Inflammatory cells and immune microenvironment in malignant lymphoma

Prognostic Significance of T-Cells and Macrophages in the Tumour Microenvironment of Nodal DLBCL

Revised International Prognostic (R-IPI) score is used widely for risk stratification of DLBCL cases, yet some patients belonging to same risk category tend to exhibit different outcomes. The role of T-cells and macrophages in prognostication of lymphomas has been a point of interest of late. We aimed to study the association of FOXP3 positive T-regulatory cells, cytotoxic T-cells and macrophages with the immunophenotypic subtypes, clinicopathological characteristics, treatment response and survival in nodal diffuse large B-cell lymphoma (DLBCL) patients. The clinicopathological and treatment data of 83 DLBCL patients diagnosed and treated at our institute from January 2015 to December 2018 were collected and followed up till June 2020. CD8, FOXP3 and CD68 immunostains were performed to highlight the cytotoxic T-cells, T-regulatory cells and macrophages respectively on the lymph node biopsies and the distribution of these cells and their association with clinico-pathological factors, treatment response and survival was analyzed. DLBCL cases with higher percentage of CD3 positive T-cells and CD8 positive cytotoxic T-cells had significant association with attainment of complete response to treatment. In addition, CD8 positive T-cells of more than 6.5% proved to be an independent predictor of treatment outcome (p = 0.022). Multivariate Cox regression survival analysis revealed that cases with 'good' R-IPI prognostic score and 'high CD68 positive macrophages in tumor microenvironment' had a significantly longer overall survival. Increased number of cytotoxic T-cells was significantly associated with complete response to treatment and higher number of macrophages correlated significantly with better overall survival signifying their antitumor effects.

The Immunology of DLBCL

Diffuse large B-cell lymphoma (DLBCL) is an aggressive malignancy and is the most common type of malignant lymphoid neoplasm. While some DLBCLs exhibit strong cell-autonomous survival and proliferation activity, others depend on interactions with non-malignant cells for their survival and proliferation. Recent next-generation sequencing studies have linked these interactions with the molecular classification of DLBCL. For example, germinal center B-cell-like DLBCL tends to show strong associations with follicular T cells and epigenetic regulation of immune recognition molecules, whereas activated B-cell-like DLBCL shows frequent genetic aberrations affecting the class I major histocompatibility complex. Single-cell technologies have also provided detailed information about cell-cell interactions and the cell composition of the microenvironment of DLBCL. Aging-related immunological deterioration, i.e., immunosenescence, also plays an important role in DLBCL pathogenesis, especially in Epstein-Barr virus-positive DLBCL. Moreover, DLBCL in "immune-privileged sites"-where multiple immune-modulating mechanisms exist-shows unique biological features, including frequent down-regulation of immune recognition molecules and an immune-tolerogenic tumor microenvironment. These advances in understanding the immunology of DLBCL may contribute to the development of novel therapies targeting immune systems.

An Immune-Related Prognostic Classifier Is Associated with Diffuse Large B Cell Lymphoma Microenvironment

Background

Diffuse large B cell lymphoma (DLBCL) is a life-threatening malignant tumor characterized by heterogeneous clinical, phenotypic, and molecular manifestations. Given the association between immunity and tumors, identifying a suitable immune biomarker could improve DLBCL diagnosis.

Methods

We systematically searched for DLBCL gene expression microarray datasets from the GEO database. Immune-related genes (IRGs) were obtained from the ImmPort database, and 318 transcription factor (TF) targets in cancer were retrieved from the Cistrome Cancer database. An immune-related classifier for DLBCL prognosis was constructed using Cox regression and LASSO analysis. To assess differences in overall survival between the low- and high-risk groups, we analyzed the tumor microenvironment (TME) and immune infiltration in DLBCL using the ESTIMATE and CIBERSORT algorithms. WGCNA was applied to study the molecular mechanisms explaining the clinical significance of our immune-related classifier and TFs.

Results

Eighteen IRGs were selected to construct the classifier. The multi-IRG classifier showed powerful predictive ability. Patients with a high-risk score had poor survival. Based on the AUC for three- and five-year survival, the classifier exhibited better predictive power than clinical data. Discrepancies in overall survival between the low- and high-risk score groups might be explained by differences in immune infiltration, TME, and transcriptional regulation.

