The immune checkpoint expression in the tumor immune microenvironment of DLBCL: Clinicopathologic features and prognosis

Unveiling vitamin C: A new hope in the treatment of diffuse large B‑cell lymphoma (Review)

Lymphoma is a malignancy of the immune system, which originates from lymphatic tissues and lymph nodes. Diffuse large B‑cell lymphoma (DLBCL) is a common type of non‑Hodgkin lymphoma, occurring in 30‑40% of all cases, which has persistent clinical challenges. The treatment of DLBCL is challenging due to its diverse genetic and biological characteristics and complex clinical physiology. Despite advancements in overall prognosis, 20‑25% of patients continue to experience relapse and 10‑15% of patients experience refractory disease. Vitamin C is a water‑soluble vitamin with antioxidant properties and notable pharmacological activity, with potential applications in cancer therapy. Pharmacological doses of vitamin C (1‑4 g/kg) can induce apoptosis in malignant cells by inhibiting and/or reversing gene mutations that are associated with hematological malignancies. For example, 10‑25% of patients with myeloid malignancies have tet methylcytosine dioxygenase 2 (TET2) gene mutations and vitamin C can regulate blood stem cell frequency and leukemia production by enhancing TET2 function. Consequently, pharmacological doses of vitamin C can inhibit the development and progression of hematological malignancies. Therefore, the present review aimed to investigate the role of vitamin C in the pathophysiology and treatment of DLBCL, whilst highlighting the potential challenges and future perspectives.

Expression and Clinical Significance of CXCR5 and LAG-3 on Peripheral Blood CD8 + T Cells in Patients With Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) exhibits substantial biological and clinical heterogeneity. This study investigated the expression and prognostic implications of C-X-C chemokine receptor type 5 (CXCR5) and lymphocyte activation gene-3 (LAG-3) on peripheral blood CD8+ T cells in patients with DLBCL. A total of 71 DLBCL patients and 71 healthy controls were enrolled. The expression levels of CXCR5 and LAG-3 on peripheral blood CD8+ T cells were assessed and analyzed for their impact on 5-year progression-free survival (PFS) and overall survival (OS). Results revealed significantly elevated CXCR5 and LAG-3 expression levels in DLBCL patients compared to controls. CXCR5 expression correlated with lactate dehydrogenase (LDH) levels, extranodal involvement, Ann Arbor stage, and International Prognostic Index (IPI) scores, while LAG-3 expression was associated with Eastern Cooperative Oncology Group (ECOG) scores, number of extranodal sites, bone marrow involvement, Ann Arbor stage, and IPI scores. Multivariate analysis identified advanced age, Ann Arbor stage III-IV, and elevated CXCR5 and LAG-3 expression as independent risk factors for poorer 5-year PFS and OS. Furthermore, patients with higher CXCR5 and LAG-3 expression levels demonstrated significantly reduced 5-year PFS and OS rates. In conclusion, elevated CXCR5 and LAG-3 expression on peripheral blood CD8+ T cells plays a pivotal role in DLBCL progression and prognosis, making these markers potential therapeutic targets or prognostic indicators.

Increased TIGIT expression correlates with impaired NK cell function in diffuse large B-cell lymphoma

Purpose

This study aims to investigate the status of natural killer (NK) cells and the role of T-cell immunoreceptor with Ig and ITIM domains (TIGIT)-mediated regulation in diffuse large B-cell lymphoma (DLBCL).

Methods

Peripheral blood samples from 30 newly diagnosed DLBCL patients and 25 healthy controls were collected. Multiparametric flow cytometry was used to analyze the expression levels of TIGIT and its family molecules (CD226 and CD96) on NK cells, as well as to assess NK cell phenotype and function. The restorative effects of TIGIT blockade on NK cell cytotoxicity were evaluated through in vitro functional assays and in vivo animal models.

