T-cell-rich large-B-cell lymphomas contain non-activated CD8+ cytolytic T cells, show increased tumor cell apoptosis, and have lower Bcl-2 expression than diffuse large-B-cell lymphomas

A Review of the Flow Cytometric Findings in Classic Hodgkin Lymphoma, Nodular Lymphocyte Predominant Hodgkin Lymphoma and T Cell/Histiocyte-Rich Large B Cell Lymphoma

Classic Hodgkin lymphoma, nodular lymphocyte predominant Hodgkin lymphoma, and T cell/histiocyte-rich large B cell lymphoma form a unique set of lymphomas with similar morphologic growth patterns (occasional neoplastic cells within a prominent cellular cell background) that are pathobiologically related. Distinguishing these entities has been historically difficult by flow cytometry; however, our laboratory has developed antibody-fluorochrome combinations capable of immunophenotyping these lymphomas. Additionally, characterization of the background reactive lymphocytes can aid in narrowing the differential diagnosis. This review summarizes the immunophenotypic features and insights of the neoplastic and reactive populations found in this unique group of lymphomas.

Identification of FCER1G related to Activated Memory CD4+ T Cells Infiltration by Gene Co-expression Network and Construction of a Risk Prediction Module in Diffuse Large B-Cell Lymphoma

Diffuse large B cell lymphoma (DLBCL) is a group of biologically heterogeneous tumors with different prognoses. The tumor microenvironment plays a vital role in the tumorigenesis and development of DLBCL, and activated memory CD4⁺ T cells are an essential component of immunological cells in the lymphoma microenvironment. So far, there are few reports about activated memory CD4+T cells infiltration and related genes in the DLBCL tumor microenvironment. This study obtained the mRNA expression profile information of the testing GSE87371 dataset and another six validation datasets (GSE53786, GSE181063, GSE10846, GSE32918, GSE32018, GSE9327, GSE3892, TCGA-DLBC) from the GEO and TCGA databases. Weighted Gene Co-expression Network Analysis (WGCNA) screened gene module associated with activated memory CD4⁺ T cells infiltration. CIBERSORT and TIMER (immune cells infiltrating estimation analysis tools) were used to identify the relationship between activated memory CD4⁺ T cells and genes associated with immune infiltrating cells in the tumor microenvironment. The least absolute shrinkage and selection operator (LASSO) built the risk prediction model and verified it using nomogram and Kaplan-Meier analysis. Further functional characterization includes Gene Ontology, KEGG pathway analysis and Gene Set Enrichment Analysis (GSEA) to investigate the role and underlying mechanisms of these genes. These results suggest that the expression of FCER1G can reflect the invasion of activated memory CD4⁺ T cells in DLBCL, which provides a new idea for studying the tumor microenvironment and may become a potential predictive biomarker for the assessment of DLBCL.

An approach to small lymph node biopsies: pearls and pitfalls of reporting in the real world

Recent advances in interventional radiology have resulted in the utilization of small lymph node biopsies, including fine-needle aspiration (FNA) and core needle biopsy (CNB) as an initial diagnostic tool in hematopathology. A major challenge to the utilization of FNA and CNB is the limited-to-scant tissue often available. We propose delegation of the task of handling biopsy specimens to the laboratory staff by the biopsy operators, in order to optimize the utilization of the specimen. Furthermore, in order to effectively diagnose hematolymphoid neoplasms a variety of ancillary tests including immunohistochemistry, flow cytometry, molecular analysis, florescence in situ hybridization (FISH) are necessary. We propose morphological evaluation coupled with careful utilization of ancillary studies along with clinical correlation to approach the correct diagnosis. Our morphological assessment considers the types of proliferating cell population: mainly small cells, sheets of large cells, or scattered large cells among small cells. This is followed by employment of the corresponding immunopanel to assess the differential diagnosis in each of the three categories. We also elaborate on the importance for pathologists to become proficient in understanding the limitations of small tissue biopsies as well as the differences in interpretation, and wording their reports to help clinicians and direct them to further investigate and/or to re-biopsy when necessary.

