Lymphoma: immune evasion strategies

Estimation of the tissue and serum levels of IL-35 in Mycosis fungoides: a case-control study

Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma (CTCL) with its etiology not yet fully understood. Interleukin (IL)-35 is an inhibitory cytokine that belongs to the IL-12 family. Elevated IL-35 in the plasma and the tumor microenvironment increases tumorigenesis and indicates poor prognosis in different types of malignancies. The objective of this study is to estimate the expression levels of IL-35 in tissue and serum of MF patients versus healthy controls. This case-control study included 35 patients with patch, plaque, and tumor MF as well as 30 healthy controls. Patients were fully assessed, and serum samples and lesional skin biopsies were taken prior to starting treatment. The IL-35 levels were measured in both serum and tissue biopsies by ELISA technique. Both tissue and serum IL-35 levels were significantly higher in MF patients than in controls (P < 0.001) and tissue IL-35 was significantly higher than serum IL-35 in MF patients (P < 0.001). Tissue IL-35 was significantly higher in female patients and patients with recurrent MF compared to male patients and those without recurrent disease (P < 0.001). Since both tissue and serum IL-35 levels are increased in MF, IL-35 is suggested to have a possible role in MF pathogenesis. IL-35 can be a useful diagnostic marker for MF. Tissue IL-35 can also be an indicator of disease recurrence.

Immunomodulatory Precision: A Narrative Review Exploring the Critical Role of Immune Checkpoint Inhibitors in Cancer Treatment

An immune checkpoint is a signaling pathway that regulates the recognition of antigens by T-cell receptors (TCRs) during an immune response. These checkpoints play a pivotal role in suppressing excessive immune responses and maintaining immune homeostasis against viral or microbial infections. There are several FDA-approved immune checkpoint inhibitors (ICIs), including ipilimumab, pembrolizumab, and avelumab. These ICIs target cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), and programmed death ligand 1 (PD-L1). Furthermore, ongoing efforts are focused on developing new ICIs with emerging potential. In comparison to conventional treatments, ICIs offer the advantages of reduced side effects and durable responses. There is growing interest in the potential of combining different ICIs with chemotherapy, radiation therapy, or targeted therapies. This article comprehensively reviews the classification, mechanism of action, application, and combination strategies of ICIs in various cancers and discusses their current limitations. Our objective is to contribute to the future development of more effective anticancer drugs targeting immune checkpoints.

Expanding cross-presenting dendritic cells enhances oncolytic virotherapy and is critical for long-term anti-tumor immunity

Immunotherapies directly enhancing anti-tumor CD8⁺ T cell responses have yielded measurable but limited success, highlighting the need for alternatives. Anti-tumor T cell responses critically depend on antigen presenting dendritic cells (DC), and enhancing mobilization, antigen loading and activation of these cells represent an attractive possibility to potentiate T cell based therapies. Here we show that expansion of DCs by Flt3L administration impacts in situ vaccination with oncolytic Newcastle Disease Virus (NDV). Mechanistically, NDV activates DCs and sensitizes them to dying tumor cells through upregulation of dead-cell receptors and synergizes with Flt3L to promote anti-tumor CD8⁺ T cell cross-priming. In vivo, Flt3L-NDV in situ vaccination induces parallel amplification of virus- and tumor-specific T cells, including CD8⁺ T cells reactive to newly-described neoepitopes, promoting long-term tumor control. Cross-presenting conventional Type 1 DCs are indispensable for the anti-tumor, but not anti-viral, T cell response, and type I IFN-dependent CD4⁺ Th1 effector cells contribute to optimal anti-tumor immunity. These data demonstrate that mobilizing DCs to increase tumor antigen cross-presentation improves oncolytic virotherapy and that neoepitope-specific T cells can be induced without individualized, ex vivo manufactured vaccines.

A Hepatitis B Virus Reactivation Case Potentially Triggered by the Onset of Diffuse Large B Cell Lymphoma

An 81-year-old man underwent rituximab-containing chemotherapy for chronic lymphocytic leukemia (CLL). Thirteen years after his last chemotherapy, he was diagnosed with hepatitis B virus (HBV) reactivation. He was then treated with entecavir, and improvement was seen in his liver injury. He developed diffuse large B cell lymphoma (DLBCL) after improvement in his hepatitis. Despite chemotherapy, he contracted the coronavirus disease 2019 (COVID-19) and died of COVID-19. We suspect that HBV reactivation was triggered by DLBCL. When HBV reactivation occurs a long time after chemotherapy has concluded, the onset of DLBCL should be considered.

