Major Histocompatibility Complex Class II and Programmed Death Ligand 1 Expression Predict Outcome After Programmed Death 1 Blockade in Classic Hodgkin Lymphoma

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.

MS4A6A is a new prognostic biomarker produced by macrophages in glioma patients

MS4A6A has been recognized as being associated with aging and the onset of neurodegenerative disease. However, the mechanisms of MS4A6A in glioma biology and prognosis are ill-defined. Here, we show that MS4A6A is upregulated in glioma tissues, resulting in unfavorable clinical outcomes and poor responses to adjuvant chemotherapy. Multivariate Cox regression analysis suggested that MS4A6A expression can act as a strong and independent predictor for glioma outcomes (CGGA1: HR: 1.765, p < 0.001; CGGA2: HR: 2.626, p < 0.001; TCGA: HR: 1.415, p < 0.001; Rembrandt: HR: 1.809, p < 0.001; Gravendeel: HR: 1.613, p < 0.001). A protein–protein interaction (PPI) network revealed that MS4A6A might be coexpressed with CD68, CD163, and macrophage-specific signatures. Enrichment analysis showed the innate immune response and inflammatory response to be markedly enriched in the high MS4A6A expression group. Additionally, single-cell RNA sequencing (scRNA-seq) analysis revealed distinctive expression features for MS4A6A in macrophages in the glioma immune microenvironment (GIME). Immunofluorescence staining confirmed colocalization of CD68/MS4A6A and CD163/MS4A6A in macrophages. Correlation analysis revealed that MS4A6A expression is positively related to the tumor mutation burden (TMB) of glioma, displaying the high potential of applying MS4A6A to evaluate responsiveness to immunotherapy. Altogether, our research indicates that MS4A6A upregulation may be used as a promising and effective indicator for adjuvant therapy and prognosis assessment.

Integration of miRNA:mRNA Co-Expression Revealed Crucial Mechanisms Modulated in Immunogenic Cancer Cell Death

Immunogenic cell death (ICD) in cancer represents a functionally unique therapeutic response that can induce tumor-targeting immune responses. ICD is characterized by the exposure and release of numerous damage-associated molecular patterns (DAMPs), which confer adjuvanticity to dying cancer cells. The spatiotemporally defined emission of DAMPs during ICD has been well described, whereas the epigenetic mechanisms that regulate ICD hallmarks have not yet been deeply elucidated. Here, we aimed to examine the involvement of miRNAs and their putative targets using well-established in vitro models of ICD. To this end, B cell lymphoma (Mino) and breast cancer (MDA-MB-231) cell lines were exposed to two different ICD inducers, the combination of retinoic acid (RA) and interferon-alpha (IFN-α) and doxorubicin, and to non ICD inducers such as gamma irradiation. Then, miRNA and mRNA profiles were studied by next generation sequencing. Co-expression analysis identified 16 miRNAs differentially modulated in cells undergoing ICD. Integrated miRNA-mRNA functional analysis revealed candidate miRNAs, mRNAs, and modulated pathways associated with Immune System Process (GO Term). Specifically, ICD induced a distinctive transcriptional signature hallmarked by regulation of antigen presentation, a crucial step for proper activation of immune system antitumor response. Interestingly, the major histocompatibility complex class I (MHC-I) pathway was upregulated whereas class II (MHC-II) was downregulated. Analysis of MHC-II associated transcripts and HLA-DR surface expression confirmed inhibition of this pathway by ICD on lymphoma cells. miR-4284 and miR-212-3p were the strongest miRNAs upregulated by ICD associated with this event and miR-212-3p overexpression was able to downregulate surface expression of HLA-DR. It is well known that MHC-II expression on tumor cells facilitates the recruitment of CD4+ T cells. However, the interaction between tumor MHC-II and inhibitory coreceptors on tumor-associated lymphocytes could provide an immunosuppressive signal that directly represses effector cytotoxic activity. In this context, MHC-II downregulation by ICD could enhance antitumor immunity. Overall, we found that the miRNA profile was significantly altered during ICD. Several miRNAs are predicted to be involved in the regulation of MHC-I and II pathways, whose implication in ICD is demonstrated herein for the first time, which could eventually modulate tumor recognition and attack by the immune system.

Role and Mechanisms of Tumor-Associated Macrophages in Hematological Malignancies

Mounting evidence has revealed that many nontumor cells in the tumor microenvironment, such as fibroblasts, endothelial cells, mesenchymal stem cells, and leukocytes, are strongly involved in tumor progression. In hematological malignancies, tumor-associated macrophages (TAMs) are considered to be an important component that promotes tumor growth and can be polarized into different phenotypes with protumor or antitumor roles. This Review emphasizes research related to the role and mechanisms of TAMs in hematological malignancies. TAMs lead to poor prognosis by influencing tumor progression at the molecular level, including nurturing cancer stem cells and laying the foundation for metastasis. Although detailed molecular mechanisms have not been clarified, TAMs may be a new therapeutic target in hematological disease treatment.

A Phase I Study of Apolizumab, an Anti-HLA-DR ß-chain Monoclonal Antibody, in Patients With Solid Tumor Malignancies

BACKGROUND

Human leukocyte antigen (HLA)-DR, a member of the major histocompatibility complex class II antigen family, is a target for antibody-based therapeutics. Apolizumab (Hu1D10, Remitogen), a humanized IgG1 monoclonal anti-HLA-DR ß-chain antibody targets the antigen, 1D10, expressed on a wide variety of hematologic and solid tumor malignancies. In this Phase 1 trial, the maximum tolerated dose and dose-limiting toxicity of weekly apolizumab in patients with advanced solid tumor malignancies were determined.

PATIENTS AND METHODS

Eligible patients with refractory solid tumors were initially screened for ID10 Ag on their tumor. Patients whose tumors expressed 1D10 were administered apolizumab 0.5, 1.0, 1.5, or 3.0 mg/kg intravenously over 90 minutes weekly for 4 consecutive weeks, followed by a 4-week break, and assessment of response. Patients whose disease had not progressed were offered additional treatment.

RESULTS

Tumors from 75 patients were screened for 1D10 Ag of which 17 patients were positive and underwent treatment. The first 3 dose levels were well-tolerated. Dose-limiting toxicities of grade 3 infusion-related hypersensitivity reactions and grade 3 headache and hypertension occurred in 2 patients, respectively, at apolizumab 3.0 mg/kg. Four patients, 1 each with breast carcinoma, melanoma, renal cell carcinoma, and sarcoma had stable disease for a median of 15 weeks (range: 12 to 19 wk).

CONCLUSION

Apolizumab can be administered safely at a maximum tolerated dose of 1.5 mg/kg for 4 consecutive weeks. Adverse events and limited clinical data in both hematologic and solid tumor malignancies resulted in discontinuation of clinical development of apolizumab. HLA-DR remains an interesting immunotherapeutic target.

Immunotherapy for triple negative breast cancer: How can pathologic responses to experimental drugs in early-stage disease be enhanced?

INTRODUCTION

: The treatment landscape of early triple negative breast cancer (TNBC) has recently expanded after the Food and Drug Administration (FDA) approval of pembrolizumab in combination with neoadjuvant chemotherapy. The addition of this immune checkpoint inhibitor (ICI) has shown to significantly increased pathological complete response (pCR) rate and event free survival (EFS) in the KEYNOTE-522 phase 3 trial. Several additional studies are ongoing with the goal of further improving outcomes and achieving an optimal integration of ICIs in the treatment of TNBC.

AREAS COVERED

: The article examines pCR and survival rates in TNBC. It appraises clinical trials investigating neoadjuvant ICIs for TNBC and the improvement of pCR rates (biomarker-driven escalation of treatment, optimization of chemotherapy backbone and addition of locoregional treatments or innovative agents). Insights on the role of pCR as surrogate endpoint and the possibility of enhancing pCR rates for women affected by early TNBC are offered.

EXPERT OPINION

: The pharmacopoeia of early TNBC is growing and becoming more heterogeneous with the advent of ICIs; to enhance the clinical benefit of patients, it is necessary to develop response endpoints that consider the mechanism of action of experimental drugs, to optimize patient selection through validated biomarkers, and to compare the most promising treatment strategies in randomized clinical trials.