Diffuse large B-cell lymphoma variants: an update

Diffuse large B-cell lymphoma (DLBCL) is the most common type of lymphoma, representing approximately one-third of all cases worldwide. In the World Health Organization (WHO) classification of lymphomas, most cases of DLBCL are designated as not otherwise specified (NOS). About 20% of cases, however, are designated as specific variants of DLBCL. These variants, 13 in total, are specified on the basis of distinctive morphological or immunophenotypic findings or distinctive biological or clinical issues associated with their diagnoses. In this review we discuss the following variants: T-cell/histiocyte-rich large B-cell lymphoma; ALK-positive large B-cell lymphoma; plasmablastic lymphoma; intravascular large B-cell lymphoma; large B-cell lymphoma with IRF4 rearrangement; primary mediastinal large B-cell lymphoma; primary cutaneous diffuse large B-cell lymphoma, leg type; primary diffuse large B-cell lymphoma of the central nervous system; diffuse large B-cell lymphoma associated with chronic inflammation; lymphomatoid granulomatosis; primary effusion lymphoma; and HHV8-positive diffuse large B-cell lymphoma, NOS. Two additional variants recognised in the WHO classification, EBV-positive diffuse large B-cell lymphoma and EBV-positive mucocutaneous ulcer are discussed elsewhere in another review within this issue of Pathology. Although not recognised as a specific variant in the current WHO classification, primary testicular diffuse large B-cell lymphoma also has unique biological features and requires some modification of the standard treatment approach for patients with DLBCL. Therefore, we suggest that primary testicular diffuse large B-cell lymphoma also should be recognised as a specific variant of DLBCL in a future version of the WHO classification.

Predominance of CD4+ T Cells in T-Cell/Histiocyte-Rich Large B-Cell Lymphoma and Identification of a Subset of Patients With Peripheral B-Cell Lymphopenia

OBJECTIVES

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL) is a morphologic variant of large B-cell lymphoma whose flow cytometry findings are not well characterized.

METHODS

Nineteen cases with flow cytometric immunophenotyping were identified from the case records of four institutions between 2001 and 2016.

RESULTS

In most cases, neoplastic B cells were not detected by flow cytometry. Overall, cases showed a predominance of CD4+ T cells, which in some cases was marked. Significant coexpression of CD57 was seen on CD4+ T cells where this marker was analyzed, which correlated with PD-1 expression. Two cases also showed a profound systemic B-cell lymphopenia, which was associated in one case with hypogammaglobulinemia.

CONCLUSIONS

Overall, our work challenges previous findings that cases of THRLBCL are rich in CD8+ T cells and highlights parallels between THRLBCL and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). Also, an association of THRLBCL with systemic B-cell lymphopenia has not been previously reported but may represent an underrecognized manifestation.

T cell-rich lymphoid infiltrates with large B cells: a review of key entities and diagnostic approach

Accurate diagnostic interpretation of a lymphoid population composed predominantly of small T cells, together with smaller numbers of large B cells, with or without a nodular architecture, is a common problem faced by the histopathologist. The differential diagnosis of this histological pattern is wide, ranging from reactive conditions such as drug reactions and viral infections, through borderline entities such as immunodeficiency-related lymphoproliferative disorders to lymphomas. The latter includes entities where the large B cells are primarily neoplastic (classical and nodular lymphocyte-predominant Hodgkin lymphomas and T cell/histiocyte-rich large B cell lymphoma) as well as T cell lymphomas such as angioimmunoblastic T cell lymphoma where the large B cells represent an epiphenomenon and may or may not be neoplastic. Several rare variants of these conditions, and the fact that treatment can significantly modify appearances, add to the diagnostic difficulty of these pathological entities. Unlike monomorphic lymphoid infiltrates, the histological pattern of T cell-rich proliferation with large B cells requires close evaluation of the inter-relationship between B cells and T cells, follicular dendritic cells and sometimes other inflammatory cells. Epstein-Barr virus plays a key role in several of these scenarios, and interpreting not only its presence but also its distribution within cellular subgroups is essential to accurate diagnosis and the avoidance of some important diagnostic pitfalls. An understanding of normal immunoarchitecture and lymphoid maturational pathways is also fundamental to resolving these cases, as is a knowledge of their common patterns of spread, which facilitates correlation with clinical and radiological findings.

T Cell/Histiocyte-Rich Large B Cell Lymphoma of the Thymus: A Diagnostic Pitfall

T cell/histiocyte-rich large B cell lymphoma (THRLBCL) is predominantly a nodal disease, with extranodal involvement, such as bone marrow, spleen, and liver. However, primary THRLBCL has never been reported in the thymus in the English literature. Here we report a case of THRLBCL presenting as mediastinal mass and lymphadenopathy. Based on the frozen section diagnosis of "thymoma," a 12 cm mass was excised. A year later she developed multiple enlarged lymph nodes and pulmonary nodules. Consultant review of the excised mediastinal mass showed scattered large atypical cells that were CD20+ and PAX-5+ and negative for pan-cytokeratin, AE1, and AE3, compatible with THRLBCL and excluding thymoma. The excised lymph nodes were replaced by diffuse infiltrate of small CD3+ lymphocytes and histiocytes with intermingled large CD20+ B lymphoma cells scattered throughout the section. A diagnosis of THRLBCL was made in lymph node, similar to previous thymic lesion. A clonal rearrangement of immunoglobulin heavy chain (IGH) gene was detected, further supporting the diagnosis. This is the first reported case of THRLBCL in thymus. Correct recognition of this entity is critical, because of the difference in therapeutic impact on these patients.

