CD10 and BCL-6 expression in paraffin sections of normal lymphoid tissue and B-cell lymphomas

Epstein-Barr virus reactivation induces divergent abortive, reprogrammed, and host shutoff states by lytic progression

Viral infection leads to heterogeneous cellular outcomes ranging from refractory to abortive and fully productive states. Single cell transcriptomics enables a high resolution view of these distinct post-infection states. Here, we have interrogated the host-pathogen dynamics following reactivation of Epstein-Barr virus (EBV). While benign in most people, EBV is responsible for infectious mononucleosis, up to 2% of human cancers, and is a trigger for the development of multiple sclerosis. Following latency establishment in B cells, EBV reactivates and is shed in saliva to enable infection of new hosts. Beyond its importance for transmission, the lytic cycle is also implicated in EBV-associated oncogenesis. Conversely, induction of lytic reactivation in latent EBV-positive tumors presents a novel therapeutic opportunity. Therefore, defining the dynamics and heterogeneity of EBV lytic reactivation is a high priority to better understand pathogenesis and therapeutic potential. In this study, we applied single-cell techniques to analyze diverse fate trajectories during lytic reactivation in three B cell models. Consistent with prior work, we find that cell cycle and MYC expression correlate with cells refractory to lytic reactivation. We further found that lytic induction yields a continuum from abortive to complete reactivation. Abortive lytic cells upregulate NFκB and IRF3 pathway target genes, while cells that proceed through the full lytic cycle exhibit unexpected expression of genes associated with cellular reprogramming. Distinct subpopulations of lytic cells further displayed variable profiles for transcripts known to escape virus-mediated host shutoff. These data reveal previously unknown and promiscuous outcomes of lytic reactivation with broad implications for viral replication and EBV-associated oncogenesis.

Characterization of unique B-cell populations in the circulation of people living with HIV prior to non-Hodgkin lymphoma diagnosis

People living with HIV (PLWH) are at higher risk of developing lymphoma. In this study, we performed cytometry by time-of-flight (CyTOF) on peripheral blood mononuclear cells of cART-naïve HIV+ individuals and cART-naïve HIV+ individuals prior to AIDS-associated non-Hodgkin lymphoma (pre-NHL) diagnosis. Participants were enrolled in the Los Angeles site of the MACS/WIHS Combined Cohort Study (MWCCS). Uniform Manifold Approximation and Projection (UMAP) and unsupervised clustering analysis were performed to identify differences in the expression of B-cell activation markers and/or oncogenic markers associated with lymphomagenesis. CD10+CD27- B cells, CD20+CD27- B cells, and B-cell populations with aberrant features (CD20+CD27+CXCR4+CD71+ B cells and CD20+CXCR4+cMYC+ B cells) were significantly elevated in HIV+ cART-naïve compared to HIV-negative samples. CD20+CD27+CD24+CXCR4+CXCR5+ B cells, CD20+CD27+CD10+CD24+CXCR4+cMYC+ B cells, and a cluster of CD20+CXCR4hiCD27-CD24+CXCR5+CD40+CD4+AICDA+ B cells were significantly elevated in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. A potentially clonal cluster of CD20+CXCR4+CXCR5+cMYC+AICDA+ B cells and a cluster of germinal center B-cell-like cells (CD19-CD20+CXCR4+Bcl-6+PD-L1+cMYC+) were also found in the circulation of HIV+ pre-NHL (cART-naïve) samples. Moreover, significantly elevated clusters of CD19+CD24hiCD38hi cMYC+ AICDA+ B regulatory cells were identified in HIV+ pre-NHL (cART-naïve) compared to HIV+ cART-naïve samples. The present study identifies unique B-cell subsets in PLWH with potential pre-malignant features that may contribute to the development of pre-tumor B cells in PLWH and that may play a role in lymphomagenesis.

Epstein-Barr virus reactivation induces divergent abortive, reprogrammed, and host shutoff states by lytic progression

Viral infection leads to heterogeneous cellular outcomes ranging from refractory to abortive and fully productive states. Single cell transcriptomics enables a high resolution view of these distinct post-infection states. Here, we have interrogated the host-pathogen dynamics following reactivation of Epstein-Barr virus (EBV). While benign in most people, EBV is responsible for infectious mononucleosis, up to 2% of human cancers, and is a trigger for the development of multiple sclerosis. Following latency establishment in B cells, EBV reactivates and is shed in saliva to enable infection of new hosts. Beyond its importance for transmission, the lytic cycle is also implicated in EBV-associated oncogenesis. Conversely, induction of lytic reactivation in latent EBV-positive tumors presents a novel therapeutic opportunity. Therefore, defining the dynamics and heterogeneity of EBV lytic reactivation is a high priority to better understand pathogenesis and therapeutic potential. In this study, we applied single-cell techniques to analyze diverse fate trajectories during lytic reactivation in two B cell models. Consistent with prior work, we find that cell cycle and MYC expression correlate with cells refractory to lytic reactivation. We further found that lytic induction yields a continuum from abortive to complete reactivation. Abortive lytic cells upregulate NFκB and IRF3 pathway target genes, while cells that proceed through the full lytic cycle exhibit unexpected expression of genes associated with cellular reprogramming. Distinct subpopulations of lytic cells further displayed variable profiles for transcripts known to escape virus-mediated host shutoff. These data reveal previously unknown and promiscuous outcomes of lytic reactivation with broad implications for viral replication and EBV-associated oncogenesis.

Ki67 proliferation index in follicular lymphoma is associated with favorable outcome in patients treated with R-CHOP

Follicular lymphoma (FL) is a common, indolent small B-cell lymphoma. While the Follicular Lymphoma International Prognostic Index is widely used, reliable prognostic and predictive biomarkers are needed. A recent study suggested that architectural patterns of CD10, BCL6, and Ki67 expression may correlate with progression-free survival (PFS) in FL patients treated with chemotherapy-free regimens. We examined the prognostic and predictive utility of architectural patterns of CD10, BCL6, Ki67, and FOXP1 in 90 patients treated with immunochemotherapy (bendamustine-rituximab [BR] and R-cyclophosphamide, doxorubicin, vincristine, prednisone [CHOP]). We found that high follicular Ki67 (≥30%) was associated with longer PFS in the subgroup of patients treated with R-CHOP but not among those treated with BR. Validation of this biomarker may support routine use of Ki67 as a predictive marker in FL.

Cancers associated with human gammaherpesviruses

Epstein-Barr virus (EBV; human herpesvirus 4; HHV-4) and Kaposi sarcoma-associated herpesvirus (KSHV; human herpesvirus 8; HHV-8) are human gammaherpesviruses that have oncogenic properties. EBV is a lymphocryptovirus, whereas HHV-8/KSHV is a rhadinovirus. As lymphotropic viruses, EBV and KSHV are associated with several lymphoproliferative diseases or plasmacytic/plasmablastic neoplasms. Interestingly, these viruses can also infect epithelial cells causing carcinomas and, in the case of KSHV, endothelial cells, causing sarcoma. EBV is associated with Burkitt lymphoma, classic Hodgkin lymphoma, nasopharyngeal carcinoma, plasmablastic lymphoma, lymphomatoid granulomatosis, leiomyosarcoma, and subsets of diffuse large B-cell lymphoma, post-transplant lymphoproliferative disorder, and gastric carcinoma. KSHV is implicated in Kaposi sarcoma, primary effusion lymphoma, multicentric Castleman disease, and KSHV-positive diffuse large B-cell lymphoma. Pathogenesis by these two herpesviruses is intrinsically linked to viral proteins expressed during the lytic and latent lifecycles. This comprehensive review intends to provide an overview of the EBV and KSHV viral cycles, viral proteins that contribute to oncogenesis, and the current understanding of the pathogenesis and clinicopathology of their related neoplastic entities.