Tumor-Specific CD4+ T Cells Restrain Established Metastatic Melanoma by Developing Into Cytotoxic CD4– T Cells

Cytotoxic CD8+ T cells are the main focus of efforts to understand anti-tumor immunity and immunotherapy. The adoptive transfer of tumor-reactive cytotoxic CD8+ T lymphocytes expanded and differentiated in vitro has long been considered the primary strategy in adaptive anti-tumor immunity, however, the majority of the transferred tumor antigen-specific CD8+ T cells differentiated into CD39+CD69+ exhausted progenies, limiting its effects in repressing tumor growth. Contrarily, less attention has been addressed to the role of CD4+ T cells during tumorigenesis. Using a mouse model of metastatic melanoma, we found that transferring tumor-specific CD4+ T cells into recipients induces substantial regression of the established metastatic tumors. Notably, in vitro activated CD4+ T cells developed into cytotoxic CD4- T cells in vivo and get exhausted gradually. The blockade of PD-L1 signaling resulted in an expansion of tumor specific CD4+ T cells, which could better control the established metastatic melanoma. Moreover, the tumor-specific memory CD4+ T cell can prevent mice from tumor metastasis, and the tumor-specific effector CD4+ T cells can also mitigate the established metastatic tumor. Overall, our findings suggest a novel mechanism of CD4+ T cells in curtailing tumor metastasis and confirm their therapeutic role in combination with PD-L1 blockade in cancer immunotherapy. Hence, a better understanding of cytotoxic CD4- T cell-mediated tumor regression could provide an alternative choice for patients exhibiting suboptimal or no response to CD8+ T cell-based immunotherapies.

Updates in the Role of Checkpoint Inhibitor Immunotherapy in Classical Hodgkin's Lymphoma

Classical Hodgkin's lymphoma is a highly curable disease, but 10-25% of patients with higher-risk disease relapse. The introduction of checkpoint inhibitors (CPIs) targeting PD-1 have changed the landscape of treatment for patients with relapsed/refractory disease to multiple lines of therapy. The depth of response to CPI as a monotherapy is highest in the first relapse as salvage therapy based on outcomes reported in several phase II studies. With earlier use of CPI and brentuximab vedotin, the optimal sequencing of therapy is evolving. In this review, we will summarize clinical investigation of anti-PD-1 mAb in earlier line settings to provide insights on utilizing these agents as chemotherapy- and radiation-sparing approaches, increasing depth of response, and as part of combination regimens.

The Role of PD-L1 Expression in Prediction and Stratification of Recurrent or Refractory Extranodal Natural Killer/T-Cell Lymphoma

Background and Aims

The clinical outcome of relapsed and refractory (RR) extranodal natural killer/T-cell lymphoma (ENKTL) is poor. It is necessary to identify RR patients in ENKTL and find novel therapeutic targets to improve the prognosis of patients with RR ENKTL.

Methods

A total of 189 ENKTL patients with effective clinical characteristics were enrolled. Paraffin specimens were collected for PD-L1 expression identification. Kaplan-Meier curve analysis was performed for survival analysis. Whole exome sequencing (WES) was performed for identifying the mutational characterization of RR and effective treatment (ET) patients.

Results

Univariate and multivariate Cox proportional hazards regression analysis showed that negative PD-L1 expression (HR = 1.132, 95% CI = 0.739-1.734, P = 0.036) was an independent predictor of poor prognosis in patients with ENKTL. The overall survival (OS) of PD-L1 positive patients was significantly higher than that of PD-L1 negative patients (P = 0.009). Then, we added PD-L1 expression as a risk factor to the model of Prognostic Index of Natural Killer Lymphoma (PINK), and named as PINK+PD-L1. The PINK+PD-L1 model can significantly distinguish RR patients, ET patients, and the whole cohort. Moreover, our data showed that PD-L1 expression was lower than 25% in most RR patients, suggesting that RR subtypes may be associated with low expression of PD-L1 (P = 0.019). According to the whole exome sequencing (WES), we found that the mutation frequencies of JAK-STAT (P = 0.001), PI3K-AKT (P = 0.02) and NF-kappa B (P < 0.001) pathways in RR patients were significantly higher than those in ET patients.

Conclusion

Patients tend to show RR when PD-L1 expression is lower than 25%. The model of PINK+PD-L1 can stratify the risk of different groups and predict OS in ENKTL patients. The mutational profile of ENKTL patients with RR is different from that of patients with ET.

A single-cell atlas of diffuse large B cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is one of the most common yet aggressive types of B cell lymphoma and remains incurable in 40% of patients. Herein, we profile the transcriptomes of 94,324 cells from 17 DLBCLs and 3 control samples using single-cell RNA sequencing. Altogether, 73 gene expression programs are identified in malignant cells, demonstrating high intra- and intertumor heterogeneity. Furthermore, 2,754 pairs of suggestive cell-cell interactions are predicted, indicating a complex and highly dynamic tumor microenvironment. Especially for B cell lymphomas, a strong costimulatory CD70-CD27 interaction is predicted between malignant and T cells. Furthermore, coinhibitory signals mediated by TIM3 or TIGIT seem to be the main driving force for T cell exhaustion. Finally, we find that chronic hepatitis B virus infection may have a significant impact on tumor cell survival and immune evasion in DLBCL. Our results provide insights into B cell lymphomagenesis and may facilitate the design of targeted immunotherapy strategies.

An evaluation of pembrolizumab for classical Hodgkin lymphoma

INTRODUCTION

Pembrolizumab is an immune checkpoint inhibitor (ICI) targeted against the programmed death 1 (PD-1) pathway, a key pathway in the biology of Classical Hodgkin lymphoma (cHL). Anti-PD-1 antibodies are approved for use in relapsed/refractory cHL but ongoing studies continue to optimize the use of this treatment.

AREAS COVERED

This review highlights recent and established data regarding pembrolizumab in the management of relapsed/refractory cHL and emerging areas of study including translational biology, combinations with chemotherapy and trials earlier in the disease courseExpert Opinion: Pembrolizumab provides superior progression free survival for patients with cHL who relapse post autologous stem cell transplant or who have chemotherapy refractory disease and should be used in these high risk populations. A key challenge remains the development of predictive biomarkers for anti-PD1 antibodies. There is promising evidence of the improved efficacy of salvage chemotherapy regimens and frontline regimens incorporating pembrolizumab but larger randomized studies are needed to demonstrate clear patient benefit.

PD-L1 overexpression correlates with JAK2-V617F mutational burden and is associated with 9p uniparental disomy in myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are chronic stem cell disorders characterized by enhanced proliferation of myeloid cells, immune deregulation, and drug resistance. JAK2 somatic mutations drive the disease in 50-60% and CALR mutations in 25-30% of cases. Published data suggest that JAK2-V617F-mutated MPN cells express the resistance-related checkpoint PD-L1. By applying RNA-sequencing on granulocytes of 113 MPN patients, we demonstrate that PD-L1 expression is highest among polycythemia vera patients and that PD-L1 expression correlates with JAK2-V617F mutational burden (R = 0.52; p < .0001). Single nucleotide polymorphism (SNP) arrays showed that chromosome 9p uniparental disomy (UPD) covers both PD-L1 and JAK2 in all MPN patients examined. MPN cells in JAK2-V617F-positive patients expressed higher levels of PD-L1 if 9p UPD was present compared to when it was absent (p < .0001). Moreover, haplotype-based association analyses provided evidence for germline genetic factors at PD-L1 locus contributing to MPN susceptibility independently of the previously described GGCC risk haplotype. We also found that PD-L1 is highly expressed on putative CD34+ CD38- disease-initiating neoplastic stem cells (NSC) in both JAK2 and CALR-mutated MPN. PD-L1 overexpression decreased upon exposure to JAK2 blockers and BRD4-targeting agents, suggesting a role for JAK2-STAT5-signaling and BRD4 in PD-L1 expression. Whether targeting of PD-L1 can overcome NSC resistance in MPN remains to be elucidated in forthcoming studies.

