Patient-derived follicular lymphoma spheroids recapitulate lymph node signaling and immune profile uncovering galectin-9 as a novel immunotherapeutic target

Follicular lymphoma (FL), the most common indolent non-Hodgkin lymphoma, constitutes a paradigm of immune tumor microenvironment (TME) contribution to disease onset, progression, and heterogenous clinical outcome. Here we present the first FL-Patient Derived Lymphoma Spheroid (FL-PDLS), including fundamental immune actors and features of TME in FL lymph nodes (LNs). FL-PDLS is organized in disc-shaped 3D structures composed of proliferating B and T cells, together with macrophages with an intermediate M1/M2 phenotype. FL-PDLS recapitulates the most relevant B-cell transcriptional pathways present in FL-LN (proliferation, epigenetic regulation, mTOR, adaptive immune system, among others). The T cell compartment in the FL-PDLS preserves CD4 subsets (follicular helper, regulatory, and follicular regulatory), also encompassing the spectrum of activation/exhaustion phenotypes in CD4 and CD8 populations. Moreover, this system is suitable for chemo and immunotherapy testing, recapitulating results obtained in the clinic. FL-PDLS allowed uncovering that soluble galectin-9 limits rituximab, rituximab, plus nivolumab/TIM-3 antitumoral activities. Blocking galectin-9 improves rituximab efficacy, highlighting galectin-9 as a novel immunotherapeutic target in FL. In conclusion, FL-PDLS maintains the crosstalk between malignant B cells and the immune LN-TME and constitutes a robust and multiplexed pre-clinical tool to perform drug screening in a patient-derived system, advancing toward personalized therapeutic approaches.

Mutational, immune microenvironment, and clinicopathological profiles of diffuse large B-cell lymphoma and follicular lymphoma with BCL6 rearrangement

BCL6-rearrangement (BCL6-R) is associated with a favorable prognosis of follicular lymphoma (FL), but the mechanism is unknown. We analyzed the clinicopathological, immune microenvironment (immune checkpoint, immuno-oncology markers), and mutational profiles of 10 BCL6-R-positive FL, and 19 BCL6-R-positive diffuse large B-cell lymphoma (DLBCL) cases (both BCL2-R and MYC-R negative). A custom-made panel included 168 genes related to aggressive B-cell lymphomas and FL. FL cases were nodal, histological grade 3A in 70%, low Ki67; and had a favorable overall and progression-free survival. DLBCL cases were extranodal in 60%, IPI high in 63%, non-GCB in 60%, EBER-negative; and had a progression-free survival comparable to that of DLBCL NOS. The microenvironment had variable infiltration of M2-like tumor-associated macrophages (TAMs) that were CD163, CSF1R, LAIR1, PD-L1, and CD85A (LILRB3) positive; but had low IL10 and PTX3 expression. In comparison to FL, DLBCL had higher TAMs, IL10, and PTX3 expression. Both lymphoma subtypes shared a common mutational profile with mutations in relevant pathogenic genes such as KMT2D, OSBPL10, CREBBP, and HLA-B (related to chromatin remodeling, metabolism, epigenetic modification, and antigen presentation). FL cases were characterized by a higher frequency of mutations of ARID1B, ATM, CD36, RHOA, PLOD2, and PRPRD (p < 0.05). DLBCL cases were characterized by mutations of BTG2, and PIM1; and mutations of HIST1H1E and MFHAS1 to disease progression (p < 0.05). Interestingly, mutations of genes usually associated with poor prognosis, such as NOTCH1/2 and CDKN2A, were infrequent in both lymphoma subtypes. Some high-confidence variant calls were likely oncogenic, loss-of-function. MYD88 L265P gain-of-function was found in 32% of DLBCL. In conclusion, both BCL6-R-positive FL and BCL6-R-positive DLBCL had a common mutational profile; but also, differences. DLBCL cases had a higher density of microenvironment markers.

Evolving therapeutic landscape in follicular lymphoma: a look at emerging and investigational therapies

Follicular Lymphoma (FL) is the most common subtype of indolent B cell non-Hodgkin lymphoma. The clinical course can be very heterogeneous with some patients being safely observed over many years without ever requiring treatment to other patients having more rapidly progressive disease requiring multiple lines of treatment for disease control. Front-line treatment of advanced FL has historically consisted of chemoimmunotherapy but has extended to immunomodulatory agents such as lenalidomide. In the relapsed setting, several exciting therapies that target the underlying biology and immune microenvironment have emerged, most notable among them include targeted therapies such as phosphoinositide-3 kinase and Enhancer of Zeste 2 Polycomb Repressive Complex 2 inhibitors and cellular therapies including chimeric antigen receptor T cells and bispecific T cell engagers. There are several combination therapies currently in clinical trials that appear promising. These therapies will likely reshape the treatment approach for patients with relapsed and refractory FL in the coming years. In this article, we provide a comprehensive review of the emerging and investigational therapies in FL and discuss how these agents will impact the therapeutic landscape in FL.

DC-SIGN binding to mannosylated B-cell receptors in follicular lymphoma down-modulates receptor signaling capacity

In follicular lymphoma (FL), surface immunoglobulin (sIg) carries mandatory N-glycosylation sites in the variable regions, inserted during somatic hypermutation. These glycosylation sites are tumor-specific, indicating a critical function in FL. Added glycan unexpectedly terminates at high mannose (Mann) and confers capability for sIg-mediated interaction with local macrophage-expressed DC-SIGN lectin resulting in low-level activation of upstream B-cell receptor signaling responses. Here we show that despite being of low-level, DC-SIGN induces a similar downstream transcriptional response to anti-IgM in primary FL cells, characterized by activation of pathways associated with B-cell survival, proliferation and cell-cell communication. Lectin binding was also able to engage post-transcriptional receptor cross-talk pathways since, like anti-IgM, DC-SIGN down-modulated cell surface expression of CXCR4. Importantly, pre-exposure of a FL-derived cell line expressing sIgM-Mann or primary FL cells to DC-SIGN, which does not block anti-IgM binding, reversibly paralyzed the subsequent Ca2+ response to anti-IgM. These novel findings indicate that modulation of sIg function occurs in FL via lectin binding to acquired mannoses. The B-cell receptor alternative engagement described here provides two advantages to lymphoma cells: (i) activation of signaling, which, albeit of low-level, is sufficient to trigger canonical lymphoma-promoting responses, and (ii) protection from exogenous antigen by paralyzing anti-IgM-induced signaling. Blockade of this alternative engagement could offer a new therapeutic strategy.