Conclusions

Our study describes a novel prognostic IRG classifier with strong predictive power in DLBCL. Our findings provide valuable guidance for further analysis of DLBCL pathogenesis and clinical treatment.

Avadomide monotherapy in relapsed/refractory DLBCL: safety, efficacy, and a predictive gene classifier

Treatment options for relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) are limited, with no standard of care; prognosis is poor, with 4- to 6-month median survival. Avadomide (CC-122) is a cereblon-modulating agent with immunomodulatory and direct antitumor activities. This phase 1 dose-expansion study assessed safety and clinical activity of avadomide monotherapy in patients with de novo R/R DLBCL and transformed lymphoma. Additionally, a novel gene expression classifier, which identifies tumors with a high immune cell infiltration, was shown to enrich for response to avadomide in R/R DLBCL. Ninety-seven patients with R/R DLBCL, including 12 patients with transformed lymphoma, received 3 to 5 mg avadomide administered on continuous or intermittent schedules until unacceptable toxicity, disease progression, or withdrawal. Eighty-two patients (85%) experienced ≥1 grade 3/4 treatment-emergent adverse events (AEs), most commonly neutropenia (51%), infections (24%), anemia (12%), and febrile neutropenia (10%). Discontinuations because of AEs occurred in 10% of patients. Introduction of an intermittent 5/7-day schedule improved tolerability and reduced frequency and severity of neutropenia, febrile neutropenia, and infections. Among 84 patients with de novo R/R DLBCL, overall response rate (ORR) was 29%, including 11% complete response (CR). Responses were cell-of-origin independent. Classifier-positive DLBCL patients (de novo) had an ORR of 44%, median progression-free survival (mPFS) of 6 months, and 16% CR vs an ORR of 19%, mPFS of 1.5 months, and 5% CR in classifier-negative patients (P = .0096). Avadomide is being evaluated in combination with other antilymphoma agents. This trial was registered at www.clinicaltrials.gov as #NCT01421524.

The tumor microenvironment shapes hallmarks of mature B-cell malignancies

B-cell tumorigenesis results from a host of known and unknown genetic anomalies, including non-random translocations of genes that normally function as determinants of cell proliferation or cell survival to regions juxtaposed to active immunoglobulin heavy chain enhancer elements, chromosomal aneuploidy, somatic mutations that further affect oncogenic signaling and loss of heterozygosity of tumor-suppressor genes. However, it is critical to recognize that even in the setting of a genetic disease, the B-cell/plasma cell tumor microenvironment (TME) contributes significantly to malignant transformation and pathogenesis. Over a decade ago, we proposed the concept of cell adhesion-mediated drug resistance to delineate a form of TME-mediated drug resistance that protects hematopoietic tumor cells from the initial effect of diverse therapies. In the interim, it has been increasingly appreciated that TME also contributes to tumor initiation and progression through sustained growth/proliferation, self-renewal capacity, immune evasion, migration and invasion as well as resistance to cell death in a host of B-cell malignancies, including mantle cell lymphoma, diffuse large B-cell lymphoma, Waldenstroms macroglobulinemia, chronic lymphocytic leukemia and multiple myeloma. Within this review, we propose that TME and the tumor co-evolve as a consequence of bidirectional signaling networks. As such, TME represents an important target and should be considered integral to tumor progression and drug response.

Epstein-Barr virus-positive diffuse large B-cell lymphoma association is not only restricted to elderly patients

Diffuse large B-cell lymphoma (DLBCL), the most common group of malignant lymphomas, account for 30% of adult non-Hodgkin lymphomas. The 2008 World Health Organization (WHO) classification included a new entity, Epstein-Barr virus (EBV)+ DLBCL of the elderly, affecting patients aged 50 years or older. However, some reports of younger EBV+ DLBCL cases, without evidence of underlying immunosuppression, can be found. The role of EBV in tumor microenvironment composition in DLBCL is still not well understood. Our aim was to assess EBV presence and latency pattern as well as tumor T-cell population in an adult DLBCL series of Argentina. The study was conducted on biopsies from 75 DLBCL patients. EBERs expression was performed by in situ hybridization, while EBV gene expression was analyzed using real-time polymerase chain reaction. LMP1, LMP2A, EBNA2, EBNA3A, CD4, CD8 and Foxp3 expression was assessed by immunohistochemistry. Nine percent of cases showed EBV expression, with similar frequency among patients younger than 50 years and 50 years or older (13% and 8%, respectively). T-cell subsets were not altered by EBV presence. Latency type II was the most frequently observed, together with lytic gene expression in EBV+ DLBCL, with ≥20% of EBERs+ cells. These findings suggest that EBV+ DLBCL in our series was similar to the previously described in Asia and Latin-America, displaying latency II or III expression profile and no age-specific characteristics. Finally, EBV+ DLBCL may be an entity that is not only restricted to patients who are older than 50 years of age, in consequence the age cutoff revision may be a current goal.