Low-Grade Primary Splenic CD10-Positive Small B-Cell Lymphoma/Follicular Lymphoma

Primary splenic lymphoma (PSL) is a rare malignancy representing about 1% of all lymphoproliferative disorders, when using a strict definition that allows only involvement of spleen and hilar lymph nodes. In contrast, secondary low-grade B-cell lymphomas in the spleen, such as follicular lymphomas (FL), lymphoplasmacytic lymphoma and chronic lymphocytic leukemia/ small lymphocytic lymphoma, particularly as part of advanced stage disease, are more common. Indolent B cell lymphomas expressing CD10 almost always represent FL, which in its primary splenic form is the focus of this review. Primary splenic follicular lymphoma (PSFL) is exceedingly infrequent. This type of lymphoproliferative disorder is understudied and, in most cases, clinically characterized by splenomegaly or cytopenias related to hypersplenism. The diagnosis requires correlation of histopathology of spleen, blood and/or bone marrow with the correct immunophenotype (determined by flow cytometry and/or immunohistochemistry) and if necessary, additional molecular profiling. Management of this incurable disease is evolving, and splenectomy remains the mainstream treatment for stage I PSFL.

Application of Hans Algorithm for Subcategorization of Diffuse Large B-Cell Lymphoma in Fine-Needle Aspiration Biopsy Cytology

INTRODUCTION

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease with remarkably variable clinical presentation and outcome. Hans algorithm subclassified DLBCL into prognostically distinct molecular subtypes by using immunohistochemistry (IHC). Fine-needle aspiration biopsy cytology (FNABC) is a first-line diagnostic modality in lymphadenopathy. The study aims to perform IHC on FNABC cell blocks (CBs) for subclassifying according to the Hans algorithm and correlate with case-matched histopathology.

METHODS

This was a retrospective study carried out between January 2017 and December 2019. All DLBCL FNABC cases with CBs and smears and which had follow-up histopathology were included in the study. Detailed cytomorphological evaluation and CD10, B-cell lymphoma 6 (BCL6), and multiple myeloma oncogene 1 IHCs were performed on CBs. The cases are divided into 3 distinct molecular subtypes based on the Hans algorithm as germinal centre B-cell (GCB), activated B-cell (ABC), and unclassified subtypes. The results were compared with the final histopathology.

RESULTS

A total of 44 cases were diagnosed as DLBCL, and 33 cases with sufficient material for further IHC were included in the study. Twelve cases were of the GCB type, 19 were of the ABC type, and 2 remained unclassified. Follow-up histopathology was available in 20 cases. Overall, histopathological concordance was found in 95% of cases (19/20). The single discordant case was classified as GCB on FNABC and was ABC on histopathology.

CONCLUSION

FNABC with CBs is an acceptable alternative to biopsy for providing a complete diagnosis of DLBCL as per the current WHO classification.

Case report of an elderly woman with atypical imaging for primary central nervous system lymphoma who needed a brain biopsy for diagnosis

Primary central nervous system lymphoma (PCNSL) is a rare form of non-Hodgkin lymphoma, but its diagnosis is challenging in some cases. A brain biopsy is the gold standard for diagnosing PCNSL, but its invasiveness can be problematic. Thus, noninvasive imaging examinations have been developed for the pre-surgical diagnosis of PCNSL, including gadolinium-enhanced magnetic resonance imaging (MRI), ¹²³I-N-isopropyl-p-iodoamphetamine single-photon emission computed tomography (¹²³I-IMP SPECT), and positron emission tomography with ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG PET). Here, we report the case of a 71-year-old woman with negative imaging findings for PCNSL, but who was diagnosed with PCNSL by a brain biopsy and histological analysis. Her imaging results were negative for gadolinium-enhanced cranial MRI, with low uptake in ¹²³I-IMP SPECT and hypometabolism in ¹⁸F-FDG PET. However, a stereotactic brain biopsy from an abnormal lesion revealed that many round cells had infiltrated into the brain. Moreover, many infiltrating cells were positive for cluster of differentiation (CD)20 and CD79a, and proliferation marker protein Ki-67-positive cells accounted for nearly 80% of all cells. Based on these results, our final pathological diagnosis was PCNSL. The present case highlights the possibility of a PCNSL diagnosis even when all imaging-related examinations display negative results.

[Research of prognostic immunophenotypes in 163 patients of diffuse large B-cell lymphoma]

Objective: To screen and analyze the prognostic protein biomarkers of DLBCL, and to explore their value in the prognostic evaluation. Methods: 163 cases of confirmed DLBCLs from January 2011 to December 2016 were collected with their clinical, pathological and follow-up data, which were all from our hospital. The expression of protein markers were tested using immunohistochemical staining (IHC) . The immune phenotypes independent of the International Prognostic Index (IPI) that affect overall survival (OS) and progression-free survival (PFS) of DLBCL were explored by COX regression model, and the effect of their co-expression on the prognosis were also analyzed. Result: BCL6 negative (PFS: HR=1.652, 95%CI 1.030-2.649, P=0.037) , P53 positive (OS: HR=1.842, 95%CI 1.008-3.367, P=0.047) , and BCL2 strong positive expressions (S+) (OS: HR=2.102, 95%CI 1.249-3.537, P=0.005; PFS: HR=2.126, 95%CI 1.312-3.443, P=0.002) are adverse prognostic factors of DLBCL that are independent of IPI. BCL6(-) (PFS: HR=2.042, 95%CI 1.021-4.081, P=0.043) , P53(+) (OS: HR=3.069, 95%CI 1.244-7.569, P=0.015) and BCL2(S+) (OS: HR=2.433, 95%CI 1.165-5.082, P=0.018; PFS: HR=3.209, 95%CI 1.606-6.410, P=0.001) are adverse prognostic factors in the group of age≤60-year-old; in the group of IPI score 0-2, cases with BCL6(-) (OS: HR=2.467, 95%CI 1.322-4.604, P=0.005; PFS: HR=2.248, 95%CI 1.275-3.965, P=0.005) and BCL2(S+) (PFS: HR=2.045, 95%CI 1.119-3.735, P=0.020) have worse prognosis. The co-expression of BCL6(-) and BCL2(S+) has significant influence on prognosis of DLBCL (P=0.005 and P<0.001) , in which BCL6(+)/non-BCL2(S+) (n=86) has the best prognosis[3-year-OS (71.6±4.9) %, 3-year-PFS (67.0±5.1) %], and BCL6(-)/BCL2(S+) (n=10) has the worst prognosis[3-year-OS (20.0±12.6) %, 3-year-PFS (10.0±9.5) %]; the co-expression of BCL6(-) and P53(+) has no significant influence on prognosis (P=0.061 and P=0.089) , however, those cases with BCL6(+)/P53(-) (n=98) often get better prognosis[3-year-OS (70.6±4.7) %, 3-year-PFS (64.6±4.9) %] than others; the co-expression of P53(+) and BCL2(S+) has significant influence on prognosis of DLBCL (P<0.001 and P<0.001) , and P53(+)/BCL2(S+) (n=5) has the worst prognosis (3-year-OS and 3-year-PFS are both 0) ; BCL2(S+) cases get shorter OS and PFS, regardless of the expression of BCL6 and P53. Conclusion: The expression and co-expression of BCL6 negative, P53 positive and BCL2(S+) have certain value in the prognostic evaluation of DLBCL, especially in the group of age≤60-year-old and IPI score 0-2.

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.

Lymphocyte predominant Hodgkin lymphoma, antigen-driven after all?

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) was suggested as an entity separate from other types of Hodgkin lymphoma 40 years ago and recognized in the WHO classification in 2001. Based on its relatively benign course with late distant relapses, relation with lymph node hyperplasia with progressively transformed germinal centers, presence of clonal immunoglobulin gene rearrangements with somatic hypermutations and ongoing mutations, and relation with a number of inherited defects affecting the immune system, it has been suspected that NLPHL might be antigen-driven. Recent evidence has shown that cases of IgD-positive NLPHL are associated with infection by Moraxella catarrhalis, a common bacterium in the upper respiratory tract and in lymph nodes. This review summarizes the evidence for NLPHL as a B-cell lymphoma involving follicular T-lymphocytes normally found in germinal centers, its molecular features and relation to inherited immune defects, and its relation and differential diagnosis from similar entities. Finally, it discusses the evidence that in many cases a watch and wait policy might be a viable initial management strategy. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

High Ki67 proliferation index but not cell-of-origin subtypes is associated with shorter overall survival in diffuse large B-cell lymphoma

Background:

CD10, BCL6, and MUM1 are commonly used immunohistochemical stains for classifying diffuse large B-cell lymphoma (DLBCL), which is useful in predicting outcome. Conflicting reports of the prognostic value of other markers such as BCL2, CD23, and Ki67 proliferation index have been reported. Our objective was to correlate these immunostains and Hans classification with response to therapy and overall survival.