Results

Compared to healthy controls, DLBCL patients exhibited significantly reduced percentages and absolute numbers of NK cells. TIGIT expression was markedly upregulated on NK cells in DLBCL patients, while CD226 expression was downregulated; however, no significant difference in CD96 expression was observed. These alterations were associated with impaired NK cell function in DLBCL patients, including reduced secretion of activation factors such as granzyme B, perforin, and CD107a. Importantly, TIGIT blockade significantly enhanced the cytotoxic activity of NK cells against DLBCL cells in both in vitro and in vivo settings.

Conclusion

Dysregulated expression of TIGIT and its family molecules on NK cells contributes to NK cell dysfunction and promotes tumor immune escape in DLBCL. These findings highlight TIGIT as a promising therapeutic target for restoring NK cell-mediated antitumor immunity in DLBCL.

SNRPB and CEP290, predicting the prognosis of diffuse large B cell lymphoma and associated with tumour immune microenvironment

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL), the most prevalent type of non-Hodgkin's lymphoma, exhibits significant correlations with efferocytosis-related molecules (ERMs) concerning invasion, metastasis, and clinical outcomes. This study aims to establish an efferocytosis-related gene signature specifically linked to DLBCL.

METHODS

Key module genes linked to DLBCL were identified via weighted gene co-expression network analysis (WGCNA) in GSE32018. Univariate Cox analysis of GSE31312 revealed ERMs associated with DLBCL survival. Differential expression analysis identified differentially expressed genes (DEGs) between DLBCL subtypes and normal samples. Venn diagram analysis identified common DEGs and key module genes. A DLBCL gene signature was built by using univariate Cox and least absolute shrinkage and selection operator (LASSO) analysis. Gene functional enrichment, immune microenvironment, and immunotherapy analyses compared two risk subgroups. Prognostic gene expression was validated at the single-cell level.

RESULTS

In the GSE32018 dataset, 1760 key module genes related to DLBCL were identified. Using GSE31312, 14 ERMs associated with DLBCL prognosis were determined.Then, an ERMs-related prognostic signature, including small nuclear ribonucleoprotein polypeptides B (SNRPB) and centrosomal protein 290 (CEP290), was established. Independent prognostic analysis showed that the RiskScore derived from this signature was a prognostic factor. Significant immune microenvironment differences were observed between two risk subgroups. Additionally, chemotherapeutic drug sensitivity results indicated the signature could predict therapeutic response. Eventually, expression of SNRPB and CEP290 was confirmed in B cells.

CONCLUSION

The prognostic signature comprised of SNRPB and CEP290 based on ERMs-DEGs was established, providing a theoretical basis and reference value for DLBCL research.

Exploring the molecular landscape of lymphocyte activation gene-3: A literature review

Molecular structure and cellular distribution of lymphocyte activation gene-3 (LAG-3) have been studied extensively since 1990. However, several unresolved questions remain. It is well-established that LAG-3 plays a significant role in maintaining immune homeostasis. The presence of deficiencies in LAG-3 has been observed to be linked with autoimmune disorders, whereas the excessive expression of LAG-3 within the tumor microenvironment hinders immune responses, particularly those mediated by lymphocytes, thereby facilitating immune evasion. Consequently, investigations into these 2 aspects have become a prominent focus in both fundamental and clinical research. The objective of this review is to examine the functions and molecular characteristics of LAG-3, as well as its current clinical applications in the context of tumor immune escape and autoimmune disease. The ultimate aim is to explore and propose novel immune therapy approach.