Biomarkers for Risk Stratification in Patients With Previously Untreated Follicular Lymphoma Receiving Anti-CD20-based Biological Therapy

Follicular lymphoma (FL) is an indolent B-cell neoplasm of germinal center origin. Standard treatment regimens consist of anti-CD20 therapy with or without chemotherapy. While high response rates to initial therapy are common, patients ultimately relapse or have progressive disease. Clinical risk factors such as the Follicular Lymphoma International Prognostic Index (FLIPI) have been identified, but there is a need for prognostic and predictive biomarkers. We studied markers of lymphoma cells and tumor microenvironment by immunohistochemistry in tissue samples from patients enrolled in 1 of 4 phase 2 trials of anti-CD20-based biological therapy for previously untreated grades 1 to 2 or 3A FL. Results were correlated with progression-free survival (PFS) and PFS status at 24 months. The 4 trials included 238 patients (51.1% male, median age: 55 y) with stage III, IV, or bulky stage II disease. By FLIPI, 24.6% had low-risk, 56.8% had intermediate-risk, and 18.6% had high-risk disease. The outcome differed significantly for patients treated with lenalidomide and rituximab (CALGB 50803) compared with the other 3 trials (median: PFS not reached vs. 3.0 y, hazard ratio=3.47, 95% confidence interval: 2.11-5.72); therefore, data were stratified by clinical trial (CALGB 50803 vs. all others) and adjusted for FLIPI risk group. Among 154 patients with available tissue, interfollicular BCL6 positivity, interfollicular CD10 positivity, and elevated Ki67 proliferation index ≥30% within neoplastic follicles were each associated with inferior PFS and a high risk of the early event by PFS status at 24 months. We identify promising biomarkers for FL risk stratification that warrant further validation in phase 3 trials.

MiR-7e-5p downregulation promotes transformation of low-grade follicular lymphoma to aggressive lymphoma by modulating an immunosuppressive stroma through the upregulation of FasL in M1 macrophages

BACKGROUND

In follicular lymphoma (FL), histologic transformation to high-grade FL and diffuse large B-cell lymphoma (DLBCL) is a critical adverse step in disease progression. Activation of the oncogene c-MYC and tumor microenvironment remodeling account for FL progression. A panel of microRNA (miRNA) was downregulated in transformed FL (tFL).

METHODS

Differentially expressed miRNAs were systematically compared in 11 lymph nodes from patients at different stages of disease. Expression of miR-7e-5p was analyzed in 46 B-cell lymphomas, including 30 FL tissues and 16 DLBCL tissues. In FL cells, transcriptional regulation of the oncogene c-MYC on its target miR-7e-5p was revealed by Chromatin Immunoprecipitation (ChIP) assay. Exosome, carrying differentially expressed miR-7e-5p was isolated and visualized by transmission electron microscope and fluorescence tracing. The effect of miR-7e-5p on recipient macrophage was determined by target gene quantification, flow cytometry, and TUNEL method in a cocultured system with miR-7e-5p-mimics or inhibitors treatment. Expression of miR-7e-5p targets, macrophage proportions, and clinical parameters were included for correlation analysis.

RESULTS

We determined that downregulation of miR-7e-5p, driven by c-MYC overexpression, was associated with poorer prognosis in FL patients. The decreased expression of miR-7e-5p in lymphoma cells led to a reduced exosomal transfer to surrounding macrophages. As a result, the target gene of miR-7e-5p, Fas ligand (FasL), was upregulated and activated the caspase signaling, which led to the apoptosis of M1 macrophages in tumor stroma. Finally, in transformed FL tissues, overexpression of FasL and activation of caspase proteins was detected in tumor stromal macrophages. Downregulation of miR-7e-5p was associated with poorer clinical outcomes.

CONCLUSION

Downregulation of exosomal miR-7e-5p induces stromal M1 macrophage apoptosis, which leads to immunosurveillance and transformation of FL.

Mediating effect of soluble B-cell activation immune markers on the association between anthropometric and lifestyle factors and lymphoma development

Sustained B-cell activation is an important mechanism contributing to B-cell lymphoma (BCL). We aimed to validate four previously reported B-cell activation markers predictive of BCL risk (sCD23, sCD27, sCD30, and CXCL13) and to examine their possible mediating effects on the association between anthropometric and lifestyle factors and major BCL subtypes. Pre-diagnostic serum levels were measured for 517 BCL cases and 525 controls in a nested case-control study. The odds ratios of BCL were 6.2 in the highest versus lowest quartile for sCD23, 2.6 for sCD30, 4.2 for sCD27, and 2.6 for CXCL13. Higher levels of all markers were associated with increased risk of chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), and diffuse large B-cell lymphoma (DLBCL). Following mutual adjustment for the other immune markers, sCD23 remained associated with all subtypes and CXCL13 with FL and DLBCL. The associations of sCD23 with CLL and DLBCL and CXCL13 with DLBCL persisted among cases sampled > 9 years before diagnosis. sCD23 showed a good predictive ability (area under the curve = 0.80) for CLL, in particular among older, male participants. sCD23 and CXCL13 showed a mediating effect between body mass index (positive) and DLBCL risk, while CXCL13 contributed to the association between physical activity (inverse) and DLBCL. Our data suggest a role of B-cell activation in BCL development and a mediating role of the immune system for lifestyle factors.

Diffuse follicular lymphoma variant with a typical diagnostic pattern and an unusually aggressive clinical presentation

Diffuse follicular lymphoma (FL) variant is a rare condition that shows distinctive clinical, morphological, immunophenotypic, and molecular features that distinguish it from classical FL. Diffuse FL variant is characterized by a predominantly diffuse growth pattern, absence of the t (14;18) IGH/BCL2 translocation, CD23 expression, and presence of 1p36 deletion. Gene mutations involving STAT6 have been reported, with nuclear expression of STAT6 and phosphorylated STAT6 detected by immunohistochemistry. Patients frequently present with inguinal node involvement and low clinical stage. We describe the case of an 80-year-old female diagnosed with diffuse FL variant, presented with a classic diagnostic pattern and an unusual aggressive clinical onset.

Mutant EZH2 Induces a Pre-malignant Lymphoma Niche by Reprogramming the Immune Response

Follicular lymphomas (FLs) are slow-growing, indolent tumors containing extensive follicular dendritic cell (FDC) networks and recurrent EZH2 gain-of-function mutations. Paradoxically, FLs originate from highly proliferative germinal center (GC) B cells with proliferation strictly dependent on interactions with T follicular helper cells. Herein, we show that EZH2 mutations initiate FL by attenuating GC B cell requirement for T cell help and driving slow expansion of GC centrocytes that become enmeshed with and dependent on FDCs. By impairing T cell help, mutant EZH2 prevents induction of proliferative MYC programs. Thus, EZH2 mutation fosters malignant transformation by epigenetically reprograming B cells to form an aberrant immunological niche that reflects characteristic features of human FLs, explaining how indolent tumors arise from GC B cells.

CXCR5+CD8+ T cells are a distinct functional subset with an antitumor activity

CXCR5 mediates homing of both B and follicular helper T (TFH) cells into follicles of secondary lymphoid organs. We found that CXCR5+CD8+ T cells are present in human tonsils and follicular lymphoma, inhibit TFH-mediated B cell differentiation, and exhibit strong cytotoxic activity. Consistent with these findings, adoptive transfer of CXCR5+CD8+ T cells into an animal model of lymphoma resulted in significantly greater antitumor activity than CXCR5-CD8+ T cells. Furthermore, RNA-Seq-based transcriptional profiling revealed 77 differentially expressed genes unique to CXCR5+CD8+ T cells. Among these, a signature comprised of 33 upregulated genes correlated with improved survival in follicular lymphoma patients. We also showed that CXCR5+CD8+ T cells could be induced and expanded ex vivo using IL-23 plus TGF-β, suggesting a possible strategy to generate these cells for clinical application. In summary, our study identified CXCR5+CD8+ T cells as a distinct T cell subset with ability to suppress TFH-mediated B cell differentiation, exert strong antitumor activity, and confer favorable prognosis in follicular lymphoma patients.