Large B-cell lymphomas poor in B cells and rich in PD-1+ T cells can mimic T-cell lymphomas

OBJECTIVES

To characterize the clinicopathologic features of cases of large B-cell lymphomas, poor in B cells and densely rich in programmed cell death-1 (PD-1)+ reactive T cells, which can mimic T-cell lymphomas.

METHODS

A single-institute retrospective review of cases between 2010 and 2013 was performed.

RESULTS

Of 178 cases of large B-cell lymphomas, eight cases of large B-cell lymphomas poor in B cells and diffusely rich in sheets of PD-1+ T cells were identified. These cases either were initially misdiagnosed as a T-cell lymphoma or substantiated a broader differential diagnosis including a T-cell lymphoma. Five cases were T-cell histiocyte-rich large B-cell lymphomas, and three cases were diagnosed as large B-cell lymphomas rich in T cells. In three of these cases, a subset of the PD-1+ T cells showed either morphologic nuclear atypia or atypical expression of T-cell antigens on flow cytometry and/or immunohistochemistry.

CONCLUSIONS

Large B-cell lymphomas poor in B cells and rich in T cells can have diffuse sheets of reactive PD-1+ T cells, some with atypical morphologic and immunophenotypic features mimicking a T-cell lymphoma. Careful assessment of the immunoarchitecture and background inflammatory and stromal cells can prevent erroneous diagnoses in such cases.

Targeting protein-protein interaction by small molecules

Protein-protein interactions (PPIs) are critical regulatory events in physiology and pathology, and they represent an important target space for pharmacological intervention. However, targeting PPIs with small molecules is challenging owing to the large surface area involved in protein-protein binding and the lack of obvious small-molecule-binding pockets at many protein-protein interfaces. Nonetheless, successful examples of small-molecule modulators of PPIs have been growing in recent years. This article reviews some of the recent advances in the discovery of small-molecule regulators of PPIs that involve key oncogenic proteins. Our discussion focuses on the three key modes of action for these small-molecule modulators: orthosteric inhibition, allosteric regulation, and interfacial binding/stabilization. Understanding the opportunities and challenges of these diverse mechanisms will help guide future efforts in developing small-molecule modulators against PPIs.

Application of Immunohistochemistry in the Diagnosis of Non-Hodgkin and Hodgkin Lymphoma

Context.—Beginning with the immunologic classifications of Lukes and Collins and Kiel and culminating in the Revised European-American Lymphoma and World Health Organization classifications, the diagnosis of lymphoid tumors relies heavily on the determination of cell lineage, maturation, and function, based on antigen expression in addition to morphology and clinical features. Technologic advances in immunology, antibody production, genetic analysis, cloning, and the identification of new genes and proteins by microarray and proteomics have provided pathologists with many antibodies to use in routine diagnosis.

Objective.—To provide guidance to the practicing pathologist in the appropriate selection of an antibody panel for the diagnosis of lymphoma based on morphology and relevant clinical data and to avoid pitfalls in the interpretation of immunohistochemical data. Attention is given to some of the newer antibodies, particularly against transcription factors, that are diagnostically and prognostically useful.

Data Sources.—The information presented in this article is based on review of the literature using the OVID database (Ovid MEDLINE 1950 to present with daily update) and 20 years of experience in diagnostic hematopathology.

Conclusions.—Immunophenotyping is required for the diagnosis and classification of lymphoid malignancies. Many paraffin-reactive antibodies are available to the pathologist but most are not specific. To avoid diagnostic pitfalls, interpretation of marker studies must be based on a panel and knowledge of a particular antigen's expression in normal, reactive, and neoplastic conditions.