Materials and Methods:

A retrospective study of patients diagnosed with DLBCL from 2008–2014 at a tertiary-care cancer hospital. The slides with the IHC stains were reviewed by two independent pathologists. The clinical outcomes––assessed independently––were response to therapy and overall survival. The treatment response evaluation was based on the new Lugano classification. Statistical analyses were conducted using the Fisher’s exact test and Kaplan–Meier survival curves. Significance was set at P < 0.05.

Results:

Forty-one patients were included in the study with a known Hans classification, available clinical data, and at least 5-year follow-up. CD10 immunostain was reported in all patients, whereas CD23 was the least reported in only four patients. No significant association was observed between CD10, BCL6, MUM1, BCL2, and both Response to therapy and overall survival. Owing to few cases reported CD23 immunostain, further analysis of association is not reported. High Ki67 proliferative index of >80% was statistically significantly associated with shorter overall survival and not statistically significant associated with no response to therapy. Hans classification subtypes were not predictive in regard to therapy response.

Conclusion:

High Ki67 expression (>80%) was associated with shorter overall survival in DLBCL. Hans classification subtypes were not predictive.

Long Non-Coding RNA Paternally Expressed Imprinted Gene 10 (PEG10) Elevates Diffuse Large B-Cell Lymphoma Progression by Regulating Kinesin Family Member 2A (KIF2A) via Targeting MiR-101-3p

Background

Diffuse large B-cell lymphoma (DLBCL) is a common malignant tumor in the immune system with high mortality. We investigated the functional effects of long non-coding RNA paternally expressed imprinted gene 10 (PEG10) on DLBCL progression.

Material/Methods

Real-time quantitative polymerase chain reaction was used to measure the level of PEG10, kinesin family member 2A (KIF2A) and microRNA-101-3p (miR-101-3p) in DLBCL tissues and cell lines. The relative protein level was detected by western blot analysis. The biological behaviors including cell proliferation, apoptosis, migration, and invasion were determined by MTT assay, flow cytometry analysis, and Transwell assays, respectively. Bioinformatics analysis and dual-luciferase reporter assay were performed to evaluate the interaction among PEG10, miR-101-3p, and KIF2A.

Results

PEG10 and KIF2A level were significantly upregulated, while miR-101-3p was downregulated in DLBCL tissues and cells. PEG10 positively regulated KIF2A level in DLBCL. PEG10, or KIF2A deletion significantly inhibited the proliferative, migratory, and invasive abilities of DLBCL cells and elevated cell apoptosis in DLBCL cells. KIF2A upregulation partially reversed the effects of PEG10 downregulation on cell growth, metastasis, and apoptosis in DLBCL. Moreover, PEG10 negatively regulated miR-101-3p level and miR-101-3p upregulation exerted inhibition effects on the progression of DLBCL. Besides, miR-101-3p was a target of PEG10 and miR-101-3p could directly target KIF2A. PEG10 promoted KIF2A level by sponging miR-101-3p.

Conclusions

Our findings revealed that PEG10 played an oncogenic role in DLBCL progression, which might be a potential target for the treatment of DLBCL.

EBV microRNA-BHRF1-2-5p targets the 3'UTR of immune checkpoint ligands PD-L1 and PD-L2

Epstein-Barr virus-positive (EBV+) diffuse large B-cell lymphomas (DLBCLs) express high levels of programmed death ligand 1 (PD-L1) and PD-L2. MicroRNA (miR) regulation is an important mechanism for the fine-tuning of gene expression via 3'-untranslated region (3'UTR) targeting, and we have previously demonstrated strong EBV miR expression in EBV+ DLBCL. Whereas the EBV latent membrane protein-1 (LMP1) is known to induce PD-L1/L2, a potential counterregulatory role of EBV miR in the fine-tuning of PD-L1/L2 expression remains to be established. To examine this, a novel in vitro model of EBV+ DLBCL was developed, using the viral strain EBV WIL, which unlike common laboratory strains retains intact noncoding regions where several EBV miRs reside. This enabled interrogation of the relationship among EBV latency genes, cell of origin (COO), PD-L1, PD-L2, and EBV miRs. The model successfully recapitulated the full spectrum of B-cell differentiation, with 4 discrete COO phases: early and late germinal center B cells (GCBs) and early and late activated B cells (ABCs). Interestingly, PD-L1/L2 levels increased markedly during transition from late GCB to early ABC phase, after LMP1 upregulation. EBV miR-BamHI fragment H rightward open reading frame 1 (BHRF1)-2-5p clustered apart from other EBV miRs, rising during late GCB phase. Bioinformatic prediction, together with functional validation, confirmed EBV miR-BHRF1-2-5p bound to PD-L1 and PD-L2 3'UTRs to reduce PD-L1/L2 surface protein expression. Results indicate a novel mechanism by which EBV miR-BHRF1-2-5p plays a context-dependent counterregulatory role to fine-tune the expression of the LMP1-driven amplification of these inhibitory checkpoint ligands. Further identification of immune checkpoint-targeting miRs may enable potential novel RNA-based therapies to emerge.

Contribution of LTi and TH17 cells to B cell aggregate formation in the central nervous system in a mouse model of multiple sclerosis

Background

In a subgroup of patients suffering from progressive multiple sclerosis (MS), which is an inflammation-mediated neurodegenerative disease of the central nervous system (CNS), B cell aggregates were discovered within the meninges. Occurrence of these structures was associated with a more severe disease course and cortical histopathology. We have developed the B cell-dependent MP4-induced experimental autoimmune encephalomyelitis (EAE) as a mouse model to mimic this trait of the human disease. The aim of this study was to determine a potential role of lymphoid tissue inducer (LTi) and T_H17 cells in the process of B cell aggregate formation in the MP4 model.

Methods

We performed flow cytometry of cerebellar and splenic tissue of MP4-immunized mice in the acute and chronic stage of the disease to analyze the presence of CD3⁻CD5⁻CD4⁺RORγt⁺ LTi and CD3⁺CD5⁺CD4⁺RORγt⁺ T_H17 cells. Myelin oligodendrocyte glycoprotein (MOG):35–55-induced EAE was used as B cell-independent control model. We further determined the gene expression profile of B cell aggregates using laser capture microdissection, followed by RNA sequencing.

Results

While we were able to detect LTi cells in the embryonic spleen and adult intestine, which served as positive controls, there was no evidence for the existence of such a population in acute or chronic EAE in neither of the two models. Yet, we detected CD3⁻CD5⁻CD4⁻RORγt⁺ innate lymphoid cells (ILCs) and T_H17 cells in the CNS, the latter especially in the chronic stage of MP4-induced EAE. Moreover, we observed a unique gene signature in CNS B cell aggregates compared to draining lymph nodes of MP4-immunized mice and to cerebellum as well as draining lymph nodes of mice with MOG:35–55-induced EAE.

Conclusion

The absence of LTi cells in the cerebellum suggests that other cells might take over the function as an initiator of lymphoid tissue formation in the CNS. Overall, the development of ectopic lymphoid organs is a complex process based on an interplay between several molecules and signals. Here, we propose some potential candidates, which might be involved in the formation of B cell aggregates in the CNS of MP4-immunized mice.

Characterization of the thymus in Lrp4 myasthenia gravis: Four cases

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction. Most patients have pathogenic autoantibodies against the acetylcholine receptor (AChR). In the last years a novel subpopulation of MG patients has been described that harbors antibodies against low-density lipoprotein receptor-related protein 4 (Lrp4), another postsynaptic neuromuscular antigen. In early-onset AChR MG (EOMG), the thymus plays an important role in immunopathogenesis, and early thymectomy is beneficial. It is still unknown if the thymus plays any role in Lrp4-MG. In this pilot study, we compared thymus samples from four patients with Lrp4-MG (one pre-treated with immunosuppressive drugs), four non-MG controls and five EOMG patients (not pretreated with immunosuppressive drugs). Immunohistochemistry of the Lrp4-MG thymi revealed normal architecture, with normal numbers and distribution of B-cells, lymphoid follicles and Hassall's corpuscles. Primary CD23⁺ lymphoid follicles were similarly infrequent in Lrp4-MG and control thymic sections. In none of the control or Lrp4-MG thymi did we find secondary follicles with CD10⁺ germinal centers. These were evident in 2 of the 5 EOMG thymi, where primary lymphoid follicles were also more frequent on average, thus showing considerable heterogeneity between patients. Even if characteristic pathological thymic changes were not observed in the Lrp4 subgroup, we cannot exclude a role for the thymus in Lrp4-MG pathogenesis, since one Lrp4-MG patient went into clinical remission after thymectomy alone (at one year follow-up) and one more improved after thymectomy in combination with immunosuppressive therapy.