Immune Escape Mechanisms in Intravascular Large B-Cell Lymphoma: A Molecular Cytogenetic and Immunohistochemical Study

OBJECTIVES

Intravascular large B-cell lymphomas (IVLBCLs) are rare extranodal LBCLs in which relapse is relatively frequent. We sought to further characterize potential immune escape mechanisms in IVLBCLs that newer therapies can exploit.

METHODS

A series of 33 IVLBCLs were evaluated for programmed cell death ligand 1 (PD-L1) and PD-L2 expression by immunohistochemistry (IHC), chromosomal alterations (CAs) in the PDL1/PDL2 locus by fluorescence in situ hybridization, and loss of major histocompatibility complex (MHC) class I and II expression by IHC.

RESULTS

Cases were subclassified as classical (n = 22) or hemophagocytic syndrome (HPS)-associated (n = 11) variants. A total of 12 cases (39%; n = 12/31) expressed PD-L1 and/or PD-L2. CAs were seen in 7 cases (7/29 [24%]) and included gains, amplifications, and rearrangements. CAs in classical variant cases (24%; n = 5/21) included gains (n =1), gains with concurrent rearrangements (n = 2), and amplifications (n = 2). The 2 HPS-associated variant cases with CAs (25%; n = 2/8) both showed amplification, including 1 case with a concurrent rearrangement. A majority of cases with CAs (71%; n = 5/7) were PD-L1/PD-L2 IHC positive. Among PD-L1/PD-L2 IHC-positive cases, 45% harbored a CA. Loss of MHC class I and/or class II was seen in 27% (n = 9/33) of cases.

CONCLUSIONS

Altogether, our data show that 65% (n = 20/31) of IVLBCLs may exploit immune evasion strategies through PD-L1/PD-L2 expression or downregulation of MHC proteins.

Biological Characteristics and Clinical Significance of Soluble PD-1/PD-L1 and Exosomal PD-L1 in Cancer

The immune checkpoint pathway consisting of the cell membrane-bound molecule programmed death protein 1 (PD-1) and its ligand PD-L1 has been found to mediate negative regulatory signals that effectively inhibit T-cell proliferation and function and impair antitumor immune responses. Considerable evidence suggests that the PD-1/PD-L1 pathway is responsible for tumor immune tolerance and immune escape. Blockage of this pathway has been found to reverse T lymphocyte depletion and restore antitumor immunity. Antagonists targeting this pathway have shown significant clinical activity in specific cancer types. Although originally identified as membrane-type molecules, several other forms of PD-1/PD-L1 have been detected in the blood of cancer patients, including soluble PD-1/PD-L1 (sPD-1/sPD-L1) and exosomal PD-L1 (exoPD-L1), increasing the composition and functional complications of the PD-1/PD-L1 signaling pathway. For example, sPD-1 has been shown to block the PD-1/PD-L immunosuppressive pathway by binding to PD-L1 and PD-L2, whereas the role of sPD-L1 and its mechanism of action in cancer remain unclear. In addition, many studies have investigated the roles of exoPD-L1 in immunosuppression, as a biomarker for tumor progression and as a predictive biomarker for response to immunotherapy. This review describes the molecular mechanisms underlying the generation of sPD-1/sPD-L1 and exoPD-L1, along with their biological activities and methods of detection. In addition, this review discusses the clinical importance of sPD-1/sPD-L1 and exoPD-L1 in cancer, including their predictive and prognostic roles and the effects of treatments that target these molecules.

Tislelizumab for Relapsed/Refractory Classical Hodgkin Lymphoma: 3-Year Follow-up and Correlative Biomarker Analysis

PURPOSE

Tislelizumab is an anti-programmed cell death protein 1 (anti-PD-1) monoclonal antibody specifically designed to minimize binding to Fcγ receptors (FcγR).

PATIENTS AND METHODS

Here, we present the extended 3-year follow-up of a phase II study of tislelizumab in 70 patients with relapsed/refractory classical Hodgkin lymphoma (cHL) who failed or were ineligible for autologous stem cell transplantation.

RESULTS

With a median follow-up of 33.8 months, the overall response rate by the independent review committee was 87.1%, and the complete response (CR) rate was 67.1%. Responses were durable as shown by a median duration of response of 31.3 months, and median progression-free survival (PFS) of 31.5 months. The 3-year PFS and overall survival rates were 40.8% and 84.8%, respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 97.1% of patients; the grade ≥3 TRAE rate was low (31.4%), and only 8.6% of patients experienced adverse events leading to treatment discontinuation. Correlative biomarker analysis showed that FcγRΙ-expressing macrophages had no observed impact on either the CR rate or PFS achieved with tislelizumab, which may be potentially related to its engineered Fc region.

CONCLUSIONS

With extended follow-up, tislelizumab yielded long-term benefits and demonstrated a favorable safety profile for patients with relapsed/refractory cHL. This trial was registered at clinicaltrials.gov as NCT03209973.

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.

Diminished Efficacy of Programmed Death-(Ligand)1 Inhibition in STK11- and KEAP1-Mutant Lung Adenocarcinoma Is Affected by KRAS Mutation Status

INTRODUCTION

STK11 and KEAP1 mutations (STK11 mutant [STK11MUT] and KEAP1MUT) are among the most often mutated genes in lung adenocarcinoma (LUAD). Although STK11MUT has been associated with resistance to programmed death-(ligand)1 (PD-[L]1) inhibition in KRASMUT LUAD, its impact on immunotherapy efficacy in KRAS wild-type (KRASWT) LUAD is currently unknown. Whether KEAP1MUT differentially affects outcomes to PD-(L)1 inhibition in KRASMUT and KRASWT LUAD is also unknown.

METHODS

Clinicopathologic and genomic data were collected from September 2013 to September 2020 from patients with advanced LUAD at the Dana-Farber Cancer Institute/Massachusetts General Hospital cohort and the Memorial Sloan Kettering Cancer Center/MD Anderson Cancer Center cohort. Clinical outcomes to PD-(L)1 inhibition were analyzed according to KRAS, STK11, and KEAP1 mutation status in two independent cohorts. The Cancer Genome Atlas transcriptomic data were interrogated to identify differences in tumor gene expression and tumor immune cell subsets, respectively, according to KRAS/STK11 and KRAS/KEAP1 comutation status.

RESULTS

In the combined cohort (Dana-Farber Cancer Institute/Massachusetts General Hospital + Memorial Sloan Kettering Cancer Center/MD Anderson Cancer Center) of 1261 patients (median age = 61 y [range: 22-92], 708 women [56.1%], 1065 smokers [84.4%]), KRAS mutations were detected in 536 cases (42.5%), and deleterious STK11 and KEAP1 mutations were found in 20.6% (260 of 1261) and 19.2% (231 of 1202) of assessable cases, respectively. In each independent cohort and in the combined cohort, STK11 and KEAP1 mutations were associated with significantly worse progression-free (STK11 hazard ratio [HR] = 2.04, p < 0.0001; KEAP1 HR = 2.05, p < 0.0001) and overall (STK11 HR = 2.09, p < 0.0001; KEAP1 HR = 2.24, p < 0.0001) survival to immunotherapy uniquely among KRASMUT but not KRASWT LUADs. Gene expression ontology and immune cell enrichment analyses revealed that the presence of STK11 or KEAP1 mutations results in distinct immunophenotypes in KRASMUT, but not in KRASWT, lung cancers.

CONCLUSIONS

STK11 and KEAP1 mutations confer worse outcomes to immunotherapy among patients with KRASMUT but not among KRASWT LUAD. Tumors harboring concurrent KRAS/STK11 and KRAS/KEAP1 mutations display distinct immune profiles in terms of gene expression and immune cell infiltration.