Biology, Clinical Course and Management of Nodular Lymphocyte-Predominant Hodgkin Lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) differs in histological and clinical presentation from classical Hodgkin lymphoma (cHL). The typical morphologic signs of NLPHL are atypical “lymphocytic and histiocytic” (L&H) cells, which are surrounded by a non-neoplastic nodular background of small lymphocytes of B-cell origin. The NLPHL cells are positive for CD45, CD19, CD20, CD22 and CD79a, but lack expression of CD15 and CD30, the typical markers for cHL. NLPHL patients are predominantly of male gender with a median age of 37 years. Patients often present in early stages (63%) and rarely have B-symptoms (9%). Treatment of NLPHL patients using standard Hodgkin lymphoma (HL) protocols leads to complete remission (CR) in more than 95% of patients. Survival and freedom from treatment failure (FFTF) are worse in advanced-stage patients than in early-stage patients. Thus, patients in advanced and in early stages with unfavorable risk factors are treated similarly to cHL patients. In contrast, patients with early-stage NLPHL without risk factors can be sufficiently treated with reduced intensity programs having less severe adverse effects. As a result, treatment of early NLPHL is less clearly defined, including radiotherapy in extended field (EF) or involved field (IF) technique, combined modality treatment, and, more recently, monoclonal antibody rituximab. Watch and wait strategy plays an important role in pediatric oncology to avoid adverse effects associated with therapy.

Epidemiology of non-Hodgkin lymphomas in Tyrol/Austria from 1991 to 2000

AIMS

To analyse the entity specific incidence and disease specific survival (DSS) of non-Hodgkin lymphomas (NHLs) in Tyrol/Austria, 1991-2000.

METHODS

Data from 1307 NHLs (excluding primary cutaneous lymphomas and monoclonal gammopathies of undetermined significance) were obtained. Current status was available for all patients. Except for 29 cases of small lymphocytic (CLL/SLL), lymphoblastic leukaemia (ALL), and myeloma (MM), which were diagnosed cytologically, diagnoses were reclassified on paraffin wax embedded archival material according to new World Health Organisation criteria. Sex specific age adjusted standardised incidence rates were computed using Segi's population weighting. Annual incidence changes were calculated by weighted least square regression analysis. Survival was estimated by the Kaplan-Meier method and compared by log rank test.

RESULTS

NHL more frequently affected men (male/female ratio, 1.52). Mean age of occurrence was 61 and 66 years for men and women, respectively. The incidence rate of 14.3 remained constant. There was a significant increase in diffuse large B cell lymphoma (DLBCL) and decrease in CLL/SLL in men, and a decrease in MM in women. Overall DSS was 64% during the mean follow up (43 months). Age, T-NHL, lambda light chain restriction in MM, and male sex in CLL/SLL were associated with poor prognosis. In B-NHL, DSS decreased in the following order: hairy cell leukaemia, marginal zone lymphoma, follicular lymphoma, Burkitt lymphoma, ALL, DLBCL, CLL, MM, and mantle cell lymphoma.

CONCLUSIONS

The incidence of NHL in Tyrol has changed in the past decade, with a significant increase in DLBCL, decrease in CLL/SLL in men, and decrease in MM in women.

T-Cell/Histiocyte-Rich Large B-Cell Lymphoma Displays a Heterogeneity Similar to Diffuse Large B-Cell Lymphoma

T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL), a proliferating peripheral B-cell neoplasm, is a morphologic variant of diffuse large B-cell lymphoma (DLBCL), which may be confused with Hodgkin's lymphoma, non-Hodgkin's lymphoma, and reactive lymphadenopathies. Though more recent studies suggested that it might be a distinct clinicopathologic entity and/or a heterogeneous entity with derivation from germinal center B cells, its histogenetic derivation remains controversial. The authors analyzed 30 cases of THRLBCL to further characterize the origin of the neoplastic cells using immunohistochemical and molecular studies for expression of Bcl-6, CD10, and CD138, as well as rearrangements of IgH/bcl-2 genes on paraffin-embedded tissue. Half of the cases (15/30) showed Bcl-6 expression and five cases (19%) showed CD10 expression, but none had CD138 expression (0/20). Only three cases showed coexpression of both Bcl-6 and CD10. Molecular studies performed in 21 cases detected rearrangement of immunoglobulin heavy gene in 18 cases, with none having detectable Bcl-2 gene rearrangement. These data indicate that similar to DLBCL, the cell origin of neoplastic cells in THRLBCL is composed of a heterogeneous group of proliferating peripheral B cells, with only some cases originating from germinal center B cells and others derived from heterogeneous origins. Lack of Bcl-2 gene rearrangements seems to argue against a possible progression from preexisting follicular lymphoma. Thus, the normal counterpart of the neoplastic cells cannot at this time be the sole basis for the subclassification of THRLBCL.

