Zhi-Zhang Yang

PD-1 expression defines two distinct T-cell sub-populations in follicular lymphoma that differentially impact patient survival

To determine the biological and clinical relevance of programmed death 1 (PD-1) in follicular lymphoma (FL), we characterized PD-1+ T-cell subsets and assessed their biological function as well as potential clinical impact. We found that PD-1 is expressed on intratumoral CD4+ T cells with both bright and dim intensity, representing two different sub-populations of cells. By immunohistochemistry, we found that CD4+PD-1high T cells predominantly reside in the lymph node follicles, while PD-1low T cells are mainly located in an interfollicular pattern. Intratumoral CD4+PD-1high T cells have a TFH cell phenotype, express CXCR5, secrete IL-21 and are BCL-6 positive with no TIM-3 expression. In contrast, CD4+PD-1low T cells have an exhausted phenotype, express TIM-3 and do not express BCL-6 and CXCR5. Functionally, CD4+PD-1high T cells actively supported B-cell growth, while CD4+PD-1low T cells displayed a reduced cytokine production and cell-signal transduction. Clinically, we observed that the numbers of CD4+ or CD8+PD-1low T cells significantly correlate with a reduced overall survival in FL patients (P=0.007 and 0.04 respectively; n=32). In contrast, the number of CD4+PD-1high T cells was not associated with patient outcome. Taken together, these results indicated that PD-1 expression defines two sub-populations with distinct functions that differentially impact patient outcome in FL.

TGF-Β upregulates CD70 expression and induces exhaustion of effector memory T cells in B-cell non-Hodgkin's lymphoma

Transforming growth factor beta (TGF-β) has an important role in mediating T-cell suppression in B-cell non-Hodgkin lymphoma (NHL). However, the underlying mechanism responsible for TGF-β-mediated inhibition of effector memory T (Tm) cells is largely unknown. As reported here, we show that exhaustion is a major mechanism by which TGF-β inhibits Tm cells, and TGF-β mediated exhaustion is associated with upregulation of CD70. We found that TGF-β upregulates CD70 expression on effector Tm cells while it preferentially induces Foxp3 expression in naive T cells. CD70 induction by TGF-β is Smad3-dependent and involves IL-2/Stat5 signaling. CD70+ T cells account for TGF-β-induced exhaustion of effector Tm cells. Both TGF-β-induced and preexisting intratumoral CD70+ effector Tm cells from B-cell NHL have an exhausted phenotype and express higher levels of PD-1 and TIM-3 compared with CD70− T cells. Signaling transduction, proliferation and cytokine production are profoundly decreased in these cells, and they are highly susceptible to apoptosis. Clinically, intratumoral CD70-expressing T cells are prevalent in follicular B-cell lymphoma (FL) biopsy specimens, and increased numbers of intratumoral CD70+ T cells correlate with an inferior patient outcome. These findings confirm TGF-β-mediated effector Tm cell exhaustion as an important mechanism of immune suppression in B-cell NHL.

Whole-exome analysis reveals novel somatic genomic alterations associated with outcome in immunochemotherapy-treated diffuse large B-cell lymphoma

Lack of remission or early relapse remains a major clinical issue in diffuse large B-cell lymphoma (DLBCL), with 30% of patients failing standard of care. Although clinical factors and molecular signatures can partially predict DLBCL outcome, additional information is needed to identify high-risk patients, particularly biologic factors that might ultimately be amenable to intervention. Using whole-exome sequencing data from 51 newly diagnosed and immunochemotherapy-treated DLBCL patients, we evaluated the association of somatic genomic alterations with patient outcome, defined as failure to achieve event-free survival at 24 months after diagnosis (EFS24). We identified 16 genes with mutations, 374 with copy number gains and 151 with copy number losses that were associated with failure to achieve EFS24 (P<0.05). Except for FOXO1 and CIITA, known driver mutations did not correlate with EFS24. Gene losses were localized to 6q21-6q24.2, and gains to 3q13.12-3q29, 11q23.1-11q23.3 and 19q13.12-19q13.43. Globally, the number of gains was highly associated with poor outcome (P=7.4 × 10−12) and when combined with FOXO1 mutations identified 77% of cases that failed to achieve EFS24. One gene (SLC22A16) at 6q21, a doxorubicin transporter, was lost in 54% of EFS24 failures and our findings suggest it functions as a doxorubicin transporter in DLBCL cells.