Differences in cerebrospinal fluid inflammatory cell reaction of patients with leptomeningeal involvement by lymphoma and carcinoma

Dissemination of neoplastic cells into the cerebrospinal fluid (CSF) and leptomeninges is a devastating complication in patients with epithelial cell neoplasia (leptomeningeal carcinomatosis [LC]) and lymphomas (lymphomatous meningitis [LyM]). Information about the surrounding inflammatory cell populations is scarce. In this study, flow cytometry immunophenotyping was used to describe the distribution of the main leukocyte populations in the CSF of 83 patients diagnosed with neoplastic meningitis (LC, n = 65; LyM, n = 18). These data were compared with those obtained in the CSF from 55 patients diagnosed with the same groups of neoplasia without meningeal involvement (solid tumors, n = 36; high-grade lymphoma, n = 19). Median (interquartile) rates of lymphocytes, monocytes, and polymorphonuclear (PMN) cells were 59.7% (range, 35-76.6%), 24% (range, 16-53%), and 1.5% (range, 0-7.6%) in LC, respectively, and 98.5% (range, 70.8-100%), 1.5% (range, 0-29.3%), and 0% in LyM, respectively (P < 0.001). No difference was observed between patients with breast adenocarcinoma (n = 30) and lung adenocarcinoma (n = 21), nor with different rates of malignant CSF involvement. Patients with lymphoma (with or without LyM) had a similar CSF leukocyte distribution, but cancer patients with LC and without LC had a distinctive PMN cell rate (P = 0.002). These data show that CSF samples from patients with LC have a greater number of inflammatory cells and a different leukocyte distribution than seen in the CSF from patients with LyM. Description of PMN cells is a distinctive parameter of patients with LC, compared with the CSF from patients with LyM and patients with cancer but without LC.

Mast cells, basophils and B cell connection network

It has been proven that both resting and activated mast cells (MCs) and basophils are able to induce a significant increase in proliferation and survival of naïve and activated B cells, and their differentiation into antibody-producing cells. The immunological context in which this regulation occurs is of particular interest and the idea that these innate cells induce antibody class switching and production is increasingly gaining ground. This direct role of MCs and basophils in acquired immunity requires cell to cell contact as well as soluble factors and exosomes. Here, we review our current understanding of the interaction between B cells and MCs or basophils as well as the evidence supporting B lymphocyte-MC/basophil crosstalk in pathological settings. Furthermore, we underline the obscure aspects of this interaction that could serve as important starting points for future research in the field of MC and basophil biology in the peculiar context of the connection between innate and adaptive immunity.

Epstein-Barr virus presence in pediatric diffuse large B-cell lymphoma reveals a particular association and latency patterns: analysis of viral role in tumor microenvironment

Non-Hodgkin's lymphoma represents 6-10% of pediatric malignancies, and diffuse large B-cell lymphoma (DLBCL) is one of the three major subtypes. The 2008 WHO classification included a new entity, Epstein-Barr virus (EBV)-positive DLBCL of the elderly, affecting patients >50 years. It has been demonstrated that EBV may play a role in tumor microenvironment composition, disturbing antitumor immune response and disease progression. As most studies were performed in adults, our aim was to assess EBV presence and latency pattern, as well as T-cell microenvironment in a pediatric DLBCL series of Argentina. The study was conducted on formalin-fixed paraffin-embedded biopsies from 25 DLBCL patients. EBV-encoded small nuclear early regions (EBERs) expression was performed by in situ hybridization, whereas EBV gene expression was analyzed using real-time PCR. Epstein-Barr virus latent membrane proteins (LMP)1, LMP2A, CD3, CD4, CD8 and Foxp3 expression were assessed by immunohistochemistry (IHC). Forty percent of cases showed EBV expression, with a significantly higher incidence among patients <10 years (p = 0.018), and with immunosuppressed (p = 0.023). T-cell subsets were not altered by EBV presence. Full EBV latency antigen expression (latency type III) was the most frequently pattern observed, together with BZLF1 lytic gene expression. One patient showed II-like pattern (LMP1 without LMP2A expression). Based exclusively on IHC, some patients showed latency II/III (EBERs and LMP1 expression) or I (EBERs only). These findings suggest that EBV association in our series was higher than the previously demonstrated for elderly DLBCL and that EBV latency pattern could be more complex from those previously observed. Therefore, EBV could be an important cofactor in pediatric DLBCL lymphomagenesis.