Reshaping the tumor microenvironment: The versatility of immunomodulatory drugs in B-cell neoplasms

Immunomodulatory drugs (IMiDs) such as thalidomide, lenalidomide and pomalidomide are antitumor compounds that have direct tumoricidal activity and indirect effects mediated by multiple types of immune cells in the tumor microenvironment (TME). IMiDs have shown remarkable therapeutic efficacy in a set of B-cell neoplasms including multiple myeloma, B-cell lymphomas and chronic lymphocytic leukemia. More recently, the advent of immunotherapy has revolutionized the treatment of these B-cell neoplasms. However, the success of immunotherapy is restrained by immunosuppressive signals and dysfunctional immune cells in the TME. Due to the pleiotropic immunobiological properties, IMiDs have shown to generate synergetic effects in preclinical models when combined with monoclonal antibodies, immune checkpoint inhibitors or CAR-T cell therapy, some of which were successfully translated to the clinic and lead to improved responses for both first-line and relapsed/refractory settings. Mechanistically, despite cereblon (CRBN), an E3 ubiquitin ligase, is considered as considered as the major molecular target responsible for the antineoplastic activities of IMiDs, the exact mechanisms of action for IMiDs-based TME re-education remain largely unknown. This review presents an overview of IMiDs in regulation of immune cell function and their utilization in potentiating efficacy of immunotherapies across multiple types of B-cell neoplasms.

Second Primary Malignancies in Patients With Melanoma Subtypes: Analysis of 120,299 Patients From the SEER Database (2000-2016)

Purpose

Evaluate incidence of second primary malignancies (SPM) after non-acral cutaneous melanoma (NACM), acral lentiginous melanoma (ALM), mucosal melanoma (MM), and uveal melanoma (UM).

Patients and Methods

First primary NACM, ALM, MM, and UM cases diagnosed 2000-2016 were extracted from SEER. Seer*Stat was used to calculate excess absolute risks (EAR) and standardized incidence ratios (SIR) of SPMs relative to a matched cohort from the general population. P-value of 0.05 determined significance.

Results

Inclusion criteria was met by 109,385 patients with NACM, 2166 with ALM, 2498 with MM, and 6250 with UM. Increased incidence of malignancies occurred after NACM (SIR 1.51; 95%CI, 1.49-1.54), ALM (SIR 1.59; 95%CI, 1.40-1.81), MM (SIR 2.14; 95%CI, 1.85-2.45), and UM (SIR 1.24; 95%CI, 1.14-1.34) relative to the general population. Cutaneous melanoma occurred more frequently after NACM (SIR 9.54; 95%CI, 9.27-9.83), ALM (SIR 12.19; 95%CI, 9.70-15.14), MM (SIR 10.05; 95%CI, 7.18-13.68), and UM (SIR 2.91; 95%CI, 2.27-3.66). Patients with initial NACM (SIR 2.44; 95%CI, 1.64-3.51) and UM (SIR 44.34; 95%CI, 29.91-63.29) demonstrated increased incidence of eye and orbit melanoma. Renal malignancies occurred more frequently after NACM (SIR 1.24; 95%CI, 1.11-1.38), MM (SIR 3.54; 95%CI, 1.62-6.72) and UM (SIR 1.68; 95%CI, 1.09-2.48). Increased incidence of thyroid malignancies was observed after NACM (SIR 1.83; 95%CI, 1.61-2.06), ALM (SIR 3.74; 95%CI, 1.71-7.11), MM (SIR 4.40; 95%CI, 1.77-9.06), and UM (SIR 3.79; 95%CI, 2.52-5.47). Increased incidence of lymphoma was observed after NACM (SIR 1.20; 95%CI, 1.09-1.31) and ALM (SIR 2.06; 95%CI, 1.13-3.46).

Conclusion

Patients with NACM, ALM, MM, and UM have increased incidence of SPMs compared to that expected from the general population. Each of these melanoma subtypes had increased occurrence of cutaneous melanoma and thyroid cancer; some, but not all, had increased occurrence of renal malignancies, eye and orbit melanoma, and lymphoma.

Molecular Aspects of Resistance to Immunotherapies-Advances in Understanding and Management of Diffuse Large B-Cell Lymphoma

Despite the unquestionable success achieved by rituximab-based regimens in the management of diffuse large B-cell lymphoma (DLBCL), the high incidence of relapsed/refractory disease still remains a challenge. The widespread clinical use of chemo-immunotherapy demonstrated that it invariably leads to the induction of resistance; however, the molecular mechanisms underlying this phenomenon remain unclear. Rituximab-mediated therapeutic effect primarily relies on complement-dependent cytotoxicity and antibody-dependent cell cytotoxicity, and their outcome is often compromised following the development of resistance. Factors involved include inherent genetic characteristics and rituximab-induced changes in effectors cells, the role of ligand/receptor interactions between target and effector cells, and the tumor microenvironment. This review focuses on summarizing the emerging advances in the understanding of the molecular basis responsible for the resistance induced by various forms of immunotherapy used in DLBCL. We outline available models of resistance and delineate solutions that may improve the efficacy of standard therapeutic protocols, which might be essential for the rational design of novel therapeutic regimens.

