+) and B cell subsets (kappa+ and lambda+ light chain) were assayed with flow cytometry. The ratio of T:B lymphocytes in reactive lymph nodes and in NS type of HD was similar. An increase of the T cell percentage (resembling an increase of the CD4+ subset) and a decrease of B cells resulted in a high ratio of T:B and was noted in the MC and LD types of HD. These HD types were associated with marked changes in lymphocytes within the lymph node, which suggested a different effect of proliferating Reed-Sternberg and Hodgkin cells in HD on the surrounding cells.

Nuclear factor-kappaB modulation as a therapeutic approach in hematologic malignancies

Nuclear factor-kappaB (NF-kappaB) is a collective term that refers to a small class of dimeric transcription factors for a number of genes, including growth factors, angiogenesis modulators, cell-adhesion molecules, and antiapoptotic factors. Although most NF-kappaB proteins promote transcription, some act as inactivating or repressive complexes. The most common p50-RelA (p65) dimer known "specifically" as NF-kappaB, is relatively abundant, controls the expression of numerous genes, and exists as an inactive cytoplasmic complex bound to inhibitory proteins of the NF-kappaB inhibitor (IkappaB) family. The inactive NF-kappaB-IkappaB complex is activated by a variety of stimuli, including proinflammatory cytokines, mitogens, growth factors, and stress-inducing agents. The release of NF-kappaB facilitates its translocation to the nucleus, where it promotes cell survival by initiating the transcription of genes encoding stress-response enzymes, cell-adhesion molecules, proinflammatory cytokines, and antiapoptotic proteins. Constitutive activation of NF-kappaB in the nucleus is observed in some hematologic disorders. With the recent approval of bortezomib for patients with advanced multiple myeloma, NF-kappaB modulation is likely to be a therapeutic endeavor of increasing interest in coming years.

Increased serum levels of interleukin-9 correlate to negative prognostic factors in Hodgkin's lymphoma

Hodgkin's lymphoma (HL) is characterised by an unbalanced cytokine secretion. Many of these cytokines have been implicated in the regulation of malignant and infiltrating cells. Interleukin-9 (IL-9) has been described to act in an autocrine fashion in HL, stimulating proliferation of the malignant cells. To investigate the potential clinical implication of this observation, a novel ELISA method was used to examine the serum levels of IL-9 in lymphoma patients. High levels of IL-9 were found in the sera from patients with HL (18/44), but not in the sera from non-Hodgkin's lymphoma patients (3/21) or healthy controls. The highest serum IL-9 levels, up to 3350 pg/ml, were observed in the nodular sclerosis subtype, and there was a correlation between IL-9 levels and the negative prognostic factors advanced stage, B-symptoms, low blood Hb and high erythrocyte sedimentation rate. Furthermore, there was no correlation between serum levels of IL-9 and IL-13, a cytokine where serum levels have been speculated to be of clinical importance. This is the first report showing that IL-9 can be measured in serum samples. A novel correlation between increased serum IL-9 levels, HL and clinical features is shown, suggesting that IL-9 is a candidate factor contributing to the development of HL.

Selectins and anti-CD15 (Lewis x/a) antibodies transmit activation signals in Hodgkin's lymphoma-derived cell lines

OBJECTIVE

The CD15 (Lewis x) cell surface oligosaccharide moiety is expressed in a variety of normal and tumor cells and recognized by selectins. The detection of CD15 on malignant Hodgkin-Reed-Sternberg (HRS) cells serves as a diagnostic marker of Hodgkin's lymphoma (HL). Retrospective studies suggest that the expression of nonsialylated CD15 molecules on HRS cells has a positive prognostic value while presence of sialylated CD15 may correlate with a poor outcome. However, the relevance of the CD15 antigen expression to the pathobiology of the disease is not clear. In this work, we studied the contribution of CD15 to cell adhesion and the activation of signaling cascades in two HL-derived cell lines, KMH-2 and L428.

METHODS

Immobilized anti-CD15 monoclonal antibodies and recombinant E- and P-selectins were used to activate KMH-2 and L428 cells. Immunoblotting, immunoprecipitation, and the electrophoretic mobility shift assay were performed to detect tyrosine phosphorylation of c-Cbl, c-Jun nuclear translocation, and AP-1 DNA binding.