Follicular Lymphoma: Recent and Emerging Therapies, Treatment Strategies, and Remaining Unmet Needs

Follicular lymphoma (FL) is a heterogeneous disease with varying prognosis owing to differences in clinical, laboratory, and disease parameters. Although generally considered incurable, prognosis for early- and advanced-stage disease has improved because of therapeutic advances, several of which have resulted from elucidation of the biologic and molecular basis of the disease. The choice of treatment for FL is highly dependent on patient and disease characteristics. Several tools are available for risk stratification, although limitations in their routine clinical use exist. For limited disease, treatment options include radiotherapy, rituximab monotherapy or combination regimens, and surveillance. Treatment of advanced disease is often determined by tumor burden, with surveillance or rituximab considered for low tumor burden and chemoimmunotherapy for high tumor burden disease. Treatment for relapsed or refractory disease is influenced by initial first-line therapy and the duration and quality of the response. Presently, there is no consensus for treatment of patients with early or multiply relapsed disease; however, numerous agents, combination regimens, and transplant options have demonstrated efficacy. Although the number of therapies available to treat FL has increased together with an improved understanding of the underlying biologic basis of disease, the best approach to select the most appropriate treatment strategy for an individual patient at a particular time continues to be elucidated. This review considers prognostication and the evolving treatment landscape of FL, including recent and emergent therapies as well as remaining unmet needs. IMPLICATIONS FOR PRACTICE: In follicular lymphoma, a personalized approach to management based on disease biology, patient characteristics, and other factors continues to emerge. However, application of current management requires an understanding of the available therapeutic options for first-line treatment and knowledge of current development in therapies for previously untreated and for relapsed or refractory disease. Thus, this work reviews for clinicians the contemporary data in follicular lymphoma, from advances in characterizing disease biology to current treatments and emerging novel therapies.

An unusual case of pediatric-type follicular lymphoma: A case report

RATIONALE

Pediatric-type follicular lymphoma (PTFL) is a rare neoplasm with features that differ from those of adult-type follicular lymphoma. Compared to patients with adult-type follicular lymphoma, PTFL patients often show an excellent response. Preoperative diagnosis is challenging and, therefore, an accurate diagnosis is based on the findings of postoperative pathological examination and immunohistochemistry.

PATIENT CONCERNS

A 13-year-old boy presented with a slow-growing mass on the right side of his neck.

DIAGNOSES

The patient was diagnosed with PTFL based on the findings of histopathological examination and immunohistochemistry.

INTERVENTION

The mass was completely resected.

OUTCOMES

After 12 months of postoperative follow-up, the patient achieved good recovery without recurrence.

LESSONS

The optimal treatment for PTFL has not yet been defined. However, patients with PTFL always show satisfactory prognoses, regardless of treatment strategy (targeted radiotherapy, multiagent chemotherapy, or "watch and wait" strategy). Clinically, pathological and immunohistochemical analyses are necessary in the diagnoses of PTFL cases, especially for distinguishing PTFL from reactive follicular hyperplasia, to avoid unnecessary treatment.

High-Throughput Platform for B-Cell Screening Based on Fluorescent Phage-Display Technology

A system for detection of malignantly transformed cells, including follicular lymphoma Bcells, was developed and experimentally validated. The system is based on the use of bacteriophages carrying exposed ligands for pathogenic B-cell receptors. The efficiency of binding to target cells is several times higher than in systems with chemically synthesized biotinylated peptides. The new method is proposed as a noninvasive diagnostic test for mapping B-cell lymphoma and for determining the specificity of B-cell receptors and high-throughput combinatorial selection of various repertories of B cells.

Novel immunotherapy approaches to follicular lymphoma

Follicular lymphoma (FL) remains a lymphoma subtype that is remarkably sensitive to immunotherapy-based treatment strategies. Anti-CD20 antibody therapy administered as a single agent and in combination as a first-line treatment and at relapse continues to be the most broadly used therapy for this disease. Autologous and allogeneic stem cell transplantation provide meaningful durable remissions for patients with FL. However, identifying the most suitable patients and the optimal timing for these approaches has become increasingly challenging with the advent of novel therapies. Lenalidomide and phosphatidylinositol 3-kinase inhibitors are emerging as agents that can be applied in the relapsed setting. Other immunotherapy approaches, including checkpoint inhibitors and chimeric antigen receptor T cells, appear promising but remain experimental. Utilization of all forms of immunotherapy requires careful consideration of the unique toxicities associated with these agents and the means to mitigate them by selection of appropriate patients, optimal timing, and the use of supportive care.

Novel Strategies for Peptide-Based Vaccines in Hematological Malignancies

Peptides vaccination is an interesting approach to activate T-cells toward desired antigens in hematological malignancies. In addition to classical tumor associated antigens, such as cancer testis antigens, new potential targets for peptide vaccination comprise neo-antigens including JAK2 and CALR mutations, and antigens from immune regulatory proteins in the tumor microenvironment such as programmed death 1 ligands (PD-L1 and PD-L2). Immunosuppressive defenses of tumors are an important challenge to overcome and the T cell suppressive ligands PD-L1 and PD-L2 are often present in tumor microenvironments. Thus, PD-L1 and PD-L2 are interesting targets for peptide vaccines in diseases where the tumor microenvironment is known to play an essential role such as multiple myeloma and follicular lymphoma. In myelodysplastic syndromes the drug azacitidine re-exposes tumor associated antigens, why vaccination with related peptides would be an interesting addition. In myeloproliferative neoplasms the JAK2 and CALR mutations has proven to be immunogenic neo-antigens and thus possible targets for peptide vaccination. In this mini review we summarize the basis for these novel approaches, which has led to the initiation of clinical trials with various peptide vaccines in myelodysplastic syndromes, myeloproliferative neoplasms, multiple myeloma, and follicular lymphoma.

Long Non-Coding RNAs Guide the Fine-Tuning of Gene Regulation in B-Cell Development and Malignancy

With the introduction of next generation sequencing methods, such as RNA sequencing, it has become apparent that alterations in the non-coding regions of our genome are important in the development of cancer. Particularly interesting is the class of long non-coding RNAs (lncRNAs), including the recently described subclass of circular RNAs (circRNAs), which display tissue- and cell-type specific expression patterns and exert diverse regulatory functions in the cells. B-cells undergo complex and tightly regulated processes in order to develop from antigen naïve cells residing in the bone marrow to the highly diverse and competent effector cells circulating in peripheral blood. These processes include V(D)J recombination, rapid proliferation, somatic hypermutation and clonal selection, posing a risk of malignant transformation at each step. The aim of this review is to provide insight into how lncRNAs including circRNAs, participate in normal B-cell differentiation, and how deregulation of these molecules is involved in the development of B-cell malignancies. We describe the prognostic value and functional significance of specific deregulated lncRNAs in diseases such as acute lymphoblastic leukemia, chronic lymphocytic leukemia, mantle cell lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, Burkitt lymphoma and multiple myeloma, and we provide an overview of the current knowledge on the role of circRNAs in these diseases.