Immune Checkpoint Blockade for the Treatment of Hodgkin Lymphoma

Classical Hodgkin lymphoma is biologically different than other lymphomas. The cancer cells only occupy a small amount of the lymph node and evade the immune system by amplification of PD-L1 and PD-L2. Therefore, checkpoint inhibitors are a logical treatment option for Hodgkin lymphoma patients to unlock the immune system. Checkpoint inhibitors have shown high response rates in clinical trials in advanced-stage Hodgkin lymphoma. The two most commonly used checkpoint inhibitors are pembrolizumab and nivolumab, both FDA approved as third-line therapy. There is increasing interest in the use of checkpoint inhibitors with combination chemotherapy or with other targeted agents in the second-line or even frontline setting. In this review, we will highlight the clinical trials that led to approvals of checkpoint inhibitors for Hodgkin lymphoma.

Amateur antigen-presenting cells in the tumor microenvironment

Presentation of tumor antigens is a critical step in producing a robust antitumor immune response. Classically tumor antigens are thought to be presented to both CD8 and CD4 T cells by professional antigen-presenting cells (pAPCs) like dendritic cells using major histocompatibility complexes (MHC) I and II. But recent evidence suggests that in the tumor microenvironment (TME) cells other than pAPCs are capable of presenting tumor antigens on both MHC I and II. The evidence currently available on tumor antigen presentation by epithelial cells, vascular endothelial cells (VECs), fibroblasts, and cancer cells is reviewed herein. We refer to these cell types in the TME as "amateur" APCs (aAPCs). These aAPCs greatly outnumber pAPCs in the TME and could, potentially, play a significant role in priming an antitumor immune response. This new evidence supports a different perspective on antigen presentation and suggests new approaches that can be taken in designing immunotherapies to increase T cell priming.

CD4+ T cells in classical Hodgkin lymphoma express exhaustion associated transcription factors TOX and TOX2

In classical Hodgkin lymphoma (cHL), the highly abundant CD4+ T cells in the vicinity of tumor cells are considered essential for tumor cell survival, but are ill-defined. Although they are activated, they consistently lack expression of activation marker CD26. In this study, we compared sorted CD4+CD26- and CD4+CD26+ T cells from cHL lymph node cell suspensions by RNA sequencing and T cell receptor variable gene segment usage analysis. This revealed that although CD4+CD26- T cells are antigen experienced, they have not clonally expanded. This may well be explained by the expression of exhaustion associated transcription factors TOX and TOX2, immune checkpoints PDCD1 and CD200, and chemokine CXCL13, which were amongst the 100 significantly enriched genes in comparison with the CD4+CD26+ T cells. Findings were validated in single-cell RNA sequencing data from an independent cohort. Interestingly, immunohistochemistry revealed predominant and high frequency of staining for TOX and TOX2 in the T cells attached to the tumor cells. In conclusion, the dominant CD4+CD26- T cell population in cHL is antigen experienced, polyclonal, and exhausted. This population is likely a main contributor to the very high response rates to immune checkpoint inhibitors in cHL.

CD74 and HLA-DRA in Cervical Carcinogenesis: Potential Targets for Antitumour Therapy

Background and Objectives: Abnormal expressions of CD74 and human leukocyte antigen-DR alpha (HLA-DRA) have been reported in various cancers, though their roles in cervical cancer remain unclear. This study aimed to evaluate the gene and protein expressions of CD74 and HLA-DRA in the progression from normal cervix to precancerous cervical intraepithelial neoplasia (CIN) and finally to squamous cell carcinoma (SCC). Materials and Methods: The gene expression profiles of CD74 and HLA-DRA were determined in formalin-fixed paraffin-embedded tissues, with three samples each from normal cervixes, human papillomavirus type 16/18-positive, low-grade CIN (LGCIN), high-grade CIN (HGCIN), and squamous cell carcinoma (SCC) using Human Transcriptome Array 2.0. Immunohistochemical expression of the proteins was semi-quantitatively assessed in another cohort of tissue microarray samples comprising 7 normal cervix cases, 10 LGCIN, 10 HGCIN, and 95 SCC. Results: The transcriptomics profile and proteins’ expression demonstrated similar trends of upregulation of CD74 and HLA-DRA from normal cervix to CIN and highest in SCC. There was a significant difference in both proteins’ expression between the histological groups (p = 0.0001). CD74 and HLA-DRA expressions were significantly associated with CIN grade (p = 0.001 and p = 0.030, respectively) but not with the subjects’ age or SCC stage. Further analysis revealed a positive correlation between CD74 and HLA-DRA proteins. Conclusions: CD74 appears to promote cervical carcinogenesis via oncogenic signalling mechanisms and may serve as a potential antitumour target. Additionally, the upregulation of HLA-DRA, often associated with stronger immunogenicity, could be a promising biomarker for developing immunotherapies.

What Happens to the Immune Microenvironment After PD-1 Inhibitor Therapy?

The fruitful results of tumor immunotherapy establish its indispensable status in the regulation of the tumorous immune context. It seems that the treatment of programmed cell death receptor 1 (PD-1) blockade is one of the most promising approaches for cancer control. The significant efficacy of PD-1 inhibitor therapy has been made in several cancer types, such as breast cancer, lung cancer, and multiple myeloma. Even so, the mechanisms of how anti-PD-1 therapy takes effect by impacting the immune microenvironment and how partial patients acquire the resistance to PD-1 blockade have yet to be studied. In this review, we discuss the cross talk between immune cells and how they promote PD-1 blockade efficacy. In addition, we also depict factors that may underlie tumor resistance to PD-1 blockade and feasible solutions in combination with it.

Lymphocyte HLA-DR/CD-38 co-expression correlates with Hodgkin lymphoma cell cytotoxicity in vitro independent of PD-1/PD1-L pathway

The interactions between Hodgkin and Reed Sternberg cells and tumor microenvironment, the changes that occur with therapy and, in particular, checkpoint inhibition are not fully understood. Understanding these is key to optimizing outcomes for patients with Hodgkin lymphoma (HL). We evaluated the immunophenotypic characteristics of cytotoxic, helper T and NK lymphocytes upon in vitro stimulation, cell-mediated cytotoxicity against HL cells, HDLM-2 and KM-H2, and the association with effector cell activation state, as well as changes in cytotoxicity following PD-1 or PDL-1 blockade. Higher HLA-DR/CD38 expression on effector cells was associated with increased cytotoxicity against HL cells. All effector cell types were cytotoxic of HL cells, though achieved maximum activation and cytotoxicity at variable timepoints. HLA-DR/CD38 co-expression correlated with cytotoxicity, but PD-1 expression did not. There was no significant change in cell-mediated cytotoxicity following PD-1/PDL-1 blockade. The mechanism of action of checkpoint inhibitors may not be limited to direct PD-1/PDL-1 blockade.

Harnessing Antitumor CD4+ T Cells for Cancer Immunotherapy

Simple Summary

Diverse evidence revealed that CD4⁺ T cells play an important role in antitumor immunity by promoting or suppressing cytotoxic T cell responses. This review outlines the role of CD4⁺ T subsets within the tumor microenvironment and summarizes the latest progress regarding their potentials in cancer immunotherapy and methods for improving outcomes in cancer strategies by modulating CD4⁺ T responses.

Abstract

Over the past decades, CD4⁺ T cells have been considered as a supporting actor in the fields of cancer immunotherapy. Until recently, accumulating evidence has demonstrated the critical role of CD4⁺ T cells during antitumor immunity. CD4⁺ T cells can either suppress or promote the antitumor cytotoxic CD8⁺ T cell responses, either in secondary lymphoid organs or in the tumor. In this review, we provide an overview of the multifaceted role of different CD4⁺ T cell subsets in cancer immune response and their contribution during cancer therapies. Specifically, we focus on the latest progress regarding the impact of CD4⁺ T cell modulation on immunotherapies and other cancer therapies and discuss the prospect for harnessing CD4⁺ T cells to control tumor progression and prevent recurrence in patients.

High efficacy of PD-1 inhibitor after initial failure of PD-L1 inhibitor in Relapsed/Refractory classical Hodgkin Lymphoma

PURPOSE

We sought to understand the clinical course and molecular phenotype of patients who showed disease progression after programmed cell death ligand 1 (PD-L1) inhibitor treatment but subsequently responded to PD-1 inhibitor treatment. We also explored the response to PD-1-axis targeted therapy of classical Hodgkin lymphoma (cHL) according to genetically driven PD-L1 and programmed cell death ligand 2 (PD-L2) expression.