RESULTS

Treatment of cells with antibodies against the sialylated and nonsialylated forms of CD15, or with immobilized selectins, induced changes in cell morphology. Tyrosine phosphorylation of c-Cbl, together with tyrosine phosphorylation of multiple protein substrates, was also induced. In addition, binding of the CD15 molecules induced nuclear translocation of c-Jun and an increase in AP-1 DNA binding activity.

CONCLUSIONS

We suggest that CD15 has a dual physiological role, both as an adhesion molecule recognized by selectins and as a regulatory molecule upstream to specific intracellular signaling cascades with implications to the pathogenesis of HL.

Expression of CCL5/RANTES by Hodgkin and Reed-Sternberg cells and its possible role in the recruitment of mast cells into lymphomatous tissue

HL is a malignant lymphoma characterized by a small number of malignant HRS cells among a major population of infiltrating reactive cells, e.g., lymphocytes and eosinophils. We previously reported that mast cells are present in HL-affected lymph nodes and therein are the predominant CD30L-expressing cells. The CD30L expressed on mast cells is functionally active and can provide stimulatory signals to HRS cells. Thus, mast cells constitute an important portion of the infiltrating reactive cells that contribute to tumor progression in HL. Control of the recruitment of this previously unrecognized cell and its interactions with tumor cells are essentially unknown. To elucidate if mast cells might be specifically attracted to the tumor area by chemokines produced by HRS cells, we investigated chemokine expression in HL cell lines and in vivo. By RNase protection assay, mRNA expression of several chemokines could be detected in the cell lines. Despite the heterogeneous expression profile exhibited by the cell lines, 4 of 5 expressed CCL5 (RANTES) mRNA. RT-PCR and immunohistochemistry confirmed expression of CCL5 in vivo. Furthermore, secreted CCL5 was detected in conditioned media from 3 of the cell lines. In a migration assay, we found that CCL5 present in conditioned medium could induce mast cell migration. Taken together, our results suggest that CCL5 produced by HRS cells is one mechanism by which mast cells can be attracted into the tumor tissue in HL.

Adoptive T-cell therapy for Epstein-Barr virus-positive Hodgkin's disease

Immunotherapy approaches with antigen-specific cytotoxic T lymphocytes (CTLs) have proved safe and effective prophylaxis and treatment of Epstein-Barr virus (EBV)-associated lymphomas arising after bone marrow transplantation. EBV is also associated with other malignancies including about 40% of cases of Hodgkin's disease making this tumor another potential target for EBV-targeted immunotherapy. While studies with autologous EBV-specific CTLs have shown antiviral activity and immune effects, the clinical responses have been less impressive than those observed in post-transplant lymphomas. There are several possible reasons why the malignant cells in EBV-positive Hodgkin's disease may be less susceptible to immunotherapy approaches, including the fact that they express a more restricted array of EBV-encoded antigens and possess many immune evasion strategies. A number of approaches to overcome these tumor evasion strategies including targeting CTLs to the expressed antigens and genetic modification of CTLs are being evaluated.

The role of CD30, CD40 and CD95 in the regulation of proliferation and apoptosis in classical Hodgkin’s lymphoma

AIMS

CD30, CD40 and CD95 are members of the tumour necrosis factor receptor superfamily. Ligation to their respective ligands (CD30L, CD40L, CD95L) will generate a diverse set of signalling cascades. We aim to study the expression pattern of CD30, CD40 and CD95 in classical Hodgkin's lymphoma (cHL) and to correlate the expressions with proliferation and apoptosis in the Hodgkin/Reed-Sternberg (H/RS) cells of cHL with or without associated Epstein-Barr virus (EBV) infection.

METHODS

A total of 66 cHL cases were retrieved from the archives. Expressions of CD30, CD40, CD95 and proliferation by Ki-67 expression were detected with an immunohistochemical staining method. Apoptosis index was assessed by in situ TUNEL staining technique on 30 randomly selected cases and the presence of EBV was determined by EBER in situ hybridisation.

