Infiltration of eosinophils in Hodgkin's disease involved lymph nodes predicts prognosis

Head and Neck Classic Hodgkin, T and NK Lymphomas with Eosinophilia

Eosinophilia is a notable feature in various hematological malignancies, including specific types of leukemias and lymphomas that may occur in the head and neck. In hematologic malignancies, eosinophilia can be primary, driven by genetic abnormalities, or secondary, resulting from cytokine and chemokine production by the neoplastic cells or the tumor microenvironment. This review examines the association between eosinophilia and head and neck hematolymphoid malignancies including Classic Hodgkin lymphoma, T-cell lymphoblastic leukemia, mature T and NK-cell lymphomas, and Langerhans cell histiocytosis. It explores the underlying mechanisms of eosinophilia in these malignancies, highlighting the role of chemokines and cytokines such as IL-5, TARC, and eotaxin. Recognition of eosinophilia may aid in the diagnosis of these conditions and understanding the mechanisms of eosinophilia may provide insights into potential prognostic implications and treatment strategies.

Eosinophils Exert Antitumorigenic Effects in the Development of Esophageal Squamous Cell Carcinoma

BACKGROUND AND AIMS

Eosinophils are present in several solid tumors and have context-dependent function. Our aim is to define the contribution of eosinophils in esophageal squamous cell carcinoma (ESCC), as their role in ESCC is unknown.

METHODS

Eosinophils were enumerated in tissues from 2 ESCC cohorts. Mice were treated with 4-NQO for 8 weeks to induce precancer or 16 weeks to induce carcinoma. The eosinophil number was modified by a monoclonal antibody to interleukin-5 (IL5mAb), recombinant IL-5 (rIL-5), or genetically with eosinophil-deficient (ΔdblGATA) mice or mice deficient in eosinophil chemoattractant eotaxin-1 (Ccl11-/-). Esophageal tissue and eosinophil-specific RNA sequencing was performed to understand eosinophil function. Three-dimensional coculturing of eosinophils with precancer or cancer cells was done to ascertain direct effects of eosinophils.

RESULTS

Activated eosinophils are present in higher numbers in early-stage vs late-stage ESCC. Mice treated with 4-NQO exhibit more esophageal eosinophils in precancer vs cancer. Correspondingly, epithelial cell Ccl11 expression is higher in mice with precancer. Eosinophil depletion using 3 mouse models (Ccl11-/- mice, ΔdblGATA mice, IL5mAb treatment) all display exacerbated 4-NQO tumorigenesis. Conversely, treatment with rIL-5 increases esophageal eosinophilia and protects against precancer and carcinoma. Tissue and eosinophil RNA sequencing revealed eosinophils drive oxidative stress in precancer. In vitro coculturing of eosinophils with precancer or cancer cells resulted in increased apoptosis in the presence of a degranulating agent, which is reversed with NAC, a reactive oxygen species scavenger. ΔdblGATA mice exhibited increased CD4 T cell infiltration, IL-17, and enrichment of IL-17 protumorigenic pathways.

CONCLUSION

Eosinophils likely protect against ESCC through reactive oxygen species release during degranulation and suppression of IL-17.

Eosinophils exert direct and indirect anti-tumorigenic effects in the development of esophageal squamous cell carcinoma

Background/Aims

Eosinophils are present in several solid tumors and have context-dependent function. Our aim is to define the contribution of eosinophils in esophageal squamous cell carcinoma (ESCC), since their role in ESCC is unknown.

Methods

Eosinophils were enumerated in tissues from two ESCC cohorts. Mice were treated with 4-nitroquinolone-1-oxide (4-NQO) for 8 weeks to induce pre-cancer or 16 weeks to induce carcinoma. Eosinophil number was modified by monoclonal antibody to IL-5 (IL5mAb), recombinant IL-5 (rIL-5), or genetically with eosinophil-deficient (ΔdblGATA) mice or mice deficient in eosinophil chemoattractant eotaxin-1 ( Ccl11 -/- ). Esophageal tissue and eosinophil specific RNA-sequencing was performed to understand eosinophil function. 3-D co-culturing of eosinophils with pre-cancer or cancer cells was done to ascertain direct effects of eosinophils.

Results

Activated eosinophils are present in higher numbers in early stage versus late stage ESCC. Mice treated with 4-NQO exhibit more esophageal eosinophils in pre-cancer versus cancer. Correspondingly, epithelial cell Ccl11 expression is higher in mice with pre-cancer. Eosinophil depletion using three mouse models ( Ccl11 -/- mice, ΔdblGATA mice, IL5mAb treatment) all display exacerbated 4-NQO tumorigenesis. Conversely, treatment with rIL-5 increases esophageal eosinophilia and protects against pre-cancer and carcinoma. Tissue and eosinophil RNA-sequencing revealed eosinophils drive oxidative stress in pre-cancer. In vitro co-culturing of eosinophils with pre-cancer or cancer cells resulted in increased apoptosis in the presence of a degranulating agent, which is reversed with N-acetylcysteine, a reactive oxygen species (ROS) scavenger. ΔdblGATA mice exhibited increased CD4 T cell infiltration, IL-17, and enrichment of IL-17 pro-tumorigenic pathways.

Conclusion

Eosinophils likely protect against ESCC through ROS release during degranulation and suppression of IL-17.