Epigenetic, Metabolic, and Immune Crosstalk in Germinal-Center-Derived B-Cell Lymphomas: Unveiling New Vulnerabilities for Rational Combination Therapies

B-cell non-Hodgkin lymphomas (B-NHLs) are highly heterogenous by genetic, phenotypic, and clinical appearance. Next-generation sequencing technologies and multi-dimensional data analyses have further refined the way these diseases can be more precisely classified by specific genomic, epigenomic, and transcriptomic characteristics. The molecular and genetic heterogeneity of B-NHLs may contribute to the poor outcome of some of these diseases, suggesting that more personalized precision-medicine approaches are needed for improved therapeutic efficacy. The germinal center (GC) B-cell like diffuse large B-cell lymphomas (GCB-DLBCLs) and follicular lymphomas (FLs) share specific epigenetic programs. These diseases often remain difficult to treat and surprisingly do not respond advanced immunotherapies, despite arising in secondary lymphoid organs at sites of antigen recognition. Epigenetic dysregulation is a hallmark of GCB-DLBCLs and FLs, with gain-of-function (GOF) mutations in the histone methyltransferase EZH2, loss-of-function (LOF) mutations in histone acetyl transferases CREBBP and EP300, and the histone methyltransferase KMT2D representing the most prevalent genetic lesions driving these diseases. These mutations have the common effect to disrupt the interactions between lymphoma cells and the immune microenvironment, via decreased antigen presentation and responsiveness to IFN-γ and CD40 signaling pathways. This indicates that immune evasion is a key step in GC B-cell lymphomagenesis. EZH2 inhibitors are now approved for the treatment of FL and selective HDAC3 inhibitors counteracting the effects of CREBBP LOF mutations are under development. These treatments can help restore the immune control of GCB lymphomas, and may represent optimal candidate agents for more effective combination with immunotherapies. Here, we review recent progress in understanding the impact of mutant chromatin modifiers on immune evasion in GCB lymphomas. We provide new insights on how the epigenetic program of these diseases may be regulated at the level of metabolism, discussing the role of metabolic intermediates as cofactors of epigenetic enzymes. In addition, lymphoma metabolic adaptation can negatively influence the immune microenvironment, further contributing to the development of immune cold tumors, poorly infiltrated by effector immune cells. Based on these findings, we discuss relevant candidate epigenetic/metabolic/immune targets for rational combination therapies to investigate as more effective precision-medicine approaches for GCB lymphomas.

Immunomodulatory Drugs for the Treatment of B Cell Malignancies

Accumulating evidence suggests that the tumor microenvironment (TME) is involved in disease progression and drug resistance in B cell malignancies, by supporting tumor growth and facilitating the ability of malignant cells to avoid immune recognition. Immunomodulatory drugs (IMiDs) such as lenalidomide have some direct anti-tumor activity, but critically also target various cellular compartments of the TME including T cells, NK cells, and stromal cells, which interfere with pro-tumor signaling while activating anti-tumor immune responses. Lenalidomide has delivered favorable clinical outcomes as a single-agent, and in combination therapy leads to durable responses in chronic lymphocytic leukemia (CLL) and several non-Hodgkin lymphomas (NHLs) including follicular lymphoma (FL), diffuse large B cell lymphoma (DLBCL), and mantle cell lymphoma (MCL). Recently, avadomide, a next generation cereblon E3 ligase modulator (CELMoD), has shown potent anti-tumor and TME immunomodulatory effects, as well as promising clinical efficacy in DLBCL. This review describes how the pleiotropic effects of IMiDs and CELMoDs could make them excellent candidates for combination therapy in the immuno-oncology era-a concept supported by preclinical data, as well as the recent approval of lenalidomide in combination with rituximab for the treatment of relapsed/refractory (R/R) FL.

Immune checkpoint inhibitors in the treatment of cancer

BACKGROUND

Immunotherapy drugs, known as immune checkpoint inhibitors (ICIs), work by blocking checkpoint proteins from binding with their partner proteins. The two main pathways that are specifically targeted in clinical practice are cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1) that showed potent immune-modulatory effects through their function as negative regulators of T cell activation.

METHODS

In view of the rapid and extensive development of this research field, we conducted a comprehensive review of the literature and update on the use of CTLA-4, PD-1 and PD-L1 targeted therapy in the treatment of several types of cancer including melanoma, non-small-cell lung carcinoma, breast cancer, hepatocellular carcinoma, hodgkin lymphoma, cervical cancer, head and neck squamous cell carcinoma.

RESULTS

Based on the last updated list released on March 2019, seven ICIs are approved by the FDA including ipilimumab, pembrolizumab, nivolumab, atezolizumab, avelumab, durvalumab, and cemiplimab.

CONCLUSION

This review also highlighted the most common adverse effects caused by ICIs and which affect people in different ways.

Prognostic Impact of Baseline Immunologic Profile in Aggressive B-cell non-Hodgkin's Lymphomas

Host immune homeostasis as an independent prognostic indicator has been inadequately evaluated in aggressive non-Hodgkin's lymphomas (NHL). The present study addresses the prognostic significance in aggressive NHLs of the immunologic profile evaluated by pretreatment serum levels of immunoglobulins (Ig) and lymphocyte-monocyte ratio (LMR). In this series of 90 patients with aggressive lymphoma, the median level for IgG was 1,024mg/dl (range 436-2236), and for LMR was 2.2 (range 0.2-13.8). CR rate was higher with IgG levels ≥1,024mg/dL (91% vs 77% p=0.059). LMR ≤ 2.2 was associated with lower 1-year PFS (73% vs. 92%, p 0.016). Patients with good/very good R-IPI showed a reduced PFS if IgG or LMR was low, while patients with poor R-IPI did better if LMR or IgG levels were high. We combined both parameters with the R-IPI and produced a four-risk prognostic score showing one-year PFS of 95% (95% CI 68%-99%), 100% (95% CI 100%-100%), 73% (95% CI 52%-86%), and 59% (95% CI 31%-79%), in patients with zero, one, two and three risk factors, respectively. The results indicate for the first time the value of baseline serum Ig levels in the prognostic assessment of aggressive lymphoma.