Composite lymphoma of follicular B-cell and peripheral T-cell types with distinct zone distribution in a 75-year-old male patient: a case study

Composite lymphoma of T-/B-cell type is rare, and follicular lymphoma composite with peripheral T-cell lymphoma (PTCL) has not previously been reported. We report such a case with both neoplastic components displaying a unique zone of distribution. A 75-year-old male patient presented with generalized lymphadenopathy. Sections of axillary lymph node demonstrated potentially 2 clonal processes, PTCL with aberrant CD20 expression and follicular lymphoma. Interestingly, the 2 neoplastic components were confined to their respective classic distribution zones, with PTCL occupying the interfollicular areas and follicular lymphoma residing in follicles. Both populations were detected by flow cytometry, but their immunophenotypes were insufficient to define clonality. Nonetheless, biclonality was demonstrated by lymphoid receptor gene rearrangement analyses. Molecular cytogenetics showed IGH/BCL2 fusion in the follicular lymphoma and amplification of IGH gene or trisomy/tetrasomy 14 in the PTCL. The current case underscores the complexity of composite lymphoma and advocates a multimodal approach to establishing the diagnosis.

Primary Cutaneous B-cell Lymphomas

B-cell lymphomas represent approximately 20% to 25% of primary cutaneous lymphomas. Within this group, most cases (>99%) are encompassed by 3 diagnostic entities: primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, and primary cutaneous diffuse large B-cell lymphoma, leg type. In this article, the authors present clinical, histopathologic, immunophenotypic, and molecular features of each of these entities and briefly discuss the rarer intravascular large B-cell lymphoma.

Percent cPRA (Calculated Panel Reactive Antibody) Value Predicts Percent of Positive Platelet Crossmatches

BACKGROUND

Platelet refractoriness or lack of platelet increase after platelet transfusion is seen in patients receiving chronic platelet transfusion support. Antibodies may develop against human platelet antigens (HPA) and/or against HLA class I antigens. Crossmatch (XM) compatible platelets or HLA-identical or HLA-compatible platelets are typically used to manage transfusion refractoriness. We aimed to determine if percent calculated Panel Reactive Antibody (% cPRA) against class I HLA antigens could predict percent positive platelet XM when looking for compatible transfusion products.

METHODS

A retrospective review of all platelet XM performed at our institution between 2008-2012 was performed, and patient characteristics recorded. For each patient, the percentage of all positive platelet XM performed was calculated and compared with the corresponding % cPRA levels against class I HLA antigens.

RESULTS

Mean and median % positive platelet XM for all 50 patients tested in the period 2008-2012 were 61% and 60% (range 0-100%), respectively. Mean and median % cPRA levels were 66% and 68% (range 0-100%), respectively. No correlation was seen between age, sex, race, or diagnosis and positive platelet XM results.

CONCLUSION

The results of our study indicate that the % cPRA correlates well with the % positive platelet XM. Thus, a higher % cPRA alerts the blood bank that additional platelets will be required for XM and/or that it would be beneficial to request HLA-identical or compatible units.

Follicular lymphoma (FL): Immunological tolerance theory in FL

The ultimate cause of follicular lymphoma (FL) remains unknown. Remarkably, almost nothing is known about immunological tolerance mechanisms that might contribute to FL development. Immunological tolerance mechanisms, like other stimuli, also induce persistent changes of B cell receptors that induce genetic instability and molecular aberrations promoting the development of a neoplasm. Using the same method as Burnet, we provide a new perspective taking advantage of the comparison of a normal linear B cell differentiation process and FL development within the framework of clonal selection theory. We propose that FL is a malignancy of cells that acquire both translocation t(14;18) and self-BCR, inducing them to proliferate and mature, resistant to negative selection. Additional genetic damage induced by non-apoptotic tolerance mechanisms, such as receptor editing, may transform a self-reactive B cell with t(14;18) into an FL. The result of tolerogenic mechanisms and genetic aberrations is the survival of FL B cell clones with similar markers and homogenous gene expression signatures despite the different stages of maturation at which the molecular damage occurs. To antagonize further growth advantage due to self-antigen recognition and chronic activation of tolerance mechanisms in the apoptosis-resistant background of FL B cells, inhibitors of BCR signaling may be promising therapeutic options.

Hepatitis C virus - associated B cell non-Hodgkin's lymphoma

The hepatitis C virus (HCV) infected patients are prone to develop bone marrow or various tissue infiltrates with monoclonal B cells, monoclonal B lymphocytosis or different types of B cell non-Hodgkin’s lymphoma (BCNHL), of which the most common are splenic marginal zone BCNHL, diffuse large BCNHL and follicular lymphoma. The association between chronic HCV infection and non Hodgkin’s lymphoma has been observed especially in areas with high prevalence of this viral infection. Outside the limitations of some studies that have been conducted, there are also geographic, environmental, and genetic factors that contribute to the epidemiological differences. Various microenvironmental signals, such as cytokines, viral antigenic external stimulation of lymphocyte receptors by HCV antigens, and intercellular interactions contribute to B cell proliferation. HCV lymphotropism and chronic antigenic stimulation are involved in B-lymphocyte expansion, as mixted cryoglobulinemia or monoclonal gammopathy of undetermined significance, which can progress to BCNHL. HCV replication in B lymphocytes has oncogenic effect mediated by intracellular HCV proteins. It is also involved in an important induction of reactive oxygen species that can lead to permanent B lymphocyte damage, as DNA mutations, after binding to surface B-cell receptors. Post-transplant lymphoproliferative disorder could appear and it has a multiclonal potentiality that may develop into different types of lymphomas. The hematopoietic stem cell transplant made for lymphoma in HCV-infected patients can increase the risk of earlier progression to liver fibrosis and cirrhosis. HCV infected patients with indolent BCNHL who receive antiviral therapy can be potentially cured. Viral clearance was related to lymphoma response, fact that highlights the probable involvement of HCV in lymphomagenesis. Direct acting antiviral drugs could be a solution for the patients who did not tolerate or respond to interferon, as they seem to be safe and highly effective. The use of chemotherapy in combination with rituximab for the treatment of BCNHL in patients infected with HCV can produce liver dysfunction. The addition of immunotherapy with rituximab can increase the viral replication, and severe complications can occure especially in patients co-infected with hepatitis B virus or immune immunodeficiency virus, in those with hepatocarcinoma, cirrhosis, or liver cytolysis. But the final result of standard immunochemotherapy applied to diffuse large BCNHL patients with HCV infection is not notably worse than in those without this viral infection. The treatment of patients chronically infected with HCV and having BCNHL is complex and requires a multidisciplinary approach and the risk / benefit ratio of rituximab treatment must be evaluated especially in those with liver cytolysis.

Follicular Lymphoma Tregs Have a Distinct Transcription Profile Impacting Their Migration and Retention in the Malignant Lymph Node

We have previously shown that regulatory T cells (Tregs) infiltrating follicular lymphoma lymph nodes are quantitatively and qualitatively different than those infiltrating normal and reactive nodes. To gain insight into how such Treg populations differ, we performed RNA sequence (RNAseq) analyses on flow sorted Tregs from all three sources. We identify several molecules that could contribute to the observed increased suppressive capacity of follicular lymphoma nodal tregs, including upregulation of CTLA-4, IL-10, and GITR, all confirmed by protein expression. In addition, we identify, and confirm functionally, a novel mechanism by which Tregs target to and accumulate within a human tumor microenvironment, through the down regulation of S1PR1, SELL (L-selectin) and CCR7, potentially resulting in greater lymph node retention. In addition we identify and confirm functionally the upregulation of the chemokine receptor CXCR5 as well as the secretion of the chemokines CXCL13 and IL-16 demonstrating the unique ability of the follicular derived Tregs to localize and accumulate within not only the malignant lymph node, but also localize and accumulate within the malignant B cell follicle itself. Such findings offer significant new insights into how follicular lymphoma nodal Tregs may contribute to the biology of follicular lymphoma and identify several novel therapeutic targets.