Eosinophils Decrease Pulmonary Metastatic Mammary Tumor Growth

Metastatic breast cancer is challenging to effectively treat, highlighting the need for an improved understanding of host factors that influence metastatic tumor cell colonization and growth in distant tissues. The lungs are a common site of breast cancer metastasis and are host to a population of tissue-resident eosinophils. Eosinophils are granulocytic innate immune cells known for their prominent roles in allergy and Th2 immunity. Though their presence in solid tumors and metastases have been reported for decades, the influence of eosinophils on metastatic tumor growth in the lungs is unclear. We used transgenic mouse models characterized by elevated pulmonary eosinophils (IL5Tg mice) and eosinophil-deficiency (ΔdblGATA mice), as well as antibody-mediated depletion of eosinophils, to study the role of eosinophils in EO771 mammary tumor growth in the lungs. We found that IL5Tg mice exhibit reduced pulmonary metastatic colonization and decreased metastatic tumor burden compared to wild-type (WT) mice or eosinophil-deficient mice. Eosinophils co-cultured with tumor cells ex vivo produced peroxidase activity and induced tumor cell death, indicating that eosinophils are capable of releasing eosinophil peroxidase (EPX) and killing EO771 tumor cells. We found that lung eosinophils expressed phenotypic markers of activation during EO771 tumor growth in the lungs, and that metastatic growth was accelerated in eosinophil-deficient mice and in WT mice after immunological depletion of eosinophils. Our results highlight an important role for eosinophils in restricting mammary tumor cell growth in the lungs and support further work to determine whether strategies to trigger local eosinophil degranulation may decrease pulmonary metastatic growth.

Extracellular DNA Traps: Origin, Function and Implications for Anti-Cancer Therapies

Extracellular DNA may serve as marker in liquid biopsies to determine individual diagnosis and prognosis in cancer patients. Cell death or active release from various cell types, including immune cells can result in the release of DNA into the extracellular milieu. Neutrophils are important components of the innate immune system, controlling pathogens through phagocytosis and/or the release of neutrophil extracellular traps (NETs). NETs also promote tumor progression and metastasis, by modulating angiogenesis, anti-tumor immunity, blood clotting and inflammation and providing a supportive niche for metastasizing cancer cells. Besides neutrophils, other immune cells such as eosinophils, dendritic cells, monocytes/macrophages, mast cells, basophils and lymphocytes can also form extracellular traps (ETs) during cancer progression, indicating possible multiple origins of extracellular DNA in cancer. In this review, we summarize the pathomechanisms of ET formation generated by different cell types, and analyze these processes in the context of cancer. We also critically discuss potential ET-inhibiting agents, which may open new therapeutic strategies for cancer prevention and treatment.

Classic Hodgkin Lymphoma Refractory for ABVD Treatment Is Characterized by Pathologically Activated Signal Transduction Pathways as Revealed by Proteomic Profiling

Simple Summary

Classic Hodgkin lymphoma (cHL) patients refractory to standard ABVD chemo-therapy are known to have a dismal prognosis. This has led to the hypothesis that ABVD treatment-sensitive and ABVD treatment-refractory tumours are biologically distinct. In this study, cHL patients refractory to standard ABVD treatment show subtle but significant differences in protein expression that enable clustering of the two response groups, thus indicating differences between ABVD sensitive and refractory patients at the molecular level, and thereby strengthening the hypothesis that ABVD sensitive and ABVD refractory tumours may be biologically distinct.

Abstract

In classic Hodgkin lymphoma (cHL), the tumour microenvironment (TME) is of major pathological relevance. The paucity of neoplastic cells makes it important to study the entire TME when searching for prognostic biomarkers. Cure rates in cHL have improved markedly over the last several decades, but patients with primary refractory disease still show inferior survival. We performed a proteomic comparison of pretreatment tumour tissue from ABVD treatment-refractory versus ABVD treatment-sensitive cHL patients, in order to identify biological differences correlating with treatment outcome. Formalin-fixed paraffin-embedded tumour tissues from 36 patients with cHL, 15 with treatment-refractory disease, and 21 with treatment-sensitive disease, were processed for proteomic investigation. Label-free quantification nano liquid chromatography tandem mass spectrometry was performed on the tissues. A total of 3920 proteins were detected and quantified between the refractory and sensitive groups. This comparison revealed several subtle but significant differences in protein expression which could identify subcluster characteristics of the refractory group. Bioinformatic analysis of the biological differences indicated that a number of pathologically activated signal transduction pathways are disturbed in ABVD treatment-refractory cHL.

A CIBERSORTx-based immune cell scoring system could independently predict the prognosis of patients with myelodysplastic syndromes

Aside from cell intrinsic factors such as genetic alterations, immune dysregulation in the bone marrow (BM) microenvironment plays a role in the development and progression of myelodysplastic syndromes (MDS). However, the prognostic implications of various immune cells in patients with MDS remain unclear. We adopted CIBERSORTx to estimate the relative fractions of 22 subtypes of immune cells in the BM of 316 patients with MDS and correlated the results with clinical outcomes. A lower fraction of unpolarized M0 macrophages and higher fractions of M2 macrophages and eosinophils were significantly associated with inferior survival. An immune cell scoring system (ICSS) was constructed based on the proportion of these 3 immune cells in the BM. The ICSS high-risk patients had higher BM blast counts, higher frequencies of poor-risk cytogenetics, and more NPM1, TP53, and WT1 mutations than intermediate- and low-risk patients. The ICSS could stratify patients with MDS into 3 risk groups with distinct leukemia-free survival and overall survival among the total cohort and in the subgroups of patients with lower and higher disease risk based on the revised International Prognostic Scoring System (IPSS-R). The prognostic significance of ICSS was also validated in another independent cohort. Multivariable analysis revealed that ICSS independently predicted prognosis, regardless of age, IPSS-R, and mutation status. Bioinformatic analysis demonstrated a significant correlation between high-risk ICSS and nuclear factor κB signaling, oxidative stress, and leukemic stem cell signature pathways. Further studies investigating the mechanistic insight into the crosstalk between stem cells and immune cells are warranted.

Relapsed and refractory classical Hodgkin lymphoma: could virotherapy help solve the equation?

