The immune microenvironment in Hodgkin lymphoma: T cells, B cells, and immune checkpoints

Proton Therapy Reduces the Effective Dose to Immune Cells in Mediastinal Hodgkin Lymphoma Patients

Purpose

Effective dose to circulating immune cells (EDIC) is associated with survival in lung and esophageal cancer patients. This study aimed to evaluate the benefit of intensity-modulated proton therapy (IMPT) for EDIC reduction compared with volumetric modulated arc therapy (VMAT) in mediastinal Hodgkin lymphoma (mHL) patients.

Materials and Methods

Ten consecutive mHL patients treated with involved-site IMPT after frontline chemotherapy were included. The mean dose to the heart, lung, and liver and the integral dose to the body were obtained, and we calculated EDIC based on these variables. The effective dose to circulating immune cells was compared between IMPT and VMAT schedules.

Results

The median EDIC was reduced from 1.93 Gy (range: 1.31-3.87) with VMAT to 1.08 Gy (0.53-2.09) with IMPT (P < .01). Integral dose reduction was the main driver of EDIC reduction with IMPT, followed by lung sparing.

Conclusion

Intensity-modulated proton therapy significantly reduced EDIC in mHL patients undergoing consolidation involved-site radiation therapy. Integral dose reduction combined with improved lung sparing was the main driver of EDIC reduction with IMPT.

Immune cells in the B-cell lymphoma microenvironment: From basic research to clinical applications

ABSTRACT

B-cell lymphoma is a group of hematological malignancies characterized by variable genetic and biological features and clinical behaviors. The tumor microenvironment (TME) is a complex network in tumors, which consists of surrounding blood vessels, extracellular matrix, immune and non-immune cells, and signaling molecules. Increasing evidence has shown that the TME, especially immune cells within, is a double-edged sword, acting either as a tumor killer or as a promoter of tumor progression. These pro-tumor activities are driven by subpopulations of immune cells that express typical markers but have unique transcriptional characteristics, making tumor-associated immune cells good targets for human anti-cancer therapy by ablating immunosuppressive cells or enhancing immune-activated cells. Thus, exploring the role of immune cells in the TME provides distinct insights for immunotherapy in B-cell lymphoma. In this review, we elucidated the interaction between immune cells and tumor cells and their function in the initiation, progression, and prognosis of B-cell lymphoma, from preclinical experiments to clinical trials. Furthermore, we outlined potential therapeutic approaches and discussed the potential clinical value and future perspectives of targeting immune cells in patients with B-cell lymphoma.

The role of IgG4-positive plasma cell population in classic Hodgkin lymphoma

The effect of IgG4, which constitutes the least of the IgG subclasses, on the pathogenesis and prognosis of lymphoma or solid tumors is one of the research topics of interest in recent years. The role of IgG4, which has been reported to suppress antitumor immunity, in classic Hodgkin's lymphoma (cHL), which is recognized by its pathognomonic microenvironment, is not yet clearly known. The aim of this study was to determine IgG4-positive plasma cell density in the cHL microenvironment and to compare it with histopathological and clinical parameters. In addition, the role of the increase in IgG4-positive cells in the development of relapse after treatment was also investigated. A retrospective cross-sectional study. Ninety-four patients with the initial diagnosis of cHL who had no comorbidity or no treatment history and forty-one reactive lymph nodes with follicular hyperplasia findings were included in the study. Three hot-spot areas were identified with reference to the IgG4 sections. Mean IgG4-positive plasmacyte counts and IgG4/IgG ratios were determined and compared with histopathological characteristics. The mean IgG4 + plasma cell count was 33.57 in cHL cases and 47.04 in the control group (p = 0.233). IgG4/IgG ratio was significantly higher in cHL compared with the control group (0.27 vs. 0.21, p = 0.021). The IgG4/IgG ratio was found to be higher in younger patients with classic Hodgkin lymphoma, with a low correlation (p = 0.028, r =  - 0.226). There was no relationship with gender, lymph node location, histological subtype, EBV positivity and bone marrow infiltration. It was observed that IgG4/IgG ratio was higher in early-stage patients (p = 0.022). No significant IgG4 + cell increase was detected in the initial diagnosis and relapse slides of six patients who developed relapse after standard treatment, resulting in a cure. Novel therapeutic modalities targeting microenvironmental components have been reported to show dramatic effects, particularly in relapsed or refractory patients. Detailed characterization of the cHL inflammatory milieu will be useful for the identification of alternative targets. IgG4 subclass antibodies, which have been described to have anti-inflammatory effects, may have prognostic significance in a proportion of cHL patients.

Hodgkin Lymphoma: A disease shaped by the tumor micro- and macroenvironment

The tumor microenvironment (TMicroE) and tumor macroenvironment (TMacroE) are defining features of classical Hodgkin lymphoma (cHL). They are of critical importance to clinicians since they explain the common signs and symptoms, allow us to classify these neoplasms, develop prognostic and predictive biomarkers, bioimaging and novel treatments. The TMicroE is defined by effects of cancer cells to their immediate surrounding and within the tumor. Effects of cancer cells at a distance or outside of the tumor define the TMacroE. Paraneoplastic syndromes are signs and symptoms due to effects of cancer at a distance or the TMacroE, which are not due to direct cancer cell infiltration. The most common paraneoplastic symptoms are B-symptoms, which manifest as fevers, chills, drenching night sweats, and/or weight loss. Less common paraneoplastic syndromes include those that affect the central nervous system, skin, kidney, and hematological autoimmune phenomena including hemophagocytic lymphohistiocytosis (HLH). Paraneoplastic signs such as leukocytosis, lymphopenia, anemia, and hypoalbuminemia are prognostic biomarkers. The neoplastic cells in cHL are the Hodgkin and Reed Sternberg (HRS) cells, which are preapoptotic germinal center B cells with a high mutational burden and almost universal genetic alterations at the 9p24.1 locus primarily through copy gain and amplification with strong activation of signaling via PD-L1, JAK-STAT, NFkB, and c-MYC. In the majority of cases of cHL over 95% of the tumor cells are non-neoplastic. In the TMicroE, HRS cells recruit and mold non-neoplastic cells vigorously via extracellular vesicles, chemokines, cytokines and growth factors such as CCL5, CCL17, IL6, and TGF-β to promote a feed-forward inflammatory loop, which drives cancer aggressiveness and anti-cancer immune evasion. Novel single cell profiling techniques provide critical information on the role in cHL of monocytes-macrophages, neutrophils, T helper, Tregs, cytotoxic CD8+ T cells, eosinophils, mast cells and fibroblasts. Here, we summarize the effects of EBV on the TMicroE and TMacroE. In addition, how the metabolism of the TMicroE of cHL affects bioimaging and contributes to cancer aggressiveness is reviewed. Finally, we discuss how the TMicroE is being leveraged for risk adapted treatment strategies based on bioimaging results and novel immune therapies. In sum, it is clear that we cannot effectively manage patients with cHL without understanding the TMicroE and TMacroE and its clinical importance is expected to continue to grow rapidly.

Integrated genetic analyses of immunodeficiency-associated Epstein-Barr virus- (EBV) positive primary CNS lymphomas

Immunodeficiency-associated primary CNS lymphoma (PCNSL) represents a distinct clinicopathological entity, which is typically Epstein-Barr virus-positive (EBV+) and carries an inferior prognosis. Genetic alterations that characterize EBV-related CNS lymphomagenesis remain unclear precluding molecular classification and targeted therapies. In this study, a comprehensive genetic analysis of 22 EBV+ PCNSL, therefore, integrated clinical and pathological information with exome and RNA sequencing (RNASeq) data. EBV+ PCNSL with germline controls carried a median of 55 protein-coding single nucleotide variants (SNVs; range 24-217) and 2 insertions/deletions (range 0-22). Genetic landscape was largely shaped by aberrant somatic hypermutation with a median of 41.01% (range 31.79-53.49%) of SNVs mapping to its target motifs. Tumors lacked established SNVs (MYD88, CD79B, PIM1) and copy number variants (CDKN2A, HLA loss) driving EBV- PCNSL. Instead, EBV+ PCNSL were characterized by SOCS1 mutations (26%), predicted to disinhibit JAK/STAT signaling, and mutually exclusive gain-of-function NOTCH pathway SNVs (26%). Copy number gains were enriched on 11q23.3, a locus directly targeted for chromosomal aberrations by EBV, that includes SIK3 known to protect from cytotoxic T-cell responses. Losses covered 5q31.2 (STING), critical for sensing viral DNA, and 17q11 (NF1). Unsupervised clustering of RNASeq data revealed two distinct transcriptional groups, that shared strong expression of CD70 and IL1R2, previously linked to tolerogenic tumor microenvironments. Correspondingly, deconvolution of bulk RNASeq data revealed elevated M2-macrophage, T-regulatory cell, mast cell and monocyte fractions in EBV+ PCNSL. In addition to novel insights into the pathobiology of EBV+ PCNSL, the data provide the rationale for the exploration of targeted therapies including JAK-, NOTCH- and CD70-directed approaches.