Clinical Safety and Immunogenicity of Tumor-Targeted, Plant-Made Id-KLH Conjugate Vaccines for Follicular Lymphoma

We report the first evaluation of plant-made conjugate vaccines for targeted treatment of B-cell follicular lymphoma (FL) in a Phase I safety and immunogenicity clinical study. Each recombinant personalized immunogen consisted of a tumor-derived, plant-produced idiotypic antibody (Ab) hybrid comprising the hypervariable regions of the tumor-associated light and heavy Ab chains, genetically grafted onto a common human IgG1 scaffold. Each immunogen was produced in Nicotiana benthamiana plants using twin magnICON vectors expressing the light and heavy chains of the idiotypic Ab. Each purified Ab was chemically linked to the carrier protein keyhole limpet hemocyanin (KLH) to form a conjugate vaccine. The vaccines were administered to FL patients over a series of ≥6 subcutaneous injections in conjunction with the adjuvant Leukine (GM-CSF). The 27 patients enrolled in the study had previously received non-anti-CD20 cytoreductive therapy followed by ≥4 months of immune recovery prior to first vaccination. Of 11 patients who became evaluable at study conclusion, 82% (9/11) displayed a vaccine-induced, idiotype-specific cellular and/or humoral immune response. No patients showed serious adverse events (SAE) related to vaccination. The fully scalable plant-based manufacturing process yields safe and immunogenic personalized FL vaccines that can be produced within weeks of obtaining patient biopsies.

Skeletal muscle radio-density is an independent predictor of response and outcomes in follicular lymphoma treated with chemoimmunotherapy

Skeletal muscle radio-density (SMD) measures muscle radiation attenuation (in Hounsfield Units, HU) on computed tomography (CT) scans. Low SMD is prognostic of poor survival in melanoma, however its significance is unknown for hematologic malignancies. We performed a single institution, retrospective review of all follicular lymphoma (FL) patients who received chemoimmunotherapy from 2004-2009. Patient demographics, FL International Prognostic Index 1 (FLIPI-1), progression free (PFS) and overall survival (OS) were collected as primary endpoints. Objective response rates (ORR) were secondary. SMD was calculated using pre-treatment CT scans. In 145 patients reviewed, median values were age 59, FLIPI-1 of 2, stage III, and 8 chemoimmunotherapy cycles received. Median PFS for those with low SMD (<36.6 and <33.1 HU for patients with BMI ≤ 25 and > 25 kg/m2, respectively) compared to those with high SMD was profoundly worse, 69.6 vs. 106.7 months (hazard ratio [HR] 1.85; p = 0.01), respectively. Median OS was not reached in patients with high SMD vs. 92.7 months in low SMD patients (HR 4.02; p = 0.0002). Multivariate analysis supported lower SMD's OS detriment (HR = 3.40; p = 0.002) independent of FLIPI-1 (HR 1.46-2.76, p = 0.05) or gender. Low SMD predicted lower ORR, 83 vs. 96% (p = 0.01). SMD predicts survival independent of FLIPI-1 and potentially chemoimmunotherapy response. SMD is an inexpensive and powerful tool that can complement FLIPI-1.

Paraneoplastic retinopathy associated with systemic follicular cell lymphoma

The authors describe two rare cases of autoimmune retinopathy associated with follicular cell lymphoma, including a 54-year-old man who experienced nyctalopia for 1 year (patient 1) and a 59-year-old man who had bilateral loss of central vision for 6 months (patient 2). Visual field testing of patient 1 revealed nonspecific defects, and multifocal electroretinogram (ERG) testing showed mildly subnormal amplitudes more pronounced in the left than the right eye. Serologic testing detected antibodies against a 47-kD protein, presumed to be alpha-enolase. Goldmann perimetry of patient 2 showed dense central scotomas, and a full-field ERG revealed reduced amplitudes of bright scotopic responses. Serological testing yielded anti-bipolar cell antibodies. A variable presentation of autoimmune retinopathy can occur in the setting of follicular cell lymphoma. Disparate serum autoantibodies may have mediated the pathogenesis of retinal degeneration in these two patients and could explain the difference in course and severity of retinopathy.

Checkpoint blockade in lymphoma

Immune checkpoint blockade therapy (CBT) was born of the combination of several elements: the understanding of some of the important immune regulation pathways in humans; the recognition that tumors can engage those pathways to evade immune responses; and the clinical development of monoclonal antibodies targeting checkpoint receptors to restore effective anti-tumor immunity. This form of therapy, focused to date mostly on the cytotoxic T-lymphocyte associated protein 4 (CTLA-4) and programmed-death 1 (PD-1) pathways, has already revolutionized the treatment of several solid tumors. Hematologic malignancies (HMs) offer a promising testing ground for this strategy, and several trials have already demonstrated evidence of therapeutic activity with checkpoint blockade, especially in lymphoma. This review will discuss the current clinical results of CBT in lymphoma in the context of their scientific underpinning, and build from this summary a projection of how the field may evolve in the near future.

B-cell receptor pathway modulators in NHL

With the recent success of the Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, and the phosphoinositide-3-kinase (PI3K) inhibitor, idelalisib, in the treatment of patients with relapsed or refractory non-Hodgkin's lymphoma (NHL), a number of new agents targeting the B-cell receptor (BCR) pathway are in clinical development. In addition, multiple trials combining these agents with conventional cytotoxic chemotherapy, immunomodulatory agents, monoclonal antibodies, or other kinase inhibitors are underway. This review will summarize the current data with the use of single agent and combination therapy with BCR inhibitors in NHL. In addition, commonly encountered as well as serious toxicities and hypothesized resistance mechanisms will be discussed. Lastly, this review will examine the future of these agents and opportunities to maneuver them into the front-line setting in selected NHL subtypes.

[Cerebral aspergillosis in an immunocompromised patient with follicular lymphoma]

We present a case of central nervous system aspergillosis in an immunocompromised 69-year-old male with a history of chemotherapeutic treatment for follicular lymphoma. The patient presented with aphasia, apraxia and confusion. An MRI of the central nervous system and Aspergillus antigen in the spinal fluid was suggestive for this invasive fungal infection. Despite treatment with voriconazole the patient succumbed to the infection. A rise in rare, severe infectious complications as presented is expected due to increasing dose-intensity of chemotherapy.

Intraclonal diversity in follicular lymphoma analyzed by quantitative ultradeep sequencing of noncoding regions

Cancers are characterized by genomic instability, and the resulting intraclonal diversity is a prerequisite for tumor evolution. Therefore, metrics of tumor heterogeneity may prove to be clinically meaningful. Intraclonal heterogeneity in follicular lymphoma (FL) is apparent from studies of somatic hypermutation (SHM) caused by activation-induced deaminase (AID) in IGH. Aberrant SHM (aSHM), defined as AID activity outside of the IG loci, predominantly targets noncoding regions causing numerous "passenger" mutations, but it has the potential to generate rare significant "driver" mutations. The quantitative relationship between SHM and aSHM has not been defined. To measure SHM and aSHM, ultradeep sequencing (>20,000-fold coverage) was performed on IGH (~1650 nt) and nine other noncoding regions potentially targeted by AID (combined 9411 nt), including the 5' untranslated region of BCL2. Single-nucleotide variants (SNVs) were found in 12/12 FL specimens (median 136 SHMs and 53 aSHMs). The aSHM SNVs were associated with AID motifs (p < 0.0001). The number of SNVs at BCL2 varied widely among specimens and correlated with the number of SNVs at eight other potential aSHM sites. In contrast, SHM at IGH was not predictive of aSHM. Tumor heterogeneity is apparent from SNVs at low variant allele frequencies; the relative number of SNVs with variable allele frequency < 5% varied with clinical grade, indicating that tumor heterogeneity based on aSHM reflects a clinically meaningful parameter. These data suggest that genome-wide aSHM may be estimated from aSHM of BCL2 but not SHM of IGH. The results demonstrate a practical approach to the quantification of intratumoral genetic heterogeneity for clinical specimens.