Classical Hodgkin lymphoma is a neoplastic hematological disease. Standard first-line therapy, including chemotherapy and radiotherapy, is curative in >85% of early-stage patients, with a 5-year survival rate of >95%. However, approximately 15% of patients have hard-to-treat lymphoma with poor outcomes, and new treatment strategies are needed for these young adults. There are several well-documented cases in the medical literature on hematologic cancer remission following natural human viral infections. Therefore, hoping to reproduce these spontaneous tumor regressions, researchers have been investigating various viruses with oncolytic properties. There is a high rationale for using virotherapy in the treatment of Hodgkin lymphoma, in which tumor cells are often infected with the Epstein-Barr virus. Modern viral technologies and current knowledge about the relationship between viruses and cancer could accelerate the discovery of effective viral oncolytic therapies. This article reviews the use of oncolytic viruses as innovative therapies for treating Hodgkin lymphoma.

Primary tumors from mucosal barrier organs drive unique eosinophil infiltration patterns and clinical associations

Eosinophils are bone marrow-derived granulocytes that display key effector functions in allergic diseases. Nonetheless, recent data highlight important roles for eosinophils in the tumor microenvironment (TME). Eosinophils have been attributed with pleiotropic and perhaps conflicting functions, which may be attributed at least in part to variations in eosinophil quantitation in the TME. Thus, a reliable, quantitative, and robust method for the assessment of eosinophilic infiltration in the TME is required. This type of methodology could standardize the identification of these cells and promote the subsequent generation of hypothesis-driven mechanistic studies. To this end, we conducted a comprehensive analysis of multiple primary tumors from distinct anatomical sites using a standardized method. Bioinformatics analysis of 10,469 genomically profiled primary tumors revealed that eosinophil abundance within different tumors can be categorized into three groups representing tumors with high, intermediate, and low eosinophil levels. Consequently, eosinophil abundance, as well as spatial distribution, was determined in tissue tumor arrays of six tumors representing all three classifications (colon and esophagus - high; lung - intermediate; cervix, ovary, and breast - low). With the exception of breast cancer, eosinophils were mainly localized in the tumor stroma. Importantly, the tumor anatomical site was identified as the primary predictive factor of eosinophil stromal density highlighting a distinction between mucosal-barrier organs versus non-mucosal barrier organs. These findings enhance our understanding of eosinophil diversity in the TME and provide a compelling rationale for future experiments assessing the activity of these cells.

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.

Tumor-associated tissue eosinophilia predicts favorable clinical outcome in solid tumors: a meta-analysis

Background

Activated eosinophils have been deemed to affect carcinogenesis and tumor progression via various mechanisms in tumor microenvironment. However, the prognostic role of tumor-associated tissue eosinophilia (TATE) in human cancers remains controversial. Therefore, we conducted this meta-analysis to better comprehend the association between TATE and clinical outcomes of patients.

Methods

We searched PubMed, Embase and EBSCO to determine the researches assessing the association between TATE and overall survival (OS) and/or disease-free survival (DFS) in patients with cancer, then combined relevant data into hazard ratios (HRs) or odds ratio (OR) for OS, DFS and clinicopathological features including lymph node metastasis etc. with STATA 12.0.

Results

Twenty six researches with 6384 patients were included in this meta-analysis. We found that the presence of TATE was significantly associated with improved OS, but not with DFS in all types of cancers. In stratified analyses based on cancer types, pooled results manifested that the infiltration of eosinophils was remarkably associated with better OS in esophageal carcinoma and colorectal cancer. In addition, TATE significantly inversely correlated with lymph node metastasis, tumor stage and lymphatic invasion of cancer.

Conclusion

TATE promotes survival in cancer patients, suggesting that it is a valuable prognostic biomarker and clinical application of biological response modifiers or agonists promoting TATE may be the novel therapeutic strategy for patients.

Regulation of Tumor Immunity by Lysophosphatidic Acid

The tumor microenvironment (TME) may be best conceptualized as an ecosystem comprised of cancer cells interacting with a multitude of stromal components such as the extracellular matrix (ECM), blood and lymphatic networks, fibroblasts, adipocytes, and cells of the immune system. At the center of this crosstalk between cancer cells and their TME is the bioactive lipid lysophosphatidic acid (LPA). High levels of LPA and the enzyme generating it, termed autotaxin (ATX), are present in many cancers. It is also well documented that LPA drives tumor progression by promoting angiogenesis, proliferation, survival, invasion and metastasis. One of the hallmarks of cancer is the ability to modulate and escape immune detection and eradication. Despite the profound role of LPA in regulating immune functions and inflammation, its role in the context of tumor immunity has not received much attention until recently where emerging studies highlight that this signaling axis may be a means that cancer cells adopt to evade immune detection and eradication. The present review aims to look at the immunomodulatory actions of LPA in baseline immunity to provide a broad understanding of the subject with a special emphasis on LPA and cancer immunity, highlighting the latest progress in this area of research.

Role of ADAM10 as a CD30 Sheddase in Classical Hodgkin Lymphoma

Cancer cells generally recruit and influence non-malignant immune cells to support the tumor growth. Classical Hodgkin lymphoma (cHL) is a good example because the affected lymphoid tissue contains only a few malignant Hodgkin and Reed-Sternberg (H-RS) cells, which are supported by a massive infiltrate of lymphocytes, fibroblasts, and innate immune cells. The transmembrane receptor CD30, which is selectively expressed on the H-RS cells, plays an important role, not only in cell stimulation and intercellular communication but also in tumor diagnosis and targeted tumor therapy. Different protein processing pathways influence its functionality. Depending on the conditions, the receptor is internalized or released. The release of CD30 occurs either as an intact molecule, embedded in the membrane of extracellular vesicles (EVs), or as a cleaved soluble ectodomain (sCD30). CD30 cleavage is predominantly catalyzed by ADAM10. The enzyme is catalytically active in cells as well as in EVs and gradually releases sCD30. Because the circulation contains no CD30⁺ donor cells, this mechanism explains that the cleaved ectodomain represents the predominant form of CD30 in the plasma of cHL patients. CD30 processing might influence the impact of CD30 antibody-drug conjugates, such as Brentuximab Vedotin (BV). Whereas, ADAM10-degraded CD30 impedes the BV efficacy, tumor-derived EVs load bystander cells with CD30 and generate new targets among supporter cells. This crossfire effect might contribute to the enormous clinical impact of BV, whereas the ADAM10-dependent cleavage to the mild systemic off-target effects of the treatment with BV.

