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

Abstract The Hodgkin and Reed/Sternberg (HRS) tumor cells of classical Hodgkin lymphoma (HL) and the lymphocyte-predominant tumor cells of nodular lymphocyte–predominant HL are both derived from germinal center B cells. HRS cells, however, have largely lost their B-cell gene-expression program and coexpress genes typical of various types of hematopoietic cells. Multiple signaling pathways show a deregulated activity in HRS cells. The genetic lesions involved in the pathogenesis of HL are only partly known, but numerous members and regulators of the NF-κB and JAK/STAT signaling pathways are affected, suggesting an important role for these pathways in HL pathogenesis. Some genetic lesions involve epigenetic regulators, and there is emerging evidence that HRS cells have undergone extensive epigenetic alterations compared with normal B cells. HRS and lymphocyte-predominant cells are usually rare in the lymphoma tissue, and interactions with other cells in the microenvironment are likely critical for HL pathophysiology. T cells represent a main population of infiltrating cells, and it appears that HRS cells both inhibit cytotoxic T cells efficiently and also receive survival signals from Th cells in direct contact with them.

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Tumor Microenvironment In Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL) Influences Occurrence of Relapses and Progression to Large Cell Lymphoma

Blood ◽

10.1182/blood.v116.21.2684.2684 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2684-2684

Author(s):

Nasir Bakshi ◽

Mansoor Aljabry ◽

Saad Akhter ◽

Irfan Maghfoor ◽

Ayman Mashi

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

Tumor Microenvironment ◽

B Cell ◽

Hodgkin Lymphoma ◽

Clinical Course ◽

Cell Lymphoma ◽

Lp Cells

Abstract Abstract 2684 NLPHL accounts for 6.5% of all Hodgkin lymphoma cases in the West. It is characterized by a nodular or a nodular & diffuse proliferation of scattered large atypical CD20+ neoplastic B-cells referred to as lymphocyte predominant (LP) cells and typically associated with small lymphocytes mainly of B-cell type. Patients with NLPHL typically have an indolent clinical course but can frequently relapse. Progression to a higher grade lymphoma, notably T-cell/Histiocyte rich B-cell lymphoma (T/HRBCL) has been described in a relatively small number of cases. Because of its rarity, limited information is available about the role of non-neoplastic lymphocytes in NLPHL. Some studies suggest that NLPHL with T-cell rich background may behave differently than the conventional type with predominance of B-cells within the nodules. The purpose of this study was to evaluate outcomes of differential tumor microenvironment namely B-cell versus T-cell rich in patients with NLPHL. We document the clinicopathologic profiles of 29 patients with biopsy proven NLPHL, consisting of 22 male & 7 female, median age 26 years (range, 13–80 years). All patients had lymphoadenopathy & 2 cases showed extranodal involvement in addition to nodal disease. Two patients had a bulky mass, and three had stage 4 disease at presentation. The pathological diagnoses was reviewed and confirmed by an expert hematopathologist in all 29 cases. The LP cells in all cases had a prototypic immunophenotype of CD20+, CD79a+, PU.1+, Bcl-6+, CD15− CD30− & Fascin−. T/HRBCL was excluded as all cases demonstrated preservation of follicular dendritic meshwork by CD21 staining. The meshwork was expanded in 20 cases & in 9 cases it was partially disrupted evincing an irregular architectural pattern. Epstein-Barr Virus encoded RNA by in situ hybridization was negative in 8/8 cases tested. 27/29 patients received systemic multi-agent chemotherapy consisting of: doxorubicin, bleomycin, vinblastine, and dacarbacin (ABVD), 24 patients; cyclophosphamide, doxorubicin, vincristin, and prednisone (CHOP), 2 patients; Rituximab + CHOP (R-CHOP), 1 patient. 9/29 (31%) cases underwent autologous stem cell transplant. One patient in stage 2A refused therapy and one patient (stage 3A) developed significantly decreased cardiac ejection fraction following initial 2 cycles of ABVD. Both of these cases did not have adequate follow-up information available. Results: Twelve of the 29 cases (42%) were designated as having T-cell rich background population, whereas 17 (58%) were considered as conventional variant with a vast predominance of non-neoplastic small lymphocytes being B-cells. A few of the cases seemed to show admixture of both B-cells & T-cells. Comparing T-cell rich & B-cell rich background NLPHL no significant differences were detected in clinical parameters: age, sex, and stage at presentation, absolute lymphocyte count, LDH & Hb. All 27 (100%) patients in this study responded to first-line treatment: 23 with complete response & 4 with partial response. 13/27 (48%) had relapse/s. Five cases had more than one relapses. No patient died within a clinical follow-up period ranging from 18 to 84 months. When the overall survival (OS) of T-cell rich NLPHL was compared with the conventional variant there was no statistical significance between the two groups (log rank p= 0.1206). However, comparison of relapse rate showed that cases with T-cell rich background had higher relapse rate as well as greater incidence of multiple relapses as compared to B-cell rich type of NLPHL even after adjusting for the type of treatment received (log rank p= 0.003). Moreover, 2/12 (17%) T-cell rich NLPHL cases showed transformation to a high grade lymphoma (both T/HRBCL) at the time of recurrence. These findings suggest that in NLPHL a tumor microenvironment rich in T-cells rather than B-cells is characterized by an unfavorable clinical course although OS appears to be similar. These cases perhaps represent a distinctive clinicopathologic variant within the framework of NLPHL. Lately, the term ‘NLPHL with nodules resembling T/HRBCL’ has been used to express the immunobiological overlap between these two entities. It is possible that such cases could be regarded as “intermediate lymphomas” treading between NLPHL and T/HRLBCL. Further studies using gene array profiling analysis may help clarify the molecular differences between these closely related entities. Disclosures: No relevant conflicts of interest to declare.