Indolent T-cell-rich small B-cell hepatic lymphoma in a Golden Retriever

An 11-year-old female spayed Golden Retriever presented for an incidentally found liver mass. The hepatic mass and intra-abdominal lymph nodes had a marked heterogeneous T-cell population and far fewer numbers of small clonal B cells. This T-cell-rich small B-cell lymphoma had a unique histological pattern and indolent clinical course.

Expression and clinical significance of miR-23a and MTSS1 in diffuse large B-cell lymphoma

The present study investigated the expression and clinical significance of micro-ribonucleic acid-23a (miR-23a) and metastasis suppressor 1 (MTSS1) in diffuse large B-cell lymphoma (DLBCL). A total of 70 cases of tumor tissues of patients with DLBCL and 30 cases of reactive lymphoid hyperplasia tissues were collected. OCI-LY10 cell was transfected with miR-23a antisense oligonucleotide (miR-23a ASO). The expression of miR-23a and MTSS1 in tumor tissues of patients with DLBCL and reactive lymphoid hyperplasia tissues were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry. Spearmans test was used for correlation analysis was also performed for their expression. The relationship of the expressions of miR-23a and MTSS1 with the pathological parameters of patients with DLBCL was further analyzed. The DLBCL OCI-LY10 cells were cultured in vitro, and gene silencing downregulated the expression of miR-23a in OCI-LY10 cells. The expression of miR-23a was studied via RT-qPCR, and the effect of downregulation of miR-23a on MTSS1 protein expression was determined by western blot analysis. Moreover, the effects of miR-23a on the proliferation, metastasis and invasion capacities of OCI-LY10 cells were observed by both methyl thiazolyl tetrazolium (MTT) assay and Transwell chamber assay. The results of RT-qPCR showed that the mRNA expression of miR-23a in DLBCL tissues was significantly higher than that of reactive hyperplasia tissues. Immunohistochemical results revealed that the positive expression rate of MTSS1 in DLBCL tissues (30.00%) was significantly lower in comparison to reactive hyperplasia tissues (90.00%). Correlation analysis revealed that the miR-23a expression had a significant negative correlation with MTSS1 expression (r=-0.538, p=0.01). The expression of miR-23a and MTSS1 were correlated with the Ann Arbor staging, extranodal invasion and International Prognostic Index (IPI) scores of patients (p<0.05). However, they had no significant correlation with the sex and age of patients (p>0.05). After the downregulation of miR-23a expression, the MTSS1 protein expression in OCI-LY10 cells showed a significant increase. However, the proliferation, metastasis and invasion capacities of OCI-LY10 cells were obviously decreased. In conclusion, miR-23a promoted the proliferation, invasion and metastasis of DLBCL OCI-LY10 cells through the targeted inhibition of MTSS1. The high expression of miR-23a and the low expression of MTSS1 protein could be used as reference indexes for the prognosis of DLBCL.

Clinicopathological Analysis of 320 Cases of Diffuse Large B-cell Lymphoma Using the Hans Classifier

The estimation of clinical prognosis for diffuse large B-cell lymphoma (DLBCL) with a quick, cost-efficient method is necessary because of the clinical heterogeneity of this disease, which leads to death, relapsed or refractory disease in approximately 40% of patients. We analyzed 320 cases diagnosed from 2007 to 2013 treated with R-CHOP therapy at Tokai University Hospital and associated institutions. DLBCL was classified according to the cell-of-origin using the Hans algorithm [germinal center B-cell-like (GCB) vs non-GCB subtypes], and into 6 subgroups derived from combinations of CD10, BCL6 and MUM1 markers. The percentage of GCB and non-GCB (NGCB) subtypes was 35% and 65%, respectively. GCB-DLBCL was characterized by lower BCL2 immunohistochemical expression, extranodal sites ＜1, better therapeutic response, and favorable overall survival (OS) and progression free survival (PFS) (P＜0.01). The most frequent subgroup was NGCB-1 (CD10^-BCL6⁺MUM1⁺, 51%) followed by GCB-1 (CD10⁺BCL6^+or-MUM1⁺, 21%), NGCB-2 (CD10^-BCL6^-MUM1⁺, 13%), GCB-2 (CD10⁺BCL6^+or-MUM1^-, 10%), GCB-3 (CD10^-BCL6⁺MUM1^-, 4%) and NGCB-3 (CD10^-BCL6^-MUM1^-, 2%). In comparison with GCB-2 and GCB-3 (both MUM1^-), the GCB-1 (MUM1⁺) was characterized by favorable PFS (5-year PFS 84% vs 65%, OR 0.368, P＜0.05), independent of high LDH (associated with unfavorable PFS, OR 7.04, P＜0.01) in the multivariate analysis. This predictive value of MUM1 was independent of CD10. Interestingly, triple-negative NGCB-3 tended to have a more favorable prognosis than the other NGCB subgroups. In conclusion, the Hans classifier is a valid method to evaluate the prognosis of DLBCL NOS. In the GCB subtypes, GCB subtypes, MUM1-positivity is associated with a more favorable outcome (PFS).

Reactive Lymphoid Hyperplasia with Giant Follicles Associated with a Posttherapeutic State of Hematological Malignancies. A Report of Eight Cases

Aims and background

To further clarify the clinicopathological, molecular genetic and karyotypic findings of reactive lymph node hyperplasia with giant follicles (RLHGF) associated with a posttherapeutic state of hematological malignancies, we studied eight such cases.

Methods

Using formalin-fixed, paraffin-embedded sections, histological, immunohistochemical, in situ hybridization (ISH), and polymerase chain reaction (PCR) were performed.

Results

Six patients had a history of malignant lymphoma (diffuse large B-cell lymphoma [DLBCL] = 4, marginal zone B-cell lymphoma = 2), and two had acute myeloid leukemia (AML). Six patients initially presented with lymphadenopathy of the head and neck area and the remaining one presented with swelling of the tonsil. All seven cases demonstrating analyzable metaphases showed a normal karyotype. Histologically, all eight lesions were characterized by numerous enlarged, bizarre-shaped coalescing lymphoid follicles with follicular lysis. Immunohistochemical and flow cytometry study demonstrated the reactive nature of the B cells in all eight lesions. However, three of our eight cases demonstrated immunoglobulin heavy-chain (IgH) gene rearrangement on PCR study. Different clonal bands were detected in the initial lymphomatous tissue and RLHGF in one of the studied cases. There was no development of B-cell lymphoma or recurrence of B-cell lymphoma in any of the three lesions demonstrating IgH rearrangement. There were no human herpes virus type-8+ or human immunodeficiency virus type-1+ cells in any of the eight lesions. ISH demonstrated Epstein-Barr virus (EBV)-encoded small RNA (EBER)+ cells in only two lesions. PCR analyses demonstrated that there was no Toxoplasma gondii DNA in any of the eight lesions.

Conclusions

As suggested in RLHGF posttransplant, RLHGF arising after therapy for hematological malignancies is also a consequence of chronic stimulation in the setting of immune deregulation rather than various infectious agents. It is important for pathologists and clinicians to be aware of this type of lesion in diagnostic practice.

Bendamustine plus Rituximab Versus R-CHOP as First-Line Treatment for Patients with Follicular Lymphoma Grade 3A: Evidence from a Multicenter, Retrospective Study

BACKGROUND

Rituximab plus bendamustine (R-B) has been demonstrated to improve outcomes and reduce toxicity compared with rituximab, cyclophosphamide, doxorubicin, and prednisone (R-CHOP) in follicular lymphoma (FL). Nevertheless, in clinical practice, many centers still prefer R-CHOP to R-B in patients with FL grade 3A (FL3A). Therefore, we retrospectively assessed patients with FL3A treated with either R-CHOP or R-B in five European cancer centers and compared their outcomes.