La maladie de Hodgkin nodulaire à prédominance lymphocytaire et ses diagnostics différentiels

Nodular lymphocyte predominance Hodgkin's disease (NLPHD), previously called nodular paragranuloma, is a rare entity recognized as a clinico-pathological entity distinct from classic Hodgkin's lymphoma. It is an indolent B cell lymphoma derived from a germinal center cell. NLPHD may closely resemble lymphocyte-rich classic Hodgkin's disease (LR-CHD) or T-cell or histiocyte-rich large B-cell lymphoma (TCRLBCL). A reproducible distinction between these entities is difficult but the classification is prognostically relevant. NLPHD is characterized by neoplastic "popcorn" cells CD20+ CD30- CD15- EMA+ Bcl6+ scattered within a nodular background predominantly composed of small B lymphocytes. LR-CHD neoplastic proliferation is composed of CD20+/- CD30+ CD15+/- EMA- Bcl6+/- Reed Sternberg or Hodgkin's cells, scattered within numerous CD3+ T cells. TCRLBCL is an agressive lymphoma composed of CD20+ CD30- CD15- EMA+/- Bcl6+/- polymorphic neoplastic cells, scattered within a mixture of CD3+ T cells and histiocytes. Epstein Barr virus is detectable within half cases of LR-CHD, but never in NLPHD and rarely in TCRLBCL. The transcription factors BOB1, PU-1, BSAP and IRF4 are new markers that could be useful for differential diagnosis.

Prognostic significance of activated cytotoxic T-lymphocytes in primary nodal diffuse large B-cell lymphomas

Clinical outcome in diffuse large B-cell lymphoma (DLBCL) remains unpredictable, despite the identification of clinical prognostic parameters. Here, we investigated in pretreatment biopsies of 70 patients with DLBCL whether numbers of activated cytotoxic T-lymphocytes (CTLs), as determined by the percentage of CD3-positive lymphocytes with granzyme B (GrB) expression, have similar prognostic value as found earlier in Hodgkin's lymphoma and anaplastic large-cell lymphoma and whether loss of major histocompatibility complex (MHC)-I molecules or expression of the GrB antagonist protease inhibitor 9 (PI9) may explain immune escape from CTL-mediated cell death. Independent of the International Prognostic Index (IPI), the presence of >/=15% activated CTLs was strongly associated with failure to reach complete remission, with a poor progression-free and overall survival time. Downregulation of MHC-I light- and/or heavy-chain expression was found in 41% of interpretable cases and in 19 of 56 interpretable cases PI9 expression was detected. We conclude that a high percentage of activated CTLs is a strong, IPI independent, indicator for an unfavorable clinical outcome in patients with primary nodal DLBCL. Although in part of DLBCL expression of PI9 and loss of MHC-I expression was found, providing a possible immune-escape mechanism in these cases, no correlation with clinical outcome was found.

Nodular lymphocyte-predominant Hodgkin lymphoma with nodules resembling T-cell/histiocyte-rich B-cell lymphoma: differential diagnosis between nodular lymphocyte-predominant Hodgkin lymphoma and T-cell/histiocyte-rich B-cell lymphoma

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and T-cell/histiocyte-rich B-cell lymphoma (T/HRBCL) are distinct tumors and are treated differently. They are linked by a morphologic and probably a biologic continuum, which renders the differential diagnosis difficult. To develop criteria to distinguish the entities along the morphologic continuum, we correlated the lymph node architecture and immunophenotype of both tumor cells and reactive components of 235 neoplasms in the spectrum of NLPHL and T/HRBCL with clinical data. Two hundred and eighteen cases fitted the World Health Organization (WHO) criteria of NLPHL (139) or T/HRBCL (79). While tumor cells in both entities were immunophenotypically similar, background composition differed: in NLPHL small B cells and CD3+CD4+CD57+ T cells were common, whereas in T/HRBCL, CD8+ cytotoxic T cells and histiocytes dominated. Follicular dendritic cells (FDCs) formed expanded meshworks in NLPHL, whereas they were absent in T/HRBCL. Seventeen cases represented a gray zone: within FDC meshworks, neoplastic B cells resided in a background depleted of small B cells but rich in T cells and histiocytes. Tumor cells either were loosely scattered or formed clusters, thus resembling areas of either T/HRBCL or inflammatory diffuse large BCL (DLBCL) within the nodules. Patients with these NLPHLs with T-cell/histiocyte-rich nodules presented at a high stage and with B symptoms, as in T/HRBCL, but had an excellent survival, as in NLPHL. This morphologic pattern suggests a biologic continuum between NLPHL and T/HRBCL.