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Malignant B Cells Induce the Conversion of CD4+CD25− T Cells to Regulatory T Cells in B-Cell Non-Hodgkin Lymphoma

PLoS ONE ◽

10.1371/journal.pone.0028649 ◽

2011 ◽

Vol 6 (12) ◽

pp. e28649 ◽

Cited By ~ 27

Author(s):

Yixiang Han ◽

Jianbo Wu ◽

Laixi Bi ◽

Shudao Xiong ◽

Shenmeng Gao ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

Regulatory T Cells ◽

B Cell ◽

Hodgkin Lymphoma ◽

Non Hodgkin Lymphoma

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Deep Profiling of the Immune Microenvironment throughout Myeloma Disease Stages

Blood ◽

10.1182/blood-2021-148590 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 727-727

Author(s):

Megan Darrington ◽

Frits van Rhee ◽

Carolina Schinke ◽

Maurizio Zangari ◽

Sharmilan Thanendrarajan ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

Nk Cells ◽

Board Of Directors ◽

Lower Percentage ◽

Population Abundance ◽

Regulatory Cells ◽

Immune Microenvironment ◽

Advisory Committees ◽

B Regulatory Cells

Abstract Background The immune system is altered in multiple myeloma (MM) and contributes to therapy resistance. The availability of novel immunotherapies necessitates understanding the influence of the immune microenvironment on disease progression which may inform sensitivity to therapy. The objective of this study is to fully characterize the immune microenvironment in MM precursor diseases and MM and identify any immune contribution to progression. To accomplish this we used high-dimensional mass cytometry (CyTOF) to investigate immune alterations associated with progression in pre-malignant and malignant stages of MM. Methods Cryopreserved bone marrow mononuclear cells (BMMCs) from healthy donors (HD, n=13), MGUS (n=21), SMM (n=19), newly diagnosed MM (NDMM, n=17), and ~3 months post- first autologous stem cell transplant (ASCT, n=21) were assessed using a panel of 35 cell surface and 3 intracellular antibodies that includes cell lineage markers for identification of immune populations and functional markers indicative of positive or negative immune regulation. BMMCs were thawed, stained with antibodies, and analyzed on a Helios mass cytometer. Data were normalized using bead normalization, transformed using the inverse hyperbolic sine function with a cofactor of 5 and gated for 45+ live, intact, singlets for global analysis by gating in FCS express and clustering by viSNE for visualization. Differences in population abundance were identified in an unbiased manner by FlowSOM and in marker intensity by CITRUS. Marker intensity analysis was performed using the multiple testing permutation procedure (SAM), with an FDR of 1% and minimum population size of 0.5%. Results To identify changes in the immune microenvironment associated with progression we compared immune population abundance and marker intensity indicative of immune status including activation, exhaustion, or senescence. MGUS was distinguished from HD by increased abundance of CD4 central memory (CM, p<0.001), effector memory (EM, p<0.001) and plasmacytoid