METHODS

Five patients in a phase II clinical trial of CS1001 (PD-L1 inhibitor) for relapsed or refractory (R/R) cHL were retrospectively reviewed. Formalin-fixed, paraffin-embedded whole tissues from the five patients were evaluated for 9p24.1 genetic alterations based on FISH and the expression of PD-L1, PD-L2, PD-1, major histocompatibility complex (MHC) class I-II, and the tumor microenvironment factorsCD163 and FOXP3 in the microenvironmental niche, as revealed by multiplex immunofluorescence.

RESULTS

All five patients showed primary refractory disease during first-line treatment. Four patients received PD-1 inhibitor after dropping out of the clinical trial, and all demonstrated at least a partial response. The progression-free survival ranged from 7 to 28 months (median = 18 months), and 9p24.1 amplification was observed in all five patients at the PD-L1/PD-L2 locus. PD-L1 and PD-L2 were colocalized on Hodgkin Reed-Sternberg (HRS) cells in four of the five (80%) patients. There was differential expression of PD-L1 and PD-L2 in cells in the tumor microenvironment in cHL, especially in HRS cells, background cells and tumor-associated macrophages.

CONCLUSIONS

PD-L1 monotherapy may not be sufficient to block the PD-1 pathway; PD-L2 was expressed in HRS and background cells in cHL. The immunologic function of the PD-L2 pathway in anti-tumor activity may be underestimated in R/R cHL. Further study is needed to elucidate the anti-tumor mechanism of PD-1 inhibitor and PD-L1 inhibitor treatment.

Circulating Tumor DNA in Lymphoma: Principles and Future Directions

Lymphomas are heterogeneous tumors with striking genetic diversity and variable outcomes even within pathologic diagnoses. Treatment response assessment relies on radiologic and nuclear scans, which cannot detect disease at the molecular level. Molecular tumor analyses require invasive tissue biopsies that cannot accurately capture spatial tumor heterogeneity within each patient. Circulating tumor DNA (ctDNA) is a minimally invasive and highly versatile biomarker that overcomes fundamental limitations of imaging scans and tissue biopsies and may aid clinical decision-making in lymphoma. In this review, we highlight the key established principles regarding ctDNA in lymphoma and emphasize the important research questions and future directions. SIGNIFICANCE: ctDNA is an emerging biomarker for lymphomas that noninvasively provides genotypic information and can measure the effectiveness of treatment by detecting the presence of minimal residual disease. Key principles have emerged related to ctDNA for lymphoma, but further studies are needed to standardize its use and establish clinical utility.

Immune Reconstitution following High-Dose Chemotherapy and Autologous Stem Cell Transplantation with or without Pembrolizumab Maintenance Therapy in Patients with Lymphoma

Autologous stem cell transplantation (ASCT) is a standard of care for patients with chemosensitive, relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) and diffuse large B cell lymphoma (DLBCL). Whereas the clinical benefit of ASCT has traditionally been attributed solely to cytoreduction from intensive chemotherapy, ASCT has important immunogenic effects that may contribute to its antitumor efficacy and could provide a favorable immune environment for post-ASCT immune-based maintenance treatments. We previously reported clinical results of a phase II trial (ClinicalTrials.gov identifier NCT02362997) testing 8 doses of pembrolizumab maintenance therapy after ASCT for patients with R/R cHL or DLBCL. To clarify the impact of pembrolizumab on immune reconstitution, we compared the kinetics of peripheral blood immune cell recovery after ASCT for trial patients receiving pembrolizumab maintenance to those of a contemporaneous control cohort of similar patients undergoing ASCT without pembrolizumab maintenance. This study was conducted to characterize the impact of post-ASCT pembrolizumab maintenance therapy on immune reconstitution for patients with R/R DLBCL and cHL and to identify candidate biomarkers of efficacy and immune-related adverse events (irAEs). Peripheral blood (PB) mononuclear cell samples were prospectively collected at 1 to 18 months after ASCT and analyzed by flow cytometry using a panel of fluorophore-conjugated monoclonal antibodies to identify B cells, natural killer (NK) cells, and various dendritic cell (DC) and T cell subsets. A median of 5 (range, 1 to 8) post-ASCT PB samples were collected from 144 patients (59 in the pembrolizumab group and 85 in the control group). Clinical characteristics of the 2 cohorts were similar. Compared with cHL patients, DLBCL patients (all of whom received anti-CD20 monoclonal antibody therapy before ASCT) had delayed CD19⁺ cell reconstitution that persisted for at least 18 months after ASCT. No other differences in immune reconstitution based on lymphoma subtype were observed. Post-ASCT pembrolizumab maintenance therapy was associated with an elevation in circulating DCs (driven by higher levels of plasmacytoid and immature DCs) that persisted for the duration of pembrolizumab treatment, along with a significant reduction in PD-1⁺ T cells that persisted for 6 to 12 months after completion of pembrolizumab therapy. Despite the key role of T cells in mediating the effects of PD-1 blockade, pembrolizumab maintenance did not affect recovery of any T cell subsets. In an exploratory analysis, a higher baseline CD4⁺ terminal effector memory cell count (defined as CD3⁺CD4⁺CD45RA⁺CD62L^-) was associated with inferior progression-free survival (PFS), but only among patients who received pembrolizumab maintenance (P = .003). As continuous variables, lower absolute levels of NK cells (P = .009), PD-1⁺ CD4⁺ T cells (P = .005), and PD-1⁺ CD8⁺ T cells (P = .005) before pembrolizumab initiation were each associated with a higher risk of grade 2+ irAEs. Our findings indicate that post-ACST pembrolizumab maintenance therapy is associated with a persistent elevation of circulating DCs, but its impact on the reconstitution of other immune cells in peripheral blood appears limited. Our study suggests that early features of post-ASCT immune reconstitution could be associated with PFS and the risk of irAE and warrant additional investigation. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

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.

Significance of trogocytosis and exosome-mediated transport in establishing and maintaining the tumor microenvironment in lymphoid malignancies

It is widely accepted that the tumor microenvironment plays an important role in the progression of lymphoid malignancies. Interaction between the tumor and its surrounding immune cells is considered a potential therapeutic target. For example, anti-programmed cell death 1 (PD-1) antibody stimulates the surrounding exhausted immune cells to release PD-1/PD-L1, thereby leading to the regression of PD-L1-positive tumors. Recently, biological phenomena, such as trogocytosis and exosome-mediated transport were demonstrated to be involved in establishing and maintaining the tumor microenvironment. We found that trogocytosis-mediated PD-L1/L2 transfer from tumor cells to monocytes/macrophages is involved in immune dysfunction in classic Hodgkin lymphoma. Exosomes derived from Epstein-Barr virus (EBV)-associated lymphoma cells induce lymphoma tumorigenesis by transferring the EBV-coding microRNAs from the infected cells to macrophages. In this review, we summarized these biological phenomena based on our findings.

Combined Identification of Novel Markers for Diagnosis and Prognostic of Classic Hodgkin Lymphoma

BACKGROUND

An effective diagnostic and prognostic marker based on the gene expression profile of classic Hodgkin lymphoma (cHL) has not yet been developed. The aim of the present study was to investigate potential markers for the diagnosis and prediction of cHL prognosis.

METHODS

The gene expression profiles with all available clinical features were downloaded from the Gene Expression Omnibus (GEO) database. Then, multiple machine learning algorithms were applied to develop and validate a diagnostic signature by comparing cHL with normal control. In addition, we identified prognostic genes and built a prognostic model with them to predict the prognosis for 130 patients with cHL which were treated with first-line treatment (ABVD chemotherapy or an ABVD-like regimen).