RESULTS

Expression of CD30, CD40 and CD95 in the H/RS cells was observed in a high proportion of the cases (100, 93.9, 90.5%, respectively). There was no significant association or correlation of the expression of these molecules with the presence of EBV. Expression of CD40 was associated with expression of the proliferation marker Ki-67 (P=0.044), whereas strong (intermediate and high) expression of CD30 showed a significant correlation with proliferation in the EBV-negative cases only (P=0.025). No correlation was observed for the expression of CD30 and CD40 with apoptosis of the H/RS cells. The childhood cases showed weaker CD95 expression in the H/RS cells than the adult cases, and the expression of CD95 was weaker than that of CD40 in the childhood group.

CONCLUSIONS

Our results showed that CD30, CD40 and CD95 are highly expressed in the H/RS cells of the majority of cases of cHL. The expression patterns seem to be independent of EBV and do not correlate with apoptosis of the H/RS cells.

Imbalances of chemokines, chemokine receptors and cytokines in Hodgkin lymphoma: classical Hodgkin lymphoma vs. Hodgkin-like ATLL

Classical Hodgkin lymphoma (HL) is characterized by the presence of Hodgkin and Reed-Sternberg cells (H&RS) and a prominent lymphocytic infiltration. We previously reported Hodgkin-like adult T-cell leukemia/lymphoma (HL-like ATLL) (new WHO classification). Various CXC and CC chemokines are expressed on H&RS cells and the relationships between chemokines and the chemokine receptor (R) are thought to be important for selectivity of local immunity of Th1 and Th2 T cells. To clarify the role of T-cell immunity in classical HL and Hodgkin-like ATLL, we performed gene expression profiling (chemokine, chemokine R and cytokine DNA chips) in 12 cases [classical HL, 8 cases [mixed cellularity (MC) type, 4; nodular sclerosis (NS) type, 4]; Hodgkin-like ATLL, 4 cases] and immunohistochemical staining in 29 cases (MC, 10; NS, 10; Hodgkin-like ATLL, 9). EBV-infected H&RS cells were detected in 9 of 10 cases of HL MC, 5 of 9 of HL-like ATLL and 2 of 10 HL NS. T-cell-directed chemokine thymus- and activation-regulated chemokine (TARC)- and/or macrophage-derived chemokine (MDC)-positive H&RS cells were detected in all 20 cases of HL MC and HL NS but only in 5 of 9 cases of HL-like ATLL. Interferon-gamma-inducible protein-10 (IP10)- and monokine induced by interferon-gamma (MIG)-positive H&RS cells were detected in all 10 HL MC but only in 5 of 10 cases of HL NS and 2 of 9 cases of HL-like ATLL. However, 2 of 5 cases of HL-like ATLL with EBV infection and 2 of 2 HL NS with EBV had IP10/MIG-positive H&RS cells. The chemokine expressions in H&RS cells seemed to be associated with EBV infection rather than histologic subtypes. In the DNA chip expression analysis, classical HL and HL-like ATLL had a mixed Th1/Th2-type profile, and HL MC (EBV-positive) and HL NS (EBV-negative) were differentially clustered. However, 2 cases of HL-like ATLL clustered with HL MS and the other 2 cases of HL-like ATLL clustered with HL NS. The former HL-like ATLL had EBV infection in H&RS cells, whereas the latter did not have EBV infection. This finding also suggests that EBV might influence local expression of chemokines rather than HL subtypes. Our results indicate that local immunologic disorder or imbalance appears to influence the formation of H&RS cells and that in HL-like ATLL, HTLV-1 infection might not be necessary for H&RS cell formation.

Nuclear transcription factor-kappaB in Hodgkin's disease

Nuclear factor-kappaB (NF-kappaB) is a transcriptional factor that was originally discovered in the nucleus of B cells that bind to the kappa light chain of the immunoglobulins. Research during 15 years, however, has revealed that NF-kappaB is present in its inactive state in the cytoplasm of almost every cell type. When activated, NF-kappaB translocates to the nucleus, binds the DNA and regulates the expression of over 200 different genes. The product of these genes regulate the immune system, cell proliferation, tumor metastasis, inflammation and viral replication. Several tumor cell types express constitutively activated form of NF-kappaB and it is required for the proliferation of the tumor cells. Numerous studies have shown that Hodgkin's disease cells exhibit constitutive active NF-kappaB. The present review examines the mechanism how NF-kappaB is activated and its relevance to Hodgkin's disease.