ICOS is widely expressed in cutaneous T-cell lymphoma, and its targeting promotes potent killing of malignant cells

The treatment of advanced-stage cutaneous T-cell lymphoma (CTCL) remains an unmet medical need. Mogamulizumab, anti-KIR3DL2, and brentuximab vedotin (BV), an anti-CD30 antibody-drug conjugate (ADC) coupled with monomethyl-auristatin-E (MMAE), provided encouraging results, but new targeted therapies are needed. Inducible T-cell costimulator (ICOS), a T-cell costimulatory receptor, is a promising therapeutic target, not only because it is expressed by malignant T cells in CTCL but also because of its connection with the suppressive activity of regulatory T (Treg) cells. Immunohistochemical analysis revealed that ICOS was widely expressed by malignant cells in skin biopsy specimens from 52 patients with mycosis fungoides and Sézary syndrome (SS), as well as in involved node biopsy specimens from patients with SS. Furthermore, flow cytometry demonstrated its strong expression by circulating tumor cells in all our patients with SS. Percentages of ICOS+ Treg cells were significantly higher in patients with SS than in healthy donors. We then investigated the preclinical efficacy of anti-ICOS ADCs generated by coupling murine anti-ICOS monoclonal antibodies with MMAE and pyrrolobenzodiazepine. In 3 CTCL cell lines (Myla, MJ, and HUT78), we observed a significant dose-dependent decrease in cell viability in the presence of anti-ICOS ADCs. In addition, anti-ICOS-MMAE ADCs had an in vitro and in vivo efficacy superior to BV in a mouse xenograft model (MyLa). Finally, we assessed the efficacy of anti-ICOS ADCs in ICOS+ patient-derived xenografts from patients with SS and angioimmunoblastic T-cell lymphoma. Collectively, our findings provide the preliminary basis for a therapeutic trial.

Natural Killer Cell Dysfunction and Its Role in COVID-19

When facing an acute viral infection, our immune systems need to function with finite precision to enable the elimination of the pathogen, whilst protecting our bodies from immune-related damage. In many instances however this "perfect balance" is not achieved, factors such as ageing, cancer, autoimmunity and cardiovascular disease all skew the immune response which is then further distorted by viral infection. In SARS-CoV-2, although the vast majority of COVID-19 cases are mild, as of 24 August 2020, over 800,000 people have died, many from the severe inflammatory cytokine release resulting in extreme clinical manifestations such as acute respiratory distress syndrome (ARDS) and hemophagocytic lymphohistiocytosis (HLH). Severe complications are more common in elderly patients and patients with cardiovascular diseases. Natural killer (NK) cells play a critical role in modulating the immune response and in both of these patient groups, NK cell effector functions are blunted. Preliminary studies in COVID-19 patients with severe disease suggests a reduction in NK cell number and function, resulting in decreased clearance of infected and activated cells, and unchecked elevation of tissue-damaging inflammation markers. SARS-CoV-2 infection skews the immune response towards an overwhelmingly inflammatory phenotype. Restoration of NK cell effector functions has the potential to correct the delicate immune balance required to effectively overcome SARS-CoV-2 infection.

New Insights into Diffuse Large B-Cell Lymphoma Pathobiology

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma (NHL), accounting for about 40% of all cases of NHL. Analysis of the tumor microenvironment is an important aspect of the assessment of the progression of DLBCL. In this review article, we analyzed the role of different cellular components of the tumor microenvironment, including mast cells, macrophages, and lymphocytes, in the tumor progression of DLBCL. We examined several approaches to confront the available pieces of evidence, whereby three key points emerged. DLBCL is a disease of malignant B cells spreading and accumulating both at nodal and at extranodal sites. In patients with both nodal and extranodal lesions, the subsequent induction of a cancer-friendly environment appears pivotal. The DLBCL cell interaction with mature stromal cells and vessels confers tumor protection and inhibition of immune response while delivering nutrients and oxygen supply. Single cells may also reside and survive in protected niches in the nodal and extranodal sites as a source for residual disease and relapse. This review aims to molecularly and functionally recapitulate the DLBCL–milieu crosstalk, to relate niche and pathological angiogenic constitution and interaction factors to DLBCL progression.

Could the menagerie of the gut microbiome really cure cancer? Hope or hype

The investigational scale of the gut microbiome is expanding rapidly. In 2018, the intersection of gut microbiota and immuno-oncology received much attention. While the impact of gut microbiota on the immune system was already established, the year received an exponential expansion of microbiome’s role in the immunotherapy setting. The microbiome research pipeline is ripe for large-scale, prospective trials. Working knowledge of immune-based cancer treatments, heterogeneity in their responses and resistance mechanisms, relevant immunological and microbiological pathways and potential for gut microbiome in enhancing the responses, is critical.