Advances and clinical applications of immune checkpoint inhibitors in hematological malignancies

Immune checkpoints are differentially expressed on various immune cells to regulate immune responses in tumor microenvironment. Tumor cells can activate the immune checkpoint pathway to establish an immunosuppressive tumor microenvironment and inhibit the anti-tumor immune response, which may lead to tumor progression by evading immune surveillance. Interrupting co-inhibitory signaling pathways with immune checkpoint inhibitors (ICIs) could reinvigorate the anti-tumor immune response and promote immune-mediated eradication of tumor cells. As a milestone in tumor treatment, ICIs have been firstly used in solid tumors and subsequently expanded to hematological malignancies, which are in their infancy. Currently, immune checkpoints have been investigated as promising biomarkers and therapeutic targets in hematological malignancies, and novel immune checkpoints, such as signal regulatory protein α (SIRPα) and tumor necrosis factor-alpha-inducible protein 8-like 2 (TIPE2), are constantly being discovered. Numerous ICIs have received clinical approval for clinical application in the treatment of hematological malignancies, especially when used in combination with other strategies, including oncolytic viruses (OVs), neoantigen vaccines, bispecific antibodies (bsAb), bio-nanomaterials, tumor vaccines, and cytokine-induced killer (CIK) cells. Moreover, the proportion of individuals with hematological malignancies benefiting from ICIs remains lower than expected due to multiple mechanisms of drug resistance and immune-related adverse events (irAEs). Close monitoring and appropriate intervention are needed to mitigate irAEs while using ICIs. This review provided a comprehensive overview of immune checkpoints on different immune cells, the latest advances of ICIs and highlighted the clinical applications of immune checkpoints in hematological malignancies, including biomarkers, targets, combination of ICIs with other therapies, mechanisms of resistance to ICIs, and irAEs, which can provide novel insight into the future exploration of ICIs in tumor treatment.

Unraveling the Immune Microenvironment in Diffuse Large B-Cell Lymphoma: Prognostic and Potential Therapeutic Implications

Diffuse large B cell lymphoma (DLBCL) is a multifaceted condition characterized by significant diversity in its molecular and pathological subtypes and clinical manifestation. Despite the progress made in the treatment of DLBCL through the development of novel drugs, an estimated one-third of patients encounter relapse or acquire refractory disease. The tumor microenvironment (TME) of DLBCL, a complex network consisting of cellular and noncellular components that engage in interactions with the tumor, is a parameter that is gaining increasing attention. The TME comprises both the immune and nonimmune microenvironments. The immune microenvironment comprises natural killer (NK) cells, dendritic cells (DCs), tumor-associated macrophages (TAMs), neutrophils, myeloid-derived suppressor cells (MDSCs), and T and B lymphocytes. The nonimmune microenvironment consists of the extracellular matrix (ECM), cancer-associated fibroblasts (CAFs), mesenchymal stromal cells, and other molecules that are secreted. Despite ongoing research, the exact impact of these components and their interaction on the progression of the disease remains elusive. A comprehensive review of significant discoveries concerning the cellular and noncellular constituents, molecular characteristics, and treatment response and prognosis of the TME in DLBCL, as well as the potential targeting of the TME with novel therapeutic approaches, is provided in this article.

SLC27A2 is a potential immune biomarker for hematological tumors and significantly regulates the cell cycle progression of diffuse large B-cell lymphoma

BACKGROUND

Research on the fatty acid metabolism related gene SLC27A2 is currently mainly focused on solid tumors, and its mechanism of action in hematological tumors has not been reported.

METHOD

This study aims to explore the pathological and immune mechanisms of the fatty acid metabolism related gene SLC27A2 in hematological tumors and verify its functional role in hematological tumors through cell experiments to improve treatment decisions and clinical outcomes of hematological tumors.

RESULT

This study identified the fatty acid metabolism related gene SLC27A2 as a common differentially expressed gene between DLBCL and AML. Immune microenvironment analysis showed that SLC27A2 was significantly positively correlated with T cell CD4 + , T cell CD8 + , endothelial cells, macrophages, and NK cells in DLBCL. In AML, there is a significant negative correlation between SLC27A2 and B cells, T cell CD8 + , and macrophages. SLC27A2 participates in the immune process of hematological tumors through T cell CD8 + and macrophages. The GESA results indicate that high expression of SLC27A2 is mainly involved in the fatty acid pathway, immune pathway, and cell cycle pathway of DLBCL. The low expression of SLC27A2 is mainly involved in the immune pathway of AML. Therefore, SLC27A2 is mainly involved in the pathological mechanisms of hematological tumors through immune pathways, and cell experiments have also confirmed that SLC27A2 is involved in the regulation of DLBCL cells.