Peripheral blood CD3+HLADR+ cells and associated gut microbiome species predict response and overall survival to immune checkpoint blockade

Background

The search for biomarkers to identify ideal candidates for immune checkpoint inhibitor (ICI) therapy is fundamental. In this study, we analyze peripheral blood CD3+HLADR+ cells (activated T-cells) as a novel biomarker for ICI therapy and how its association to certain gut microbiome species can indicate individual treatment outcomes.

Methods

Flow cytometry analysis of peripheral mononuclear blood cells (PBMCs) was performed on n=70 patients undergoing ICI therapy for solid malignancies to quantify HLA-DR on circulating CD3+ cells. 16s-rRNA sequencing of stool samples was performed on n=37 patients to assess relative abundance of gut microbiota.

Results

Patients with a higher frequency of CD3+HLADR+ cells before treatment initiation showed a significantly reduced tumor response and overall survival (OS), a worst response and experienced less toxicities to ICI therapy. As such, patients with a frequency of CD3+HLADR+ cells above an ideal cut-off value of 18.55% had a median OS of only 132 days compared to 569 days for patients below. Patients with increasing CD3+HLADR+ cell counts during therapy had a significantly improved OS. An immune signature score comprising CD3+HLADR+ cells and the neutrophil-lymphocyte ratio (NLR) was highly significant for predicting OS before and during therapy. When allied to the relative abundance of microbiota from the Burkholderiales order and the species Bacteroides vulgatus, two immune-microbial scores revealed a promising predictive and prognostic power.

Conclusion

We identify the frequencies and dynamics of CD3+HLADR+ cells as an easily accessible prognostic marker to predict outcome to ICIs, and how these could be associated with immune modulating microbiome species. Two unprecedented immune-microbial scores comprising CD3+HLADR+, NLR and relative abundance of gut bacteria from the Burkhorderiales order or Bacteroides vulgatus species could accurately predict OS to immune checkpoint blockade.

JAK/STAT blockade reverses the malignant phenotype of Hodgkin and Reed-Sternberg cells

Constitutive activation of the JAK/STAT pathway is a common phenomenon in classic Hodgkin lymphoma (cHL). The clinical potential of anti-JAK/STAT therapy is being explored in early-stage clinical trials. Notwithstanding, very little information is available about the complex biological consequences of this blockade. Here, we investigated the effects of JAK/STAT pharmacological inhibition on cHL cell models using ruxolitinib, a JAK 1/2 inhibitor that induces apoptosis by concentration- and time-dependent mechanisms. An unbiased whole-transcriptome approach identified expression of the anti-GCSF receptor (CSF3R) as a potential surrogate biomarker of JAK/STAT overactivation. In addition, longitudinal gene expression analyses provided further mechanistic information about pertinent biological pathways involved, including 37 gene pathways distributed in 3 main clusters: cluster 1 was characterized by upregulation of the G2/M checkpoint and major histocompatibility complex-related clusters; 2 additional clusters (2 and 3) showed a progressive downregulation of the tumor-promoting inflammation signatures: JAK/STAT and interleukin 1 (IL-1)/IL-4/IL-13/IL-17. Together, our results confirm the therapeutic potential of JAK/STAT inhibitors in cHL, identify CSF3R as a new biomarker, and provide supporting genetic data and mechanistic understanding.

A Review of Hodgkin Lymphoma in the Era of Checkpoint Inhibitors

Hodgkin lymphoma (HL) is a hematopoietic malignancy of B-cells that has a bimodal distribution with respect to age and incidence. With the introduction of doxorubicin (Adriamycin), bleomycin, vinblastine, and dacarbazine (ABVD) and radiation combined, the prognosis of HL has significantly improved, with five-year survival rates approaching 95%. While HL has become highly curable, the side effect profiles of ABVD are dire and warrant continuous review. Because HL is often diagnosed in populations in their 20s-30s, patients are forced to undergo fertility preservation procedures as well as deal with other long-term side effects of chemotherapy (including doxorubicin dose-dependent cardiotoxicity and bleomycin-induced lung toxicity). The opportunity cost of the treatment in the short term and vulnerability to treatment-induced malignancies decades later dramatically affect the quality of life of HL patients. New therapies have developed over the past several decades with respect to immunotherapies, particularly programmed death protein 1 inhibitors (e.g., nivolumab and pembrolizumab). Studies have shown checkpoint inhibitors to be effective in treating HL with an objective response rate of 69% for relapsed/refractory classical HL for nivolumab use. Checkpoint inhibitors will continue to help maintain the high five-year survival rate for HL and hopefully have a more favorable side effect profile in the short term, as well as later in the patient's life. This article seeks to summarize treatment options for HL while comparing outcomes and side effect profiles with the addition of checkpoint inhibitors.

Unraveling the Immune Microenvironment in Classic Hodgkin Lymphoma: Prognostic and Therapeutic Implications

Classic Hodgkin lymphoma (cHL) is a lymphoid neoplasm composed of rare neoplastic Hodgkin and Reed-Sternberg (HRS) cells surrounded by a reactive tumor microenvironment (TME) with suppressive properties against anti-tumor immunity. TME is mainly composed of T cells (CD4 helper, CD8 cytotoxic and regulatory) and tumor-associated macrophages (TAMs), but the impact of these cells on the natural course of the disease is not absolutely understood. TME contributes to the immune evasion of neoplastic HRS cells through the production of various cytokines and/or the aberrant expression of immune checkpoint molecules in ways that have not been fully understood yet. Herein, we present a comprehensive review of findings regarding the cellular components and the molecular features of the immune TME in cHL, its correlation with treatment response and prognosis, as well as the potential targeting of the TME with novel therapies. Among all cells, macrophages appear to be a most appealing target for immunomodulatory therapies, based on their functional plasticity and antitumor potency.

Identification and Interpretation of eQTL and eGenes for Hodgkin Lymphoma Susceptibility

Genome-wide association studies (GWAS) have revealed approximately 100 genomic signals associated with Hodgkin lymphoma (HL); however, their target genes and underlying mechanisms causing HL susceptibility remain unclear. In this study, transcriptome-wide analysis of expression quantitative trait loci (eQTL) was conducted to identify target genes associated with HL GWAS signals. A mixed model, which explains polygenic regulatory effects by the genomic covariance among individuals, was implemented to discover expression genes (eGenes) using genotype data from 462 European/African individuals. Overall, 80 eGenes were identified to be associated with 20 HL GWAS signals. Enrichment analysis identified apoptosis, immune responses, and cytoskeletal processes as functions of these eGenes. The eGene of rs27524 encodes ERAP1 that can cleave peptides attached to human leukocyte antigen in immune responses; its minor allele may help Reed-Sternberg cells to escape the immune response. The eGene of rs7745098 encodes ALDH8A1 that can oxidize the precursor of acetyl-CoA for the production of ATP; its minor allele may increase oxidization activity to evade apoptosis of pre-apoptotic germinal center B cells. Thus, these minor alleles may be genetic risk factors for HL susceptibility. Experimental studies on genetic risk factors are needed to elucidate the underlying mechanisms of HL susceptibility and improve the accuracy of precision oncology.

The emerging role of the branched chain aminotransferases, BCATc and BCATm, for anti-tumor T-cell immunity

Challenges regarding successful immunotherapy are associated with the heterogeneity of tumors and the complex interactions within the surrounding tumor microenvironment (TME), particularly those between immune and tumor cells. Of interest, T cells receive a myriad of environmental signals to elicit differentiation to effector subtypes, which is accompanied by metabolic reprogramming needed to satisfy the high energy and biosynthetic demands of their activated state. However, T cells are subjected to immunosuppressive signals and areas of oxygen and nutrient depletion in the TME, which causes T-cell exhaustion and helps tumor cells escape immune detection. The cytosolic and mitochondrial branched chain amino transferases, BCATc and BCATm, respectively, are responsible for the first step of the branched chain amino acid (BCAA) degradation, of which, metabolites are shunted into various metabolic processes. In recent years, BCAT isoenzymes have been investigated for their role in a variety of cancers found throughout the body; however, a gap of knowledge exists regarding the role BCAT isoenzymes play within immune cells of the TME. The aim of this review is to summarize recent findings about BCAAs and their catabolism at the BCAT step during T-cell metabolic reprogramming and to discuss the BCAT putative role in the anti-tumor immunity of T cells. Not only does this review acknowledges gaps pertaining to BCAA metabolism in the TME but it also identifies the practical application of BCAA metabolism in T cells in response to cancer and spotlights a potential target for pharmacological intervention.