T-cell/histiocyte-rich large B-cell lymphoma: a heterogeneous entity with derivation from germinal center B cells

T-cell/histiocyte-rich large B-cell non-Hodgkin's lymphoma (THRLBCL) is an unusual morphologic variant of diffuse large B-cell lymphoma. We reviewed 30 cases of THRLBCL to evaluate its heterogeneity based on morphologic, immunophenotypic, and genetic features. Cases were classified according to the appearance of the large neoplastic B cells into three morphologic variants: 1) lymphocytic and histiocytic (L&H-like) (resembling the L&H cells of nodular lymphocyte predominance Hodgkin's lymphoma (14 cases); 2) centroblast (or immunoblast)-like (10 cases), and 3) Reed-Sternberg cell-like (resembling the neoplastic cells of classic Hodgkin's lymphoma) (6 cases). We used a panel of immunohistochemical stains, including those with specificity for germinal center B cells: CD20, CD79a, CD30, CD15, epithelial membrane antigen, BCL-2, BCL-6, and CD10. The /JH polymerase chain reaction assay was further performed to investigate a relationship to follicular lymphoma. The results were correlated with Epstein-Barr virus status as determined by staining for latent membrane protein and EBER-1 in situ hybridization. All cases were of B-cell immunophenotype with strong surface CD20 reactivity in the neoplastic large lymphoid cells, although CD79a was more inconsistently and weakly expressed (10 of 17). Nuclear positivity for the BCL-6 protein was detected in the tumor cells in 26 of 29 (90%) cases. However, differences in expression of other antigens were encountered in the histologic subtypes. Epithelial membrane antigen positivity, a feature often seen in nodular lymphocyte predominance Hodgkin's lymphoma, was observed in 11 of 30 (37%) cases and was most commonly seen in cases with L&H cell morphology (8 of 14; 57%). CD30 expression was observed in 9 of 30 (30%) cases but was most frequent in cases with Reed-Sternberg-like morphology (3 of 6 [50%]). CD10 expression was infrequent overall (3 of 29; 10%), with 2 of 3 positive cases identified in the centroblastic group. The overall rarity of positivity for CD10, BCL-2 (3 of 22; 13%), and -2 JH rearrangement (1 of 28; 4%) indicates a lack of connection to follicular lymphoma for all subtypes. The three cases that were negative for BCL-6 protein were LMP-1 positive and EBER-1 positive by in situ hybridization, and 2 of 3 had neoplastic cells with Reed-Sternberg-like morphology. These results demonstrate that although a large proportion of THRLBCL represent tumors of germinal center B cell derivation, they exhibit a diversity of morphologic and immunophenotypic features. A subset of THRLBCL may be related to nodular lymphocyte predominance Hodgkin's lymphoma. A small percentage show features closely resembling classic Hodgkin's lymphoma and could be considered a variant of grey zone lymphoma.

T-cell/histiocyte-rich large B-cell lymphoma is a disseminated aggressive neoplasm: differential diagnosis from Hodgkin's lymphoma

AIMS

An accurate diagnosis of T-cell/histiocyte-rich large B-cell lymphoma needs to take into consideration those forms of Hodgkin's lymphoma also characterized by a predominance of small lymphocytes and histiocytes, i.e. nodular lymphocyte predominance Hodgkin's lymphoma and lymphocyte-rich classical Hodgkin's lymphoma. We have studied the clinical, phenotypic and genetic features of a series of 12 cases of T-cell/histiocyte-rich large B-cell lymphoma along with 18 cases of Hodgkin's lymphoma for comparative purposes.

METHODS AND RESULTS

Of the Hodgkin's lymphoma cases, there were 11 lymphocyte predominance type and seven classic type. T-cell/histiocyte-rich large B-cell lymphomas presented usually in advanced stages (III or IV in 11/12 cases), frequently with 'B' symptoms (6/9 cases), and followed a more aggressive course than Hodgkin's lymphoma (4/8 patients died due to the tumour in T-cell/histiocyte-rich large B-cell lymphoma versus 0/15 in Hodgkin's lymphoma). T-cell/histiocyte-rich large B-cell lymphoma cases showed diffuse effacement of the nodal architecture by a proliferation of scattered large atypical B-cells obscured by a background of small T-lymphocytes (more CD8+, TIA1+ than CD57+). Five cases showed also a prominent histiocytic component. The large B-cells expressed CD45 and often EMA (6/10 cases). On the other hand, CD 30, CD15 and latent infection by Epstein-Barr virus (EBV) were generally lacking. bc l6 and CD10 were, respectively, detected in 6/6 and 1/5 cases. Conventional polymerase chain reaction (PCR) showed monoclonal immunoglobulin heavy chain (IgH) gene rearrangements in all T-cell/histiocyte-rich large B-cell lymphomas studied (5/5), but did not detect any case with t(14;18) involving the major breakpoint region (0/4).