Parotid gland follicular lymphoma lacking both cytoplasmic and surface light chains: a rare case

Immunoglobulin light chain (LC) restriction is detected in the majority of B-cell non-Hodgkin lymphoma (B-NHL) by flow cytometric immunophenotyping (FCI) and serves as a surrogate marker of monoclonality. Even though it is known a small percentage of mature B-NHLs lacking surface LC, deficiency of both cytoplasmic and surface LCs has been reported in only three B-NHL cases. We report a primary parotid gland follicular lymphoma in a 63-year-old man and the lymphoma cells were deficient of cytoplasmic/surface LCs. Compared to previous reports, we used a more sensitive FCI method by combining both monoclonal and polyclonal anti-LC antibodies. Lacking LCs poses as a pitfall for the initial diagnosis of B-NHL, as well as for detecting minimal residual disease. It is important to be aware of this rare immunophenotypic aberrancy.

Follicular lymphoma with progression to diffuse large B-cell lymphoma and concurrent CD5-negative mantle cell lymphoma-3 entities in a lymph node

A 68-year-old woman with a history of follicular lymphoma had pathological findings of grade 3B follicular lymphoma, mantle cell lymphoma (MCL), and diffuse large B-cell lymphoma (DLBCL) identified in 1 lymph node. The DLBCL appeared to be a transformation of the follicular lymphoma. The nodules were diffusely and strongly positive for CD20, BCL6, and BCL2. CD43 highlighted smaller lymphocytes in a fraction of the nodules. BCL1 staining was variable with a mixture of nodular and mantle zone patterns. The diffuse areas showed weaker positivity for CD10, BCL2, and BCL6. CD3 and CD5 highlighted intermixed T cells. The Ki-67 proliferative index was overall estimated to be 60%. Fluorescent in situ hybridization performed on the lymph node was positive for CCND1/IGH. The patterns of BCL1 and BCL6 staining demonstrated 2 separate populations of neoplastic B lymphocytes.

Active idiotypic vaccination versus control immunotherapy for follicular lymphoma

PURPOSE

Idiotypes (Ids), the unique portions of tumor immunoglobulins, can serve as targets for passive and active immunotherapies for lymphoma. We performed a multicenter, randomized trial comparing a specific vaccine (MyVax), comprising Id chemically coupled to keyhole limpet hemocyanin (KLH) plus granulocyte macrophage colony-stimulating factor (GM-CSF) to a control immunotherapy with KLH plus GM-CSF.

PATIENTS AND METHODS

Patients with previously untreated advanced-stage follicular lymphoma (FL) received eight cycles of chemotherapy with cyclophosphamide, vincristine, and prednisone. Those achieving sustained partial or complete remission (n=287 [44%]) were randomly assigned at a ratio of 2:1 to receive one injection per month for 7 months of MyVax or control immunotherapy. Anti-Id antibody responses (humoral immune responses [IRs]) were measured before each immunization. The primary end point was progression-free survival (PFS). Secondary end points included IR and time to subsequent antilymphoma therapy.

RESULTS

At a median follow-up of 58 months, no significant difference was observed in either PFS or time to next therapy between the two arms. In the MyVax group (n=195), anti-Id IRs were observed in 41% of patients, with a median PFS of 40 months, significantly exceeding the median PFS observed in patients without such Id-induced IRs and in those receiving control immunotherapy.

CONCLUSION

This trial failed to demonstrate clinical benefit of specific immunotherapy. The subset of vaccinated patients mounting specific anti-Id responses had superior outcomes. Whether this reflects a therapeutic benefit or is a marker for more favorable underlying prognosis requires further study.

Mesenchymal stromal cells support the viability and differentiation of follicular lymphoma-infiltrating follicular helper T-cells

The biology of follicular lymphoma (FL) is largely dictated by the immune-effector and stromal cells that comprise its tumor microenvironment. FL-infiltrating T-cell populations that are thought to be fundamental to FL biology are follicular helper T-cells (TFH), follicular regulatory T-cells (TFR), a recently described population that regulates TFH activity, and regulatory T-cells (Treg). These T-cell populations have dynamic interactions with mesenchymal stromal cells (MSCs) in the tumor microenvironment. Whereas MSCs have been shown to support FL B-cell and Treg viability, their effects on FL-infiltrating TFH and TFR cells have not been described. Herein we show that MSCs support the viability of FL-infiltrating TFH and TFR, as well as Tregs, in part through an IL-6-dependent mechanism. We further demonstrate that MSCs mediate TFH to TFR conversion by inducing the expression of FoxP3 in TFH cells, demonstrating for the first time that human TFR can be derived from TFH cells. Given that the balance of TFH and TFR populations likely dictate, in part, the biology of this disease, our data support the potential for targeting MSCs as a therapeutic strategy.

Pattern of CD14+ follicular dendritic cells and PD1+ T cells independently predicts time to transformation in follicular lymphoma

PURPOSE

Transformation of follicular lymphoma is a critical event associated with a poor prognosis. The role of the tumor microenvironment in previous transformation studies has yielded conflicting results.

EXPERIMENTAL DESIGN

To define cell subtypes associated with transformation, we examined tissue specimens at diagnosis from patients with follicular lymphoma that later transformed and, using immunohistochemistry (IHC), stained for CD68, CD11c, CD21, CXCL13, FOXP3, PD1, and CD14. Cell content and the pattern of expression were evaluated. Those identified as significantly associated with time to transformation (TTT) and overall survival (OS) were further characterized by flow cytometry and multicolor IHC.

RESULTS

Of note, 58 patients were analyzed with median TTT of 4.7 years. The pattern of PD1(+) and CD14(+) cells rather than the quantity of cells was predictive of clinical outcomes. On multivariate analysis, including the follicular lymphoma international prognostic index score, CD14(+) cells localized in the follicle were associated with a shorter TTT (HR, 3.0; P = 0.004). PD1(+) cells with diffuse staining were associated with a shorter TTT (HR, 1.9; P = 0.045) and inferior OS (HR, 2.5; P = 0.012). Multicolor IHC and flow cytometry identified CD14(+) cells as follicular dendritic cells (FDC), whereas PD1(+) cells represented two separate populations, TFH and exhausted T cells.

CONCLUSION

These results identify the presence of PD1(+) T cells and CD14(+) FDC as independent predictors of transformation in follicular lymphoma. Clin Cancer Res; 20(11); 2862-72. ©2014 AACR.