Immune Biomarkers in the Peripheral Blood and Tumor Microenvironment of Classical Hodgkin Lymphoma Patients in Relation to Tumor Burden and Response to Treatment

In classical Hodgkin lymphoma (cHL), the malignant cells represent only a small fraction of the tumor. Yet, they orchestrate a lymphocyte-dominated tumor microenvironment (TME) that supports their survival and growth. The systemic effects of this local immunomodulation are not fully elucidated. Here, we aimed at characterizing circulating lymphocytes and plasma proteins in relation to clinical parameters and treatment effect. Peripheral blood (PB) samples were obtained from 48 consecutive patients at diagnosis and at 2 time points after successful primary treatment. Single-cell suspensions were prepared from lymph node (LN) biopsies obtained for routine diagnostic purposes. Twenty healthy individuals were included as controls. Cells from PB and LN were analyzed by flow cytometry, and plasma proteins by Proximity Extension Assay. We found that the frequencies of T and B cells positively correlated between the LN and the PB compartments. Compared to controls, cHL patients had higher frequencies of proliferating T cells as well as higher expression of programmed death (PD)-1 and cytotoxic T lymphocyte antigen (CTLA)-4 in circulating T cells, and lower naive T-cell frequencies. Advanced-stage patients had fewer NK cells with a functionally impaired phenotype. Differences in the immune profile were observed in patients with a high tumor burden and with high inflammation, respectively. Most of these deviations disappeared after standard first-line treatment. Patients who received radiotherapy involving the mediastinum had low T-cell counts for a prolonged period. Our findings suggest that the immunomodulation of lymphocytes in the TME of cHL might affect immune biomarkers in the PB.

Phenotype, Function, and Clinical Significance of CD26+ and CD161+Tregs in Splenic Marginal Zone Lymphoma

PURPOSE

Regulatory T-cells (Treg) are essential to Tregs homeostasis and modulate the antitumor immune response in patients with lymphoma. However, the biology and prognostic impact of Tregs in splenic marginal zone lymphoma (SMZL) have not been studied.

EXPERIMENTAL DESIGN

Biopsy specimens from 24 patients with SMZL and 12 reactive spleens (rSP) from individuals without lymphoma were analyzed by using CITE-seq (cellular indexing of transcriptomes and epitopes by sequencing), CyTOF (mass cytometry) analysis, and flow cytometry to explore the phenotype, transcriptomic profile, and clinical significance of intratumoral Tregs and their subsets. The biological characteristics and cell signaling pathways of intratumoral Treg subsets were confirmed by in vitro functional assays.

RESULTS

We found that Tregs are more abundant in SMZL patients' spleens than rSP, and Tregs from patients with SMZL and rSP can be separated into CD161+Treg and CD26+Treg subsets. CD161+Tregs are increased in SMZL but have dysregulated immune function. We found that CD161+Treg and CD26+Tregs have unique gene expression and phenotypic profiles and are differentially correlated with patient outcomes. Specifically, increased CD161+Tregs are significantly associated with a favorable prognosis in patients with SMZL, whereas CD26+Tregs are associated with a poor prognosis. Furthermore, activation of the IL2/STAT5 pathway contributes to the induction of CD26+Tregs and can be reversed by STAT5 inhibition.

CONCLUSIONS

IL2/STAT5-mediated expansion of CD26+Tregs contributes to a poor clinical outcome in SMZL and may represent a therapeutic opportunity in this disease.

Quantitative Plasma Proteomics to Identify Candidate Biomarkers of Relapse in Pediatric/Adolescent Hodgkin Lymphoma

Classical pediatric Hodgkin Lymphoma (HL) is a rare malignancy. Therapeutic regimens for its management may be optimized by establishing treatment response early on. The aim of this study was to identify plasma protein biomarkers enabling the prediction of relapse in pediatric/adolescent HL patients treated under the pediatric EuroNet-PHL-C2 trial. We used untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomics at the time of diagnosis—before any therapy—as semiquantitative method to profile plasma proteins specifically associated with relapse in 42 children with nodular sclerosing HL. In both the exploratory and the validation cohorts, six proteins (apolipoprotein E, C4b-binding protein α chain, clusterin, fibrinogen γ chain, prothrombin, and vitronectin) were more abundant in the plasma of patients whose HL relapsed (|fold change| ≥ 1.2, p < 0.05, Student’s t-test). Predicting protein function with the Gene Ontology classification model, the proteins were included in four biological processes (p < 0.01). Using immunoblotting and Luminex assays, we validated two of these candidate biomarkers—C4b-binding protein α chain and clusterin—linked to innate immune response function (GO:0045087). This study identified C4b-binding protein α chain and clusterin as candidate early plasma biomarkers of HL relapse, and important for the purpose of shedding light on the molecular scenario associated with immune response in patients treated under the EuroNet-PHL-C2 trial.

High percentages of peripheral blood T-cell activation in childhood Hodgkin's lymphoma are associated with inferior outcome

The aims of this study were to investigate the activation of T lymphocytes in peripheral blood from children with Hodgkin's lymphoma (HL) and explore their roles for prognosis in HL. A cohort of 52 newly diagnosed children with HL during the past 10 years was enrolled for analysis in this study. Peripheral blood samples of the patients were acquired before treatment in our hospital, and T-cell subsets were detected by a four-color flow cytometer. CD4+ T cells and CD4+/CD8+ T-cell ratio decreased significantly in patients with HL vs. healthy controls. CD8+ T cells, CD3+CD4+HLA-DR+ T cells, and CD3+CD8+HLA-DR+ T cells increased markedly in patients with HL vs. healthy controls. Receiver-operating characteristic (ROC) curve analysis showed that CD3+CD4+HLA-DR+ T cells and CD3+CD8+HLA-DR+ T cells each distinguished the high-risk group from the low- and intermediate-risk group. The area under the ROC curve for predicting high-risk patients was 0.795 for CD3+CD4+HLA-DR+ T cell and 0.784 for CD3+CD8+HLA-DR+ T cell. A comparison of peripheral blood T-cell subsets that responded differently to therapy showed significantly higher percentages of CD3+CD4+HLA-DR+ T cells and CD3+CD8+HLA-DR+ T cells in patients who achieved complete remission compared to those who did not achieve complete remission. In addition, high percentages of both CD3+CD4+HLA-DR+ T cells and CD3+CD8+HLA-DR+ T cells were associated with inferior event-free survival. Peripheral immune status may be related to disease severity in HL. CD3+CD4+HLA-DR+ T cells and CD3+CD8+HLA-DR+ T cells may be a novel indicator for risk stratification of HL and may be an independent risk factor for inferior outcome in childhood HL.

Blood-circulating EV-miRNAs, serum TARC, and quantitative FDG-PET features in classical Hodgkin lymphoma

Blood-based biomarkers are gaining interest for response evaluation in classical Hodgkin lymphoma (cHL). However, it is unknown how blood-based biomarkers relate to quantitative ¹⁸F-FDG-PET features. We correlated extracellular vesicle-associated miRNAs (EV-miRNA), serum TARC, and complete blood count (CBC) with PET features (e.g., metabolic tumor volume [MTV], dissemination and intensity features) in 30 cHL patients at baseline. EV-miR127-3p, EV-miR24-3p, sTARC, and several CBC parameters showed weak to strong correlations with MTV and dissemination features, but not with intensity features. Two other EV-miRNAs only showed weak correlations with PET features. Therefore, blood-based biomarkers may be complementary to PET features, which warrants further exploration of combining these biomarkers in prognostic models.

Current and Emerging Approaches to Study Microenvironmental Interactions and Drug Activity in Classical Hodgkin Lymphoma

Simple Summary

In classical Hodgkin Lymphoma (cHL), the tumor microenvironment (TME) plays an important role in tumor progression and treatment response, making its evaluation critical for determining prognosis, treatment strategies and predicting an increase in drug toxicity. Therefore, there is a need to utilize more complex systems to study the cHL-TME and its interplay with tumor cells. To evaluate new anticancer drugs and to find the mechanisms of drug resistance, this review summarizes emerging approaches for the analysis of the TME composition and to identify the state of the disease; the in vitro techniques used to determine the mechanisms involved in the building of an immunosuppressive and protective TME; new 3-dimensional (3D) models, the heterospheroids (HS), developed to mimic TME interactions. Here, we describe the present and likely future clinical applications indicated by the results of these studies and propose a classification for the in vitro culture methods used to study TME interactions in cHL.

Abstract

Classic Hodgkin lymphoma is characterized by a few tumor cells surrounded by a protective and immunosuppressive tumor microenvironment (TME) composed by a wide variety of noncancerous cells that are an active part of the disease. Therefore, new techniques to study the cHL-TME and new therapeutic strategies targeting specifically tumor cells, reactivating the antitumor immunity, counteracting the protective effects of the TME, were developed. Here, we describe new methods used to study the cell composition, the phenotype, and the spatial distribution of Hodgkin and Reed–Sternberg (HRS) cells and of noncancerous cells in tumor tissues. Moreover, we propose a classification, with increasing complexity, of the in vitro functional studies used to clarify the interactions leading not only to HRS cell survival, growth and drug resistance, but also to the immunosuppressive tumor education of monocytes, T lymphocytes and fibroblasts. This classification also includes new 3-dimensional (3D) models, obtained by cultivating HRS cells in extracellular matrix scaffolds or in sponge scaffolds, under non-adherent conditions with noncancerous cells to form heterospheroids (HS), implanted in developing chick eggs (ovo model). We report results obtained with these approaches and their applications in clinical setting.