MATERIALS AND METHODS

We retrospectively assessed 132 patients affected by FL grade 3A treated with either R-B or R-CHOP in the first line and evaluated outcome and toxicity according to the type of treatment. This study included 101 patients who were a subgroup of a previously published cohort.

RESULTS

R-B was less toxic and achieved a similar percentage of complete remissions compared with R-CHOP (97% vs. 96%, p = .3). During follow-up, 10 (16%) patients relapsed after R-B and 29 (41%) after R-CHOP (p = .001), leading to a median progression-free survival (PFS) of 15 versus 11.7 years, respectively (p = .03). Furthermore, R-B overcame the negative prognostic impact of BCL2 expression (15 vs. 4.8 years; p = .001). However, median overall survival was similar between both groups (not reached for both; p = .8).

CONCLUSION

R-B as a first-line treatment of FL3A is better tolerated than R-CHOP and seems to induce more profound responses, leading to a significantly lower relapse rate and prolonged PFS. Therefore, R-B is a valid treatment option for FL grade 3A.

IMPLICATIONS FOR PRACTICE

Rituximab plus bendamustine (R-B) has shown to be less toxic and more effective than rituximab, cyclophosphamide, doxorubicin, and prednisone (R-CHOP) in follicular lymphoma grade 3A. Although both regimens can induce a complete remission in >95% of patients, relapses occur more frequently after R-CHOP than R-B, leading to a significantly longer progression-free survival in the latter. R-B is also able to overcome the impact of negative prognosticators, such as BCL2 expression. However, because of the indolent course of this disease and efficient salvage treatments, overall survival was similar in both treatment groups. Therefore, R-B is a valid treatment option in this patient setting.

Prognostic Significance of in situ Phenotypic Marker Expression in Diffuse Large B-cell Lymphomas

Diffuse large B-cell lymphomas (DLBCL) are the most common lymphoid malignancies, and encompass all malignant lymphomas characterized by large neoplastic cells and B-cell derivation. In the last decade, DLBCL has been subjected to intense clinical, phenotypic and molecular studies, and were found to represent a heterogeneous group of tumors. These studies suggested new disease subtypes and variants with distinct clinical characteristics, morphologies, immunophenotypes, genotypes or gene expression profiles, associated with distinct prognoses or unique sensitivities to particular therapy regimens. Unfortunately, the reliability and reproducibility of the molecular results remains unclear due to contradictory reports in the literature resulting from small sample sizes, referral and selection biases, and variable methodologies and cut-off levels used to determine positivity. Here, we review phenotypic studies on the prognostic significance of protein expression profiles in DLBCL and reconsider our own retrospective data on 301 primary DLBCL cases obtained on a previously validated tissue microarray in light of powerful statistical methods of determining optimal cut-off values of phenotypic factors for prediction of outcome.

Immunohistochemical profile and prognostic significance in primary central nervous system lymphoma: Analysis of 89 cases

The majority of primary central nervous system lymphomas (PCNSLs) are diffuse large B cell lymphoma, characterized by poor prognosis. In the present study, the expression of cluster of differentiation (CD)10, B cell lymphoma (BCL)-6, multiple myeloma-1 (MUM-1), BCL-2, CD138 and Ki-67 was analyzed by immunohistochemistry in 89 Chinese PCNSL cases, and the potential prognostic significance was evaluated. CD10, BCL-6, MUM-1, BCL-2 and CD138 were positive in 16.9 (15/89), 51.7 (46/89), 92.1 (82/89), 73.3 (63/86) and 0% (0/65) of all cases, respectively. According to the Hans algorithm, 71 patients (79.8%) were classified into the non-germinal center B cell-like (non-GCB) group, indicating a post-germinal center origin of PCNSL. The median follow-up time of 73 patients was 13 months [95% confidence interval (CI), 10.93-15.08]. The median overall survival (OS) time was 45.3 months (95% CI, 25.01-65.59) and the median progression-free survival (PFS) time was 30.0 months (95% CI, 13.43-46.57). Age (>60 years) was associated with a shorter OS time (P=0.009). Ki-67 (cutoff point 90%) was associated with shorter OS (P=0.037) and shorter PFS (P=0.039) times. No other immunohistochemical markers were associated with prognosis. On multivariate analysis, age (>60 years) was associated with shorter OS time (P=0.038), but immunophenotype and expression status of Ki-67, CD10, BCL-6 and BCL-2 did not predict prognosis. In conclusion, high Ki-67 expression may predict poor prognosis in PCNSL. The present study was limited by its sample size and short follow-up time. This requires more evidence to further clinical study.

Diagnostic Algorithm of Common Mature B-Cell Lymphomas by Immunohistochemistry

CONTEXT

- Different types of mature B-cell lymphomas, including plasma cell neoplasms, exhibit distinct immunohistochemical profiles, which enable them to be correctly diagnosed. However, except for rare examples of lymphoma-specific immunohistochemistry, such as cyclin D1 in mantle cell lymphoma and annexin A1 in hairy cell leukemia, immunohistochemical profiles of mature B-cell lymphomas overlap and lack specificity.

OBJECTIVES

- To systemically review immunohistochemical features associated with commonly encountered mature B-cell lymphomas based on the presence or absence of CD5 and CD10; to review the immunophenotypic profile of plasma cells derived from plasma cell myelomas and B-cell lymphomas; and to review a group of rare, aggressive B-cell lymphomas with antigen expression features of plasma cells.

DATA SOURCES

- Published and PubMed-indexed English literature was reviewed.

CONCLUSIONS

- Although the presence or absence of CD5 and CD10 expression should be included in the initial immunohistochemistry screening panel for mature B-cell lymphomas, appropriate and judicial use of other B-cell antigens is necessary to ensure correct diagnoses. Furthermore, although the status of CD5 and CD10 expression is associated with certain prototypes of B-cell lymphomas, their expression is not specific. Plasma cells from plasma cell neoplasias and B-cell lymphomas exhibit overlapping but relatively distinct immunophenotypes; thus, a panel of immunohistochemical markers (CD19, CD45, CD56, and CD117) can be employed for their proper identification. Lastly, CD138 staining results are almost always positive in a group of aggressive B-cell lymphomas with plasmablastic features, including plasmablastic plasma cell myeloma, plasmablastic lymphoma, and ALK-1⁺ large B-cell lymphoma.

Reactive Lymphoid Hyperplasia of the Lymph Nodes with Giant Follicles: A Clinicopathologic Study of 14 Japanese Cases, with Special Reference to Epstein-Barr Virus Infection

To clarify the clinicopathologic and immunohistochemical features of reactive lymphoid hyperplasia with giant follicles (RHGF) among Japanese, 14 patients were studied. The subjects consisted of 9 males and 5 females, ranging in age from 9 to 61 years, with a mean age of 30 years and a median age of 24 years. None of the patients exhibited systemic symptoms. The affected lymph nodes were located in the head and neck area except in 1 case. At the time of lymph node biopsy, 1 patient was diagnosed as having acute infectious mononucleosis (IM) and 2 patients had a recent history of acute IM. One each with myelogenous leukemia or diffuse large B-cell lymphoma had a history of peripheral blood stem cell transplantation. There were no recurrences during follow-up periods ranging from 3 to 50 months. Histologically, 14 lesions were characterized by numerous enlarged, coalescing lymphoid follicles with distortion rather than effacement of the lymph node architecture. By in situ hybridization, Epstein-Barr virus (EBV) genomes were demonstrated in 5 (36%) of 14 cases. The present study indicates that a portion of RHGF appears to represent a histologic finding of acute IM. Moreover, as previously stated, RHGF should be differentiated from follicular lymphoma, particularly the floral variant.

