Higher infiltration of intratumoral CD25+ FOXP3+ lymphocytes correlates with a favorable prognosis in patients with diffuse large B-cell lymphoma

Distribution and clinical features of lymphomas involving skin in Taiwan

A wide variety of primary and secondary lymphoma types involves the skin. However, reports with comparisons between both groups are limited in Taiwan. We retrospectively enrolled all cutaneous lymphomas and evaluated their clinicopathologic features. There were 221 cases of lymphoma: 182 (82.3%) primary and 39 (17.7%) secondary. Mycosis fungoides was the most common primary T-cell lymphoma, 92 (41.7%) cases, followed by CD30-positive T-cell lymphoproliferative disorders including lymphomatoid papulosis (n = 33, 14.9%) and cutaneous anaplastic large cell lymphoma (n = 12, 5.4%). The most frequent primary B-cell lymphomas were marginal zone lymphoma (n = 8, 3.6%) and diffuse large B-cell lymphoma (DLBCL), leg type (n = 8, 3.6%). DLBCL including variants was the most common secondary lymphoma involving skin. Most primary lymphomas presented at low-stage (T-cell, 86%; B-cell, 75%), whereas the majority of secondary lymphomas presented at high-stage (T-cell, 94%; B-cell, 100%). Patients with secondary lymphomas had an older mean age, more frequent B symptoms, lower serum albumin and hemoglobin, and a higher frequency of atypical lymphocytes in blood than those with primary lymphomas. In primary lymphomas, older age, lymphoma types, decreased lymphocyte counts and atypical lymphocytes in blood were poorer prognostic factors. In secondary lymphoma patients, lymphoma types, high serum lactate dehydrogenase and low hemoglobin levels predicted poorer survival. We found that the distribution of primary cutaneous lymphomas in Taiwan mirrors that of other Asian countries but shows some differences as compared with Western countries. Primary cutaneous lymphomas have a better prognosis than secondary lymphomas. Histologic classification of lymphomas highly correlated with disease presentation and prognosis.

Treg-selective IL-2 starvation synergizes with CD40 activation to sustain durable responses in lymphoma models

BACKGROUND

Roughly half of all diffuse large B-cell lymphomas (DLBCLs) are infiltrated by large numbers of regulatory T-cells (Tregs). Although the presence of 'effector' Tregs in particular is associated with an inferior prognosis in patients on standard rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) immunochemotherapy, the role of this cell type during lymphoma initiation and progression is poorly understood.

METHODS

Here, we use tissue microarrays containing prospectively collected DLBCL patient specimens, as well as data from publicly available cohorts to explore the mutational landscape of Treg-infiltrated DLBCL. We further take advantage of a model of MYC-driven lymphoma to mechanistically dissect the contribution of Tregs to lymphoma pathogenesis and to develop a strategy of Treg-selective interleukin-2 (IL-2) starvation to improve immune control of MYC-driven lymphoma.

RESULTS

We find that all genetic DLBCL subtypes, except for one characterized by co-occurring MYD88/CD79 mutations, are heavily infiltrated by Tregs. Spectral flow cytometry and scRNA-sequencing reveal the robust expression of functional and immunosuppressive markers on Tregs infiltrating MYC-driven lymphomas; notably, we find that intratumoral Tregs arise due to local conversion from naïve CD4+ precursors on tumor contact. Treg ablation in Foxp3iDTR mice, or by antibody-mediated Treg-selective blockade of IL-2 signaling, strongly reduces the lymphoma burden. We identify lymphoma B-cells as a major source of IL-2, and show that the effects of Treg depletion are reversed by the simultaneous depletion of Foxp3-negative CD4+ T-cells, but not CD8+ T-cells or natural killer (NK) cells. The inhibition of ATP hydrolyzation and adenosine production by Tregs at least partly phenocopies the effects of Treg depletion. Treg depletion further synergizes with pro-apoptotic CD40 activation to sustain durable responses.