The molecular basis for the generation of Hodgkin and Reed-Sternberg cells in Hodgkin's lymphoma

Hodgkin's lymphoma (HL) is a lymphoid neoplasm with a low frequency of malignant tumor cells, known as Hodgkin and Reed-Sternberg (H-RS) cells, in a background of mixed cellular infiltrates. Despite extensive studies on H-RS cells, the molecular mechanisms of their growth and regulation have remained uncertain for a long period. Recently, constitutively activated nuclear factor-kappaB (NF-kappaB) was reported to be a unique and common characteristic of H-RS cells that prevents the cells from undergoing apoptosis. NF-kappaB triggers proliferation and provides a molecular basis for these cells' aberrant growth and cytokine gene expression. In HL pathogenesis associated with Epstein-Barr virus infection, the activation of NF-kappaB is induced by viral latent membrane protein 1 (LMP1). Coupled with recent insights into the molecular mechanisms of activation of NF-kappaB signaling in H-RS cells, this review discusses a linkage between LMP1 and HL via CD99, which has recently been reported to be down-regulated by LMP1 through the NF-kappaB signaling pathway. This down-regulation leads to the generation of cells with H-RS phenotypes related to the clinical and histologic characteristics of HL.

Distribution of human CD30 gene promoter microsatellite alleles in healthy and human immunodeficiency virus-1 infected populations

The human CD30 gene, found on chromosome 1; 1p36, contains a microsatellite of the type [(CCAT)2-12CCACTTATGCAT]n within the promoter. As the microsatellite has been shown to be both polymorphic and involved in the transcriptional regulation of this gene, it is of potential interest with respect to interindividual differences in CD30 expression. Here we describe a method for determining length variation of this repeat region and determine the frequency and distribution of alleles of the CD30 microsatellite within the Western Australian population. As soluble CD30 levels are predictive for disease associated with human immunodeficiency virus (HIV)-1 infection, we also determined allele frequencies in an HIV+ cohort.

NF-kappaB activation in cancer: a challenge for ubiquitination- and proteasome-based therapeutic approach

Nuclear factor-kappa B (NF-kappaB) activation relies primarily on ubiquitin-mediated degradation of its inhibitor IkappaB. NF-kappaB plays an important role in many aspects of tumor development, progression, and therapy. Some types of cancer are characterized by constitutive NF-kappaB activity, whereas in others such activity is induced following chemotherapy. NF-kappaB-harboring tumors are generally resistant to chemotherapy and their eradication requires NF-kappaB inhibition. Here we describe the mechanisms of NF-kappaB activation in normal and tumor cells, review prevalent notions regarding the factor's contribution to tumorigenicity and discuss present and future options for NF-kappaB inhibition in cancer. The ubiquitination-mediated activation of NF-kappaB is intersected by another cancer-associated protein, beta-catenin. We, therefore, compare the related activation pathways and discuss the possibility of differential targeting of the involved ubiquitination machinery.

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders

Epstein-Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.

Chemokines, cytokines and their receptors in Hodgkin's lymphoma cell lines and tissues

BACKGROUND

Hodgkin's lymphoma (HL) is characterized by a minority of neoplastic cells, the so-called Reed-Sternberg (RS) cells, and an admixture of reactive cells including lymphocytes, plasma cells, eosinophils and histiocytes. Cytokines produced in HL, either by RS or infiltrating cells, might explain the presence and maintenance of an impaired immune response. Chemokines (cytokines with chemoattractant properties) produced by RS cells play a major role in leukocyte trafficking. These molecules with specific receptor affinities contribute, for example by attracting TH2-like T cells, to the maintenance of a favorable environment for survival of RS cells.

RESULTS AND DISCUSSION

Cross-talk between RS cells and reactive elements involves several cytokine/chemokines that process proliferative [interleukin (IL)-13 and IL-17], immunosuppressive (IL-10 and transforming growth factor-beta) and background formation (IL-5, TARC, MDC, IP-10, RANTES, Mig and others) messages. These autocrine and paracrine interactions lead to an environment where RS cells are able to proliferate, escape from apoptosis and survive host anti-tumor defense.

CONCLUSIONS

The proper modulation of these complex pathways may allow the development of new strategies in HL therapy.