Immune and Inflammatory Cells of the Tumor Microenvironment Represent Novel Therapeutic Targets in Classical Hodgkin Lymphoma

Classical Hodgkin Lymphoma (cHL) is a B-cell malignancy that, typically, responds well to standard therapies. However, patients who relapse after standard regimens or are refractory to induction therapy have a dismal outcome. The implementation of novel therapies such as the anti-CD30 monoclonal antibody Brentuximab Vedotin and immune checkpoint inhibitors has provided curative options for many of these patients. Nonetheless, responses are rarely durable, emphasizing the need for new agents. cHL is characterized by a unique microenvironment in which cellular and humoral components interact to promote tumor survival and dissemination. Knowledge of the complex composition of cHL microenvironment is constantly evolving; in particular, there is growing interest in certain cell subsets such as tumor-associated macrophages, myeloid-derived suppressor cells and neutrophils, all of which have a relevant role in the pathogenesis of the disease. The unique biology of the cHL microenvironment has provided opportunities to develop new drugs, many of which are currently being tested in preclinical and clinical settings. In this review, we will summarize novel insights in the crosstalk between tumor cells and non-malignant inflammatory cells. In addition, we will discuss the relevance of tumor-microenvironment interactions as potential therapeutic targets.

High tumour plasma cell infiltration reflects an important microenvironmental component in classic Hodgkin lymphoma linked to presence of B-symptoms

Plasma cells are important prognostic actors in different malignancies. The tumour microenvironmental composition in classic Hodgkin lymphoma (cHL) is a major prognostic key element; however, clinicopathological studies regarding plasma cells in cHL are lacking. The aim of this study was to investigate CD138+ (also termed SDC1+) plasma cell and IgG4 producing (IgG4+) plasma cells infiltration in the microenvironment of cHL. Immunohistochemistry with anti-CD138 and IgG4 antibodies was performed on diagnostic tumour biopsies from 124 patients with cHL, on tissue micro array (TMA). In 120 cases, CD138+ plasma cell-infiltration was associated with the presence of B-symptoms (P = 0·028) and advanced stage, IIB-IVB (P = 0·009). In multivariate analysis, CD138+ plasma cells correlated with eosinophil infiltration (P = 0·013). The subgroup of IgG4+ plasma cells was analysed in 122 cases and only correlated to CD138+ plasma cells (P = 0·004). Patients with high proportion of tumour infiltrating CD138+ plasma cells (defined as ≥10%), had a more inferior event-free survival (P = 0·007) and overall survival (P = 0·004) than patients with a low proportion of infiltrating CD138+ plasma cells (<10%), although significance was not maintained in multivariate analysis. In summary, a high proportion of tumour-associated plasma cells in cHL reflect an important component in the microenvironment of cHL.

CD30 on extracellular vesicles from malignant Hodgkin cells supports damaging of CD30 ligand-expressing bystander cells with Brentuximab-Vedotin, in vitro

The goal of targeted immunotherapy in cancer is to damage both malignant and tumor-supporting cells of the microenvironment but spare unaffected tissue. The malignant cells in classical Hodgkin lymphoma (cHL) selectively express CD30. They release this receptor on extracellular vesicles (EVs) for the tumor-supporting communication with CD30 ligand (CD30L)-positive bystander cells. Here, we investigated how CD30-positive EVs influence the efficacy of the CD30 antibody drug conjugate (ADC) Brentuximab Vedotin (SGN-35). The malignant cells and the EVs expressed the active sheddase ADAM10. ADAM10 cleaved and released the CD30 ectodomain (sCD30), causing a gradual depletion of SGN-35 binding sites on EVs and creating a soluble competitor of the ADC therapy. In a 3D semi-solid tumor microenvironment model, the EVs were retained in the matrix whereas sCD30 penetrated readily into the surrounding culture medium. This resulted in a lowered ratio of EV-associated CD30 (CD30EV) to sCD30 in the surrounding medium in comparison to non-embedded cultures. A low percentage of CD30EV was also detected in the plasma of cHL patients, supporting the clinical relevance of the model. The adherence of CD30EV but not sCD30 to CD30-/CD30L+ mast cells and eosinophils allowed the indirect binding of SGN-35. Moreover, SGN-35 damaged CD30-negative cells, provided they were loaded with CD30+ EVs.

An anergic immune signature in the tumor microenvironment of classical Hodgkin lymphoma is associated with inferior outcome

OBJECTIVE

The classical Hodgkin lymphoma (cHL) tumor microenvironment shows an ongoing inflammatory response consisting of varying degrees of infiltrating eosinophils, mast cells, macrophages, regulatory T lymphocytes (Tregs), and activated lymphocytes surrounding the malignant cells. Herein, different immune signatures are characterized and correlated with treatment outcome.

METHODS

Tumor-infiltrating leukocytes were phenotyped in biopsies from 459 patients with cHL. Time to progression (TTP) (primary progression, relapse, or death from cHL) and overall survival were analyzed using Cox proportional hazards regression.

RESULTS

The leukocyte infiltration in the microenvironment was highly diverse between patients and was categorized in 4 immune signatures (active, anergic, innate, or mixed). A high proportion of Tregs (anergic) resulted in shorter TTP (median 12.9-year follow-up) in age-adjusted analyses (hazard ratio = 1.82; 95% confidence interval 1.05-3-15). Epstein-Barr virus (EBV)-positive cases had higher proportions of macrophages and activated lymphocytes than EBV negative, but neither of those leukocytes predicted prognosis.