CONCLUSION

The combined data implicate Tregs as a potential therapeutic target in DLBCL, especially in combination with other immunotherapies.

Proliferative Tumor-Infiltrating Lymphocytes' Abundance within the Microenvironment Impacts Clinical Outcome in Cutaneous B-Cell Lymphomas

Primary cutaneous large B-cell lymphoma, leg-type (PCLBCL-LT) is the most aggressive primary cutaneous B-cell lymphoma (PCBCL). Tumor microenvironment has a crucial role in tumor development, and tumor-infiltrating lymphocytes (TILs) can be targeted by immunotherapies. We characterized TILs in 20 PCBCLs to identify the tumor microenvironment features associated with clinical outcomes. We developed a seven‒multiplex immunofluorescence panel using Opal staining and image analysis using HALO software. In PCLBCL-LT, TILs were sparsely intermingled within tumor infiltrate in contrast to those in indolent PCBCL where TILs were scattered around tumor nodule edges with variable tumor infiltration. In PCLBCL-LT, TILs were composed of CD8 and CD4, whereas CD4 was predominant in indolent PCBCL. Proliferative TILs (CD3+Ki-67+ cells) were more abundant in PCLBCL-LT (P = 0.0036) than in indolent PCBCL. In PCLBCL-LT, proliferative TILs' abundance tended to be associated with better progression-free survival. These data were confirmed in a second independent cohort of 23 cases showing that proliferative TILs were more abundant in PCLBCL-LT (P = 0.0205) and that in PCLBCL-LT, high CD3+Ki-67+ cell density was associated with better progression-free survival (P = 0.002). These distinct TILs composition and distribution among PCBCL suggest that proliferative T lymphocytes represent a good prognostic factor in PCLBCL-LT and that stimulating their functions may represent a therapeutic approach.

Prognostic value of FOXP3+ regulatory T cells in patients with diffuse large B-cell lymphoma: a systematic review and meta-analysis

OBJECTIVES

We aimed to comprehensively evaluate the relationship between forkhead box P3 (FOXP3+) regulatory T cell (Treg) expression and diffuse large B-cell lymphoma (DLBCL) prognosis and to explore the sources of heterogeneity of the results.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

We searched the Cochrane Library, PubMed, Embase and Web of Science databases up to 5 December 2021.

ELIGIBILITY CRITERIA

We included studies that analysed the prognostic significance of FOXP3+ Tregs in DLBCL. We included studies reported in Chinese or English that reported HRs and related 95% CIs for prognosis.

DATA EXTRACTION AND SYNTHESIS

We extracted data from eligible studies. HRs and 95% CIs were used to assess the prognostic value.

RESULTS

Fourteen eligible studies were identified. FOXP3+ Treg expression was not associated with overall survival (OS) (HR=0.72, 95% CI 0.45 to 1.16) or progression-free survival (HR=0.86, 95% CI 0.54 to 1.38). The three approaches used to measure FOXP3+ Treg expression (pinteraction<0.001) may be the source of the heterogeneity of the results. Subgroup analysis found that a higher expression of FOXP3+ Tregs was associated with better OS in all populations and in Asians when FOXP3+ Treg expression was measured by the number of positive cells (HR=0.36 (95% CI 0.22 to 0.58) in the former, HR=0.33 (95% CI 0.20 to 0.55) in the latter) or the percentage of positive cells (HR=0.49 (95% CI 0.27 to 0.89) in the former, HR=0.38 (95% CI 0.21 to 0.70) in the latter). However, when measured by the score, inverse results were found (HR=1.56, 95% CI 1.01 to 2.42).

CONCLUSIONS

Approaches to measuring FOXP3+ Treg expression might be the major source of heterogeneity in studies of the prognostic significance of FOXP3+ Tregs in DLBCL. FOXP3+ Treg expression might be used to predict the prognosis of patients with DLBCL when FOXP3+ Treg expression is calculated by the number or the percentage of positive cells, especially in Asian populations.