and monocyte-derived dendritic cells (DC, p< 0.01). In MGUS, TIM3 and CD57 were elevated on NK cells and NKT cells, respectively, compared to HD suggesting reduced activity. In SMM increased abundance of B regulatory cells (3.0 vs 5.9 %, p<0.01) but reduced inhibitory markers on T cells including PD1, CTLA4 CD55, FOXP3 and TIGIT was observed compared to MGUS. NDMM was distinguished from SMM by reduced abundance of CD4 EM (p<0.01), CD8 early EM (p< 0.001), and B regulatory cells (p<0.01) and increased abundance of active Tregs (CD38+, P<0.01) and total NK cells (p<0.01) which had increased CD55, a complement inhibitory protein. Post-ASCT changes in immune abundance include increased total CD8 and CD8 terminal effectors (CD57 +, p< 0.0001), B regulatory cells (p<0.0001), and reduced total CD4 and CD4 CM (p<0.0001), compared to NDMM. CD4 T cells post-ASCT were characterized by reduced CD127 and CCR7 and increased CD28, CTLA4, FOXP3 and TIGIT and CD8 T cells had reduced CD28, CD127 and CCR7 and increased CD57 and TIGIT compared to NDMM. Interestingly, significant difference in NK cells were not observed but post-ASCT NK cells may be active as suggested by reduced CD59 and TIM3 compared to NDMM. To determine whether the immune microenvironment had normalized by 3 months post-ASCT we compared population abundance to HD, MGUS, and SMM cases. Immune abundance post-ASCT revealed a significantly lower percentage of CD4 CM, 4 -8 - T cells, normal PCs, and post-switch B cells (25+) and elevated CD8 terminal effector (57+) and B regulatory cells than all 3 other groups. Overall major differences in abundance of total T and B cells and their subsets were observed with differences in NK cells between stages primarily reflected in marker expression (e.g. CD161+ subset) rather than abundance. Conclusions Early changes in the immune microenvironment observed in MGUS/SMM lead to immune suppression and eventually immune evasion allowing MM to emerge. In this study the immune ME did not appear to normalize 3 months post-therapy indicated by an increase in B regulatory cells and markers of inactive effector cells. Profiling of the immune microenvironment throughout MM treatment may allow us to identify novel therapeutic targets and optimal timing of administration of novel immunotherapies and patients that would most benefit from these therapies. Disclosures Walker: Sanofi: Speakers Bureau; Bristol Myers Squibb: Research Funding. Morgan: BMS: Membership on an entity's Board of Directors or advisory committees; Jansen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees.

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The Tumor Microenvironment of Nodular Lymphocyte Predominant Hodgkin Lymphoma Is a Unique Immunobiological Entity Distinct from Classical Hodgkin Lymphoma

Blood ◽

10.1182/blood-2018-99-115836 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 4123-4123

Author(s):

Jay Gunawardana ◽

Karolina Bednarska ◽

Soi C Law ◽

Justina Lee ◽

Muhammed Bilal Sabdia ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Board Of Directors ◽