RESULTS

A diagnostic prediction signature was constructed and showed high specificity and sensitivity (training cohort: AUC=0.981,95% CI 0.933-0.998, P<0.001, validation cohort: AUC=0.955,95% CI 0.895-0.986, P<0.001). Additionally, nine prognostic genes (LAMP1, STAT1, MMP9, C1QB, ICAM1, CD274, CCL19, HCK and LILRB2) were screened and a prognostic prediction model was constructed with them, which had been confirmed effectively predicting prognosis (P<0.001). Furthermore, the results of the immune infiltration assessment indicated that the high scale of the fraction of CD8 + T cells, M1 macrophages, resting mast cells associated with an adverse outcome in cHL, and naive B cells related to prolonged survival. In addition, a nomogram that combined the prognostic prediction model and clinical characteristics is also suggested to have a good predictive value for the prognosis of patients.

CONCLUSION

The new markers found in this study may be helpful for the diagnosis and prediction of the prognosis of cHL.

Immunology 101: fundamental immunology for the practicing hematologist

From an evolutionary perspective, the immune system developed primarily to protect the host from pathogens. In the continuous balance between killing pathogens and protecting host tissues, selective pressures have shaped the discriminatory functions of the immune system. In addition to protection against microbial pathogens, the immune system also plays a critical role in antitumor immunity. Immune dysfunction, either under- or overactivity, is found in a wide range of hematologic disorders. Here we review the fundamental features of the immune system and the key concepts critical to understanding the impact of immune dysfunction on hematologic disorders.

Body mass index is not associated with survival outcomes and immune-related adverse events in patients with Hodgkin lymphoma treated with the immune checkpoint inhibitor nivolumab

Background

Overweight and obese patients with solid tumors receiving anti-programmed cell death-1 (PD-1)/PD-ligand-1(PD-L1) immune checkpoint inhibitors exhibit improved survival and higher risk of immune-related adverse events (irAEs) than those with a normal body mass index (BMI). In classic Hodgkin lymphoma (cHL), the impact of BMI on survival and immune-related toxicity is unknown. We evaluated for the first time associations of BMI with survival and irAEs in patients with relapsed/refractory (RR)-cHL undergoing PD-1 blockade.

Methods

Data from a multicenter study on 133 patients treated with the anti-PD1 antibody nivolumab (July 2015–December 2016) were retrieved from a prospective database. Progression-free (PFS), overall survival (OS), incidence and severity of irAEs according to BMI categories were estimated by Kaplan–Meier method, landmark-analyses and Cox regressions.

Results

Patients, mostly males (63%, n = 84) with a median age of 35 years (range, 15–82), advanced stage (75%), B symptoms (63%), bulky disease (24%), a median of 4 previous treatments (range, 1–9), received a median of 18 nivolumab doses (range, 1–57). No statistically significant differences across BMI subgroups emerged as to PFS, with 1-year rates of 67.1% for both normal weight (n = 66; 49.6%) and overweight (n = 31; 23.3%) patients. Underweight (n = 12; 9%) and obese (n = 24; 18%) patients had a 1-year PFS of 54.5% and 49%, respectively. In survival analyses, BMI either as a continuous (P = 0.5) or categorical (P for trend = 0.63) variable failed to associate with PFS. Response rates and time-to-response did not cluster in any BMI subset. No BMI-related differences in OS emerged across normal, overweight and obese patients but underweight patients had the worst survival. Occurrence of irAEs of whatever severity did not statistically associate with BMI.

Conclusions

In patients with RR-cHL receiving nivolumab, no statistically significant differences emerged in response rates, PFS and OS across BMI categories of normal weight, overweight and obese. Overweight/obese patients did not display an increased risk of irAEs. The exquisite sensitivity to anti-PD-1 antibodies, the unique cytokine milieu and effector pathways triggered by nivolumab in cHL, may represent biologic ‘equalizers’ counteracting the immunoregulatory effects of adiposity. Differently from solid tumors, BMI is not associated with treatment efficacy and immune-related toxicity and does not represent a predictive tool for PD-1-targeted immunotherapies in cHL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03134-4.

Efficacy, safety, and biomarker analysis of Camrelizumab in Previously Treated Recurrent or Metastatic Nasopharyngeal Carcinoma (CAPTAIN study)

BACKGROUND

This study aimed to evaluate the antitumor activity of camrelizumab, an antiprogrammed cell death-1 antibody, in pretreated recurrent or metastatic nasopharyngeal carcinoma (NPC) and to explore predictive biomarkers.

METHODS

Patients with recurrent (not amenable to locally curative treatment) or metastatic NPC who had failed at least two lines of chemotherapy were eligible to receive camrelizumab (200 mg intravenously every 2 weeks) for 2 years or until disease progression, intolerable adverse events, withdrawal of consents, or investigator decision. The primary endpoint was objective response rate (ORR) assessed by an independent review committee (IRC). Programmed cell death-ligand 1 (PD-L1) expression was assessed by immunohistochemistry. Other immune-related biomarkers including major histocompatibility complex class I and major histocompatibility complex class II (MHC-II) were assessed by multiplex immunofluorescence staining.

RESULTS

Between August 14, 2018, and December 30, 2019, a total of 156 patients were enrolled. The IRC-assessed ORR was 28.2% (95% CI 21.3% to 36.0%). The median progression-free survival was 3.7 months (95% CI 2.0 to 4.1) per IRC, and the median overall survival was 17.4 months (95% CI 15.2 to 21.9). The ORRs were 35.2% (95% CI 25.3% to 46.1%) vs 19.4% (95% CI 10.4% to 31.4%) in patients with tumor PD-L1 expression of ≥10% and<10%, respectively. Patients with durable clinical benefit (DCB), which was defined as complete response, partial response or stable disease of ≥18 weeks, had higher density of MHC-II+ cell in stroma than patients without DCB (median 868.1 (IQR 413.4-2854.0) cells/mm2 vs median 552.4 (IQR 258.4 to 1242.1) cells/mm2). MHC-II+ cell density did not correlate with PD-L1 expression, and a composite of high stromal MHC-II+ cell density and tumor PD-L1 expression further enriched patients who could benefit from camrelizumab.

CONCLUSIONS

Camrelizumab had clinically meaningful antitumor activity in patients with recurrent or metastatic NPC. The composition of both MHC-II+ cell density and PD-L1 expression could result in better patient selection.

Dynamic CD4+ T cell heterogeneity defines subset-specific suppression and PD-L1-blockade-driven functional restoration in chronic infection

Inhibiting PD-1:PD-L1 signaling has transformed therapeutic immune restoration. CD4+ T cells sustain immunity in chronic infections and cancer, yet little is known about how PD-1 signaling modulates CD4+ helper T (TH) cell responses or the ability to restore CD4+ TH-mediated immunity by checkpoint blockade. We demonstrate that PD-1:PD-L1 specifically suppressed CD4+ TH1 cell amplification, prevents CD4+ TH1 cytokine production and abolishes CD4+ cytotoxic killing capacity during chronic infection in mice. Inhibiting PD-L1 rapidly restored these functions, while simultaneously amplifying and activating TH1-like T regulatory cells, demonstrating a system-wide CD4-TH1 recalibration. This effect coincided with decreased T cell antigen receptor signaling, and re-directed type I interferon (IFN) signaling networks towards dominant IFN-γ-mediated responses. Mechanistically, PD-L1 blockade specifically targeted defined populations with pre-established, but actively suppressed proliferative potential, with limited impact on minimally cycling TCF-1+ follicular helper T cells, despite high PD-1 expression. Thus, CD4+ T cells require unique differentiation and functional states to be targets of PD-L1-directed suppression and therapeutic restoration.