CONCLUSIONS

Abundant Tregs (anergic signature) indicate a shorter TTP, particularly in younger patients. This is probably due to a reduced ability of the immune system to attack the tumor cells. Our data warrant further investigation if these suggested immune signatures could predict outcome of immunotherapy such as immune checkpoint inhibitors.

Eosinophils: The unsung heroes in cancer?

Prolonged low-grade inflammation or smoldering inflammation is a hallmark of a cancer. Eosinophils are components of the immune microenvironment that modulates tumor initiation and progression. Although canonically associated with a detrimental role in allergic disorders, these cells can induce a protective immune response against helminthes, viral and bacterial pathogens. Eosinophils are a source of anti-tumorigenic (e.g., TNF-α, granzyme, cationic proteins, and IL-18) and protumorigenic molecules (e.g., pro-angiogenic factors) depending on the milieu. In several neoplasias (e.g., melanoma, gastric, colorectal, oral and prostate cancer) eosinophils play an anti-tumorigenic role, in others (e.g., Hodgkin's lymphoma, cervical carcinoma) have been linked to poor prognosis, whereas in yet others they are apparently innocent bystanders. These seemingly conflicting results suggest that the role of eosinophils and their mediators could be cancer-dependent. The microlocalization (e.g., peritumoral vs intratumoral) of eosinophils could be another important aspect in the initiation/progression of solid and hematological tumors. Increasing evidence in experimental models indicates that activation/recruitment of eosinophils could represent a new therapeutic strategy for certain tumors (e.g., melanoma). Many unanswered questions should be addressed before we understand whether eosinophils are an ally, adversary or neutral bystanders in different types of human cancers.

The prognostic value of biological markers in paediatric Hodgkin lymphoma

BACKGROUND

Many biological and inflammatory markers have been proposed as having a prognostic value at diagnosis of Hodgkin lymphoma (HL), but very few have been validated in paediatric patients. We explored the significance of these markers in a large population of 769 affected children.

PATIENTS AND METHODS

By using the database of patients enrolled in A.I.E.O.P. (Associazione Italiana di Emato-Oncologia Pediatrica) trial LH2004 for paediatric HL, we identified 769 consecutive patients treated with curative intent from 1st June 2004 to 1st April 2014 with ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine), or hybrid COPP/ABV (cyclophosphamide, vincristine, prednisone, procarbazine, doxorubicin, bleomycin and vinblastine) regimens.

RESULTS

On multivariate analysis with categorical forms, the 5-year freedom from progression survival was significantly lower in patients with stage IV or elevated value of platelets, eosinophils and ferritin at diagnosis. Furthermore, stage IV and eosinophils seem to maintain their predictive value independently of interim (after IV cycles of chemotherapy) positron emission tomography.

CONCLUSION

Using the combination of four simple markers such as stage IV and elevated levels of platelets, ferritin and eosinophils, it is possible to classify the patients into subgroups with very different outcomes.

Clinical features of AIDS patients with Hodgkin's lymphoma with isolated bone marrow involvement: report of 12 cases at a single institution

Objective

To study the main clinical and histopathological features of 12 patients with Hodgkin’s lymphoma (HL) diagnosed primarily from bone marrow (BM) involvement.

Methods

We included 12 acquired immunodeficiency syndrome (AIDS) patients with HL assisted in the F. J. Muñiz Infectious Diseases Hospital since January 2002 to December 2013. The diagnosis of HL with primary BM involvement in patients was confirmed by clinical, histopathological, and immunohistochemical findings.

Results

All patients presented “B” symptoms and pancytopenia. All of them had stage IV neoplasm disease because of BM infiltration. The median of CD4⁺ T-cell counts was 114 cells/μL, and mixed cellularity (MC) was the most frequent histopathological subtype of 92% cases.

Conclusion

When other causes are excluded, BM biopsy should be performed in AIDS patients with “B” symptoms and pancytopenia to evaluate BM infiltration by atypical lymphocytes.

Mast cells play a protumorigenic role in primary cutaneous lymphoma

Primary cutaneous lymphomas (PCLs) are clonal T- or B-cell neoplasms, which originate in the skin. In recent years, mast cells were described as regulators of the tumor microenvironment in different human malignancies. Here, we investigated the role of mast cells in the tumor microenvironment of PCL. We found significantly increased numbers of mast cells in skin biopsies from patients with cutaneous T-cell lymphoma (CTCL) and cutaneous B-cell lymphoma (CBCL). Mast cell infiltration was particularly prominent in the periphery, at lymphoma rims. Interestingly, CTCL and CBCL patients with a progressive course showed higher mast cell counts than stable patients, and mast cell numbers in different stages of CTCL correlated positively with disease progression. In addition, mast cell numbers positively correlated with microvessel density. Incubating primary CTCL cells with mast cell supernatant, we observed enhanced proliferation and production of cytokines. In line with our in vitro experiments, in a mouse model of cutaneous lymphoma, tumor growth in mast cell-deficient transgenic mice was significantly decreased. Taken together, these experiments show that mast cells play a protumorigenic role in CTCL and CBCL. Our data provide a rationale for exploiting tumor-associated mast cells as a prognostic marker and therapeutic target in PCL.