Plasma cytokine profiles at diagnosis in pediatric patients with non-hodgkin lymphoma

Non-Hodgkin lymphoma (NHL) has been associated with elevated levels of inflammatory and immune-regulating cytokines, and polymorphisms in the genes encoding interleukin (IL)-10 and tumor necrosis factor (TNF)-α have been associated with increased incidence of certain subtypes of NHL. The aim of the present study was to screen for a broader spectrum of growth factors and inflammatory mediators and to compare the profiles in different subtypes of NHL in pediatric patients. Serum samples were collected at diagnosis from 31 pediatric patients diagnosed with NHL admitted at Rigshospitalet, Copenhagen, between 1995 and 2008. Cytokines and growth factors were measured in serum using the Luminex platform by application of a 30-plex kit. Levels of IL-6, IL-2R, IL-10, TNF-RI, and macrophage inflammatory protein-1α were significantly higher in patients with anaplastic large-cell lymphoma compared with patients diagnosed with B-cell lymphomas and lymphoblastic lymphomas. High levels of IL-4, IL-13, TNF-RI, and epidermal growth factor were associated with a poorer general condition at diagnosis. The present study suggests that NHL subgrouping and the general condition of pediatric patients at diagnosis are associated with plasma levels of growth factors and inflammatory mediators at presentation.

Microenvironment-centred dynamics in aggressive B-cell lymphomas

Aggressive B-cell lymphomas share high proliferative and invasive attitudes and dismal prognosis despite heterogeneous biological features. In the interchained sequence of events leading to cancer progression, neoplastic clone-intrinsic molecular events play a major role. Nevertheless, microenvironment-related cues have progressively come into focus as true determinants for this process. The cancer-associated microenvironment is a complex network of nonneoplastic immune and stromal cells embedded in extracellular components, giving rise to a multifarious crosstalk with neoplastic cells towards the induction of a supportive milieu. The immunological and stromal microenvironments have been classically regarded as essential partners of indolent lymphomas, while considered mainly negligible in the setting of aggressive B-cell lymphomas that, by their nature, are less reliant on external stimuli. By this paper we try to delineate the cardinal microenvironment-centred dynamics exerting an influence over lymphoid clone progression in aggressive B-cell lymphomas.

Plasmin inhibitor reduces T-cell lymphoid tumor growth by suppressing matrix metalloproteinase-9-dependent CD11b(+)/F4/80(+) myeloid cell recruitment

Activation of the fibrinolytic system during lymphoma progression is a well-documented clinical phenomenon. But the mechanism by which the fibrinolytic system can modulate lymphoma progression has been elusive. The main fibrinolytic enzyme, plasminogen (Plg)/plasmin (Plm), can activate matrix metalloproteinases (MMPs), such as MMP-9, which has been linked to various malignancies. Here we provide the evidence that blockade of Plg reduces T-cell lymphoma growth by inhibiting MMP-9-dependent recruitment of CD11b(+)F4/80(+) myeloid cells locally within the lymphoma tissue. Genetic Plg deficiency and drug-mediated Plm blockade delayed T-cell lymphoma growth and diminished MMP-9-dependent CD11b(+)F4/80(+) myeloid cell infiltration into lymphoma tissues. A neutralizing antibody against CD11b inhibited T-cell lymphoma growth in vivo, which indicates that CD11b(+) myeloid cells have a role in T-cell lymphoma growth. Plg deficiency in T-cell lymphoma-bearing mice resulted in reduced plasma levels of the growth factors vascular endothelial growth-A and Kit ligand, both of which are known to enhance myeloid cell proliferation. Collectively, the data presented in this study demonstrate a previously undescribed role of Plm in lymphoproliferative disorders and provide strong evidence that specific blockade of Plg represents a promising approach for the regulation of T-cell lymphoma growth.