The Need for Standardization in Next-Generation Sequencing Studies for Classic Hodgkin Lymphoma: A Systematic Review

Classic Hodgkin lymphoma (cHL) constitutes a B cell-derived neoplasm defined by a scarce tumoral population, termed Hodgkin and Reed–Sternberg (HRS) cells, submerged into a histologically heterogeneous microenvironment. The paucity of HRS cells has historically hampered genetic studies, rendering the identification of the recurrent genetic lesions and molecular pathways deregulated in this lymphoma difficult. The advent of high-throughput sequencing methods such as next-generation sequencing (NGS) could sensibly optimize the identification of the mutational landscape of cHL. However, there is no current consensus either in the design of panels for targeted NGS or in its most relevant clinical applications. In this work, we systematically review the current state of NGS studies of cHL, stressing the need for standardization both in the candidate genes to be analyzed and the bioinformatic pipelines. As different institutions have developed and implemented their own customized NGS-based protocols, to compare and systematically review the major findings of this ongoing research area could be of added value for centers that routinely perform diagnostic, monitoring and genotyping strategies in cHL samples. The results of this systematic review should contribute to the interdepartmental harmonization and achievement of a consensus in the current clinical applications of NGS studies of cHL.

Checkpoint CD47 expression in classical Hodgkin lymphoma

The glycoprotein CD47 regulates antiphagocytic activity via signal regulatory protein alpha (SIRPa). This study investigated CD47 expression on Hodgkin and Reed–Sternberg (HRS) cells in the classical Hodgkin lymphoma (cHL) tumour microenvironment and its correlation with prognosis, programmed‐death (PD) immune markers, and SIRPa⁺ leukocytes. We conducted immunohistochemistry with CD47 and SIRPa antibodies on diagnostic biopsies (tissue microarrays) from cHL patients from two cohorts (n = 178). In cohort I (n = 136) patients with high expression of CD47 on HRS cells (n = 48) had a significantly inferior event‐free survival [hazard ratio (HR) = 5.57; 95% confidence interval (CI), 2.78–11.20; p < 0.001] and overall survival (OS) (HR = 8.54; 95% CI, 3.19–22.90; p < 0.001) compared with patients with low expression (n = 88). The survival results remained statistically significant in multivariable Cox regression adjusted for known prognostic factors. In cohort II (n = 42) high HRS cell CD47 expression also carried shorter event‐free survival (EFS) (HR = 5.96; 95% CI, 1.20–29.59; p = 0.029) and OS (HR = 5.61; 95% CI, 0.58–54.15; p = 0.136), although it did not retain statistical significance in the multivariable analysis. Further, high CD47 expression did not correlate with SIRPa⁺ leukocytes or PD‐1, PD‐L1 and PD‐L2 expression. This study provides a deeper understanding of the role of CD47 in cHL during an era of emerging CD47 therapies.

The Hodgkin Lymphoma Immune Microenvironment: Turning Bad News into Good

The classic Hodgkin lymphoma (cHL) tumor microenvironment (TME) is by far the most abundant component of tumors and is responsible for most of their biological and clinical characteristics. Recent advances in our knowledge of these networks in cellular interactions allow us to understand that the neoplastic Hodgkin and Reed Sternberg (HRS) cells, although they are in the minority, are the main architects of this dysregulated immune milieu. Here, we review the major changes that have happened in recent years: from TME as a helpless bystander, reflecting an ineffective immune response, to a dynamic tumor-promoting and immunosuppressive element. The HRS cells promote survival through interconnected intrinsic and extrinsic alterations, boosting pro-tumoral signaling pathways through genetic aberrations and autocrine growth signals, in parallel with abnormal cytokine secretion for the recruitment and selection of the best cell partners for this immunosuppressive TME. In turn, cHL is already proving to be the perfect model with which to address an immune checkpoint blockade. Preliminary data demonstrate the utility of druggable key signaling pathways in this ensemble, such as JAK-STAT, NF-κB, and others. In addition, myriad biomarkers predicting a response await validation by new in situ multiplex analytical methods, single-cell gene expression, and other techniques. Together, these components will define the functional phenotypes with which we will elucidate the molecular pathogenesis of the disease and improve the survival of patients who are refractory to conventional therapies.

Macrophage Infiltration Correlates with Genomic Instability in Classic Hodgkin Lymphoma

Hodgkin lymphoma (HL) is a biologically diverse group of lymphoid tumors, which accounts for 1% of all de novo neoplasms in the world’s population. It is divided into two main groups: the more common classic Hodgkin lymphoma (cHL) and the less common nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). cHL is further divided into four subtypes, which differ in morphology and the contents of tumor microenvironment. Macrophages are one of the components of tumor microenvironment known to contribute to creating an immunosuppressive microenvironment, which inhibits the activity of cells expressing granzyme B against tumor cells, even when tumor cells are infected with Epstein–Barr virus (EBV). Our research aimed to explore the association between the specific contents of tumor microenvironment and the genetic anomalies in tumor cells. The presence and the relative percentage of cytotoxic T lymphocytes and macrophages was detected by immunohistochemical staining of the antigens specific for certain cell populations. Fluorescent in situ hybridization was used to detect anomalies in the genome of tumor cells and in situ hybridization was used to detect the presence of EBV. Our results show an association between the number of CD163+ macrophages and the number of TP53 copies or BCL6 gene translocation. Patients who had a higher number of CD163+ macrophages infiltrating tumor tissue and three or higher number of copies of TP53 showed poorer survival. We conclude that the presence of macrophages may contribute to genetic instability in cHL, which drives the progression of cHL and decreases survival of the patients.

The Effect of the Tumor Microenvironment on Lymphoid Neoplasms Derived from B Cells

Lymphomas are characteristic tumors surrounded by an inflammatory microenvironment. The cells of the microenvironment are essential for the growth and survival of neoplastic cells and are recruited through the effect of cytokines/chemokines. Lymphomas include heterogeneous groups of neoplasms infiltrating various lymphoid structures which may arise from B lymphocytes, T lymphocytes, and natural killer (NK) cells at various stages of their differentiation state. In this review article, we analyze the literature data concerning the involvement of the tumor microenvironment (TME) in the progression of lymphomas and the recent advances in the analysis of microenvironment components in the most common forms: some mature B cell lymphoma neoplasms and classic Hodgkin lymphomas. The complex crosstalk between the TME and tumor cells led to the discovery of many mechanisms usable as molecular-targeted therapy through the control of diverse elements of the TME, varying from inhibitors of angiogenic cytokines and their receptors to the regulation of cells' activities and the novel immune checkpoint inhibitors.

The prognostic significance of immune checkpoint receptor expression in patients with lymphoma: Association with disease status and clinical outcomes

INTRODUCTION

Little is known about the expression of immune checkpoint receptors in the peripheral blood of lymphoma patients. Herein, we assessed the expression of inhibitory checkpoint receptors, including CTLA-4, PD-1/PDL-1, LAG-3, and TIM-3 in the peripheral blood of lymphoma patients and its correlation with the clinical outcomes of patients. Therefore, 47 classical Hodgkin lymphoma (cHL), 48 non-Hodgkin lymphoma patients with diffuse large B-cell lymphoma (DLBCL) subtype, and 30 healthy controls were recruited.

METHODS

The expression of inhibitory receptors was evaluated using SYBR Green real-time PCR method.

RESULTS

CTLA-4, LAG-3, and TIM-3 genes were significantly upregulated in both cHL and DLBCL patients compared to the healthy controls. In addition, the level of these molecules was differentially expressed in cHL and DLBCL patients at different disease phases compared to the healthy controls. The CTLA-4 gene was highly expressed in newly diagnosed (ND) cHL patients compared to the relapsed ones. Relapsed DLBCL patients had significantly increased LAG-3 expression compared to patients at remission, as well as ND patients. Regarding cHL patients, high CTLA-4 expression was correlated with low lactate dehydrogenase level and better performance status, whereas the level of LAG-3 was significantly elevated in patients with poor performance status. Lower initial PD-1 expression was associated with improved disease-free survival in cHL patients.

CONCLUSIONS

Inhibitory immune checkpoint receptors are aberrantly expressed in the peripheral blood of cHL and DLBCL patients in which high LAG-3 in DLBCL patients and PD-1/LAG-3 in cHL patients are associated with relapse occurrence and worse prognosis, respectively.

Checkpoint protein expression in the tumor microenvironment defines the outcome of classical Hodgkin lymphoma patients

Emerging evidence indicates a major impact for the tumor microenvironment (TME) and immune escape in the pathogenesis and clinical course of classical Hodgkin lymphoma (cHL). We used gene expression profiling (n=88), CIBERSORT, and multiplex immunohistochemistry (n=131) to characterize the immunoprofile of cHL TME, and correlated the findings with survival. Gene expression analysis divided tumors into subgroups with T cell-inflamed and non-inflamed TME. Several macrophage-related genes were upregulated in samples with the non-T cell-inflamed TME, and based on the immune cell proportions, the samples clustered according to the content of T cells and macrophages. A cluster with high proportions of checkpoint protein (PD-1, PD-L1, IDO-1, LAG-3, and TIM-3) positive immune cells translated to unfavorable overall survival (OS) (5-year OS 76% vs. 96%, P=0.010), and remained as an independent prognostic factor for OS in multivariable analysis (HR 4.34, 95% CI 1.05-17.91, P=0.043). cHLs with high proportions of checkpoint proteins overexpressed genes coding for cytolytic factors, proposing paradoxically that they were immunologically active. This checkpoint molecule gene signature translated to inferior survival in a validation cohort of 290 diagnostic cHL samples (P<0.001) and in an expansion cohort of 84 cHL relapse samples (P=0.048). Our findings demonstrate the impact of T cell- and macrophage-mediated checkpoint system on the survival of patients with cHL.