The role of B7 costimulation in benzene immunotoxicity and its potential association with cancer risk

Benzene is a recognized human carcinogen; however, there are still some gaps in the knowledge regarding the mechanism of toxicity of this organic solvent and potential early biomarkers for the damage caused by it. In a previous study, our research group demonstrated that the adhesion molecules of the immune system (B7.1 and B7.2) could be potential biomarkers in the early detection of immunotoxicity caused by benzene exposure. Therefore, this study was developed to deepen the understanding regarding this important topic, aiming to contribute to the comprehension of the benzene toxicity mechanism mediated by B7.1 and B7.2 and its potential association with the risk of carcinogenicity. B7.1 and B7.2 protein expression in blood monocytes and B7.1 and B7.2 gene expression in PBMCs were evaluated. Additionally, complement C3 and C4 levels in serum were measured, as well as p53 gene expression in PBMCs. Seventy-four gas station workers (GSW group) and 71 non-occupationally exposed subjects (NEG) were evaluated. Our results demonstrated decreased levels of B7.1 and B7.2 protein and gene expression in the GSW group compared to the NEG (n = 71) (p < 0.01). Along the same lines, decreased levels of the complement system were observed in the GSW group (p < 0.01), demonstrating the impairment of this immune system pathway as well. Additionally, a reduction was observed in p53 gene expression in the GSA group (p < 0.01). These alterations were associated with both the benzene exposure biomarker evaluated, urinary trans, trans-muconic acid, and with exposure time (p < 0.05). Moreover, strong correlations were observed between the gene expression of p53 vs. B7.1 (r = 0.830; p < 0.001), p53 vs. B7.2 (r = 0.685; p < 0.001), and B7.1 vs. B7.2 (r = 0.702; p < 0.001). Taken together, these results demonstrate that the immune system co-stimulatory molecule pathway is affected by benzene exposure. Also, the decrease in p53 gene expression, even at low exposure levels, reinforces the carcinogenicity effect of benzene in this pathway. Therefore, our results suggest that the promotion of immune evasion together with a decrease in p53 gene expression may play an important role in the benzene toxicity mechanism. However, further and targeted studies are needed to confirm this proposition.

Response to R-CHOP in HPV-related squamous cell carcinoma of base of tongue: a case report

Background

Synchronous squamous cell carcinoma of the head and neck (HNSCC) and non-Hodgkin's lymphoma is a rare clinical scenario. It is unknown whether the R-CHOP chemotherapy for lymphoma would also be active against HNSCC. Herein, we present such a case and a review of the literature.

Case presentation

A 64 year-old female presented with painless jaundice. CT demonstrated a retroperitoneal mass and pathology showed follicular lymphoma. A base-of-tongue HPV⁺ squamous cell carcinoma was found incidentally on staging CT. R-CHOP chemotherapy was initiated. After 3 cycles of R-CHOP the lymphoma had a complete metabolic response and, unexpectedly, the HNSCC also demonstrated excellent response. The patient received another 3 cycles followed by radiation to the HNSCC and to date is in remission for both cancers.

Conclusions

This case highlights the exquisite sensitivity of HPV-related HNSCC, which should be taken into consideration in treatment prioritization of a concurrent diagnosis of a second cancer.

A review of immune therapy in cancer and a question: can thermal therapy increase tumor response?

Immune therapy is a successful cancer treatment coming into its own. This is because checkpoint molecules, adoptive specific lymphocyte transfer and chimeric antigen T-cell (CAR-T) therapy are able to induce more durable responses in an increasing number of malignancies compared to chemotherapy. In addition, immune therapies are able to treat bulky disease, whereas standard cytotoxic therapies cannot treat large tumour burdens. Checkpoint inhibitor monoclonal antibodies are becoming widely used in the clinic and although more complex, adoptive lymphocyte transfer and CAR-T therapies show promise. We are learning that there are nuances to predicting the successful use of the checkpoint inhibitors as well as to specific-antigen adoptive and CAR-T therapies. We are also newly aware of a here-to-fore unrealised natural force, the status of the microbiome. However, despite better understanding of mechanisms of action of the new immune therapies, the best responses to the new immune therapies remain 20-30%. Likely the best way to improve this somewhat low response rate for patients is to increase the patient's own immune response. Thermal therapy is a way to do this. All forms of thermal therapy, from fever-range systemic thermal therapy, to high-temperature HIFU and even cryotherapy improve the immune response pre-clinically. It is time to test the immune therapies with thermal therapy in vivo to test for optimal timing of the combinations that will best enhance tumour response and then to begin to test the immune therapies with thermal therapy in the clinic as soon as possible.