Hodgkin Lymphoma ◽

Research Funding ◽

Host Immunity ◽

Immune Checkpoints ◽

Classical Hodgkin Lymphoma ◽

Advisory Committees ◽

Immune Effector

Abstract There is proven pre-clinical and clinical efficacy of mono or combinatorial immune strategies to boost host anti-lymphoma immunity, with classical Hodgkin Lymphoma (cHL) seen as the 'poster child'. Approaches include blockade of immune-checkpoints on exhausted tumor-specific T-cells (via mAb blockade of PD-1, TIM3, LAG3, TIGIT or their ligands), activation of T-cells via mAbs agonistic to CD137, and finally modulation of FOXP3, CTLA-4 and/or LAG3 regulatory T-cells (Tregs) or immunosuppressive tumor-associated macrophages (TAMs). In contrast, studies characterizing the circulating and intra-tumoral microenvironment (TME) of the distinct but rare CD20+ Hodgkin Lymphoma entity (5-8% of HL), Nodular Lymphocyte Predominant Hodgkin Lymphoma (NLPHL), are minimal. Furthermore, to our knowledge no functional profiling studies comparing the host immunity of NLPHL with cHL has been performed. We compared host immunity in 29 NLPHL patients, 30 cHL patients and 10 healthy individuals, with a focus on pertinent and clinically actionable immune parameters. Paraffin-embedded tissue and paired (pre- and post-therapy) peripheral blood mononuclear cells samples were interrogated by digital multiplex hybridization (Nanostring Cancer Immune Profiling Panel) and flow cytometry. Although cytotoxic T-cell gene counts (CD8a, CD8b) were similar, compared to cHL there were higher levels of the immune effector activation marker CD137 (gene counts 439 vs. 287; P<0.01). Consistent with this, CD4 and the Treg markers LAG3, FOXP3 and CTLA-4 were lower in NLPHL (2-4 fold lower, all P<0.05), with no difference in T-helper cell activation markers CD40L and CD30L seen between tumors. TAMs and dendritic cell markers MARCO, CD36, CD68, CD163, COLEC12 and CD11b were all lower in NLPHL than cHL (all P<0.05). In line with the known 'rossette' formed around LP cells by PD-1+ T-lymphocytes, we observed strikingly elevated PD-1 and the other T-cell checkpoints TIM3 and TIGIT in NLPHL (all 2-3 fold, P<0.001). However, in line with the known gene amplification of PD-L1 on HRS cells and its presence on TAMs, gene counts of this checkpoint ligand were 2-fold higher in cHL (P<0.001). Flow cytometry profiling of immune subsets in peripheral blood showed findings consistent with findings in the TME. Specifically, there was elevation of multiple exhaustion markers within CD4, CD8, and NK immune effector cells, with a striking proportion of highly anergic dual-LAG3/PD-1 positive CD8+ T-cells. Also there was elevation of immune-suppressive monocyte/macrophages in cHL relative to NLPHL. Relative to healthy lymph nodes, there was prominent up-regulation of a range of T-cell associated exhaustion markers in both NLPHL and cHL, indicating dysregulated priming of effector immune responses and host immune homeostasis. Comparison between NLPHL and cHL illustrated that NLPHL had a myriad of features that marked its intratumoral TME as a unique immunobiological entity typified by elevated immune checkpoint markers and T-cells with a highly anergic phenotype. Put together, these findings indicate that distinct immune evasion mechanisms are operative within the TME of NLPHL, including markedly higher levels of multiple immune-checkpoints relative to cHL. In contrast, Treg subsets and immune-suppressive monocyte/macrophages were relatively lower than that seen in cHL. T-cells frequently had dual immune-checkpoint expression. The findings from this study provides a compelling pre-clinical rationale for targeting PD-1 or combinatory checkpoint inhibition in NLPHL and sets the basis for future 'chemo-free' rituximab + checkpoint inhibitor clinical trials. Disclosures Tobin: Amgen: Other: Educational Travel; Celgene: Research Funding. Birch:Medadvance: Equity Ownership. Keane:Takeda: Other: Educational Meeting; BMS: Research Funding; Roche: Other: Education Support, Speakers Bureau; Celgene: Consultancy, Research Funding; Merck: Consultancy. Gandhi:BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Takeda: Honoraria; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Expression of CD1c, CD1d and Presence of Invariant NKT Cells in Hodgkin Lymphoma.

Blood ◽

10.1182/blood.v114.22.3659.3659 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3659-3659

Author(s):

Chuanhui Xu ◽

Riemer de Vries ◽

Lydia Visser ◽

Arjan Diepstra ◽

Stephan D Gadola ◽

...

Keyword(s):