Regulatory T cells (Tregs) in lymphoid malignancies and the impact of novel therapies

Regulatory T cells (Tregs) are responsible for maintaining immune homeostasis by controlling immune responses. They can be characterized by concomitant expression of FoxP3, CD25 and inhibitory receptors such as PD-1 and CTLA-4. Tregs are key players in preventing autoimmunity and are dysregulated in cancer, where they facilitate tumor immune escape. B-cell lymphoid malignancies are a group of diseases with heterogenous molecular characteristics and clinical course. Treg levels are increased in patients with B-cell lymphoid malignancies and correlate with clinical outcomes. In this review, we discuss studies investigating Treg immunobiology in B-cell lymphoid malignancies, focusing on clinical correlations, mechanisms of accumulation, phenotype, and function. Overarching trends suggest that Tregs can be induced directly by tumor cells and recruited to the tumor microenvironment where they suppress antitumor immunity to facilitate disease progression. Further, we highlight studies showing that Tregs can be modulated by novel therapeutic agents such as immune checkpoint blockade and targeted therapies. Treg disruption by novel therapeutics may beneficially restore immune competence but has been associated with occurrence of adverse events. Strategies to achieve balance between these two outcomes will be paramount in the future to improve therapeutic efficacy and safety.

Case Report: Immune Microenvironment and Mutation Features in a Patient With Epstein–Barr Virus Positive Large B-Cell Lymphoma Secondary to Angioimmunoblastic T-Cell Lymphoma

On rare occasions, secondary Epstein–Barr virus (EBV)-associated B-cell lymphoma can develop in patients with angioimmunoblastic T-cell lymphoma (AITL). Here, we describe the tumor microenvironment and mutation features of a patient with EBV + large B-cell lymphoma (LBCL) secondary to AITL. He was admitted to hospital due to a 1-year history of fever and enlarged right inguinal lymph nodes. A biopsy of the right inguinal lymph node demonstrated that numerous diffuse medium-sized atypical lymphocytes proliferated, together with increased extrafollicular follicular dendritic cell meshwork, and the lymphocytes expressed CD3, CD4, BCL6, CD10, PD-1, CXCL13, and Ki-67 (75%). Thus, a diagnosis of AITL was made. However, the disease progressed following treatment by CHOP regimen (cyclophosphamide, adriamycin, vincristine, and prednisone). Biopsy showed that most of the cells were positive for CD20 staining and IgH rearrangement. Analysis of 22 kinds of immune cells showed that the numbers of activated NK cells and activated memory T cells increased, while the T-follicular helper population decreased in the transformed sample. In addition, compared with the primary sample, RHOA (G17V) mutation was not detected, while JAK2 and TRIP12 gene mutations were detected in the transformed sample. Overall, we described the immune microenvironment and mutation features of a patient with EBV + LBCL secondary to AITL. This study will help us to understand the mechanisms by which AITL transforms to B-cell lymphoma.

Identification of CXCR4 Upregulation in Diffuse Large B-Cell Lymphoma Associated with Prognostic Significance and Clinicopathological Characteristics

Background

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous malignant lymphoma with distinct characteristics. Patients with treatment failure after the standard immunochemotherapy have worse prognosis, which implies the necessity to uncover novel targets. The C-X-C chemokine receptor 4 (CXCR4) overexpression has been identified in several hematopoietic malignancies. However, the expression signatures and prognostic significance of CXCR4 in DLBCL associated with clinicopathological features remain unclear.

Methods

Gene expression profiles of DLBCL were obtained from the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Then, a meta-analysis with an integrated bioinformatic analysis was performed to assess the relationship between CXCR4 expression and clinicopathological features of DLBCL. Finally, experimental verification including immunohistochemical (IHC) staining and real-time quantitative PCR (qPCR) was carried out using patient samples. In vitro cell line viability tests were conducted using CXCR4 inhibitor WZ811.