CONCLUSIONS

The differential diagnosis of T-cell/histiocyte-rich large B-cell lymphoma from Hodgkin's lymphoma is facilitated by the integration of different immunophenotypic, molecular and clinical findings. T-cell/histiocyte-rich large B-cell lymphoma is a monoclonal neoplasm of bc l6+ B-cells with a phenotypic profile similar to lymphocyte predominance Hodgkin's lymphoma, suggesting a germinal centre origin and a possible relation to this disease. Therefore, in order to distinguish it from lymphocyte predominance Hodgkin's lymphoma, characterization of the reactive background, IgH gene rearrangement studies by conventional PCR and clinical features are more useful. In contrast, T-cell/histiocyte-rich large B-cell lymphoma can be distinguished from classical Hodgkin's lymphoma thanks to the presence of monoclonal IgH rearrangement and the CD 30-CD15-CD45+EMA+ immunophenotypic profile of the neoplastic cells in T-cell/histiocyte-rich large B-cell lymphoma.

Expression of cytolytic lymphocyte-associated antigens in pulmonary lymphomatoid granulomatosis

Paraffin-embedded lung wedge biopsy specimens from 14 patients with pulmonary lymphomatoid granulomatosis (LYG) were analyzed using immunoperoxidase stains specific for T cell- and natural killer cell-associated antigens. Nine cases had a minor population of CD20+ large B-cells (B-cell LYG) amidst a background of CD3- and betaF1-immunoreactive T cells. In 8 of the 9 B-cell LYG cases, the majority of the background T lymphocytes had a cytotoxic phenotype as defined by the expression of CD8 and the cytotoxic granule proteins TIA-1 (granule membrane protein 17) and granzyme B. Five cases lacked CD20+ large cells and, instead, showed predominantly CD3+ and betaF1 + T cells (T-cell LYG). Whereas the small, medium, and large atypical lymphocytes were all positive for CD3 and betaF1 in the T-cell LYG cases, immunoreactivity for CD8, TIA-1, and granzyme B was limited to the small lymphocytes, with a distribution indistinguishable from that seen in B-cell LYG. These findings indicate that LYG is composed of a heterogeneous group of lymphoproliferative disorders that share, as unifying features, a relative paucity of neoplastic cells and a prominent reactive infiltrate rich in cytolytic lymphocytes.

T-cell-rich B-cell lymphoma - diagnostic and therapeutic aspects

BACKGROUND

Morphologically, T-cell-rich B-cell lymphoma (TCRB-NHL) may be indistinguishable from Hodgkin's disease (HD). Immunophenotyping may be helpful in the separation of these entities. TCRB-NHL is occasionally misdiagnosed and treated as HD. However, information is limited regarding clinical characteristics and outcome of this patient population. Furthermore, knowledge concerning any association with Epstein-Barr virus (EBV) in TCRB-NHL, as well as the immunophenotype of reactive T-cells and the expression of T-cell intracellular antigen-1 (TIA-1), granzyme B (GrB) and the CD3-zeta-chain is limited.

PATIENTS AND METHODS

We have re-evaluated 251 tumour biopsies from patients aged > or =15 years with HD diagnosed 1985-1994. Reclassification from HD to TCRB-NHL was done in 12 cases (5%). Six TCRB-NHL patients initially diagnosed and treated as B-NHL were also included. All TCRB-NHL biopsies were analysed for latent membrane protein 1 (LMP-1), CD4, CD8, CD56, CD57, TIA-1, GrB and CD3-zeta-chain.

RESULTS

Twelve cases of TCRB-NHL were initially subclassified as HD (lymphocyte predominance 5, nodular sclerosis 3, and mixed cellularity 4). Of these 12 TCRB-NHL patients, 6 were given radiotherapy alone, 5 MOPP/ABVD or similar combination chemotherapy, and one patient combined modality treatment. Male sex (p<0.05) and inguinal involvement (p<0.001) were significantly more frequent when TCRB-NHL patients receiving HD treatment (n=12) were compared with the remaining patients with confirmed (conf) HD, while no significant differences were seen with regard to stage, bone marrow infiltration, splenomegaly or cause-specific survival. Similar results were achieved when all TCRB-NHL patients (n=18) were compared to conf HD patients. Lymphoma cells in three samples stained positively for LMP-1. A decreased expression of CD3-zeta-chain was seen in 9/14 tumour biopsies.

CONCLUSION

Immunohistochemistry makes it possible to identify cases of TCRB-NHL that are morphologically difficult to distinguish from HD. The outcome of TCRB-NHL patients treated as having HD was comparable with that of the remaining HD population.