T Cells ◽

B Cells ◽

Hodgkin Lymphoma ◽

Cell Lines ◽

Conflicts Of Interest ◽

Cell Suspensions ◽

Inkt Cell ◽

Inkt Cells ◽

Lipid Antigens ◽

The Mean

Abstract Abstract 3659 Poster Board III-595 Introduction Hodgkin lymphoma (HL) is a B-cell neoplasm characterized by a minority of neoplastic cells, the so-called Hodgkin and Reed-Sternberg (HRS) cells. The HRS cells are located within an extensive infiltrate of reactive cells, including T cells, B cells, plasma cells, stromal cells, eosinophils and macrophages. CD1 molecules are non-classical MHC I-like molecules that present lipid antigens to T cells, triggering a specific immune response. Of the five CD1 isoforms (CD1a, CD1b, CD1c, CD1d and CD1e) expressed in human tissue, only CD1c and CD1d are expressed in B cells. The T cell receptors (TCRs) of T cells that recognize CD1c are indistinguishable from those that recognize MHC class I or II complexes. In contrast, CD1d presents lipid antigens to invariant Natural Killer T cells (iNKT cells), which are characterized by the expression of a semi-invariant Vα24Jα18 chain plus a limited set of β chains. CD4− and CD4+ iNKT cells were demonstrated as two distinct functional subsets in terms of cytokine production and cytotoxic activation. Immunoregulatory CD1 restricted T cells have been implicated in the pathogenesis of many cancers, but its role in HL is still unknown. In this study, we analyzed the expression of CD1c, CD1d and presence of iNKT cells in HL. Methods Expression of CD1c and CD1d was determined by immunocytochemistry in four HL cell lines KMH2, L1236, L428 and U-HO1. CD1c and CD1d expression in both HRS cells and reactive cells was studied in 46 HL patient tissues by immunohistochemistry. Cell suspensions of ten HL cases were studied for the presence of iNKT cells using monoclonal antibodies against human iNKT cell (clone 6B11) and TCR Vβ11 (clone C21) by flow cytometry. The percentage of CD4+ iNKT cells was determined in the gated iNKT cell population. Results Cytoplasmic CD1d expression was found in four HL cell lines and membranous CD1d expression was found in KMH2 and L1236. CD1c expression was negative in all four HL cell lines. CD1d expression was detected in HRS cells in 46% (21/46) of the HL cases. No correlation was observed between CD1d expression and presence of EBV in HRS cells. In contrast, CD1c expression was negative in HRS cells in all HL cases. Both CD1c and CD1d were detected in reactive cells in all HL cases albeit at varying frequencies. The mean percentage of CD1d restricted iNKT cells was 4% (range 0.8-8%) in HL cell suspensions irrespective of CD1d expression status in HRS cells. In reactive lymph node (RLN) the mean percentage of iNKT cells was also 4% (range 0.4-7%). Approximately half of the iNKT cells were CD4+ in both HL and RLN cell suspensions. Conclusion Expression of CD1d was found in four HL cell lines and in HRS cells of ∼50% of the HL cases. In HL cell suspensions, about 4% (range 0.8-8%) of the reactive background cells were iNKT cells. Disclosures: No relevant conflicts of interest to declare.

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CD70+ non-Hodgkin lymphoma B cells induce Foxp3 expression and regulatory function in intratumoral CD4+CD25− T cells

Blood ◽

10.1182/blood-2007-03-082578 ◽

2007 ◽

Vol 110 (7) ◽

pp. 2537-2544 ◽

Cited By ~ 114

Author(s):

Zhi-Zhang Yang ◽

Anne J. Novak ◽

Steven C. Ziesmer ◽

Thomas E. Witzig ◽

Stephen M. Ansell

Keyword(s):

T Cells ◽

B Cells ◽

B Cell ◽

Hodgkin Lymphoma ◽

Foxp3 Expression ◽

Regulatory Function ◽

Forkhead Box P3 ◽

Non Hodgkin Lymphoma ◽

Forkhead Box

Foxp3 expression was initially thought to be restricted to the CD4+CD25+ regulatory T-cell population. However, recent studies suggest that forkhead box P3 (Foxp3) is expressed in CD4+CD25− T cells in aged mice. In the present study in B-cell non-Hodgkin lymphoma (NHL), we found that a subset of intratumoral but not peripheral blood CD4+CD25− T cells, comprising about 15% of intratumoral CD4+ T cells, express Foxp3 and are capable of suppressing the proliferation of autologous infiltrating CD8+ T cells. In vitro activation with OKT3/anti-CD28 antibody (Ab) or dendritic cells (DCs) induced Foxp3 expression in a subset of these CD4+CD25−Foxp3− T cells. We found that the presence of lymphoma B cells during activation augmented activation-induced Foxp3 expression in CD4+CD25− T cells. We also found that CD70+ lymphoma B cells significantly contributed to the activation-induced Foxp3 expression in intratumoral CD4+CD25− T cells. Furthermore, the blockade of CD27-CD70 interaction by anti-CD70 Ab abrogated lymphoma B-cell–mediated induction of Foxp3 expression in intratumoral CD4+CD25− T cells. Taken together, these studies reveal a novel role for NHL B cells in the development of intratumoral regulatory T cells.