Results

DLBCL patients with activated B-cell-like (ABC) subtype have higher expression level of CXCR4 with worse survival. Differential expressed genes in the CXCR4-upregulation group were enriched in canonical pathways associated with oncogenesis. DLBCL with CXCR4 upregulation had lower degree of CD8⁺ T cell infiltration. TIMER analysis demonstrated that the CXCR4 expression was positively correlated with the expression of CD5, MYC, NOTCH1, PDCD1, CD274, mTOR, FOXO1, and hnRNPA2B1 in DLBCL. IHC study in patient samples showed the positive correlation between CXCR4 and nongerminal center B-cell (non-GCB) subtype and mTOR expression. Meanwhile, quantitative polymerase chain reaction results revealed that high CXCR4 mRNA level was correlated to double-hit DLBCL. Finally, cell viability test showed that WZ811 exerted antiproliferation effect in DLBCL cell lines in a dose-dependent manner.

Conclusion

CXCR4 was upregulated in ABC-DLBCL associated with worse prognosis. Our analysis predicted CXCR4 as a potential target for DLBCL treatment, which may serve as an inhibitor both on BCR signaling and nuclear export warranting further investigation in clinical trials.

Tumor Immune Microenvironment in Lymphoma: Focus on Epigenetics

Lymphoma is a neoplasm arising from B or T lymphocytes or natural killer cells characterized by clonal lymphoproliferation. This tumor comprises a diverse and heterogeneous group of malignancies with distinct clinical, histopathological, and molecular characteristics. Despite advances in lymphoma treatment, clinical outcomes of patients with relapsed or refractory disease remain poor. Thus, a deeper understanding of molecular pathogenesis and tumor progression of lymphoma is required. Epigenetic alterations contribute to cancer initiation, progression, and drug resistance. In fact, over the past decade, dysregulation of epigenetic mechanisms has been identified in lymphomas, and the knowledge of the epigenetic aberrations has led to the emergence of the promising epigenetic therapy field in lymphoma tumors. However, epigenetic aberrations in lymphoma not only have been found in tumor cells, but also in cells from the tumor microenvironment, such as immune cells. Whereas the epigenetic dysregulation in lymphoma cells is being intensively investigated, there are limited studies regarding the epigenetic mechanisms that affect the functions of immune cells from the tumor microenvironment in lymphoma. Therefore, this review tries to provide a general overview of epigenetic alterations that affect both lymphoma cells and infiltrating immune cells within the tumor, as well as the epigenetic cross-talk between them.

Implication of immune cell signature of tumor microenvironment in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease with complex tumor microenvironment (TME) alterations. However, immune cell signatures of TME and their prognostic value remain unclear in DLBCL. We aimed to identify high-risk DLBCL with specific immune cell signatures in TME. Clinical and gene expression data of DLBCL patients were obtained from previously reported retrospective datasets in Gene Expression Omnibus (GSE10846⁶ and GSE53786¹⁶ ) and a multi-center prospective clinical trial NHL001 (NCT01852435). Patients treated with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) regimen (n = 159) from GSE10846 were referred as training cohort for CHOP regimen, while patients treated with rituximab-CHOP (R-CHOP) regimen (n = 192) from GSE10846 as training cohort for R-CHOP regimen. Patients from NHL001 (n = 68) and GSE53786 (n = 57) were referred as validation cohorts for R-CHOP regimen. CIBERSORT was applied to estimate the relative proportions of 22 subtype of immune cells. We established a prognostic model for model for R-CHOP regimen included Age, performance status, lactate dehydrogenase, T cells follicular helper and macrophages M0, defining a low-risk group with 2-years OS of 92.9% and a high-risk group with 2-years OS of 52.5% (HR 6.57 [3.27-13.18], p < 0.0001). Immune cell signatures could be used as prognostic markers and provided further insights for individualized immunotherapeutic strategies in DLBCL.