IL-10 induces the development of immunosuppressive CD14+HLA-DRlow/− monocytes in B-cell non-Hodgkin lymphoma

The biological role of monocytes and macrophages in B-cell non-Hodgkin lymphoma (NHL) is not fully understood. We have previously reported that monocytes from patients with B-cell NHL have an immunosuppressive CD14+HLA-DRlow/− phenotype that correlates with a poor prognosis. However, the underlying mechanism by which CD14+HLA-DRlow/− monocytes develop in lymphoma is unknown. In the present study, we found that interleukin (IL)-10, which is increased in the serum of patients with B-cell NHL, induced the development of the CD4+HLA-DRlow/− population. Using peripheral blood samples from patients with B-cell NHL, we found that absolute numbers of CD14+ monocytic cells with an HLA-DRlow/− phenotype were higher than healthy controls and correlated with a higher International Prognostic Index score. IL-10 serum levels were elevated in lymphoma patients compared with controls and were associated with increased peripheral monocyte counts. Treatment of monocytes with IL-10 in vitro significantly decreased HLA-DR expression and resulted in the expansion of CD14+HLA-DRlow/− population. We found that lymphoma B cells produce IL-10 and supernatants from cultured lymphoma cells increased the CD14+HLA-DRlow/− population. Furthermore, we found that IL-10-induced CD14+HLA-DRlow/− monocytes inhibited the activation and proliferation of T cells. Taken together, these results suggest that elevated IL-10 serum levels contribute to increased numbers of immunosuppressive CD14+HLA-DRlow/− monocytes in B-cell NHL.

Denileukin Diftitox in Combination with Rituximab for Previously Untreated Follicular B-cell Non-Hodgkin's Lymphoma

Follicular lymphoma exhibits intratumoral infiltration by non-malignant T lymphocytes, including CD4+CD25+ regulatory T (Treg) cells. We combined denileukin diftitox with rituximab in previously untreated, advanced-stage follicular lymphoma patients anticipating that denileukin diftitox would deplete CD25+ Treg cells while rituximab would deplete malignant B cells. Patients received rituximab 375 mg/m2 weekly for 4 weeks and denileukin diftitox 18 mcg/kg/day for 5 days every 3 weeks for 4 cycles; neither agent was given as maintenance therapy. Between August 2008 and March 2010, 24 patients were enrolled. One patient died before treatment was given and was not included in the analysis. Eleven of 23 patients (48%; 95% confidence interval (CI): 27–69%) responded; 2 (9%) had complete responses and 9 (39%) had partial responses. The progression-free rate at 2 years was 55% (95%CI: 37–82%). Thirteen patients (57%) experienced grade ⩾3 adverse events and one patient (4%) died. In correlative studies, soluble CD25 and the number of CD25+ T cells decreased after treatment; however, there was a compensatory increase in IL-15 and IP-10. We conclude that although the addition of denileukin diftitox to rituximab decreased the number of CD25+ T cells, denileukin diftitox contributed to the toxicity of the combination without an improvement in response rate or time to progression.