Invariant Natural Killer T Cells in Immune Regulation of Blood Cancers: Harnessing Their Potential in Immunotherapies

Invariant natural killer T (iNKT) cells are a unique innate T lymphocyte population that possess cytolytic properties and profound immunoregulatory activities. iNKT cells play an important role in the immune surveillance of blood cancers. They predominantly recognize glycolipid antigens presented on CD1d, but their activation and cytolytic activities are not confined to CD1d expressing cells. iNKT cell stimulation and subsequent production of immunomodulatory cytokines serve to enhance the overall antitumor immune response. Crucially, the activation of iNKT cells in cancer often precedes the activation and priming of other immune effector cells, such as NK cells and T cells, thereby influencing the generation and outcome of the antitumor immune response. Blood cancers can evade or dampen iNKT cell responses by downregulating expression of recognition receptors or by actively suppressing or diverting iNKT cell functions. This review will discuss literature on iNKT cell activity and associated dysregulation in blood cancers as well as highlight some of the strategies designed to harness and enhance iNKT cell functions against blood cancers.

Checkpoint Inhibitors and Other Immune Therapies for Hodgkin and Non-Hodgkin Lymphoma

OPINION STATEMENT

Treatment for relapsed/refractory (R/R) Hodgkin and non-Hodgkin lymphoma remains challenging. The introduction of rituximab to B cell non-Hodgkin lymphoma (B-NHL) treatment significantly improved patients' response rate and survival; however, approximately one third of patients with diffuse large B cell lymphoma, the most common B-NHL subtype, still have a relapse or become refractory after first-line therapy. More recently, antibody therapies and small-molecule inhibitors were approved for treating R/R lymphomas; these agents include brentuximab vedotin, ibrutinib, and idelalisib. Immune checkpoint inhibitors and other immune therapies are emerging treatments currently being evaluated in various clinical trials for their efficacy against lymphoid malignancies. Striking results from these treatment modalities have been observed in solid tumors, and evidence is accumulating to support their use in various lymphomas. The most exciting results from immune checkpoint inhibitor therapy have been seen in patients with R/R Hodgkin lymphoma, in whom the overall response rate has reached 60-80 %. Results in NHL are more similar to those seen in other solid malignancies, ranging between 20 and 40 %, depending on the histology. Formal approval of these drugs is being awaited, as are the results of combination therapy with checkpoint inhibitors and other treatment modalities, including conventional chemotherapy, small-molecule inhibitors, and other immune therapies. Although response rates have been promising, attention must be paid to the management of unique immune-related adverse events, which warrant close monitoring in some cases. Identification of biomarkers that predict response or severe adverse events using either the tumor specimen or peripheral blood would aid in selecting patients suited for these types of treatment as well as determining the ideal sequence of treatment within the realm of immune therapies.

Risk-adapted transplant strategies for high-risk Hodgkin lymphoma: are we there?

PURPOSE OF REVIEW

The treatment of high-risk classic Hodgkin lymphoma (cHL) patients remains challenging, especially after autologous stem cell transplant (ASCT) failure. Moreover, the outcome of chemorefractory patients is still poor.

RECENT FINDINGS

The development of novel targeted therapies has changed the therapeutic options for high-risk patients. To improve outcome, treatment algorithms should integrate up-front, newly established prognostic markers. Tandem ASCT instead of single ASCT has been proposed as an option to improve outcome for high-risk patients. Availability of less toxic reduced intensity conditioning regimens and recent development in haploidentical transplantation have widened applicability and improved outcomes of allo-hematopoietic cell transplantation. Their exact role in cHL is still controversial and there is no consensus on the optimal transplantation strategy. In this context, results of tandem ASCT should also be compared with those of the autologous/reduced intensity conditioning-allo tandem approach. In this review, we discuss how transplantation strategies (auto and allo) can fit into the salvage treatment plan for patients with relapsed/refractory cHL, taking into account the new drugs available and integrating modern risk assessment.

SUMMARY

We speculated that improvements could be achieved by transplanting patients in earlier phases of their disease, if necessary after 'bridging' using the new drugs, and we propose an algorithm integrating the different treatment options.

HLA dependent immune escape mechanisms in B-cell lymphomas: Implications for immune checkpoint inhibitor therapy?

Antigen presentation by tumor cells in the context of Human Leukocyte Antigen (HLA) is generally considered to be a prerequisite for effective immune checkpoint inhibitor therapy. We evaluated cell surface HLA class I, HLA class II and cytoplasmic HLA-DM staining by immunohistochemistry (IHC) in 389 classical Hodgkin lymphomas (cHL), 22 nodular lymphocyte predominant Hodgkin lymphomas (NLPHL), 137 diffuse large B-cell lymphomas (DLBCL), 39 primary central nervous system lymphomas (PCNSL) and 19 testicular lymphomas. We describe a novel mechanism of immune escape in which loss of HLA-DM expression results in aberrant membranous invariant chain peptide (CLIP) expression in HLA class II cell surface positive lymphoma cells, preventing presentation of antigenic peptides. In HLA class II positive cases, HLA-DM expression was lost in 49% of cHL, 0% of NLPHL, 14% of DLBCL, 3% of PCNSL and 0% of testicular lymphomas. Considering HLA class I, HLA class II and HLA-DM together, 88% of cHL, 10% of NLPHL, 62% of DLBCL, 77% of PCNSL and 87% of testicular lymphoma cases had abnormal HLA expression patterns. In conclusion, an HLA expression pattern incompatible with normal antigen presentation is common in cHL, DLBCL, PCNSL and testicular lymphoma. Retention of CLIP in HLA class II caused by loss of HLA-DM is a novel immune escape mechanism, especially prevalent in cHL. Aberrant HLA expression should be taken into account when evaluating efficacy of checkpoint inhibitors in B-cell lymphomas.