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Immunophenotypes Based on the Tumor Immune Microenvironment Allow for Unsupervised Penile Cancer Patient Stratification

Cancers ◽

10.3390/cancers12071796 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1796 ◽

Cited By ~ 2

Author(s):

Chengbiao Chu ◽

Kai Yao ◽

Jiangli Lu ◽

Yijun Zhang ◽

Keming Chen ◽

...

Keyword(s):

T Cells ◽

Cell Death ◽

Programmed Cell Death ◽

Cytotoxic T Lymphocyte ◽

Granzyme B ◽

Expression Patterns ◽

Tumor Infiltrating Lymphocytes ◽

Immune Checkpoints ◽

Immune Microenvironment ◽

Tumor Immune Microenvironment

The tumor immune microenvironment (TIME) plays an important role in penile squamous cell carcinoma (peSCC) pathogenesis. Here, the immunophenotype of the TIME in peSCC was determined by integrating the expression patterns of immune checkpoints (programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1), cytotoxic T lymphocyte antigen 4 (CTLA-4), and Siglec-15) and the components of tumor-infiltrating lymphocytes, including CD8+ or Granzyme B+ T cells, FOXP3+ regulatory T cells, and CD68+ or CD206+ macrophages, in 178 patients. A high density of Granzyme B, FOXP3, CD68, CD206, PD-1, and CTLA-4 was associated with better disease-specific survival (DSS). The patients with diffuse PD-L1 tumor cell expression had worse prognoses than those with marginal or negative PD-L1 expression. Four immunophenotypes were identified by unsupervised clustering analysis, based on certain immune markers, which were associated with DSS and lymph node metastasis (LNM) in peSCC. There was no significant relationship between the immunophenotypes and high-risk human papillomavirus (hrHPV) infection. However, the hrHPV–positive peSCC exhibited a higher density of stromal Granzyme B and intratumoral PD-1 than the hrHPV–negative tumors (p = 0.049 and 0.002, respectively). In conclusion, the immunophenotypes of peSCC were of great value in predicting LNM and prognosis, and may provide support for clinical stratification management and immunotherapy intervention.

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EPEN-23. A COMPUTATIONAL ANALYSIS OF THE TUMOUR IMMUNE MICROENVIRONMENT IN PAEDIATRIC EPENDYMOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa222.160 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii312-iii312

Author(s):

Timothy Ritzmann ◽

Anbarasu Lourdusamy ◽

Andrew Jackson ◽

Lisa Storer ◽

Andrew Donson ◽

...

Keyword(s):

Gene Expression ◽

T Cells ◽

T Cell ◽

B Cells ◽

Computational Analysis ◽

Immune Cell ◽

Cell Populations ◽

Immune Microenvironment ◽

Tumour Immunity ◽

Follicular Helper

Abstract Ependymoma is the third commonest childhood brain tumour. Relapse is frequent, often fatal and current therapeutic strategies are inadequate. Previous ependymoma research describes an immunosuppressive environment with T-cell exhaustion, indicating a lack of response to T-cell directed immunotherapy. Understanding the immune microenvironment is therefore critical. We present a computational analysis of ependymoma, gene expression derived, immune profiles. Using 465 ependymoma samples from gene expression datasets (GSE64415, GSE50385, GSE100240) and two RNA-seq databases from UK ependymomas, we applied bulk tumour deconvolution methods (CIBERSORT and xCell) to infer immune cell populations. Additionally, we measured checkpoint blockade related mRNAs and used immunohistochemistry to investigate cell populations in ependymoma sections. CIBERSORT indicated high proportions of M2-like macrophages and smaller proportions of activated natural killer (NK) cells, T follicular helper cells, CD4+ memory T-cells and B-cells. xCell overlapped with the M2-like macrophage and CD4+ memory T-cell signatures seen in CIBERSORT. On immunohistochemistry, T and B cells were scarce, with small numbers of CD8+, CD4+ and CD20+ cells in the parenchyma but greater numbers in surrounding regions. CD68 was more highly expressed in the parenchyma. Analysis of nine checkpoint ligands and receptors demonstrated only the TIM3/GAL9 combination was reliably detectable. GAL9 is implicated in tumour interactions with T-cells and macrophages elsewhere, possibly contributing to poorer outcomes. Our study supports the presence of myeloid cells being leading contributors to the ependymoma immune microenvironment. Further work will delineate the extent of myeloid contribution to immunosuppression across molecular subtypes. Modulation of tumour immunity may contribute to better clinical outcomes.

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