Post-Transplant Nivolumab Plus Unselected Autologous Lymphocytes in Refractory Hodgkin Lymphoma: A Feasible and Promising Salvage Therapy Associated With Expansion and Maturation of NK Cells

Immune checkpoint inhibitors (CI) have demonstrated clinical activity in Hodgkin Lymphoma (HL) patients relapsing after autologous stem cell transplantation (ASCT), although only 20% complete response (CR) rate was observed. The efficacy of CI is strictly related to the host immune competence, which is impaired in heavily pre-treated HL patients. Here, we aimed to enhance the activity of early post-ASCT CI (nivolumab) administration with the infusion of autologous lymphocytes (ALI). Twelve patients with relapse/refractory (R/R) HL (median age 28.5 years; range 18-65), underwent lymphocyte apheresis after first line chemotherapy and then proceeded to salvage therapy. Subsequently, 9 patients with progressive disease at ASCT received early post-transplant CI supported with four ALI, whereas 3 responding patients received ALI alone, as a control cohort. No severe adverse events were recorded. HL-treated patients achieved negative PET scan CR and 8 are alive and disease-free after a median follow-up of 28 months. Four patients underwent subsequent allogeneic SCT. Phenotypic analysis of circulating cells showed a faster expansion of highly differentiated NK cells in ALI plus nivolumab-treated patients as compared to control patients. Our data show anti-tumor activity with good tolerability of ALI + CI for R/R HL and suggest that this setting may accelerate NK cell development/maturation and favor the expansion of the “adaptive” NK cell compartment in patients with HCMV seropositivity, in the absence of HCMV reactivation.

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.

Classical Hodgkin lymphoma

Classical Hodgkin lymphoma is one of the more frequent lymphomas and is generally considered a highly curable disease with standard first-line chemotherapy and radiotherapy in some cases. Despite these outstanding results, major problems remain unresolved. First, there are still patients who will not be cured with front-line regimens and, second, many patients who are cured of classical Hodgkin lymphoma continue to die prematurely due to the late toxic effects of their therapy. Because the median age of patients with classical Hodgkin lymphoma is in the mid-30s, the disease's impact on the number of years lost from productive life is remarkable. In recent years, the gold standard of chemotherapy (often combined with radiotherapy) has changed, with the approval of immunotherapy mostly in relapse settings.

Single-cell profiling reveals the importance of CXCL13/CXCR5 axis biology in lymphocyte-rich classic Hodgkin lymphoma

Lymphocyte-rich classic Hodgkin lymphoma (LR-CHL) is a rare subtype of Hodgkin lymphoma. Recent technical advances have allowed for the characterization of specific cross-talk mechanisms between malignant Hodgkin Reed-Sternberg (HRS) cells and different normal immune cells in the tumor microenvironment (TME) of CHL. However, the TME of LR-CHL has not yet been characterized at single-cell resolution. Here, using single-cell RNA sequencing (scRNA-seq), we examined the immune cell profile of 8 cell suspension samples of LR-CHL in comparison to 20 samples of the mixed cellularity (MC, 9 cases) and nodular sclerosis (NS, 11 cases) subtypes of CHL, as well as 5 reactive lymph node controls. We also performed multicolor immunofluorescence (MC-IF) on tissue microarrays from the same patients and an independent validation cohort of 31 pretreatment LR-CHL samples. ScRNA-seq analysis identified a unique CD4⁺ helper T cell subset in LR-CHL characterized by high expression of Chemokine C-X-C motif ligand 13 (CXCL13) and PD-1. PD-1⁺CXCL13⁺ T cells were significantly enriched in LR-CHL compared to other CHL subtypes, and spatial analyses revealed that in 46% of the LR-CHL cases these cells formed rosettes surrounding HRS cells. MC-IF analysis revealed CXCR5⁺ normal B cells in close proximity to CXCL13⁺ T cells at significantly higher levels in LR-CHL. Moreover, the abundance of PD-1⁺CXCL13⁺ T cells in the TME was significantly associated with shorter progression-free survival in LR-CHL (P = 0.032). Taken together, our findings strongly suggest the pathogenic importance of the CXCL13/CXCR5 axis and PD-1⁺CXCL13⁺ T cells as a treatment target in LR-CHL.

Emerging Landscape of Immunotherapy for Primary Central Nervous System Lymphoma

Simple Summary

Primary central nervous system lymphoma (PCNSL) is characterized by its location in the central nervous system comprising the brain, the eye, the cerebrospinal fluid and the spinal cord and a poor prognosis with the current chemotherapies. Immunotherapies represent a new paradigm in the care of patients with B-cell lymphoma, but, till recently, immunotherapies studies excluded patients with PCNSL because of the lack of knowledge on the immune network in the brain. Recent studies shed a new light on the origin and characteristics of the CNS immune cells. We review the current experimental preclinical and clinical developments of immunotherapies in CNS lymphoma as well as the effects of targeted therapies on the brain microenvironment. We provide perspectives for improving the efficacy of immunotherapies in the specific setting of PCNSL for a better prognosis of this disease.

Abstract

Primary central nervous system lymphoma (PCNSL) is, mainly, a diffuse large B-cell lymphoma (DLBCL) with a non-germinal center B-cell (non-GCB) origin. It is associated with a poor prognosis and an unmet medical need. Immunotherapy has emerged as one of the most promising areas of research and is now part of the standard treatment for many solid and hematologic tumors. This new class of therapy generated great enthusiasm for the treatment of relapsed/refractory PCNSL. Here, we discuss the challenges of immunotherapy for PCNSL represented by the lymphoma cell itself and the specific immune brain microenvironment. We review the current clinical development from the anti-CD20 monoclonal antibody to CAR-T cells, as well as immune checkpoint inhibitors and targeted therapies with off-tumor effects on the brain microenvironment. Perspectives for improving the efficacy of immunotherapies and optimizing their therapeutic role in PCNSL are suggested.

Tumor-Specific Major Histocompatibility-II Expression Predicts Benefit to Anti-PD-1/L1 Therapy in Patients With HER2-Negative Primary Breast Cancer

PURPOSE

Immunotherapies targeting PD-1/L1 enhance pathologic complete response (pCR) rates when added to standard neoadjuvant chemotherapy (NAC) regimens in early-stage triple-negative, and possibly high-risk estrogen receptor-positive breast cancer. However, immunotherapy has been associated with significant toxicity, and most patients treated with NAC do not require immunotherapy to achieve pCR. Biomarkers discerning patients benefitting from the addition of immunotherapy from those who would achieve pCR to NAC alone are clearly needed. In this study, we tested the ability of MHC-II expression on tumor cells, to predict immunotherapy-specific benefit in the neoadjuvant breast cancer setting.

PATIENTS AND METHODS

This was a retrospective tissue-based analysis of 3 cohorts of patients with breast cancer: (i) primary nonimmunotherapy-treated breast cancers (n = 381), (ii) triple-negative breast cancers (TNBC) treated with durvalumab and standard NAC (n = 48), and (iii) HER2-negative patients treated with standard NAC (n = 87) or NAC and pembrolizumab (n = 66).

RESULTS

HLA-DR positivity on ≥5% of tumor cells, defined a priori, was observed in 10% and 15% of primary non-immunotherapy-treated hormone receptor-positive and triple-negative breast cancers, respectively. Quantitative assessment of MHC-II on tumor cells was predictive of durvalumab + NAC and pembrolizumab + NAC (ROC AUC, 0.71; P = 0.01 and AUC, 0.73; P = 0.001, respectively), but not NAC alone (AUC, 0.5; P = 0.99).

CONCLUSIONS

Tumor-specific MHC-II has a strong candidacy as a specific biomarker of anti-PD-1/L1 immunotherapy benefit when added to standard NAC in HER2-negative breast cancer. Combined with previous studies in melanoma, MHC-II has the potential to be a pan-cancer biomarker. Validation is warranted in existing and future phase II/III clinical trials in this setting.

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.

9p24.1 alterations and programmed cell death 1 ligand 1 expression in early stage unfavourable classical Hodgkin lymphoma: an analysis from the German Hodgkin Study Group NIVAHL trial

High programmed cell death 1 ligand 1 (PD-L1) protein expression and copy number alterations (CNAs) of the corresponding genomic locus 9p24.1 in Hodgkin- and Reed-Sternberg cells (HRSC) have been shown to be associated with favourable response to anti-PD-1 checkpoint inhibition in relapsed/refractory (r/r) classical Hodgkin lymphoma (cHL). In the present study, we investigated baseline 9p24.1 status as well as PD-L1 and major histocompatibility complex (MHC) class I and II protein expression in 82 biopsies from patients with early stage unfavourable cHL treated with anti-PD-1-based first-line treatment in the German Hodgkin Study Group (GHSG) NIVAHL trial (ClinicalTrials.gov Identifier: NCT03004833). All evaluated specimens showed 9p24.1 CNA in HRSC to some extent, but with high intratumoral heterogeneity and an overall smaller range of alterations than reported in advanced-stage or r/r cHL. All but two cases (97%) showed PD-L1 expression by the tumour cells in variable amounts. While MHC-I was rarely expressed in >50% of HRSC, MHC-II expression in >50% of HRSC was found more frequently. No obvious impact of 9p24.1 CNA or PD-L1 and MHC-I/II expression on early response to the highly effective anti-PD-1-based NIVAHL first-line treatment was observed. Further studies evaluating an expanded panel of potential biomarkers are needed to optimally stratify anti-PD-1 first-line cHL treatment.