Mast cells and eosinophils in mastocytosis, chronic eosinophilic leukemia, and non-clonal disorders

Mast cells and eosinophils often travel in the same biologic circles. In non-clonal states, such as allergic and inflammatory conditions, cell-to-cell contact and the pleiotropic actions of multiple cytokines and chemokines, derived from local tissues or mast cells themselves, foster the co-recruitment of these cells to the same geographic cellular niche. While eosinophils and mast cells serve critical roles as part of the host immune response and in maintenance of normal homeostasis, these cell types can undergo neoplastic transformation due to the development of clonal molecular abnormalities that arise in early hematopoietic progenitors. The dysregulated tyrosine kinases, D816V KIT and FIP1L1-PDGFRA, are the prototypic oncogenic lesions resulting in systemic mastocytosis (SM) and chronic eosinophilic leukemia, respectively. We review the pathobiology of these myeloproliferative neoplasms (MPNs) with a focus on the relationship between mast cells and eosinophils, and discuss murine models, which further elucidate how the phenotype of these diseases can be influenced by stem cell factor (SCF) and expression of the potent eosinophilopoietic cytokine, interleukin-5 (IL-5). Therapy of SM and FIP1L1-PDGFRA-positive disease and the prognostic relevance of increased peripheral blood and tissue mast cells in hematolymphoid malignancies will also be addressed.

Eosinophilic lung diseases

Accurate diagnosis of eosinophilic lung diseases is essential to optimizing patient outcomes, but remains challenging. Signs and symptoms frequently overlap among the disorders, and because these disorders are infrequent, expertise is difficult to acquire. Still, these disorders are not rare, and most clinicians periodically encounter patients with one or more of the eosinophilic lung diseases and need to understand how to recognize, diagnose, and manage these diseases. This review focuses on the clinical features, general diagnostic workup, and management of the eosinophilic lung diseases.

Predictors of histology, tissue eosinophilia and mast cell infiltration in Hodgkin's lymphoma--a population-based study

OBJECTIVE

Classical Hodgkin's lymphoma (HL) lesions comprise few tumour cells, surrounded by numerous inflammatory cells. Like in other malignancies, the microenvironment is presumed to be clinically important in HL; however, microenvironment predictors remain poorly characterised. The aim of this study was to investigate how selected patient characteristics and genetic factors affect HL phenotype, in particular tissue eosinophilia, mast cell counts and HL histological subtype.

METHODS

In a population-based study, patients with HL were interviewed about potential HL risk factors. Available tumours, n=448, were classified histologically; the number of eosinophils and mast cells were estimated, and eosinophil cationic protein (ECP) and eosinophil protein-x (EPX) gene polymorphisms were determined. Associations were assessed in regression models.

RESULTS

Self-reported history of asthma was predictive of having tumour eosinophilia [≥200 eosinophils/10 high power fields, univariate odds ratio (OR)=2.22, 95% CI 1.06-4.64, P=0.03]. High numbers of eosinophils were predominantly seen in patients carrying the genotype ECP434GG [multivariate relative levels (RLs)=1.84, 95% CI 1.02-3.30, P=0.04]. Lower number of eosinophils was seen in Epstein-Barr virus (EBV)-positive tumours (univariate RL=0.52, 95% CI 0.3-0.9, P=0.02) and in older patients (univariate RL=0.85, 95% CI 0.73-0.99, P=0.03). Well-known factors such as young age, female sex and EBV-negative status predicted nodular sclerosis histology.

CONCLUSION

The number of eosinophils in HL tumours is influenced by patient traits such as asthma, ECP genotype and EBV status. EBV status was predictive of histology.

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.

Tumor-infiltrating macrophages correlate with adverse prognosis and Epstein-Barr virus status in classical Hodgkin's lymphoma

BACKGROUND

Classical Hodgkin's lymphoma is characterized by a minority of neoplastic cells surrounded by a heterogeneous background population of non-neoplastic cells including lymphoma-associated macrophages. High levels of expression of both the monocyte/macrophage lineage-associated antigens CD68 and CD163 have been suggested to have pro-tumor effects. The aim of our study was to correlate expression of CD68 and CD163 with the clinico-pathological features and prognosis of a cohort of patients with previously untreated Hodgkin's lymphoma.

DESIGN AND METHODS

A tissue microarray was constructed from paraffin-embedded tumor tissues from 288 cases of classical Hodgkin's lymphoma. CD68 and CD163 expression was assessed immunohistochemically and the degree of macrophage infiltration within the tumor was scored using point grid counting. Clinical data were obtained from clinical records.

RESULTS

The patients' median age was 37 years (range, 6-86 years). The male to female ratio was 1.2. In classical Hodgkin's lymphoma (n = 288) high CD68 and CD163 expression correlated, at the univariate level, with poorer overall survival (P=0.002 and P=0.03, respectively) and event-free survival (P=0.03 and P=0.04, respectively). At the multivariate level, high CD68 expression remained significantly predictive of overall survival (P=0.004). In addition, we demonstrated that both high CD68 and CD163 expression were associated with the presence of Epstein-Barr virus in the neoplastic cells (P=0.001 and P=0.0002, respectively).

CONCLUSIONS

In classical Hodgkin's lymphoma, high expression of the macrophage/monocyte-related antigens CD68 and CD163 correlates with adverse outcome and with the presence of Epstein-Barr virus in the tumor cell population.

Targeting CCL11 in the treatment of ovarian cancer

IMPORTANCE OF THE FIELD

The chemokine network, comprised of mediators of inflammation, has been implicated in the development of a number of human cancers. The eosinophil chemoattractant CCL11 was recently shown to play a role in the development of ovarian cancer. Here we review findings regarding CCL11 and discuss its use as a target in the treatment of ovarian cancer.

AREAS COVERED IN THIS REVIEW

We review published findings related to the physiological actions of CCL11, its tumourigenic effects, the chemokine network and inflammatory response present in ovarian cancer, and the current state of therapeutics targeting CCL11 and its receptors. Findings published within the last 10 years receive particular attention.

WHAT THE READER WILL GAIN

An overview of the emerging role of the chemokine network in malignancy and a review of the role of CCL11 in ovarian tumourigenesis. The reader will be presented with a description of the unique aspects of CCL11 action and the inflammatory environment in the setting of ovarian malignancy that make this chemokine an attractive target for intervention.