The expression and clinical relevance of PD-1, PD-L1, and TP63 in patients with diffuse large B-cell lymphoma

Abstract Latest study showed that a novel translocation between programmed cell death ligand 1 (PD-L1) (cluster of differentiation 274) and TP63 (tumor protein 63) can be found in diffuse large B-cell lymphoma (DLBCL), resulting in their conjunct overexpression in tumor cells at RNA level. However, the expressed pattern of these 2 genes at protein level in DLBCL remains largely unknown, and the clinical relevance of PD-L1 and TP63 expression in DLBCL are also unclear. Tumor tissues from 76 Chinese DLBCL patients were immunostained for programmed cell death 1 (PD-1), PD-L1, and TP63 using the EnVision system. Clinical relevance of PD-1, PD-L1, and TP63 in 74 DLBCL were analyzed by chi-square test, the Kaplan–Meier curves with log rank test, and Coxs proportional hazards regression model. PD-1 was mainly expressed in tumor-infiltrating lymphocytes (TILs) of 39.5% patients. PD-L1 was expressed in tumor cells of 26.3% patients, and TP63 was immunostained in nucleoli of tumor cells of 31.6% cases. PD-1 expression was significantly associated with the patients’ gender and B symptoms (P = 0.032, P = 0.026). DLBCL with PD-L1 or TP63 expression in tumor cells showed low International Prognostic Index (IPI) score (P = 0.007, P = 0.009). PD-1+ TILs was related to prolonged overall survival rate (OS) of DLBCL patients (P = 0.02), whereas PD-L1 expression was associated with worse clinical outcome of patients (P = 0.049). Immunoreactivity of TP63 was not correlated with patients’ survival time. Besides, PD-1 expression, patients’ age, Ann Arbor stage, and IPI score were significant prognostic markers for OS, but PD-L1 and TP63 had no prognostic significance. PD-1, PD-L1, and TP63 are frequently expressed in DLBCL. PD-1/PD-L1/TP63 blockade may be a potential therapeutic strategy for some patients.

Genetic diversity of newly diagnosed follicular lymphoma

Follicular lymphoma (FL) is the second most common form of non-Hodgkin lymphoma (NHL) and often follows an indolent disease course with slow progression.1, 2 However, patients may develop resistant disease; in addition, transformation to a more aggressive subtype of lymphoma occurs at a rate of 2–3% per year.3, 4, 5, 6 FL arises from germinal center B cells and the most common molecular defect is t(14;18)(q32;q21) in 85–90% of the cases, which results in the IGH-BCL2 fusion gene and the overexpression of the anti-apoptotic oncogene BCL2.7 However, the t(14;18) is also observed in healthy individuals and FL patients who are in long-term remission2 suggesting the existence of additional genomic alternations that impact disease course. Recently, massive parallel exome or whole genome sequencing of FL tumors and follow-up validation studies have discovered that point mutations in genes involved in epigenetic regulation and chromatin modification, including MLL2, EZH2, CREBBP, EP300 and MEF2B, dominate the FL landscape.8, 9, 10, 11, 12 Mutations in JAK-STAT pathway genes and B-cell receptor (BCR)/NF-κB signaling genes have also been identified, but with lower frequencies.11

Whole-exome analysis reveals novel somatic genomic alterations associated with cell of origin in diffuse large B-cell lymphoma

Whole-exome analysis reveals novel somatic genomic alterations associated with cell of origin in diffuse large B-cell lymphoma

Inhibiting IL-2 signaling and the regulatory T-cell pathway using computationally designed peptides.

SummaryBackground Increased serum levels of soluble interleukin-2 (IL-2) receptor alpha (sIL-2Rα) are an indicator of poor prognosis in patients with B-cell non-Hodgkin lymphoma (NHL). By binding to IL-2, sIL-2Rα upregulates Foxp3 expression and induces the development of regulatory T (Treg) cells. Methods To inhibit the binding of IL-2 to sIL-2Rα with the goal of suppressing the induction of Foxp3 and decreasing Treg cell numbers, we developed peptides by structure-based computational design to disrupt the interaction between IL-2 and sIL-2Rα. Each peptide was screened using an enzyme-linked immunosorbent assay (ELISA), and 10 of 22 peptides showed variable capacity to inhibit IL-2/sIL-2Rα binding. Results We identified a lead candidate peptide, CMD178, which consistently reduced the expression of Foxp3 and STAT5 induced by IL-2/sIL-2Rα signaling. Furthermore, production of cytokines (IL-2/interferon gamma [IFN-γ]) and granules (perforin/granzyme B) was preserved in CD8+ T cells co-cultured with IL-2–stimulated CD4+ T cells that had been pretreated with CMD178 compared to CD8+ cells co-cultured with untreated IL-2–stimulated CD4+ T cells where it was inhibited. Conclusions We conclude that structure-based peptide design can be used to identify novel peptide inhibitors that block IL-2/sIL-2Rα signaling and inhibit Treg cell development. We anticipate that these peptides will have therapeutic potential in B-cell NHL and other malignancies.