Follicular Colonization of Nodal Marginal-Zone B-Cell Lymphoma Resembling Follicular Lymphoma: Report of 6 Cases

The formation of neoplastic B-cell follicles is accepted as a diagnostic criterion of follicular lymphoma. However, extranodal marginal-zone B-cell lymphomas (MZBLs) of mucosa-associated lymphoid tissue (MALT) type also sometimes contain numerous lymphoid follicles and may even have a predominantly follicular growth pattern. However, morphologic, immunohistochemical, and genotypic findings suggest that lymphoid follicles in extranodal MZBLs are neoplastic follicles formed as the result of colonization of previously reactive follicles by tumor cells (centrocyte-like cells). We present here 6 cases of nodal MZBL demonstrating a follicular growth pattern. Immunohistochemical study demonstrated that the tumor cells were CD10-, CD20+, CD79a+,CD 138-, Bcl-2+, Bcl-6and IRF4+. Residual nonneoplastic follicular center cells were CD1O+, CD20+, CD79a+, Bcl-2-, and Bcl-6+. CD21/CD23 immunostain demonstrated a disrupted follicular dendritic cell pattern characteristic of follicular colonization in extranodal MZBL of MALT type. Taken in conjunction with the morphologic findings, nodal MZBL may also show a follicular growth pattern similar to extranodal MZBL of MALT type. The marginal-zone nature is most recognizable on immunohistochemistry, although the histologic appearance alone may cause some diagnostic problems. It is important for pathologists to consider this type of lesion in diagnostic practice.

Pediatric Hodgkin lymphoma in a South Indian regional cancer center: its immunomorphology, tumor-associated macrophages, and association with Epstein-Barr virus

Pediatric Hodgkin lymphoma (HL) comprises approximately a fifth of all patients with HL in India. Seventy-four cases of pediatric classical Hodgkin Lymphoma (cHL) from a regional cancer center in southern India were analyzed on a tissue microarray (TMA) for the stage of B-cell differentiation of the Hodgkin/Reed Sternberg (HRS) cell by immunohistochemistry (IHC) using CD10, bcl6, MUM1/IRF4, and CD 138. Fifty-two of seventy-four (70.3%) cases were of late germinal center/early post-germinal center phenotype (CD10-/bcl6-/MUM1+/CD138-). Epstein-Barr virus (EBV) association using Epstein-Barr virus encoded RNA (EBER) RISH and EBV-LMP1 immunohistochemistry (IHC) revealed an EBV association of 93%. Tumor-associated macrophages (TAM) in the microenvironment were also assessed on the TMA by CD68 IHC, and most cases (59.7%) showed >25% TAMs, with no case showing ≤5%. These findings indicate that pediatric cHL in India is a tumor, predominantly, of late germinal center/early post-germinal center B cells, is almost invariably EBV associated, and with a high number of TAMs in the microenvironment. This latter finding suggests that criteria other than TAM scores need to be developed for risk stratification of pediatric EBV-associated HL especially in developing countries.

Central nervous system infiltrates are characterized by features of ongoing B cell-related immune activity in MP4-induced experimental autoimmune encephalomyelitis

In multiple sclerosis (MS) lymphoid follicle-like aggregates have been reported in the meninges of patients. Here we investigated the functional relevance of B cell infiltration into the central nervous system (CNS) in MP4-induced experimental autoimmune encephalomyelitis (EAE), a B cell-dependent mouse model of MS. In chronic EAE, B cell aggregates were characterized by the presence of CXCL13(+) and germinal center CD10(+) B cells. Germline transcripts were expressed in the CNS and particularly related to TH17-associated isotypes. We also observed B cells with restricted VH gene usage that differed from clones found in the spleen. Finally, we detected CNS-restricted spreading of the antigen-specific B cell response towards a myelin and a neuronal autoantigen. These data imply the development of autonomous B cell-mediated autoimmunity in the CNS in EAE - a concept that might also apply to MS itself.

MYC deregulation in lymphoid tumors: molecular mechanisms, clinical consequences and therapeutic implications

MYC is one of the most frequently deregulated oncogenes in human malignancies. It encodes a leucine zipper transcription factor that modulates a broad spectrum of cellular genes responsible for enhancing cell proliferation, cellular metabolism, growth, angiogenesis, metastasis, genomic instability, stem cell self-renewal and reduced differentiation. MYC functions predominantly as an amplifier of expression of already active genes, potentiating the pre-existing transcriptional program, although it can also repress certain transcriptional targets. In mouse models, MYC induces lymphomas, but requires cooperation with other lesions, including inactivation of the p53 pathway, structural alterations of BCL2 family members, or increased PI3K activity. In human B-cell tumors, MYC rearrangements involving the 8q24 region and immunoglobulin heavy or light genes are a hallmark of Burkitt lymphoma (BL), but can also occur in other lymphoid malignancies, that include diffuse large B-cell lymphoma (DLBCL), B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma (BCLU), plasma cell myeloma (PCM), mantle cell lymphoma (MCL) and plasmablastic lymphoma. For non-BL lymphoid malignancies, MYC fusions represent secondary genetic events and exist in the context of complex karyotypes. Regardless of the mechanism deregulating MYC, lymphomas over-expressing MYC are addicted to this oncogene, highlighting the potential clinical utility of MYC targeting strategies. Several promising approaches for pharmaceutical intervention have been suggested which are now in preclinical or clinical development. Herein, we therefore review the molecular pathogenetic mechanisms associated with MYC deregulation in human B-cell lymphomas and their implications for therapies targeting MYC.

Clinicopathologic Study of Cutaneous Pseudolymphomas

A study was conducted to determine the clinical and histopathologic findings of cutaneous pseudolymphomas. In the period between July of 1989 and December of 2002, 42 cases were collected. Clinical records and pathology slides of the patients were reviewed retrospectively. A striking common clinical feature was a pruritic papule, nodule, or plaque with a smooth surface on the head and neck. The histologic patterns were diverse, MF-like, perivascular/periadnexal, nodular, diffuse, pseudolymphomatous folliculitis, and acral pseudolymphomatous angiokeratoma of children (APACHE) patterns. The most common pattern was a multinodular pattern with an extension into the deep dermis and subcutaneous adipose tissue. The differentiation between cutaneous lymphomas and pseudolymphomas must depend on a constellation of criteria, never on a single criterion.

Diagnostic accuracy of endoscopic biopsies for the diagnosis of gastrointestinal follicular lymphoma: a clinicopathologic study of 48 patients

The purpose of this study was to reveal the diagnostic accuracy of initial pathologic assessment of biopsied samples in patients with gastrointestinal follicular lymphoma lesions. A total of 48 patients with follicular lymphoma (Lugano system stage I: n = 30; II1: n = 4; II2: n = 4; IV: n = 10) with gastrointestinal involvement who underwent endoscopic biopsy were enrolled and retrospectively reviewed. Nine (18.8%) of the 48 patients were not appropriately diagnosed as having follicular lymphoma at the initial biopsy. The initial pathological diagnosis included extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (n = 4), necrotic tissue (n = 2), duodenitis (n = 1), or suspected lymphoma of unspecified subtype (n = 2). The reasons for these inappropriate diagnoses were insufficient histopathologic analysis lacking CD10 and BCL2 staining (n = 7) and unsuitable biopsy samples taken from erosions or ulcers that contained scanty lymphoma cells or no lymphoid follicles (n = 2). In conclusion, incomplete histopathologic analysis and unsuitable biopsy samples are pitfalls in the diagnosis of gastrointestinal follicular lymphoma.