TAKE HOME MESSAGE

Targeting CCL11 and its receptors through the use of monoclonal antibodies and small-molecule inhibitors may represent a beneficial new avenue of ovarian cancer treatment.

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.

Retrospective analysis of the prognostic role of tissue eosinophil and mast cells in Hodgkin's lymphoma

The composition of reactive cell populations, which constitute the majority of tumor load in Hodgkin's lymphoma (HL), can influence the prognosis of the disease. Besides widely accepted and applied prognostic scores, the authors evaluate biological factors that may have a prognostic impact. Previous data indicate that the rate of eosinophils and mast cells in the reactive cell population, determined already at diagnosis, can be used for this purpose. Histological samples from 104 patients with HL with an average follow-up period of 110 (24-214) months were retrospectively analyzed. Mast cell positivity was associated with better overall survival, although this difference was only of borderline statistical significance (p=0.092). No significant difference was found in parameters like overall survival (OS, p=0.906) or event-free survival (EFS, p=0.307) of eosinophil-positive vs. -negative cases or in EFS (p=0.742) of mast cell-positive vs. -negative individuals (criterion for a positive specimen was more than 5% of appropriate cells in the reactive cell population). Looking at the effect of eosinophilia and mastocytosis together, there was no significant difference between the subgroups categorized according to the combined presence of the two cell types. It seems that tissue eosinophil and mast cell predominance have no prognostic value that could be used in clinical practice, although a tendency for correlation of mast cell positivity with overall survival could be seen. For a definitive statement, multicenter studies should be performed involving a higher number of patients suffering from HL.

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.

Mast cells and eosinophils in invasive breast carcinoma

Background

Inflammatory cells in the tumour stroma has gained increasing interest recently. Thus, we aimed to study the frequency and prognostic impact of stromal mast cells and tumour infiltrating eosinophils in invasive breast carcinomas.

Methods

Tissue microarrays containing 234 cases of invasive breast cancer were prepared and analysed for the presence of stromal mast cells and eosinophils. Tumour infiltrating eosinophils were counted on hematoxylin-eosin slides. Immunostaining for tryptase was done and the total number of mast cells were counted and correlated to the proliferation marker Ki 67, positivity for estrogen and progesterone receptors, clinical parameters and clinical outcome.

Results

Stromal mast cells were found to correlate to low grade tumours and estrogen receptor positivity. There was a total lack of eosinophils in breast cancer tumours.

Conclusion

A high number of mast cells in the tumours correlated to low-grade tumours and estrogen receptor positivity. Eosinophils are not tumour infiltrating in breast cancers.

IL-9 expression contributes to the cellular composition in Hodgkin lymphoma

OBJECTIVES

The presence of numerous mast cells or eosinophils in Hodgkin lymphoma (HL) tumours have both been described as negative prognostic factors. One cytokine related to HL is interleukin-9 (IL-9) and it is known to affect both mast cells and eosinophils. The aim of this study was to explore if the expression of IL-9 correlates to the presence of these inflammatory cells in HL tumours.

METHODS

In 131 HL biopsies, immunostainings for IL-9 and IL-9 receptor (IL-9R) were performed. The same material was previously stained for mast cells and eosinophils. These data were correlated to clinical and survival data from all patients.

RESULTS

Fifty-three percent of cases were positive for IL-9 and 19% were positive for IL-9R in the cytoplasm of the tumour cells. The IL-9 positive patients had more eosinophils (P = 0.002) and mast cells (P = 0.02) in their tumours, more often a nodular sclerosis histology (P < 0.0001), a higher white-blood-cell count (P = 0.006) and a higher erythrocyte sedimentation rate (P = 0.003) at the time of diagnosis.

CONCLUSIONS

IL-9 expression is related to the histology, clinical picture and the presence of eosinophils and mast cells in HL. These results indicate that IL-9 is an important part of the cytokine network and inflammatory infiltrate in HL.

Bone marrow biopsy in Hodgkin's lymphoma

In the study of patients with Hodgkin's lymphoma (HL) the evaluation of bone marrow biopsy (BMB) can be difficult. In this review we analyze the main diagnostic features and the clinical risk factors of BM involvement. Although the role of BMB is criticized by some authors, its value is irreplaceable in the staging of HL and in the diagnosis of primary medullary HL. The Ann Arbor staging committee criteria should be revised and updated in the light of the current immunohistochemical studies that give a fundamental help in the diagnostic process. A single BMB should be adequate for diagnosis in most instances. In cases of suspicious involvement a controlateral BMB could be performed.

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.

Bystander cells and prognosis in Hodgkin lymphoma. Review based on a doctoral thesis

Hodgkin lymphoma (HL) is characterised histologically by a minority of malignant Hodgkin and Reed-Sternberg (HRS) cells surrounded by benign cells, and clinically by a relatively good prognosis. The treatment, however, leads to a risk of serious side effects. Knowledge about the biology of the disease, particularly the interaction between the HRS cells and the surrounding cells, is essential in order to improve diagnosis and treatment. HL patients with abundant eosinophils in the tumours have a poor prognosis, therefore the eosinophil derived protein eosinophil cationic protein (ECP) was studied. Serum-ECP (S-ECP) was elevated in most HL patients. It correlated to number of tumour eosinophils, nodular sclerosis (NS) histology, and the negative prognostic factors high erythrocyte sedimentation rate (ESR) and blood leukocyte count (WBC). A polymorphism in the ECP gene (434(G>C)) was identified and the 434GG genotype correlated to NS histology and high ESR. The poor prognosis in patients with abundant eosinophils in the tumours has been proposed to depend on HRS cell stimulation by the eosinophils via a CD30 ligand (CD30L)-CD30 interaction. However, CD30L mRNA and protein were detected in mast cells and the predominant CD30L expressing cell in HL is the mast cell. Mast cells were shown to stimulate HRS cell lines via CD30L-CD30 interaction. The number of mast cells in HL tumours correlated to worse relapse-free survival, NS histology, high WBC, and low blood haemoglobin. Survival in patients with early and intermediate stage HL, diagnosed between 1985 and 1992, was generally favourable and comparatively limited treatment was sufficient to produce acceptable results for most stages. The majority of relapses could be salvaged. Patients treated with a short course of chemotherapy and radiotherapy had an excellent outcome. In conclusion prognosis is favourable in early and intermediate stages and there are possibilities for further improvements based on the fact that mast cells and eosinophils affect the biology and prognosis of HL.