Update on front-line therapy for follicular lymphoma: chemo-immunotherapy with rituximab and survival

Over the last three decades, there has been a wide range of options in the management of follicular lymphoma, including observation (watching and waiting), single-agent or combination (e.g., alkylating agents, anthracyclines or purine nucleoside analogs) radiation therapy, immunotherapy alone or in combination with chemotherapy, and interferon. A number of trials studying the treatment of follicular lymphoma patients have investigated the benefit of adding rituximab either concurrently or sequentially to chemotherapy. In the current review, these studies were selected based on the fact that they were randomized Phase III studies with two arms comparing chemotherapy alone with rituximab-based chemo-immunotherapy regimens. In September 2006, the US FDA approved the use of rituximab (Rituxan) as front-line treatment of patients with follicular lymphoma in combination with cyclophosphamide, vincristine and prednisone (R-CVP) as well as for the treatment of patients with low-grade non-Hodgkin's Lymphoma who achieve stable disease or better following first-line treatment with the same chemotherapy regimen (CVP --> R). The European Medicines Agency also approved the use of rituximab (MabThera) as front-line treatment of patients with stage III-IV disease in combination with CVP chemotherapy. In conclusion, although the clinical studies discussed in this article provide evidence for a progression-free survival benefit, overall survival advantage was clearly shown for the first time in a recent update of the initial study in patients with follicular lymphoma.

Impact of pretransplantation conditioning regimens on outcomes of allogeneic transplantation for chemotherapy-unresponsive diffuse large B cell lymphoma and grade III follicular lymphoma

Patients with chemorefractory non-Hodgkin lymphomas generally have a poor prognosis. We used the observational database of the Center for International Blood and Marrow Transplant Research to study the outcome of 533 patients with refractory diffuse large B cell lymphoma (DLBCL) or grade III follicular lymphoma (FL-III) who underwent allogeneic hematopoietic cell transplantation (allo-HCT) using either myeloablative (MA; n = 307) or reduced-intensity/nonmyeloablative conditioning (RIC/NST; n = 226) between 1998 and 2010. We analyzed nonrelapse mortality (NRM), relapse/progression, progression-free survival (PFS), and overall survival (OS). Only 45% of the patients at transplantation had a Karnofsky performance score of ≥90%. Median follow-up of surviving patients after MA and RIC/NST allo-HCT is 35 months and 30 months, respectively. At 3 years, MA allo-HCT was associated with a higher NRM compared with RIC/NST (53% versus 42%; P = .03), similar PFS (19% versus 23%; P = .40), and lower OS (19% versus 28%; P = .02), respectively. On multivariate analysis, FL-III histology was associated with lower NRM (relative risk [RR], .52), reduced risk of relapse/progression (RR, .42), and superior PFS (RR, .51) and OS (RR, .53), whereas MA conditioning was associated with reduced risk of relapse/progression (RR, .66). Despite a refractory state, a small subset of DLBCL and FL-III patients can attain durable remissions after allo-HCT. Conditioning regimen intensity was not associated with PFS and OS despite a higher risk of relapse/progression with RIC/NST allo-HCT.

Polymorphisms in pattern-recognition genes in the innate immunity system and risk of non-Hodgkin lymphoma

The pattern-recognition pathway plays an important role in infection recognition and immune responses, and previous studies have suggested an association between genetic variation in innate immunity genes and non-Hodgkin lymphoma (NHL). We evaluated NHL risk associated with genetic variation in pattern-recognition genes using data from a case-control study of NHL conducted in Connecticut women. Single nucleotide polymorphisms (SNPs) in 27 pattern-recognition genes were genotyped in 432 Caucasian incident NHL cases and 494 frequency-matched controls. Unconditional logistic regression was used to compute odds ratios (ORs) for NHL and common NHL subtypes in relation to individual SNPs and haplotypes. A gene-based analysis that adjusted for the number of tagSNPs genotyped in each gene showed a significant association with overall NHL for the MBP gene (P = 0.028), with the diffuse large B-cell lymphoma (DLBCL) subtype for the MASP2 gene (P = 0.011), and with the follicular lymphoma (FL) subtype for DEFB126 (P = 0.041). A SNP-based analysis showed that MBP rs8094402 was associated with decreased risks of overall NHL (allele risk OR = 0.72, P-trend = 0.0018), DLBCL (allele risk OR = 0.72, P-trend = 0.036), and FL (allele risk OR = 0.67, P-trend = 0.021), while MASP2 rs12711521 was associated with a decreased risk of DLBCL (allele risk OR = 0.57, P-trend = 0.0042). We also observed an increased risk of FL for DEFB126 rs6054706 (allele risk OR = 1.39, P-trend = 0.033). Our results suggest that genetic variation in pattern-recognition genes is associated with the risk of NHL or specific NHL subtypes, but these preliminary findings require replication in larger studies.

The tumor microenvironment in follicular lymphoma

Like other B-cell lymphomas, the development and progression of follicular lymphoma (FL) involves complex interactions between the neoplastic B cells and the surrounding microenvironment. Malignant B cells can manipulate the microenvironment by skewing the differentiation of immune cells, attracting regulatory T cells or suppressive monocytes, or secreting cytokines that promote an immunosuppressive environment. The importance of the microenvironment in FL has been demonstrated using methodologies such as gene expression profiling, which has shown that the nature of the tumor microenvironment predicts survival in patients with FL and may influence the response to immunotherapy and risk of transformation. Strategies that both enhance an effective antitumor response and reverse immunosuppression and dysfunction will be essential in the development of effective immunotherapeutic approaches in this disease.

Pretreatment circulating serum cytokines associated with follicular and diffuse large B-cell lymphoma: a clinic-based case-control study

BACKGROUND

Abnormal immune function is a key factor in predisposition to non-Hodgkin lymphoma (NHL). We evaluated the association of 30 cytokines individually and as a profile with diffuse large B-cell (DLBCL) and follicular (FL) lymphomas.

METHODS

We used a multiplexed assay to measure 30 cytokine concentrations in pre-treatment serum in a case-control study of 234 FL, 188 DLBCL, and 400 control participants. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age and sex, and polytomous regression was used to evaluate heterogeneity between FL and DLBCL. Principal components analysis (PCA) was used to assess cytokine profiles associated with FL and DLBCL.

RESULTS

In single cytokine modeling, we found that 12 of the 30 circulating serum cytokines were significantly (P<0.05) associated with FL and/or DLBCL after accounting for multiple testing (q<0.05). Soluble IL-2R (sIL-2R) had the strongest association with both FL (OR=6.0 for highest versus lowest tertile, 95% CI 3.8-9.5; p-trend=1.8 × 10(-21)) and DLBCL (OR=7.6, 95% CI 4.5-13.1; p-trend=7.2 × 10(-20)). IL1RA and IL-12p40 also showed similar associations for DLBCL and FL. In contrast, HGF, MIG, and MIP-1α had a stronger association with DLBCL compared to FL, and IL-6, IL-8, IL-10, IFN-γ, IP-10, and VEGF were only statistically significantly associated with DLBCL after accounting for multiple testing. However, in PCA modeling, a cytokine profile based on sIL-2R, IL-1RA, MIG, IP-10, IL-8, and IL-12p40 explained most of the variability between controls and both FL and DLBCL.

CONCLUSIONS

We identified some cytokines unique to DLBCL, but overall cytokine associations were more similar than distinct for DLBCL and FL. While these data are limited by concerns of reverse causality, they do suggest cytokines and cytokine profiles that can be prioritized in future studies.