Clinicopathologic significance of tumor microenvironment CD11c, and FOXP3 expression in diffuse large B-cell lymphoma patients receiving rituximab, cyclophosphamide, anthracycline, vincristine, and prednisone (R-CHOP) combination chemotherapy

BACKGROUND/AIMS

CD11c is a dendritic cell marker in humans, which potentially induces a cytotoxic effect on lymphoma cells. Forkhead boxP3 (FOXP3) is a regulator of T lymphocyte in the microenvironment of the lymphoma. The principal objective of this study was to determine whether the tumors' microenvironment expressions of CD11c and FOXP3 are predictive of clinical outcomes in diffuse large B-cell lymphoma (DLBCL) patients receiving treatment with rituximab, cyclophosphamide, anthracycline, vincristine, and prednisone (R-CHOP) combination chemotherapy.

METHODS

The study population consisted of 100 patients with DLBCL. The CD11c and FOXP3 expression in primary tumors' microenvironment were evaluated using an immunohistochemistry (IHC).

RESULTS

CD11c and FOXP3 expression positivity in microenvironment were 25% and 35%, respectively. Each one counted for 1 point. In CD11c and FOXP3 stain, positive was counted as 0 and negative was 1. The points were separated into low risk (0 to 1) and high risk (2) groups. Only the extranodal DLBCL patient group analysis conveyed significant differences of progression-free survival (p = 0.019) and overall survival (p = 0.039) between the two groups.

CONCLUSIONS

We can achieve possible clinical significance of lymphoma tumor microenvironments through CD11c and FOXP3 IHC stains in extranodal DLBCL patients receiving R-CHOP therapy.

Mechanisms of tumour escape from immune surveillance

The progressive growth and spread of tumour cells in the form of metastases requires an interaction of healthy host cells, such as endothelial cells, fibroblasts, and other cells of mesenchymal origin with immune cells taking part in innate and adaptive responses within the tumour lesion and entire body. The host cells interact with tumour cells to create a dynamic tumour microenvironment, in which healthy cells can both positively and negatively influence the growth and spread of the tumour. The balance of cellular homeostasis and the effect of substances they secrete on the tumour microenvironment determine whether the tumour has a tendency to grow or disappear, and whether the cells remain within the lesion or are capable of metastasis to other regions of the body. Intercellular interactions also determine the tumour’s susceptibility to radiation or other types of cancer treatment. They may also be a rational explanation for differences in treatment outcomes, in which some metastases regress and others progress in response to the same treatment method.

Treatments for hematologic malignancies in contrast to those for solid cancers are associated with reduced red cell alloimmunization

Red cell alloimmunization may induce severe hemolytic side effects. Identification of risk-modifying conditions will help tailor preventative strategies. This study aims to quantify the associations of hematologic malignancies and solid cancers with red cell alloimmunization in patients receiving red cell transfusions. We performed a nested multicenter case-control study in a source population of 24,063 patients receiving their first and subsequent red cell transfusions during an 8-year follow-up period. Cases (n=505), defined as patients developing a first transfusion-induced red cell alloantibody, were each compared with 2 non-alloimmunized controls (n=1010) who received a similar number of red cell units. Using multivariate logistic regression analyses, we evaluated the association of various malignancies and treatment regimens with alloimmunization during a delineated 5-week risk period. The incidence of alloimmunization among patients with acute (myeloid or lymphoid) leukemia and mature (B- or T-cell) lymphoma was significantly reduced compared to patients without these malignancies: adjusted relative risks (RR) with 95% confidence interval (CI) 0.36 (range 0.19-0.68) and 0.30 (range 0.12-0.81). Associations were primarily explained by immunosuppressive treatments [RR for (any type of) chemotherapy combined with immunotherapy 0.27 (95%CI: 0.09-0.83)]. Alloimmunization risks were similarly diminished in allogeneic or autologous stem cell transplanted patients (RR 0.34, 95%CI: 0.16-0.74), at least during the six months post transplant. Alloimmunization risks of patients with other hematologic diseases or solid cancers, and their associated treatment regimens were similar to risks in the general transfused population. Our findings suggest that, in contrast to malignancies in general, hemato-oncological patients treated with dose-intensive regimens have strongly diminished risk of red cell alloimmunization.