Immune-Proteome Profiling in Classical Hodgkin Lymphoma Tumor Diagnostic Tissue

In classical Hodgkin Lymphoma (cHL), immunoediting via protein signaling is key to evading tumor surveillance. We aimed to identify immune-related proteins that distinguish diagnostic cHL tissues (=diagnostic tumor lysates, n = 27) from control tissues (reactive lymph node lysates, n = 30). Further, we correlated our findings with the proteome plasma profile between cHL patients (n = 26) and healthy controls (n = 27). We used the proximity extension assay (PEA) with the OlinkTM multiplex Immuno-Oncology panel, consisting of 92 proteins. Univariate, multivariate-adjusted analysis and Benjamini–Hochberg’s false discovery testing (=Padj) were performed to detect significant discrepancies. Proteins distinguishing cHL cases from controls were more numerous in plasma (30 proteins) than tissue (17 proteins), all Padj < 0.05. Eight of the identified proteins in cHL tissue (PD-L1, IL-6, CCL17, CCL3, IL-13, MMP12, TNFRS4, and LAG3) were elevated in both cHL tissues and cHL plasma compared with control samples. Six proteins distinguishing cHL tissues from controls tissues were significantly correlated to PD-L1 expression in cHL tissue (IL-6, MCP-2, CCL3, CCL4, GZMB, and IFN-gamma, all p ≤0.05). In conclusion, this study introduces a distinguishing proteomic profile in cHL tissue and potential immune-related markers of pathophysiological relevance.

Mechanisms of Immunosuppressive Tumor Evasion: Focus on Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is a malignancy with high heterogeneity in its biological features and treatments. Although the overall survival (OS) of patients with ALL has recently improved considerably, owing to the application of conventional chemo-therapeutic agents, approximately 20% of the pediatric cases and 40-50% of the adult patients relapse during and after the treatment period. The potential mechanisms that cause relapse involve clonal evolution, innate and acquired chemoresistance, and the ability of ALL cells to escape the immune-suppressive tumor response. Currently, immunotherapy in combination with conventional treatment is used to enhance the immune response against tumor cells, thereby significantly improving the OS in patients with ALL. Therefore, understanding the mechanisms of immune evasion by leukemia cells could be useful for developing novel therapeutic strategies.

Immunosuppressive Microenvironment and Efficacy of PD-1 Inhibitors in Relapsed/Refractory Classic Hodgkin Lymphoma: Checkpoint Molecules Landscape and Macrophage Populations

Simple Summary

Classic Hodgkin lymphoma contains rare malignant Hodgkin/Reed–Sternberg cells and abundant reactive populations in the tumor microenvironment. Many aspects of the interaction between tumor cells and immune cells remain unclear. Nevertheless, the microenvironment is believed to play a crucial role in tumor resistance and progression. Current knowledge about the role and dynamics of the tumor microenvironment in Hodgkin lymphoma during anti-PD-1 treatment is limited. The aim of this study was to identify possible predictive and prognostic morphological markers in the treatment of patients with relapsed or refractory classic Hodgkin lymphoma treated with nivolumab and to assess the variability of reactive cell populations after nivolumab therapy. The study was aimed to optimize therapeutic strategy in patients with relapsed or refractory classic Hodgkin lymphoma.

Abstract

To date, the impact of the tumor microenvironment on the prognosis of patients with classic Hodgkin lymphoma (cHL) during anti-PD-1 therapy has been studied insufficiently. This retrospective study included 61 primary samples of lymph nodes from patients who had relapsed/refractory (r/r) cHL and were treated with nivolumab. Repeated samples were obtained in 15 patients at relapse or disease progression after immunotherapy. Median follow-up was 55 (13–63) months. The best overall response rate and progression-free survival (PFS) were analyzed depending on the expression of CD68, CD163, PD-1, LAG-3, TIM-3, CTLA-4, TIGIT, CD163/c-maf in the tumor microenvironment in primary and sequential biopsies. The combination of CD163/c-maf antibodies was used for the identification of M2 macrophages (M2). A low number of macrophages in primary samples was associated with inferior PFS during nivolumab treatment (for CD163-positive cells p = 0.0086; for CD68-positive cells p = 0.037), while a low number of M2 with higher PFS (p = 0.014). Complete response was associated with a lower level of M2 (p = 0.011). In sequential samples (before and after nivolumab therapy) an increase in PD-1 (p = 0.011) and LAG-3 (p = 0.0045) and a depletion of CD68 (p = 0.057) and CD163 (p = 0.0049)-positive cells were observed. The study expands understanding of the cHL microenvironment structure and dynamics during nivolumab therapy in patients with r/r cHL.

Hodgkin Lymphoma: A Special Microenvironment

Classical Hodgkin’s lymphoma (cHL) is one of the most particular lymphomas for the few tumor cells surrounded by an inflammatory microenvironment. Reed-Sternberg (RS) and Hodgkin (H) cells reprogram and evade antitumor mechanisms of the normal cells present in the microenvironment. The cells of microenvironment are essential for growth and survival of the RS/H cells and are recruited through the effect of cytokines/chemokines. We summarize recent advances in gene expression profiling (GEP) analysis applied to study microenvironment component in cHL. We also describe the main therapies that target not only the neoplastic cells but also the cellular components of the background.

Reverted exhaustion phenotype of circulating lymphocytes as immune correlate of anti-PD1 first-line treatment in Hodgkin lymphoma

While classical Hodgkin lymphoma (HL) is highly susceptible to anti-programmed death protein 1 (PD1) antibodies, the exact modes of action remain controversial. To elucidate the circulating lymphocyte phenotype and systemic effects during anti-PD1 1st-line HL treatment we applied multicolor flow cytometry, FluoroSpot and NanoString to sequential samples of 81 HL patients from the NIVAHL trial (NCT03004833) compared to healthy controls. HL patients showed a decreased CD4 T-cell fraction, a higher percentage of effector-memory T cells and higher expression of activation markers at baseline. Strikingly, and in contrast to solid cancers, expression for 10 out of 16 analyzed co-inhibitory molecules on T cells (e.g., PD1, LAG3, Tim3) was higher in HL. Overall, we observed a sustained decrease of the exhausted T-cell phenotype during anti-PD1 treatment. FluoroSpot of 42.3% of patients revealed T-cell responses against ≥1 of five analyzed tumor-associated antigens. Importantly, these responses were more frequently observed in samples from patients with early excellent response to anti-PD1 therapy. In summary, an initially exhausted lymphocyte phenotype rapidly reverted during anti-PD1 1st-line treatment. The frequently observed IFN-y responses against shared tumor-associated antigens indicate T-cell-mediated cytotoxicity and could represent an important resource for immune monitoring and cellular therapy of HL.

Efficacy and safety of GLS-010 (zimberelimab) in patients with relapsed or refractory classical Hodgkin lymphoma: A multicenter, single-arm, phase II study

BACKGROUND

GLS-010 (zimberelimab) is a novel, fully human, anti-programmed death-1 monoclonal antibody that shows promising efficacy and safety in advanced solid tumors. This trial aimed to evaluate the efficacy and safety of GLS-010 (zimberelimab) in Chinese patients with relapsed or refractory classical Hodgkin lymphoma (r/r-cHL).

METHODS

This phase II, single-arm, open-label, multicenter clinical trial was conducted at 24 centers in China and enrolled patients with r/r-cHL after two or more lines of therapy. The patients were administered intravenous GLS-010 (zimberelimab) (240 mg, once every 2 weeks) until progression, death, unacceptable toxicity, or consent withdrawal. The primary end-point was the objective response rate assessed by an independent radiology review committee (IRC). This study was registered (NCT03655483).

RESULTS

Eighty-five patients were enrolled between August 2018 and August 2019. The median follow-up was 15.8 months. Seventy-seven patients (90.6%; 95% confidence interval [CI] 82.3-95.9) had an IRC-assessed objective response. The complete response rate was 32.9% (n = 28). The 12-month progression-free survival and overall survival rates were 78% (95% CI 67.5-85.6) and 99% (95% CI 91.9-99.8), respectively. Treatment-related adverse events (TRAEs) were observed in 92.9% of participants. Grade III or IV TRAEs occurred in 24 (28.2%) of the 85 participants. The most common grade III or IV TRAEs were abnormal hepatic function (5.9%), hyperuricemia (4.7%), decreased neutrophil count (3.5%), and increased weight (3.5%). Only one grade V AE, gastrointestinal infection, occurred.

CONCLUSIONS

GLS-010 (zimberelimab) appears to be effective and safe for the treatment of Chinese patients with r/r-cHL. Long-term follow-up is required to confirm these clinical benefits.