The role of cytotoxic and regulatory T cells in relapsed/refractory Hodgkin lymphoma

Recent data suggests the presence of cytotoxic (TIA-1 and granzyme B+) and regulatory T-cells (FOXP3+) in classical Hodgkin lymphoma (cHL) tissues has been shown to correlate with poor overall survival in mainly diagnostic biopsies. By tissue microarray analyses, we extend this observation to a cohort of relapsed/refractory cHL tissue biopsies and analyze immunohistochemical expression of FOXP3, TIA-1, and granzyme B in the inflammatory background and the tumor microenvironment. High expression of TIA-1 (>50%) correlated with poor overall survival (P<0.0001), low expression of FOXP3 (<25%) correlated with poor overall survival (P<0.01), and combined high TIA-1 (>50%) and low FOXP3 (<25%) correlated with poor overall survival (P<0.0001). Expression of cytotoxic and regulatory T-cells shows prognostic significance in the relapsed/refractory clinical setting of cHL.

Expression of HLA class I and HLA class II by tumor cells in Chinese classical Hodgkin lymphoma patients

BACKGROUND

In Caucasian populations, the tumor cells of Epstein Barr virus (EBV)-positive classical Hodgkin Lymphomas (cHL) patients more frequently express HLA class I and HLA class II molecules compared to EBV-negative cHL patients. HLA expression (in relation to EBV) in Asian cHL patients has not been previously investigated.

METHODOLOGY/PRINCIPAL FINDINGS

We randomly selected 145 cHL patients with formalin-fixed, paraffin embedded tissue blocks available from 5 hospitals from the Northern part of China. Hematoxylin & Eosin-stained slides were used to re-classify the histological subtypes according to the WHO classification. EBV status was determined by visualization of EBERs in tumor cells using in situ hybridization. Membranous expression of HLA molecules was detected by immunohistochemistry using antibodies HC-10 (class I heavy chain) and anti-beta2-microglobulin for HLA class I, and CR3/43 for HLA class II. EBV+ tumor cells were observed in 40% (58/145) of the cHL patients. As expected, the percentage of EBV+ cases was much higher in the mixed cellularity subtype (71%) than in the nodular sclerosis subtype (16%) (p<0.001). Expression of HLA class I was observed in 79% of the EBV+ cHL cases and in 30% of the EBV-cases (p<0.001). For HLA class II, 52% of EBV+ cHL cases were positive, compared to 43% in EBV- cases (p = 0.28).

CONCLUSIONS

The results in the Northern China population were similar to those in the Caucasian population for HLA class I, but not for HLA class II.

EGR-1 activation by EGF inhibits MMP-9 expression and lymphoma growth

Progression of hematologic malignancies is strongly dependent on bidirectional interactions between tumor cells and stromal cells. Expression of members of the matrix metalloproteinase (MMP) family by stromal cells is a central event during these interactions. However, although several studies have focused on the mechanisms responsible for induction of MMP in stromal cells, the signals that negatively regulate their secretion of in these cells remain largely unknown. Here, we provide evidence that MMP-9 production by stromal cells is suppressed through activation of early growth response protein 1 (EGR-1), thereby inhibiting the growth of thymic lymphoma. We found that EGR-1 expression is induced in stromal cells after contact with lymphoma cells via epidermal growth factor (EGF). Moreover, development of thymic lymphoma was inhibited when induced by lymphoma cells overexpressing EGF compared with control lymphoma cells. Using transgenic mice containing MMP-9 promoter-driven luciferase transgene in its genome, we further demonstrated that EGF/EGR-1 repressed transcriptional activation of the MMP-9 gene by stromal cells. De novo expression of EGR-1 alone by gene transfer or exposure to recombinant human EGF also inhibited MMP-9 expression. Taken together, these results indicate that EGR-1 could be a source of novel targets for therapeutic intervention in lymphoid tumors in which MMP-9 plays a critical role.

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

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