Aberrant immunoarchitecture distinguishes hyperplastic germinal centres in pattern 1 angioimmunoblastic T-cell lymphoma from reactive follicles

We compare 30 biopsies each of Pattern 1 angioimmunoblastic T-cell lymphoma (AITL1) and reactive lymphoid hyperplasia (RLH) by immunohistology, in-situ hybridization for Epstein-Barr virus-encoded RNA and T-cell receptor-γ (TRG)-clonality. AITL1 cases, more often than RLH controls, were older [median ages 61 (range 23-79) vs 46 (range 11-59) years, p < 10(-4)], non-Chinese [16/30 (53%) vs 8/28 (29%), p = 0.035], presented nodally [29/30 (97%) vs 23/30 (77%), p = 0.024], showed: pan-T cell antigen attenuation [25/29 (86%) vs 5/21 (24%), p = 1.0 × 10(-5)], CD4 predominance [25/28 (89%) vs 12/23 (52%), p = 3.4 × 10(-3)], interfollicular lymphoid CD10-positivity [16/30 (53%) vs 1/29 (3%), p = 1.5 × 10(-5)], TRG clonality [16/28 (57%) vs 1/20 (5%), p = 1.4 × 10(-4)], higher maximum number of Epstein-Barr virus-encoded RNA + nuclei per 0.5-mm high-power field [median 6 (range 0-70) vs 1 (range 0-40), p = 0.012] and interfollicular Ki-67 proliferation fraction [median 40% (range 10-80%) vs 20% (range 5-40), p < 10(-4)], whereas their germinal centres (GCs) more often showed attenuation of CD10 [30/30 (100%) vs 11/29 (38%), p = 5.3 × 10(-8)] and CD57 [18/25 (72%) vs 4/22 (18%), p = 2.4 × 10(-4)] (respectively). GC-predominant PD-1 and ICOS immunoreactivity were more often seen in RLH [20/22 and 9/19 controls (91% and 47%)] than AITL1 [9/25 and 3/19 cases (36% and 16%), p = 1.0 × 10(-4) and 0.033, respectively]. Significant independent predictors against AITL1 were: solid GC CD10 immunoreactivity {p = 0.023, odds ratio (OR) for AITL1 0.01 [95% confidence interval (CI): 0.0002-0.529]}; lower interfollicular proliferation fraction [p = 0.047, OR for AITL1 1.1 (95% CI: 1.001-1.209) per % rise in Ki-67]; younger presenting age [p = 0.028, OR for AITL1 1.136 (95% CI: 1.014-1.272) per year older]. Hence, GCs and perifollicular zones in AITL1 are distinct from those in RLH.

TLR2-activated B cells are phenotypically similar to the abnormal circulating B cells seen preceding the diagnosis of AIDS-related NHL diagnosis

BACKGROUND

AIDS-related non-Hodgkin lymphoma (AIDS-NHL) is a common AIDS-defining cancer. Prior studies suggest that chronic B-cell activation precedes AIDS-NHL diagnosis. Activation of B cells by multiple factors, including Toll-like receptor (TLR) signaling, leads to the expression of activation-induced cytidine deaminase (AID), a DNA mutating molecule that can contribute to oncogene translocations/mutations, leading to NHL. The goal of this study was to determine whether surface markers expressed on activated and/or germinal center B cells, and AID expression, were elevated on circulating B cells preceding AIDS-NHL and to determine if TLR signaling contributes to this activated B-cell phenotype.

METHODS

Stored viable peripheral blood mononuclear cell specimens, obtained before AIDS-NHL diagnosis, were assessed by multicolor flow cytometry. Additionally, B cells isolated from peripheral blood mononuclear cell were exposed to TLR ligands in vitro, after which B-cell phenotype was assessed by flow cytometry.

RESULTS

An elevated fraction of B cells expressing CD10, CD71, or CD86 was seen in those who went on to develop AIDS-NHL. AID expression was detected in some who developed AIDS-NHL, but not in HIV+ or HIV- controls. TLR2-stimulated purified B cells exhibited the activated B-cell phenotype observed in HIV+ subjects before AIDS-NHL diagnosis.

CONCLUSIONS

These results indicate that an elevated fraction of B cells display an activated/germinal center phenotype in those HIV+ subjects who go on to develop AIDS-NHL and suggest that TLR2-mediated activation may play a role in HIV infection-associated B-cell activation, potentially contributing to the genesis of AIDS-NHL.

Follicular lymphoma in young adults: a clinicopathological and molecular study of 200 patients

Follicular lymphoma is clinically heterogenous, and therefore necessitates the identification of prognostic markers to stratify risk groups and optimize clinical management. It is relatively rare in patients younger than 40 years, and the clinicopathologic characteristics and biological behavior in this age group are poorly understood. In the current study, samples from a cohort of 200 patients between 19 and 40 years were evaluated retrospectively with respect to clinical, histologic, and genetic features. These were then correlated with clinical outcome. The median age at presentation was 35 years with a slight female prepoderance (56%). Most of the cases are presented with nodal disease (90%). Concomitant follicular lymphoma and diffuse large B-cell lymphoma were observed in 7 (4%) patients. Immunohistologic studies showed the expression of CD10 (91%), BCL6 (97%), BCL2 (95%), MUM1/IRF4 (12%), MDM2 (17%), and CD23 (25%). BCL2 rearrangement was present in 74%, and BCL6 in 20%. The estimated overall survival of patients was 13 years (mean). The presence of anemia, elevated lactose dehydrogenase, bone marrow involvement, and high-risk follicular lymphoma international prognostic index correlated with adverse overall survival. Our findings revealed that follicular lymphoma in young adults demonstrate similarities with that of older adults, including the frequency of presentation at various anatomic sites, grade, and adverse prognostic factors.

Oral follicular lymphomas. A short report of 8 cases with assessment of the IGH/BCL2 gene fusion with fluorescence in situ hybridization

OBJECTIVE

To present the clinicopathologic features and confirm the presence of the IGH/BCL2 gene fusion in an oral follicular lymphoma (OFL) series.

STUDY DESIGN

Cases of OFLs were retrieved from a data base of non-Hodgkin lymphomas (NHL). Fluorescence in situ hybridization (FISH) was performed to confirm the IGH/BCL2 fusion.

RESULTS

Eight (8.7%) of 92 NHL were OFLs. Six (75%) patients were male and two female (mean age: 73.4 ± 14.8). The most frequent site was the palate. Five of the 8 patients are alive and without disease. Five (three grade 1 and two grade 2) of six successfully hybridized cases revealed the IGH/BCL2 gene fusion. The sixth case, a grade 3 follicular lymphoma (FL), demonstrated multiple BCL2 signals without IGH/BCL2 fusion.

CONCLUSIONS

OFLs exhibit an indolent clinical behavior. In the present study, 5/6 cases in which FISH was successful had an IGH/BCL2 fusion as would result from the t(14; 18)(q32; q21) translocation commonly seen in FL of extraoral sites.

Tissue microarray in a subset of South African patients with DLBCL

Tissue samples from 93 de novo diffuse large B-cell lymphoma patients seen between 1995 and 2009 randomly receiving either standard combination chemotherapy (CHOP, n=48) or the identical program with rituximab (n=45) were subtyped using an investigational immunohistochemical (IHC) based tissue microarray (TMA) and contrasted to the approximately corresponding categories as defined either by Hans and associates using a three marker panel into germinal or non-germinal centre subtypes or by Choi and colleagues with two additional antibodies into germinal centre (GCB) or activated B-cells (ABC). Each of these primary subdivisions was further evaluated for expression of BCL2 and LMO2 both of which are recognised to predicate response. The addition of rituximab to the uniform drug regimen did not show any significant improvement in 5 years overall (63% versus 59%, p 0.68) or event-free survival (42% versus 39%, p 0.94), for CHOP versus R-CHOP comparisons. Similarly no differences were evident in subtype analysis. Interestingly however, when segregated on the Choi criteria, cytotoxic drugs alone showed a non-significant trend in improved survival (74% versus 55%, p 0.32) as well as event-free survival (44% versus 40%, p 0.42) for the germinal centre as opposed to the activated B-cell subtype. Nevertheless not even a small difference could be demonstrated in the presence of the anti CD 20 monoclonal antibody. According to Choi, both regimens (chemotherapy or immunotherapy antibody) revealed similar results to the Hans algorithm on 5 years OS as well as 3 year EFS when comparing GCB versus ABC or non-GCB subgroups. BCL2 and LMO2 marker expression of the respective immunohistochemical (IHC) subtype, despite small sample size, revealed the following. Analysis by Choi criteria on survival for BCL2, no matter for which subsets (GCB or ABC) or treatment modality (chemotherapy with or without the addition of rituximab) showed no difference in 5 years OS or EFS. In contrast, a significant difference for better EFS (p=0.0015) in the BCL2 positive group of the ABC subgroups subtypes treated with rituximab containing chemotherapy. For LMO2 similar results on survival outcome were seen thus showing no difference in 5 years OS or EFS - regardless of subtype or treatment modality. Also here, this was contrasted by better EFS (p=0.039) in the LMO2 positive group of ABC subtypes when treated with the rituximab containing regimen. The use of the IHC based TMA methodology has shown to be a simple, cost effective and a robust alternative to gene expression profiling (GEP) which is currently regarded as the gold standard for the classification in lymphomas. It provides a useful prognostic tool in stratifying DLBCL or other entities in future, even when frozen tissue samples are not available for GEP analysis. With the current budgetary limitations in South African public hospitals chemotherapy protocols for lymphoproliferative disorders exclude agents such as rituximab. Local therapeutic drug committees consider the approximately 15% overall survival benefit seen at 5 years for DLBCL when rituximab is added to combination chemotherapy as too marginal for justifying the arising additional expenses. Accordingly, demonstration that a specific molecular subtype accounts for superior outcome, when using these regimens, is needed. Such an option would provide convincing evidence for the use of immunochemotherapy in a resource constrained setting.