Extracellular vesicle miRNA predict FDG-PET status in patients with classical Hodgkin Lymphoma

Minimally-invasive tools to assess tumour presence and burden may improve clinical management. FDG-PET (metabolic) imaging is the current gold standard for interim response assessment in patients with classical Hodgkin Lymphoma (cHL), but this technique cannot be repeated frequently. Here we show that microRNAs (miRNA) associated with tumour-secreted extracellular vesicles (EVs) in the circulation of cHL patients may improve response assessment. Small RNA sequencing and qRT-PCR reveal that the relative abundance of cHL-expressed miRNAs, miR-127-3p, miR-155-5p, miR-21-5p, miR-24-3p and let-7a-5p is up to hundred-fold increased in plasma EVs of cHL patients pre-treatment when compared to complete metabolic responders (CMR). Notably, in partial responders (PR) or treatment-refractory cases (n = 10) the EV-miRNA levels remain elevated. In comparison, tumour specific copy number variations (CNV) were detected in cell-free DNA of 8 out of 10 newly diagnosed cHL patients but not in patients with PR. Combining EV-miR-127-3p and/or EV-let-7a-5p levels, with serum TARC (a validated protein cHL biomarker), increases the accuracy for predicting PET-status (n = 129) to an area under the curve of 0.93 (CI: 0.87-0.99), 93.5% sensitivity, 83.8/85.0% specificity and a negative predictive value of 96%. Thus the level of tumour-associated miRNAs in plasma EVs is predictive of metabolic tumour activity in cHL patients. Our findings suggest that plasma EV-miRNA are useful for detection of small residual lesions and may be applied as serial response prediction tool.

Malignancy Risk of Immunoglobin G4-Related Disease: Evidence from a Large Cohort Multicenter Retrospective Study

Introduction

The aim of this work was to evaluate the prevalence of malignancies in a multicenter cohort of Chinese patients with immunoglobulin G4-related disease (IgG4-RD) and to identify the related risk factors of malignancy in IgG4-RD patients.

Methods

We retrospectively analyzed 602 IgG4-RD patients who were recruited in five medical centers from 2009 to 2020. Standardized prevalence ratios (SPRs) against the general Chinese population were calculated along with 95% confidence intervals (CIs). We identified the risk factors of malignancy in IgG4-RD and calculated the odds ratios (ORs) of different factors. We then developed and validated a prediction model for malignancy risk of IgG4-RD based on our cohort.

Results

We observed a significantly increased prevalence of total malignancies in this cohort compared to the general Chinese population (SPR 8.66 [95% CI 5.84, 12.31]). Logistic regression analysis indicated that eosinophil percentage (OR 1.096 [95% CI 1.019–1.179], P = 0.016), serum albumin-to-globulin ratio (AGR) (OR 0.185 [95% CI 0.061–0.567], P = 0.002) and autoimmune pancreatitis (OR 2.400 [95% CI 1.038–5.549], P = 0.041) were three potential risk factors of malignancy in IgG4-RD patients. Four predictors were included in our final prediction model: age at IgG4-RD diagnosis, eosinophil percentage, AGR and autoimmune pancreatitis. The nomogram performed well in the internal validation cohort, with a concordance index (C-index) of 0.738.

Conclusions

A significantly increased prevalence of total malignancies was observed in our multicenter cohort. Eosinophil percentage and autoimmune pancreatitis are risk factors, whereas AGR is negatively associated with malignancy in IgG4-RD. A prediction model for malignancy risk of IgG4-RD was first developed and validated in our study.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-021-00326-8.

Immunotherapy in the treatment of lymphoma

Relapsed or refractory non-Hodgkin’s lymphomas, especially diffuse large B-cell lymphoma as well as relapsed or refractory Hodgkin lymphomas are hard-to-treat diseases. Patients who do not respond to initial therapy or experience relapse are treated with salvage regimens, and if eligible for aggressive therapy, treatment is continued with high-dose chemotherapy and autologous stem cell transplantation. Current therapy options can cure substantial numbers of patients, however for some it is still an uncurable disease. Numerous new drugs and cell therapies are being investigated for the treatment of relapsed or refractory lymphomas. Different types of immunotherapy options have shown promising results, and some have already become the standard of care. Here, we review immunotherapy options for the treatment of lymphoma and discuss the results, positions, practical aspects, and future directions of different drugs and cellular therapies for the treatment of this disease.

Epstein-Barr virus recruits PDL1-positive cells at the microenvironment in pediatric Hodgkin lymphoma

BACKGROUND

Classic Hodgkin lymphoma (cHL) is a lymphoid malignancy in which the microenvironment, where the neoplastic cells are immersed, contributes to the lymphomagenesis process. Epstein-Barr virus (EBV) presence also influences cHL microenvironment composition and contributes to pathogenesis. An increase in PDL1 expression in tumor cells and at the microenvironment was demonstrated in adult cHL. Therefore, our aim was to assess PD1/PDL1 pathway and EBV influence on this pathway in pediatric cHL, given that in Argentina, our group proved a higher incidence of EBV-associated pediatric lymphoma in children.

METHODS

For that purpose, EBV presence was assessed by in situ hybridization, whereas PD1 and PDL1 expressions were studied by immunohistochemistry. PDL1 genetic alterations were analyzed by FISH, and survival was evaluated for PD1 and PDL1 expressions.

RESULTS

EBV presence demonstrated no influence neither on PD1 expression at the microenvironment nor on PDL1 expression at HRS tumor cells. Unexpectedly, only 38% pediatric cHL displayed PDL1 genetic alterations by FISH, and no difference was observed regarding EBV presence. However, in EBV-related cHL cases, a higher number of PDL1 + cells were detected at the microenvironment.

CONCLUSION

Even though a high cytotoxic environment was previously described in EBV-related pediatric cHL, it might be counterbalanced by an immunoregulatory micro-environmental PDL1 + niche. This regulation may render a cytotoxic milieu that unsuccessfully try to eliminate EBV + Hodgkin Reed Sternberg tumor cells in pediatric patients.

The Impact of Prior Salvage Treatment With Immune Checkpoint Inhibitors on Hodgkin Lymphoma Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation: A Single-Center Experience

INTRODUCTION

The objective of the study was to assess the impact of the previous use of immune-checkpoint inhibitors (ICIs) on the clinical course of Hodgkin Lymphoma (HL) patients undergoing autologous hematopoietic stem cell transplantation (ASCT).

METHODS

A single-center, retrospective chart review of adult HL patients who received ASCT from January 1, 2014, to December 31, 2019, was conducted. Primary endpoints included the length of stay (LOS) and the composite outcome of late-onset noninfectious fever (LONIF) or late-onset hypotension (LOH) requiring intravenous fluid (IVF) resuscitation. Secondary endpoints included number of days until neutrophil engraftment, documented infections, and corticosteroid use.

RESULTS

A total of 52 HL patients were included. Nine (17%) received ICI before ASCT, and 43 (83%) patients underwent standard salvage chemotherapy. The composite outcome of LONIF or LOH requiring IVF resuscitation was significantly higher in patients previously treated with ICIs compared with those who received standard non-ICI salvage chemotherapy (78% vs. 33%; P = .022). The differences between the median LOS and time to neutrophil engraftment were not statistically significant (P = .94 and P = .083, respectively). All LONIF patients received systemic corticosteroids with symptom resolution.

CONCLUSION

The composite outcome of LONIF or LOH requiring IVF resuscitation was significantly higher in patients who received prior ICI salvage therapy. LOS and time to neutrophil engraftment were not affected by prior ICI therapy. Early institution of steroids may prevent the evolution of additional sequelae associated with engraftment or engraftment-like syndrome that can complicate ASCT.

AYA Considerations for Aggressive Lymphomas

PURPOSE OF REVIEW

Lymphoma is the one of the most common cancer diagnoses among adolescents and young adults (AYAs) aged 15-39. Despite significant advances in outcomes observed in older adults and younger children, improvements in AYAs have lagged behind. The reasons for this are likely multifactorial including disparities in access to health insurance, low rates of enrollment to clinical trials, potential differences in disease biology, and unique psychosocial challenges. Here we will review Hodgkin lymphoma (HL) and primary mediastinal B cell lymphoma (PMBCL), two of the most common aggressive lymphomas that occur in AYAs. We will discuss the current knowledge about disease biology in AYAs, adult and pediatric treatment strategies, novel targeted therapies, and ongoing AYA clinical trials in these lymphoma subtypes. We also will review unique considerations for treatment-related toxicities in AYAs and psychosocial issues relevant to this population.

RECENT FINDINGS

Pediatric and adult trials in HL and PMBCL have demonstrated that treatment with dose-intense chemotherapeutic regimens with or without radiation results in high cure rates but can also be associated with long-term toxicity which must be considered in this young population. Novel targeted agents such as the antibody-drug conjugate brentuximab vedotin and/or antibodies targeted against PD-1/PD-L1 have demonstrated activity in the relapsed setting and are currently being evaluated in the upfront setting, which may reduce our reliance on therapies associated with long-term toxicity. AYA-focused clinical trials are currently underway to better elucidate the optimal therapy for lymphomas in this age group. There is an urgent need for clinical trials including AYAs in order to increase the knowledge of age-specific outcomes, toxicities, disease biology, and the need to develop comprehensive AYA care models that meet the unique and complex care needs of this patient population.