Emerging therapies provide new opportunities to reshape the multifaceted interactions between the immune system and lymphoma cells

The acquisition of a complete neoplastic phenotype requires cancer cells to develop escape mechanisms from the host immune system. This phenomenon, commonly referred to as 'immune evasion,' represents a hallmark of cancers and results from a Darwinian selection of the fittest tumor clones. First reported in solid tumors, cancer immunoescape characterizes several hematological malignancies. The biological bases of cancer immunoescape have recently been disclosed and include: (i) impaired human leukocyte antigen-mediated cancer cell recognition (B2M, CD58, CTIIA, CD80/CD86, CD28 and CTLA-4 mutations); (ii) deranged apoptotic mechanisms (reduced pro-apoptotic signals and/or increased expression of anti-apoptotic molecules); and (iii) changes in the tumor microenvironment involving regulatory T cells and tumor-associated macrophages. These immune-escape mechanisms characterize both Hodgkin and non-Hodgkin (B and T cell) lymphomas and represent a promising target for new anti-tumor therapies. In the present review, the principles of cancer immunoescape and their role in human lymphomagenesis are illustrated. Current therapies targeting these pathways and possible applications for lymphoma treatment are also addressed.

Collision tumor consisting of primary follicular lymphoma and adenocarcinoma in the cecum: A case report and literature review

The present study reports the case of a collision tumor consisting of follicular lymphoma (FL) and adenocarcinoma in the cecum of a 73-year-old man. To the best of our knowledge, the present study is the 11th case of a collision tumor consisting of colon adenocarcinoma and lymphoma to be reported in the literature, and the first case of cecum adenocarcinoma with low grade FL in the same segment of the cecum and the same regional lymph node to be reported. The present study reviewed the literature to determine treatment options for patients with collision tumors. The present patient was administered with adjuvant chemotherapy for T3N1M0 colon cancer following surgery, due to the dominance of colon adenocarcinoma in the collision tumor. Following the completion of treatment, progression of the untreated FL was observed. In the literature, patients with collision tumors are administered with chemotherapy for stage IV FL, and following the completion of treatment patients have presented with a recurrence of early stage colon adenocarcinoma. The recommended treatment for collision tumors is dependent on the dominant tumor; however, the treatment options for collision tumors in the literature appeared to exacerbate the other tumor. The characteristics of the tumors altered following chemotherapy, and immunological alterations in the tumors due to chemotherapy appear to have contributed to the exacerbation of the tumors. Therefore, patients with early-stage tumors should be considered at risk of recurrence of other malignancies, which are present in collision tumors.

In situ vaccination for the treatment of cancer

Vaccination has had a tremendous impact on human health by harnessing the immune system to prevent and eradicate infectious diseases and this same approach might be used in cancer therapy. Cancer vaccine development has been slowed hindered by the paucity of universal tumor-associated antigens and the difficulty in isolating and preparing individualized vaccines ex vivo. Another approach has been to initiate or stimulate an immune response in situ (at the tumor site) and thus exploit the potentially numerous tumor-associated antigens there. Here, we review the many approaches that have attempted to accomplish effective in situ vaccination, using intratumoral administration of immunomodulators to increase the numbers or activation state of either antigen present cells or T cells within the tumor.

Immunosuppressive cells in tumor immune escape and metastasis

Tumor immune escape and the initiation of metastasis are critical steps in malignant progression of tumors and have been implicated in the failure of some clinical cancer immunotherapy. Tumors develop numerous strategies to escape immune surveillance or metastasize: Tumors not only modulate the recruitment and expansion of immunosuppressive cell populations to develop the tumor microenvironment or pre-metastatic niche but also switch the phenotype and function of normal immune cells from a potentially tumor-reactive state to a tumor-promoting state. Immunosuppressive cells facilitate tumor immune escape by inhibiting antitumor immune responses and furthermore promote tumor metastasis by inducing immunosuppression, promoting tumor cell invasion and intravasation, establishing a pre-metastatic niche, facilitating epithelial-mesenchymal transition, and inducing angiogenesis at primary tumor or metastatic sites. Numerous translational studies indicate that it is possible to inhibit tumor immune escape and prevent tumor metastasis by blocking immunosuppressive cells and eliminating immunosuppressive mechanisms that are induced by either immunosuppressive cells or tumor cells. Furthermore, many clinical trials targeting immunosuppressive cells have also achieved good outcome. In this review, we focus on the underlying mechanisms of immunosuppressive cells in promoting tumor immune escape and metastasis, discuss our current understanding of the interactions between immunosuppressive cells and tumor cells in the tumor microenvironment, and suggest future research directions as well as potential clinical strategies in cancer immunotherapy.

In situ vaccination: Cancer immunotherapy both personalized and off-the-shelf

As cancer immunotherapy continues to benefit from novel approaches which cut immune 'brake pedals' (e.g. anti-PD1 and anti-CTLA4 antibodies) and push immune cell gas pedals (e.g. IL2, and IFNα) there will be increasing need to develop immune 'steering wheels' such as vaccines to guide the immune system specifically toward tumor associated antigens. Two primary hurdles in cancer vaccines have been: identification of universal antigens to be used in 'off-the-shelf' vaccines for common cancers, and 2) logistical hurdles of ex vivo production of individualized whole tumor cell vaccines. Here we summarize approaches using 'in situ vaccination' in which intratumoral administration of off-the-shelf immunomodulators have been developed to specifically induce (or amplify) T cell responses to each patient's individual tumor. Clinical studies have confirmed the induction of systemic immune and clinical responses to such approaches and preclinical models have suggested ways to further potentiate the translation of in situ vaccine trials for our patients.