Abstract 3287: Expression of CD14 and SIRP-α defines distinct populations of intratumoral monocytes/macrophages in B-cell non-Hodgkin lymphomas

BACKGROUND Monocytes and macrophages (mo/mΦ) are part of composition of tumor microenvironment in B-cell non-Hodgkin lymphoma (B-NHL). CD14+HLA-DRlow monocytes are immunosuppressive and this phenotype is promoted by increased expression of IL-10 in lymphoma. Despite their association with poor outcome, monocytes retain phagocytic function particularly in the presence of monoclonal antibodies and can be associated with an improved outcome in patients treated with rituximab. The aim of this study was to determine the prevalence of CD14+HLA-DRlow mo/mΦ in B-NHL tissue compared to normal tissue, and to determine whether their phenotype suggests that they are capable of phagocytic function. METHODS Tissue mo/mΦ were isolated by negative selection from 13 diagnostic B-NHL biopsy specimens and 6 normal tissues using a monocyte enrichment kit. Morphological and immunophenotypic characteristics of isolated mo/mΦ were determined by flow cytometry, immunocytochemistry and cytometry by time-of-flight (CyTOF). The purity of isolated tissue mo/mΦ was more than 95%, being confirmed by Giemsa stain and flow cytometry. RESULTS Increased numbers of CD68+ cells in initial B-NHL biopsies when compared to normal tissue was confirmed by immunohistochemistry and flow cytometry. However, CD14 expression was substantially lower than CD68 expression in the tissues suggesting that many CD68+ mo/mΦ are CD14 negative. Using a monocyte enrichment kit to isolate all mo/mΦ, we found that CD14 negative mo/mΦ constituted half the tissue mo/mΦ. Furthermore, we found by flow cytometry, CyTOF and Giemsa stain that CD14- mo/mΦ constituted 2 populations: a more frequent population of larger cells and a less common population of smaller cells. While all cells expressed CD68, the larger cells had increased expression of CD32, CD64 and HLA-DR. The CD14+ cells typically also expressed CD163 and CD33 and were a subset of the larger monocyte population, while the population of small cells was positive only for CD68 and CD45. Using CD14 and SIRP-α, we could identify 3 populations of mo/mΦ: CD14+SIRP-αhigh, CD14-SIRP-αlow and CD14-SIRP-α- cells. CD14+SIRP-αhigh cells and CD14-SIRP-αlow cells typically constitute the population of larger cells, while CD14-SIRP-α- cells constituted the population of smaller cells. Interestingly, while the CD14-SIRP-α- cells lack the typical phenotypic markers of mo/mΦ, they morphologically have the appearance of monocytic cells and this population appears expanded in lymphoma tissue. CONCLUSIONS We have identified a unique population of small mo/mΦ that have an immature phenotype and lack expression of CD14, SIRP-α, CD163, and other FcγR markers. This subset of mo/mΦ is prevalent in lymphoma and may have limited phagocytic function. This CD68+CD14-SIRP-α- mo/mΦ subpopulation may account for prognostic differences in the outcome of lymphoma patients treated with or without monoclonal antibodies. Citation Format: Ya-Ping Chen, Zhi-Zhang Yang, Jose C. Villasboas, Tammy Price-Troska, Anne J. Novak, Stephen M. Ansell. Expression of CD14 and SIRP-α defines distinct populations of intratumoral monocytes/macrophages in B-cell non-Hodgkin lymphomas. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3287.