Evaluation of BCL-6, CD10, CD138 and MUM-1 expression in diffuse large B-cell lymphoma patients: CD138 is a marker of poor prognosis

The diffuse large B-cell lymphoma (DLBCL) encompasses two major groups of tumors with uneven survival outcomes--germinal center B-cell (GCB) and non-germinal center B-cell (non-GCB). In the present study, we investigated the expression of GCB markers (BCL-6 and CD10) and non-GCB markers (CD138 and MUM-1) in an effort to evaluate their prognostic value. Paraffin-embedded tumor biopsies of 46 Jordanian DLBCL patients were analyzed, retrospectively, by immunohistochemistry to investigate the expression of BCL-6, CD10, CD138 and MUM-1. In addition, survival curves were calculated with reference to marker expression, age, sex and nodal involvement. Positive expression of BCL-6, CD10, CD138 and MUM-1 was shown in 78%, 61%, 39% and 91% of the cases, respectively, that of BCL-6 being associated with better overall survival (p = 0.02), whereas positive CD138 was linked with poor overall survival (p = 0.01). The expression of CD10 and MUM-1 had no impact on the overall survival. Among the clinical characteristics studied, diagnosis at an early age, nodal involvement and maleness were associated with a higher overall survival for DLBCL patients. Our results underline the importance of BCL-6 as a marker of better prognosis and CD138 as a marker of poor prognosis for DLBCL patients.

Selective immunophenotyping for diagnosis of B-cell neoplasms: immunohistochemistry and flow cytometry strategies and results

Determining the immunophenotype of hematologic malignancies is now an indispensable part of diagnostic classification, and can help to guide therapy, or to predict clinical outcome. Diagnostic workup should be guided by morphologic findings and evaluate clinically important markers, but ideally should avoid the use of overly broad panels of immunostains that can reveal incidental findings of uncertain significance and give rise to increased costs. Here, we outline our approach to diagnosis of B-cell neoplasms, combining histologic and clinical data with tailored panels of immunophenotyping reagents, in the context of the 2008 World Health Organization classification. We present data from cases seen at our institution from 2004 through 2008 using this approach, to provide a practical reference for findings seen in daily diagnostic practice.

Lymphocyte-predominant Hodgkin lymphoma: what is the optimal treatment?

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a unique diagnostic entity, with only ∼500 new cases in the United States per year with a similar infrequent incidence worldwide. NLPHL also has distinctive pathobiology and clinical characteristics compared with the more common classical Hodgkin lymphoma (cHL), including CD20 positivity of the pathognomic lymphocytic and histiocytic cells and an overall more indolent course with a higher likelihood of delayed relapses. Given the limited numbers of prospective NLPHL-focused trials, management algorithms historically have typically been centered on retrospective data with guidelines often adopted from cHL and indolent B-cell lymphoma treatment approaches. Key recent publications have delineated that NLPHL has a higher level of pathological overlap with cHL and the aggressive B-cell lymphomas than with indolent B-cell lymphomas. Over the past decade, there has been a series of NLPHL publications that evaluated the role of rituximab in the frontline and relapsed setting, described the relative incidence of transformation to aggressive B-cell lymphomas, weighed the benefit of addition of chemotherapy to radiation treatment for patients with early-stage disease, considered what should be the preferred chemotherapy regimen for advanced-stage disease, and even assessed the potential role of autologous stem cell transplantation for the management of relapsed disease. General themes within the consensus guidelines include the role for radiation treatment as a monotherapy for early-stage disease, the value of large B-cell lymphoma-directed regimens for transformed disease, the utility of rituximab for treatment of relapsed disease, and, in the pediatric setting, the role of surgical management alone for patients with early-stage disease.

Synchronous adenocarcinoma and follicular lymphoma of the stomach

A 73-year-old Japanese man with synchronous follicular lymphoma and adenocarcinoma of the stomach underwent curative surgical resection. The follicular lymphoma lesion was preoperatively diagnosed as extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) according to biopsy samples. However, postoperative pathological evaluations revealed components of CD10-positive and CD10-negative lymphoma cells within the lymphoma lesion. This case highlights the potential difficulty of diagnosing gastric follicular lymphoma. In such cases, conducting repeat pathological examinations of biopsy samples or resected specimens is required to obtain a correct diagnosis of follicular lymphoma.

Nodal and leukemic small B-cell neoplasms

The small B-cell neoplasms represent some of the most frequently encountered lymphoproliferative disorders in routine surgical pathology practice. This report reviews the current diagnostic criteria for classifying small B-cell neoplasms and distinguishing them from newly recognized precursor conditions that do not appear to represent overt lymphomas. Newly available immunohistochemical stains and molecular studies that may assist in the diagnosis and classification of these neoplasms are also discussed.

Promising personalized therapeutic options for diffuse large B-cell Lymphoma Subtypes with oncogene addictions

Currently, two major classification systems segregate diffuse large B-cell lymphoma (DLBCL) into subtypes based on gene expression profiles and provide great insights about the oncogenic mechanisms that may be crucial for lymphomagenesis as well as prognostic information regarding response to current therapies. However, these current classification systems primarily look at expression and not dependency and are thus limited to inductive or probabilistic reasoning when evaluating alternative therapeutic options. The development of a deductive classification system that identifies subtypes in which all patients with a given phenotype require the same oncogenic drivers, and would therefore have a similar response to a rational therapy targeting the essential drivers, would significantly advance the treatment of DLBCL. This review highlights the putative drivers identified as well as the work done to identify potentially dependent populations. These studies integrated genomic analysis and functional screens to provide a rationale for targeted therapies within defined populations. Personalizing treatments by identifying patients with oncogenic dependencies via genotyping and specifically targeting the responsible drivers may constitute a novel approach for the treatment of DLBCL.

Immunophenotype classification and therapeutic outcomes of Chinese primary gastrointestinal diffuse large B-cell lymphoma

Background

Recent studies showed that diffuse large B-cell lymphoma (DLBCL) could be classified into germinal centre B cell-like (GCB) and non-germinal centre B cell-like (non-GCB) phenotypes according to CD10,Bcl-6 and MUM1 expression. But primary gastrointestinal DLBCL has rarely been studied. This study was aimed to investigate the relationship between immunophenotypic classification, therapeutic outcomes and the prognosis of patients with primary gastrointestinal DLBCL.

Methods

Between 1998 and 2010, there were 151 patients studied at Shanghai Renji Hospital with a histopathological diagnosis of primary gastrointestinal DLBCL. Immunohistochemistry was performed using EnVision methods for CD10, BCL-6 and MUM1. The clinicopathologic features and follow-up data were analyzed by the Kaplan-Meier method, log-rank test and χ2 test.

Results

According to the expression of CD10, BCL-6 and MUM1, 31.8 % (48/151) of the cases belonged to the GCB subtype and 68.2 % (103/151) belonged to the non-GCB subtype. There was a significant difference of local lymph node metastasis between the GCB and non-GCB groups (P < 0.05). Patients in the GCB group had a better survival rate than those in the non-GCB group (5-year survival rate, 65.2 % vs 36.4 %, P < 0.05). In the GCB group, there was no significant difference in survival rates in patients receiving R-CHOP and CHOP therapy (P > 0.05). In the non-GCB group, the survival rate in patients treated with R-CHOP therapy was significantly longer than those treated with CHOP therapy (5-year survival rate, 62.8 % vs 30.8 %, P < 0.05).

Conclusions

The immunophenotype classification of gastrointestinal DLBCL, which is closely related to local lymph node metastasis, is found to have prognostic significance. Immunophenotype classification is also useful in selecting the chemotherapy protocol.