PCR-Free Shallow Whole Genome Sequencing for Chromosomal Copy Number Detection from Plasma of Cancer Patients Is an Efficient Alternative to the Conventional PCR-Based Approach

Somatic copy number alterations can be detected in cell-free DNA (cfDNA) by shallow whole genome sequencing (sWGS). PCR is typically included in library preparations, but a PCR-free method could serve as a high-throughput alternative. To evaluate a PCR-free method for research and diagnostics, archival peripheral blood or bone marrow plasma samples, collected in EDTA- or lithium-heparin-containing tubes, were collected from patients with non-small-cell lung cancer (n = 10 longitudinal samples; 4 patients), B-cell lymphoma (n = 31), and acute myeloid leukemia (n = 15), or from healthy donors (n = 14). sWGS was performed on PCR-free and PCR library preparations, and the mapping quality, percentage of unique reads, genome coverage, fragment lengths, and copy number profiles were compared. The percentage of unique reads was significantly higher for PCR-free method compared with PCR method, independent of the type of collection tube: EDTA PCR-free method, 96.4% (n = 35); EDTA PCR method, 85.1% (n = 32); heparin PCR-free method, 94.5% (n = 25); and heparin PCR method, 89.4% (n = 10). All other evaluated metrics were highly comparable for PCR-free and PCR library preparations. These results demonstrate the feasibility of somatic copy number alteration detection by PCR-free sWGS using cfDNA from plasma collected in EDTA- or lithium-heparin-containing tubes and pave the way for an automated cfDNA analysis workflow for samples from cancer patients.

Pembrolizumab in the treatment of refractory primary mediastinal large B-cell lymphoma: safety and efficacy

Introduction: Primary mediastinal large B-cell lymphoma (PMBL) is a rare subtype of lymphoma, clinically and biologically distinct from diffuse large B-cell lymphoma (DLBCL) that shows overlapping features with classical Hodgkin lymphoma (cHL). If first-line strategies lead to 80-85% of curability, relapse occurs early with a chemo-refractory disease and a poor outcome. The presence of 9p24.1 rearrangement, conducting to the overexpression of the immune checkpoint molecules PDL1 and 2, has paved the way for immune checkpoint blockers development in these entities. Pembrolizumab, an anti PD-1 checkpoint antibody, was initially approved in solid cancer and later on in the lymphoma field in cHL.Areas covered: We summarize the biology and clinical need in PMBL, leading to the rationale for checkpoint inhibitors development, as well as pembrolizumab clinical studies in this entity. To do so, we performed a PubMed search using the terms: 'PMBCL,' 'lymphoma,' 'Immune checkpoint,' and 'Pembrolizumab.'Expert opinion: Pembrolizumab showed tolerable safety profile and efficacy data in patients with PMBL who have relapsed after, or are ineligible for autologous stem cell transplant (ASCT). Some combination strategies have shown promising preliminary results, while others are currently being conducted.

EBV-positive B-cell lymphomas and lymphoproliferative disorders: Review from the perspective of immune escape and immunodeficiency

Background

Epstein‐Barr virus (EBV) is detected in a variety of B‐cell lymphomas (BCLs) and B‐cell lymphoproliferative disorders (B‐LPDs). Immunodeficiency has been considered to play a key role in the pathogenesis of these diseases. In addition, immune escape of tumor cells may also contribute to the development of EBV⁺ BCLs and B‐LPDs. The PD‐1/PD‐L1 pathway is particularly important for immune escape of tumor cells that contribute to development of lymphoma through suppression of cytotoxic T‐cell function. We now consider PD‐L1 immunohistochemistry (IHC) a very useful method for predicting whether tumor cells of lymphoid malignancies are characterized by the immune escape mechanism.

Methods

We reviewed articles of EBV⁺ BCLs and B‐LPDs from the perspective of immune escape and immunodeficiency, particularly focusing on PD‐L1 IHC.

Results

Based on PD‐L1 IHC, we consider that EBV⁺ BCL and B‐LPD can be classified into three types: “immunodeficiency”, “immune escape”, and “immunodeficiency + immune escape” type. The immunodeficiency type includes EBV⁺ diffuse large BCL (DLBCL) of the elderly, EBV⁺ sporadic Burkitt lymphoma, EBV⁺ mucocutaneous ulcer, and methotrexate (MTX)‐associated B‐LPD. The immune escape type includes EBV⁺ classic Hodgkin lymphoma (CHL) and EBV⁺ DLBCL of the young. The immunodeficiency + immune escape type includes CHL type MTX‐associated LPD and a minor subset of EBV⁺ DLBCL of the elderly.

Conclusions

Recently, good results have been reported for immune check‐point inhibitors in treating lymphoma. Lymphomas and LPDs characterized by immune escape are regarded as good candidates for PD1/PD‐L1 blockade therapy. Therefore, from both the clinical and pathological perspective, we suggest that lymphoma diagnosis should be made considering immune escape and immunodeficiency.

Human leukocyte antigen class II-based immune risk model for recurrence evaluation in stage I-III small cell lung cancer

Background

Immunotherapy has revolutionized therapeutic patterns of small cell lung cancer (SCLC). Human leukocyte antigen class II (HLA class II) is related to antitumor immunity. However, the implications of HLA class II in SCLC remain incompletely understood.

Materials and methods

We investigated the expression patterns of HLA class II on tumor cells and tumor-infiltrating lymphocytes (TILs) by immunohistochemistry staining and its association with clinical parameters, immune markers, and recurrence-free survival (RFS) in 102 patients with stage I–III SCLC with radical surgery. Additionally, an HLA class II-based immune risk model was established by least absolute shrinkage and selection operator regression. With bioinformatics methods, we investigated HLA class II-related enrichment pathways and immune infiltration landscape in SCLC.

Results

HLA class II on tumor cells and TILs was positively expressed in 9 (8.8%) and 45 (44.1%) patients with SCLC, respectively. HLA class II on TILs was negatively associated with lymph node metastasis and positively correlated with programmed death-ligand 1 (PD-L1) on TILs (p<0.001) and multiple immune markers (CD3, CD4, CD8, FOXP3; p<0.001). Lymph node metastasis (OR 0.314, 95% CI 0.118 to 0.838, p=0.021) and PD-L1 on TILs (OR 3.233, 95% CI 1.051 to 9.95, p=0.041) were independent predictive factors of HLA class II on TILs. HLA class II positivity on TILs prompted a longer RFS (40.2 months, 95% CI 31.7 to 48.7 vs 28.8 months, 95% CI 21.4 to 36.3, p=0.014). HLA class II on TILs, PD-L1 on TILs, CD4, and FOXP3 were enrolled in the immune risk model, which categorized patients into high-risk and low-risk groups and had better power for predicting the recurrence than tumor stage. Pathway enrichment analyses showed that patients with high HLA class II expression demonstrated signatures of transmembrane transportation, channel activity, and neuroactive ligand–receptor interaction. High-risk SCLC patients had a higher proportion of T follicular helper cells (p=0.034) and a lower proportion of activated memory CD4-positive T cells (p=0.040) and resting dendritic cells (p=0.045) versus low-risk patients.

Conclusions

HLA class II plays a crucial role in tumor immune microenvironment and recurrence prediction. This work demonstrates the prognostic and clinical values of HLA class II in patients with SCLC.