CONCLUSION

In summary, our research results comprehensively report for the first time the mechanism of action of SLC27A2 in the immune microenvironment of DLBCL and AML, and for the first time verify the cycle and apoptotic effects of the fatty acid related gene SLC27A2 in DLBCL cells through cell experiments. Research can help improve the treatment of AML and DLBCL patients.

TIGIT is Frequently Expressed in the Tumor Microenvironment of Select Lymphomas: Implications for Targeted Therapy

Immune checkpoint inhibitors against Programmed Cell Death Protein 1/Programmed Cell (PD-1/PD-L1) and CTLA-4/B7 axes have had limited success in hematologic malignancies, requiring the need to explore alternative targets such as T-cell immunoreceptor with Ig and ITIM domains (TIGIT)/CD155 to improve durable clinical responses. We undertook this study to investigate the expression profile of TIGIT such that the potential efficacy of TIGIT blockade could be mapped among lymphoma subtypes. We validated an immunohistochemical assay for TIGIT and evaluated its expression in lymphoma and tumor microenvironment (TME) cells in 661 lymphoma/leukemia biopsies. Multiplex immunofluorescence was used for correlation with normal TME cell subsets. Tumor or TME TIGIT-positivity was defined as moderate to strong membrane staining in at least 10% of tumor or TME cells, respectively. TME TIGIT expression was correlated with overall survival and progression-free survival and comparison with PD-L1 expression. In most cases, lymphoma cells were TIGIT-negative except for angioimmunoblastic and peripheral T-cell lymphomas, which showed 91% and 47% positivity, respectively. A high proportion of small B-cell lymphoma and anaplastic large cell lymphoma cases had TIGIT-positive TME cells. Chronic lymphocytic leukemia/small lymphocytic lymphoma patients with TIGIT-negative TME cells showed significantly shorter overall survival ( P =0.04). No other statistically significant differences were found. When TIGIT was expressed in TME cells, there were a comparable number of TIGIT-positive only and dual TIGIT/PD-L1 positive cases except for more TIGIT-positive only cases in CLL/SLL. TIGIT expression shows distinctive profiles among lymphoma subtypes. Chronic lymphocytic leukemia/small lymphocytic lymphoma and anaplastic large cell lymphoma demonstrated high TME TIGIT expression compared with PD-L1, with a high proportion of dual TIGIT and PD-L1-positivity. Our results are likely to contribute to the design and correlative study of therapeutic response in clinical trials targeting TIGIT alone or in combination with PD1/PDL1.

Presence of Epstein-Barr virus (EBV) antigens detected by sensitive methods has no influence on local immune environment in diffuse large B cell lymphoma

EBV+ diffuse large B cell lymphoma (DLBCL) not otherwise specified (NOS) is a new entity confirmed by the World Health Organization (WHO) in 2017. In this new entity, the virus may contribute to a tolerogenic microenvironment. Traces of the virus have been described in DLBCL with more sensitive methods, in cases that were originally diagnosed as negative. The aim of this study was to analyze the expression of immune response genes in the tumor microenvironment to disclose the role of the virus and its traces in DLBCL. In 48 DLBCL cases, the expression of immune response genes and the presence of molecules that induce tolerance, such as TIM3, LAG3 and PDL1 by immunohistochemistry (IHC), were studied. To broaden the study of the microenvironment, tumor-associated macrophages (TMAs) were also explored. No significant differences were observed in the expression of immune response genes in the EBV+ DLBCL and those cases that were EBV- DLBCL but that exhibited viral traces, assessed by ViewRNA assay. Only the EBV+ DLBCL cases displayed a significantly higher increase in the expression of CD8 and cytotoxic T cells detected by gene expression analysis, and of PDL1 in tumor cells and in the expression of CD68 in the tumor microenvironment detected by IHC, not observed in those cases with viral traces. The increase in CD8 and cytotoxic T cells, PDL1 and CD68 markers only in EBV+ DLBCL may indicate that traces of viral infection might not have influence in immune response markers.