Germline variation in complement genes and event-free survival in follicular and diffuse large B-cell lymphoma

The complement pathway plays a central role in innate immunity, and also functions as a regulator of the overall immune response. We evaluated whether polymorphisms in complement genes are associated with event-free survival (EFS) in follicular lymphoma (FL) and diffuse large B-cell (DLBCL) lymphoma. We genotyped 167 single nucleotide polymorphisms (SNPs) from 30 complement pathway genes in a prospective cohort study of newly diagnosed FL (N = 107) and DLBCL (N = 82) patients enrolled at the Mayo Clinic from 2002 to 2005. Cox regression was used to estimate hazard ratios (HRs) for individual SNPs with EFS, adjusting for FLIPI or IPI and treatment. For gene-level analyses, we used a principal components based gene-level test. In gene-level analyses for FL EFS, CFH (P = 0.009), CD55 (P = 0.006), CFHR5 (P = 0.01), C9 (P = 0.02), CFHR1 (P = 0.03), and CD46 (P = 0.03) were significant at P < 0.05, and these genes remained noteworthy after accounting for multiple testing (q < 0.15). SNPs in CFH, CFHR1, and CFHR5 showed stronger associations among patients receiving any rituximab, while SNPs from CD55 and CD46 showed stronger associations among patients who were observed. For DLBCL, only CLU (P = 0.001) and C7 (P = 0.03) were associated with EFS, but did not remain noteworthy after accounting for multiple testing (q>0.15). Genes from the regulators of complement activation (CFH, CD55, CFHR1, CFHR5, CD46) at 1q32-q32.1, along with C9, were associated with FL EFS after adjusting for clinical variables, and if replicated, these findings add further support for the role of host innate immunity in FL prognosis.

Long-term follow-up of reduced-intensity allogeneic hematopoietic stem cell transplantation for refractory or relapsed follicular lymphoma

Although allogeneic hematopoietic stem cell transplantation (HSCT) is considered the only curative treatment for refractory or relapsed follicular lymphoma (FL), transplant-related mortality (TRM) greatly interferes with the success. A variety of reduced-intensity conditionings (RICs) have been used to reduce TRM, but an optimal conditioning for FL has not been fully established. We retrospectively evaluated the outcome of allogeneic HSCT for FL with RIC consisting of fludarabine and melphalan. Nineteen adult patients with relapsed or refractory FL were conditioned with fludarabine (125 mg/m2) and melphalan (140 mg/m2), and received grafts from an HLA-identical sibling (n = 6) or an unrelated donor (n = 13). For the prophylaxis of graft-versus-host disease (GVHD), cyclosporine A or tacrolimus with short-term methotrexate was given. There were no early deaths before engraftment, and all patients achieved engraftment. Three patients died of extensive-type chronic GVHD (n = 2) or bacterial infection (n = 1) without disease progression. With a median follow-up period of 75.2 months (range: 33.3–111.9 months), 16 patients were alive without disease progression. Both the 5-year overall and progression-free survival rates were 84.2% (95% CI: 67.7–100%). These results strongly suggest that allogeneic HSCT with RIC using fludarabine and melphalan could be a promising treatment choice for refractory or relapsed FL.

The composition of the microenvironment in follicular lymphoma is associated with the stage of the disease

The role of regulatory and follicular helper T-cells as prognostic markers in follicular lymphoma was evaluated within the setting of prospective, randomized trials because the previously published results were contradictory. Two hundred sixty-four diagnostic tissue specimens from patients suffering from follicular lymphoma who received therapy within prospective randomized trials of the German Low Grade Lymphoma Study Group were analyzed immunohistochemically for FoxP3 and PD-1 expression to detect regulatory and follicular helper T-cells, respectively. We did not find any correlation between the content of regulatory and follicular helper T-cells and the time to treatment failure or overall survival in patients with advanced stages of follicular lymphoma in need of treatment. However, a perifollicular pattern of regulatory T-cells was associated with a poorer prognosis. The content of regulatory T-cells was positively and the content of follicular helper T-cells inversely correlated with a higher stage of the disease at diagnosis, implying that the microenvironment changes during tumor dissemination. This finding is independent of any therapy administered and needs to be considered when possible biomarkers related to the microenvironment of follicular lymphoma are studied.

A rare fraction of drug-resistant follicular lymphoma cancer stem cells interacts with follicular dendritic cells to maintain tumourigenic potential

Follicular lymphoma (FL) comprises nearly 25% of non-Hodgkin lymphoma cases and is clinically characterized by initial sensitivity to chemotherapy followed by relapse. FL stroma contains a special type of stromal cell found in the germinal centre of lymph nodes-the follicular dendritic cell (FDC). We first isolated tumourigenic cells from the FL cell line FLK-1 by side population (SP) technique, and found that SP cells, which express ABCG2, were enriched by chemotherapy and radiation treatments. In vitro, SP cells were attracted by and adhered to FDCs through chemokine (C-X-C motif) ligand 12/chemokine (C-X-C motif) receptor 4 (CXCL12/CXCR4) signalling. In vivo, limiting dilution assays showed SP cells were highly enriched in cancer stem cells (CSC), but required FDC for tumour formation in non-obese diabetic/severe combined immunodeficiency mice. Treatment with AMD3100, a specific CXCL12/CXCR4 inhibitor, eliminated tumour growth. These findings were then verified with FL cells isolated from an FL patient's ascitic fluid (FLA-1). Finally, we detected the ABCG2 expressing lymphoma cells in FL clinical specimens. Thus, we found that the highly tumourigenic FL cells having CSC-like activities (FL-SC) interact with FDCs in a CXCL12/CXCR4 dependent manner to resist chemotherapy. Our results indicate the importance of FL-SC and niche cell signalling in maintaining tumourigenicity. These signals represent novel targets for CSC eradication.

Pharmacokinetics and tolerability of human mouse chimeric anti-CD22 monoclonal antibody in Chinese patients with CD22-positive non-Hodgkin lymphoma

The safety and pharmacokinetics assessment of antibodies targeting CD22 (e.g., epratuzumab) have been established in western Caucasian populations, but there are no reports of the effects in Chinese populations. This dose-escalation study examines the safety, pharmacokinetics and biologic effects of multiple doses of anti-CD22 human-murine chimeric monoclonal antibody SM03 in 21 Chinese patients with CD22-positive non-Hodgkin lymphoma. Most of drug-related adverse events (AEs) were mild and reversible. Two patients experienced serious AEs (hemorrhage); one patient had grade 4 neutropenia; one patient had asymptomatic grade III prolongation of activated partial thromboplastin time (APTT). Major AEs included fever (71%), prolongation of APTT (42.8%), leukocytopenia (44.4%), alanine transaminase elevation (28.6%), elevated serum creatinine (23.8%) and injection site skin redness (14.3%). Circulating B cells transiently decreased without significant effects on T cells or immunoglobulin levels. Pharmacokinetic data revealed that mean maximum observed SM03 concentration and mean AUC from time zero to infinity increased in a dose-dependent manner up to 360 mg/m (2) SM03. Mean clearance was similar at doses ≤ 360 mg/m (2) and decreased significantly at dose 480 mg/m (2), supporting saturation of B-cell binding at 360 mg/m (2). Across all dose levels and histologies, one patient achieved partial response at 480 mg/m (2) dose; 14 patients had stable disease as best response and four patients progressed. Overall, SM03 was tolerated at doses ranging from 60-480 mg/m (2) and had potential efficacy in Chinese patients with follicular lymphoma.