Classic Hodgkin lymphoma in Guatemalan children of age less than six years: analysis of immune regulatory pathways and the tumor microenvironment

Classic Hodgkin lymphoma (cHL) in young children (ages 0-6) is rare in high income countries (HICs) but is more prevalent in low- and middle-income countries (LMICs) like Guatemala. Given that the majority of cHL studies have evaluated adolescent/adults, and the immune system changes with age, we sought to characterize Epstein-Barr virus (EBV) expression, immune regulatory pathway markers and the tumor microenvironment in 42 children ages 0-6 with cHL from Guatemala. We found a very high frequency of EBV expression (97.5%). Hodgkin cells showed increased expression of PD1 ligands and CD137, indicative of shared immune regulatory mechanisms with adult cHL. Pediatric cHL also showed an increase in CD8+ tumor infiltrating lymphocytes and tumor associated macrophages within the tumor microenvironment. Despite 25 having high risk disease, only 4 patients died from progressive disease, relapse or infection.

The derived neutrophil-lymphocyte ratio and the neutrophil-lymphocyte ratio are related to poor prognosis in Hodgkin lymphoma patients

INTRODUCTION

The inflammatory and immune cells have an important impact on Hodgkin lymphoma (HL). The derived neutrophil-lymphocyte ratio (dNLR) has been confirmed to have a similar prognostic value as the neutrophil-lymphocyte ratio (NLR) in many kinds of tumors, but it has not been explored as a prognostic marker for Hodgkin lymphoma patients.

OBJECTIVE

The aim of the study is to evaluate the prognostic value of dNLR and NLR in HL.

METHODS

This retrospective study included 213 newly diagnosed HL patients from 2008 to 2019. Then, the prognostic significance of dNLR and NLR in these patients was evaluated. Meanwhile, subgroup analyses based on the Ann Arbor stage and histotype were also carried out. Finally, propensity score matching was used to reduce selection bias.

RESULTS

Patients with dNLR ≥ 2.1 showed shorter overall survival (OS) (P = 0.006). Also, patients with NLR ≥ 3.0 showed worse OS (P = 0.005) and progression-free survival (PFS) (P = 0.031). These results were also found in patients with early-stage and mixed cellularity subtype HL. Besides, high dNLR represented an independent prognostic marker for OS and high NLR remained an independent prognostic factor for OS and PFS on multivariable analysis.

CONCLUSION

Elevated dNLR and NLR were related to worse survival in HL patients. For the first time, the dNLR has shown the potential to be a new prognostic factor for patients with HL.

Prognostic factors affecting survival in children and adolescents with HIV and Hodgkin lymphoma in South Africa

South African children with Hodgkin lymphoma (HL) and human immunodeficiency virus (HIV) have low 5-year overall survival (OS) rates. In this retrospective multicenter study, 271 South African pediatric patients with HL were studied to determine OS and prognostic factors in those with HIV and HL. Univariate risk factor analysis was performed to analyze prognostic factors. The 29 HIV-infected patients were younger (p = .021), more likely to present with wasting (0.0573), stunting (0.0332), and Stage IV disease (p = .000) than HIV-uninfected patients. The 5- and 10-year OS of HIV-infected patients of 49% and 45% versus 84% and 79%, respectively for HIV-uninfected patients (p = .0001) appeared to be associated with hypoalbuminemia (<20 g/dL) and CD4 percentage of <15%. Causes of death in the HIV-infected group included disease progression (6/14), infection (4/14), unknown (3/14), and second malignancy (1/14). HIV-infected pediatric patients with HL experience increased mortality due to post-therapy opportunistic and nosocomial infections.

Essential role of the linear ubiquitin chain assembly complex and TAK1 kinase in A20 mutant Hodgkin lymphoma

More than 70% of Epstein-Barr virus (EBV)-negative Hodgkin lymphoma (HL) cases display inactivation of TNFAIP3 (A20), a ubiquitin-editing protein that regulates nonproteolytic protein ubiquitination, indicating the significance of protein ubiquitination in HL pathogenesis. However, the precise mechanistic roles of A20 and the ubiquitination system remain largely unknown in this disease. Here, we performed high-throughput CRISPR screening using a ubiquitin regulator-focused single-guide RNA library in HL lines carrying either wild-type or mutant A20. Our CRISPR screening highlights the essential oncogenic role of the linear ubiquitin chain assembly complex (LUBAC) in HL lines, which overlaps with A20 inactivation status. Mechanistically, LUBAC promotes IKK/NF-κB activity and NEMO linear ubiquitination in A20 mutant HL cells, which is required for prosurvival genes and immunosuppressive molecule expression. As a tumor suppressor, A20 directly inhibits IKK activation and HL cell survival via its C-terminal linear-ubiquitin binding ZF7. Clinically, LUBAC activity is consistently elevated in most primary HL cases, and this is correlated with high NF-κB activity and low A20 expression. To further understand the complete mechanism of NF-κB activation in A20 mutant HL, we performed a specifically designed CD83-based NF-κB CRISPR screen which led us to identify TAK1 kinase as a major mediator for NF-κB activation in cells dependent on LUBAC, where the LUBAC-A20 axis regulates TAK1 and IKK complex formation. Finally, TAK1 inhibitor Takinib shows promising activity against HL in vitro and in a xenograft mouse model. Altogether, these findings provide strong support that targeting LUBAC or TAK1 could be attractive therapeutic strategies in A20 mutant HL.

Frequent altered distribution of peripheral B-lymphocyte subsets in pediatric and adolescent patients with classical Hodgkin lymphoma

Peripheral lymphopenia is a well-known negative prognostic marker in classical Hodgkin lymphoma (cHL). We characterized the peripheral B-cell compartment in a prospective cohort of 83 pediatric cHL patients. We observed significantly low total B-cell counts (<100 cells/µl) in 31 of 83 patients (37%). More specifically, there was a smaller peripheral IgD^highCD27^- naïve B-cell pool among B-cell lymphopenic patients than for non-B-cell lymphopenic patients (p < 0.01). The B-cell count was lower in patients without in situ Epstein Barr Virus (EBV) expression than among those with in situ EBV expression (p = 0.03). Peripheral B-cell lymphopenia was associated with the presence of poor prognostic features, such as advanced lymphoma stage (p < 0.01) and the presence of B symptoms (p = 0.04). Of interest, B-cell lymphopenia resolved in all six studied patients in long-term remission. Our findings support that cHL tumor-associated factors interfere with the distribution of peripheral B-cell subsets.

Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: an uncommon case with lymph node involvement and the classic Hodgkin's lymphoma

Here we describe an unusual case of an indolent CD8+ T-cell lymphoproliferative disorder in the gastrointestinal tract (ITCLD-GT) accompanied by neck lymph node infiltration and new onset of classic Hodgkin's lymphoma after two years follow-up. Previously, this 42-year-old Asian man suffered from diarrhea and abdominal pain for two years. Intestinal biopsies showed a group of small to intermediate-sized lymphocytes which were monomorphic as well as arranged in a nodular pattern with no clear boundary and were diagnosed as ITCLD-GT. He did not receive chemotherapy or have any disease progression in the gastrointestinal tract (GIT) during the follow-up until a development of neck lymphadenopathy, which led to an eventual mixed cellularity type of Hodgkin's lymphoma, one type of classic HL diagnosis. Interestingly, besides the Hodgkin's cells, the same pathological T-cells in the GIT were present in the Hodgkin's lymphoma lesions. These two pathological T cells in GIT and neck lymph node had the identical histopathological and molecular abnormalities that confirmed the abenteric distant infiltration of ITCLD-GT to the neck lymph node in this patient. This is the first case of ITCLD-GT that has a definite distant lymph node invasion. ITCLD-GT usually has a relatively good prognosis but patients with ITCLD-GT may have abenteric distant infiltration. Thus, long-term follow-up and further study of the underlying mechanisms of this process are necessary.

Molecular Pathogenesis of Hodgkin Lymphoma: Past, Present, Future

Our understanding of the tumorigenesis of classical Hodgkin lymphoma (cHL) and the formation of Reed–Sternberg cells (RS-cells) has evolved drastically in the last decades. More recently, a better characterization of the signaling pathways and the cellular interactions at play have paved the way for new targeted therapy in the hopes of improving outcomes. However, important gaps in knowledge remain that may hold the key for significant changes of paradigm in this lymphoma. Here, we discuss the past, present, and future of cHL, and review in detail the more recent discoveries pertaining to genetic instability, anti-apoptotic signaling pathways, the tumoral microenvironment, and host-immune system evasion in cHL.

Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: an uncommon case with lymph node involvement and the classic Hodgkin's lymphoma

Here we describe an unusual case of an indolent CD8+ T-cell lymphoproliferative disorder in the gastrointestinal tract (ITCLD-GT) accompanied by neck lymph node infiltration and new onset of classic Hodgkin's lymphoma after two years follow-up. Previously, this 42-year-old Asian man suffered from diarrhea and abdominal pain for two years. Intestinal biopsies showed a group of small to intermediate-sized lymphocytes which were monomorphic as well as arranged in a nodular pattern with no clear boundary and were diagnosed as ITCLD-GT. He did not receive chemotherapy or have any disease progression in the gastrointestinal tract (GIT) during the follow-up until a development of neck lymphadenopathy, which led to an eventual mixed cellularity type of Hodgkin's lymphoma, one type of classic HL diagnosis. Interestingly, besides the Hodgkin's cells, the same pathological T-cells in the GIT were present in the Hodgkin's lymphoma lesions. These two pathological T cells in GIT and neck lymph node had the identical histopathological and molecular abnormalities that confirmed the abenteric distant infiltration of ITCLD-GT to the neck lymph node in this patient. This is the first case of ITCLD-GT that has a definite distant lymph node invasion. ITCLD-GT usually has a relatively good prognosis but patients with ITCLD-GT may have abenteric distant infiltration. Thus, long-term follow-up and further study of the underlying mechanisms of this process are necessary.

EBNA2-deleted Epstein-Barr virus (EBV) isolate, P3HR1, causes Hodgkin-like lymphomas and diffuse large B cell lymphomas with type II and Wp-restricted latency types in humanized mice

EBV transforms B cells in vitro and causes human B-cell lymphomas including classical Hodgkin lymphoma (CHL), Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL). The EBV latency protein, EBNA2, transcriptionally activates the promoters of all latent viral protein-coding genes expressed in type III EBV latency and is essential for EBV's ability to transform B cells in vitro. However, EBNA2 is not expressed in EBV-infected CHLs and BLs in humans. EBV-positive CHLs have type II latency and are largely driven by the EBV LMP1/LMP2A proteins, while EBV-positive BLs, which usually have type I latency are largely driven by c-Myc translocations, and only express the EBNA1 protein and viral non-coding RNAs. Approximately 15% of human BLs contain naturally occurring EBNA2-deleted viruses that support a form of viral latency known as Wp-restricted (expressing the EBNA-LP, EBNA3A/3B/3C, EBNA1 and BHRF1 proteins), but whether Wp-restricted latency and/or EBNA2-deleted EBV can induce lymphomas in humanized mice, or in the absence of c-Myc translocations, is unknown. Here we show that a naturally occurring EBNA2-deleted EBV strain (P3HR1) isolated from a human BL induces EBV-positive B-cell lymphomas in a subset of infected cord blood-humanized (CBH) mice. Furthermore, we find that P3HR1-infected lymphoma cells support two different viral latency types and phenotypes that are mutually exclusive: 1) Large (often multinucleated), CD30-positive, CD45-negative cells reminiscent of the Reed-Sternberg (RS) cells in CHL that express high levels of LMP1 but not EBNA-LP (consistent with type II viral latency); and 2) smaller monomorphic CD30-negative DLBCL-like cells that express EBNA-LP and EBNA3A but not LMP1 (consistent with Wp-restricted latency). These results reveal that EBNA2 is not absolutely required for EBV to form tumors in CBH mice and suggest that P3HR1 virus can be used to model EBV positive lymphomas with both Wp-restricted and type II latency in vivo.

Prognostic Impact of Tumor-Associated Macrophages on Survival Is Checkpoint Dependent in Classical Hodgkin Lymphoma

Tumor microenvironment and immune escape affect pathogenesis and survival in classical Hodgkin lymphoma (cHL). While tumor-associated macrophage (TAM) content has been associated with poor outcomes, macrophage-derived determinants with clinical impact have remained undefined. Here, we have used multiplex immunohistochemistry and digital image analysis to characterize TAM immunophenotypes with regard to expression of checkpoint molecules programmed cell death ligand 1 (PD-L1) and indoleamine 2,3-dioxygenase 1 (IDO-1) from the diagnostic tumor tissue samples of 130 cHL patients, and correlated the findings with clinical characteristics and survival. We show that a large proportion of TAMs express PD-L1 (CD68⁺, median 32%; M2 type CD163⁺, median 22%), whereas the proportion of TAMs expressing IDO-1 is lower (CD68⁺, median 5.5%; CD163⁺, median 1.4%). A high proportion of PD-L1 and IDO-1 expressing TAMs from all TAMs (CD68⁺), or from CD163⁺ TAMs, is associated with inferior outcome. In multivariate analysis with age and stage, high proportions of PD-L1⁺ and IDO-1⁺ TAMs remain independent prognostic factors for freedom from treatment failure (PD-L1⁺CD68⁺/CD68⁺, HR = 2.63, 95% CI 1.17–5.88, p = 0.019; IDO-1⁺CD68⁺/CD68⁺, HR = 2.48, 95% CI 1.03–5.95, p = 0.042). In contrast, proportions of PD-L1⁺ tumor cells, all TAMs or PD-L1⁻ and IDO-1⁻ TAMs are not associated with outcome. The findings implicate that adverse prognostic impact of TAMs is checkpoint-dependent in cHL.

Outcome after autologous stem cell transplantation in primary refractory or relapsed Hodgkin lymphoma-a long-term follow-up single center experience

Autologous stem cell transplantation (autoSCT) can achieve long-term remission in primary refractory or relapsed Hodgkin lymphoma (r/r HL); however, still up to 50% of patients relapse after autoSCT. In this retrospective analysis, we investigated the impact of autologous stem cell transplantation in a consecutive, unselected cohort of primary refractory and relapsed Hodgkin lymphoma patients (n = 66) with the majority of patients treated in the pre-brentuximab vedotin and immune checkpoint inhibitor era. In our cohort, a 5-year overall survival (OS) from autoSCT of 59.5% and a 5-year progression-free survival (PFS) after autoSCT of 46.1% was achieved. Multivariate analysis revealed primary refractory disease and early relapse (< 12 months) after initial therapy as well as the presence of B symptoms at relapse as independent risk factors associated with a higher risk for relapse and an inferior PFS and OS. Several other clinical factors, including the presence of extranodal disease at relapse and failure to achieve a complete response to salvage chemotherapy, were associated with a trend towards an inferior survival. Patients relapsing after autoSCT had a particularly poor outcome, regardless of eligibility to undergo allogeneic stem cell transplantation (alloSCT). We further evaluated recently published prognostic models for r/r HL patients undergoing autoSCT and could validate several risk scores in our independent "real world" cohort.

The Evolving Role of Brentuximab Vedotin in Classical Hodgkin Lymphoma

The arrival of the CD30 directed antibody-drug conjugate, brentuximab vedotin (BV), has altered the approach to patients with classical Hodgkin lymphoma. Since initial approval in 2011, BV has been extensively studied in previously untreated and relapsed/refractory patients. Treatment indications for the antibody-drug conjugate have been expanded from the previously treated population to include maintenance therapy after autologous stem cell transplantation and recently, combination with chemotherapy in newly diagnosed advanced stage patients. This article will review the evolution of BV in classical Hodgkin lymphoma, detailing the studies that led to the approved indications and discussion of recent trials in combination with chemotherapy and immunotherapy.

Increased IgG4-positive plasma cells in nodular-sclerosing Hodgkin lymphoma: a diagnostic pitfall

AIMS

Despite increasing interest in the recently established immunoglobulin 4-related disease (IgG4-RD), its pathogenesis and aetiology remain largely unclear. Characteristic histopathological features are one of the key elements of diagnosis, including 'storiform' fibrosis, obliterative phlebitis, increased lymphoplasmacytic infiltration and increased levels of IgG4 in serum and tissue. Histopathological features of IgG4-RD are striking but not specific, and can pose a pitfall for surgical pathologists. This paper aims to determine the actual amount of IgG4+ plasma cells in nodular-sclerosing Hodgkin lymphoma (NSHL) and its potential to be misdiagnosed in routine clinical practice.

METHODS AND RESULTS

IgG4+ plasma cells per high-power field (HPF) and the ratio of IgG4+ versus IgG+ plasma cells (IgG4/IgG ratio) in lymph node biopsies of 24 patients with nodular-sclerosing Hodgkin lymphoma (NSHL) were determined using immunohistochemistry and consensus scoring criteria as used for IgG4-RD. Ten lymph node biopsies with reactive follicular hyperplasia were assessed for comparison. Higher numbers of IgG4+ plasma cells (P < 0.001) were observed in NSHL versus follicular hyperplasia (mean 34 versus 8 per HPF) with a mean IgG4/IgG ratio of 0.38 versus 0.18. Five cases (21%) fulfilled the consensus criteria of IgG4-RD, with >50 IgG4+ plasma cells per HPF and an IgG4/IgG ratio of >0.4. The mean count of IgG4+ plasma cells per HPF in NSHL varied greatly (3-88) with increased numbers of IgG4+ plasma cells seen near areas of fibrosclerosis.

CONCLUSIONS

Significantly higher levels of IgG4+ plasma cells are common in NSHL, emphasising the need to exclude Reed-Sternberg cells by morphology and immunohistochemistry in biopsies where IgG4-RD is suspected.