Early and intermediate stage Hodgkin's lymphoma--report from the Swedish National Care Programme

In Sweden a National Care Programme provides treatment principles for Hodgkin's lymphoma (HL) since 1985, for early and intermediate stages often less extensive than international recommendations. The purpose is to evaluate long-term results of these principles. A total of 308 patients (167 men and 141 women), 17-59 yr old (median 31), diagnosed during 1985-92, pathological stage (PS) I-III1A and I-IIB and clinical stage (CS) I-IIA, mean follow-up 8.8 yr, were studied. Staging laparotomy was recommended in CS IIA. Recommended treatment was mantle or mini-mantle radiotherapy (RT) alone in CS IA, and PS I-IIA and subtotal nodal irradiation in PS III1A if the disease was not bulky. Patients in PS I-IIA and III1A with bulky disease, and PS I-IIB received one cycle of mechlorethamine, vincristine, prednisone, procarbazine/doxorubicin, bleomycin, vinblastine, lacarbazine (MOPP/ABVD) before irradiation. The remaining patients received three to four cycles of MOPP/ABVD with RT to bulky disease. Relapse-free (RFS), Hodgkin specific (HLS), and overall survival (OS) at 10 yr were 74%, 92% and 85%. In the individual stages, RFS ranged from 53% (PSIII1A) to 90% (PS IA). RFS (P = 0.006), HLS, and OS were significantly better in patients treated with chemotherapy compared with those treated with RT alone, especially in patients with bulky disease (P = 0.0005). The international prognostic score did not provide any prognostic information. The OS rates are in agreement with results from international centres during that time. The recommended treatment was sufficient to produce the desired results of <20-30% recurrences, except in PS III1A. Most relapses could be salvaged. Patients with risk factors treated with one MOPP/ABVD and RT had an excellent outcome, superior to those without risk factors treated with RT alone. These results favour the trend to treat early and intermediate stages with a short course of chemotherapy followed by limited RT.

Mast cell infiltration correlates with poor prognosis in Hodgkin's lymphoma

Hodgkin's lymphoma (HL) is characterized by a few Hodgkin, Reed-Sternberg cells (HRS) surrounded by benign cells. We recently reported that mast cells were the predominant CD30L-positive cells in HL tumours, and that they activate HRS in vitro through CD30L-CD30 interaction. Here, we investigated the clinical importance of mast cell infiltration in the tumours of 123 patients. Tumour specimens were stained with a mast-cell-specific antibody that detects tryptase. Mast cells were detected in virtually every case and increasing numbers of mast cells correlated to nodular sclerosis histology (P = 0.008). Patients with higher mast cell infiltration had a worse relapse-free survival (P = 0.01).

Eosinophilic lung disease in the tropics

Paul Ehrlich first described the eosinophil in 1879. It is a pro-inflammatory cell that is involved in the immune defense against various offenders in atopic and nonatopic individuals. Eosinophils derive from an unknown progenitor cell in the bone marrow. This article reviews the etiology and effects of this condition.

Tissue eosinophilia in relation to immunopathological and clinical characteristics in Hodgkin's disease

Eosinophils frequently infiltrate tissues involved by Hodgkin's disease (HD), and blood eosinophilia is frequently observed. However, the clinical significance and the mechanisms underlying eosinophilia need further elucidation. In this study the grade of eosinophilic infiltration (EoI) was evaluated in biopsies from 259 HD-patients. In a selected group (n=32), the numbers of Hodgkin-Reed-Sternberg (HRS)-cells were counted, and the phenotype of small lymphocytes, the expression of cytotoxic lymphocyte-associated proteins, CD3-zeta-chain, HLA-DR, proliferation markers, latent membrane protein 1 (LMP-1) and blood lymphocyte function were evaluated. Samples from 88 HD patients (34%) showed high EoI. Significantly higher EoI was seen in nodular sclerosis 2 (NS2; p<0.001), bulky disease (p<0.05) and in patients <50 years (p<0.05). Patients with high EoI did not differ from the remainder with regard to distribution of sex, stage, B-symptoms, blood lymphocyte function and outcome. HRS-cells were significantly more frequent in NS HD as compared to mixed cellularity (MC) (p<0.001) irrespective of EoI. LMP-1-expression, proliferative fraction and phenotypes of small lymphocytes did not differ between the cases with low and high EoI, respectively. MC HD samples had significantly higher numbers of small cells positive for CD8 (p<0.01), T-cell intracellular antigen-1 (p<0.01) and Granzyme B (p<0.05) than NS. LMP-1-positive cases had significantly higher frequency of CD8-positive cells than LMP-1-negative. In conclusion, high EoI remains a feature of certain clinical subgroups of HD. However, there was no association between the degree of EoI and numbers of HRS-cells, phenotypes of small lymphocytes, EBV status and clinical outcome. Determination of EoI is of limited diagnostic and prognostic clinical value in HD. However, the differences in small cell distribution of CD8, TIA-1, GrB and CD57 between the histopathological groups and between LMP-1-expressing/non-expressing cases may contribute to our understanding of the biology of the disease.