Gene expression profiles associated with early relapse during first remission induction in canine multicentric high-grade B-cell lymphoma

Although chemotherapy using CHOP-based protocol induces remission in most cases of canine multicentric high-grade B-cell lymphoma (mhBCL), some cases develop early relapse during the first induction protocol. In this study, we examined the gene expression profiles of canine mhBCL before chemotherapy and investigated their associations with early relapse during the first whole CHOP-based protocol. Twenty-five cases of mhBCL treated with CHOP-based protocol as first induction chemotherapy were included in this study. Sixteen cases completed the first whole CHOP-based protocol without relapse (S-group), and nine developed relapse during the chemotherapy (R-group). RNA-seq was performed on samples from neoplastic lymph nodes. Differentially expressed genes (DEGs) were extracted by the comparison of gene expression profiles between S- and R-groups, and the differences in the expression levels of these genes were validated by RT-qPCR. Extracted 179 DEGs included the genes related to chemokine CC motif ligand, T-cell receptor signaling pathway, and PD-L1 expression and PD-1 checkpoint pathway. We focused on chemokine CC motif ligand, and CCL4 was confirmed to be significantly downregulated in the R-group (P=0.039). We also focused on the genes related to T-cell signaling pathway, and CD3E (P=0.039), ITK (P=0.023), and LAT (P=0.023) genes were confirmed to be significantly upregulated in the R-group. The current results suggest that both changes in tumor cells and the interactions between tumor cells and immune cells are associated with the efficacy of the chemotherapy for first remission induction.

Establishment and evaluation of a nomogram for predicting the survival outcomes of patients with diffuse large B-cell lymphoma based on International Prognostic Index scores and clinical indicators

Background

Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive lymphoma, treatment outcomes of patients vary greatly. The current International Prognostic Index (IPI) is not enough to distinguish patients with poor prognosis, and genetic testing is very expensive, so a inexpensive risk prediction tool should be developed for clinicians to quickly identify the poor prognosis of DLBCL patients.

Methods

DLBCL patients (n=420; 18-80 years old) who received a combination of cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP) with or without rituximab (R-CHOP) at our hospital between 2008 and 2017 were included in the study. Potential predictors of survival were determined by univariate and multivariate Cox regression analyses, and significant variables were used to construct predictive nomograms. The new prediction models were assessed using concordance indexes (C-indexes), calibration curves, and their clinical utility was assessed by decision curve analyses (DCAs).

Results

The 5-year overall survival (OS) rate was 70.62% and the 5-year progression-free survival (PFS) rate was 59.02%. The multivariate Cox analysis indicated that IPI, Ki-67, the lymphocyte/monocyte ratio, and first-line treatment with rituximab were significantly associated with survival. The C-index results indicated that a predictive model that included these variables had better discriminability for OS (0.73 vs. 0.67) and PFS (0.68 vs. 0.63) than the IPI-based model. The calibration plots showed good agreement with observations and nomogram predictions. The DCAs demonstrated the clinical value of the nomograms.

Conclusions

Our study identified prognostic factors in patients who were newly diagnosed with DLBCL to construct an individualized risk prediction model, combined IPI with common clinical indicators. Our model might be a valuable tool that could be used to predict the prognosis of DLBCL patients who receive standard first-line treatment regimens. It enables clinicians to quickly identify some patients with possible poor prognosis and choose more active treatment for patients, such as chimeric antigen receptor T-cell (CART) Immunotherapy and other new drugs therapy, so as to prolong the PFS and OS of patients.