Combined histologic and molecular features reveal previously unappreciated subsets of lymphoma in AKXD recombinant inbred mice

Hematopoietic neoplasms developing in AKXD recombinant inbred, NFS.V(+) and ICSBP knockout mice were assessed using morphologic, cytologic and molecular criteria that relate these disorders to human lymphoma and leukemia. Lymphoma types included precursor T-cell and B-cell lymphoblastic, small lymphocytic, splenic marginal zone, follicular, and diffuse large cell (DLCL). In addition to previously defined subtypes of DLCL composed of centroblasts or immunoblasts, two additional subtypes are defined here: lymphoblastic lymphoma like (LL) and lymphoma characterized by a histiocytic reaction (HS). DLCL(HS) were distinguished from true histiocytic lymphomas by the presence of clonal Ig gene rearrangements.

Leukocytoclasis: ultrastructural in situ nick end labeling study in anaphylactoid purpura

In order to characterize leukocytoclasis of polymorphonuclear neutrophils (PMNs), the method of in situ nick end labeling for DNA breakdown was applied on tissue samples from 36 patients with anaphylactoid purpura at ultrastructural, as well as light microscopic, level. Light microscopic immuno-peroxidase technique showed positively labeled PMNs infiltrating in the dermis of 24 cases in which leukocytoclastic vasculitis was fully developed, suggesting that breakdown of DNA strands is triggered in the PMNs. Electron microscopic immuno-gold technique employed in six patients with the fully developed stage of inflammation identified the DNA breaks in the nuclei of PMNs. Ultrastructure of these cells, however, showed that only a minor population ( approximately 1/60) of PMNs showed the condensed and marginated nuclei, being compatible with typical apoptotic change. However, the majority of immuno-gold-labeled cells showed relatively intact nuclei without margination of condensed heterochromatin and with disintegrated cytoplasmic organelles and plasma membrane, suggesting that apoptotic cell removal mechanism may be incomplete. The immuno-gold-positive nuclear debris scattering in the tissue is most likely the remnants of unsatisfactory disposal by apoptosis of potentially injurious PMNs, resulting in the vascular and perivascular damage in leukocytoclastic vasculitis in anaphylactoid purpura.

Molecular analysis reveals somatically mutated and unmutated clonal and oligoclonal B cells in T-cell-rich B-cell lymphoma

This paper describes the immunohistology and molecular genetics of 18 cases of T-cell-rich B-cell lymphoma (TCRBL). In all cases, the large B cells stained strongly for CD20, with more variable expression of CD79a, and were negative for CD30 and CD15. The majority of T cells were predominantly positive for TIA-1 and negative for CD57; a large population of histiocytes was present in all cases. Epstein-Barr virus (EBV)-coded RNA (EBER) was found in B blasts from four cases and in one case was present among the background lymphoid cells. IgH PCR products were generated in 16/18 cases and revealed clonal, oligoclonal and polyclonal PCR products in 12, two and two cases, respectively. In addition, TCRG clonal gene rearrangements were identified in two cases. TCRB gene rearrangements were polyclonal. Sequence analysis of seven cases with clonal/oligoclonal IgH gene rearrangements revealed functional sequences with predominant V(H)3 gene usage associated with various D genes and J(H)4 or J(H)6 gene segments. Four cases displayed varying degrees of replacement and silent mutations (1.8-21%), with one case exhibiting intraclonal heterogeneity; the distribution of mutations was indicative of antigen selection in three cases. The remaining three cases, including two cases with functional oligoclonal IgH rearrangements, harboured unmutated V region genes. The EBV-positive cases were associated with clonal, oligoclonal and polyclonal PCR products and with mutated and germline clonal sequences. These data indicate that TCRBL may be a heterogeneous entity associated with clonal and oligoclonal B cells derived from both germinal centre and naïve B cells.

Intra-tumoral cytolytic cells: pattern of distribution in B-cell non Hodgkin s lymphoma

Non-Hodgkin s lymphomas (NHLs) constitute a heterogeneous group of lymphoid neoplasms and a majority of them in India are of B-cell phenotype. Varying numbers of T lymphocytes and natural killer (NK) cells are consistently present within the lymph nodes (LNs). The role of these reactive cells is becoming understood. TIA-1 is a cytotoxic granule associated RNA binding protein, the expression of which is restricted to cytotoxic T lymphocytes (CTLs) and NK cells. Snap frozen lymph node biopsies obtained from 41 B-cell NHLs were localized for intra-tumoral TIA-1 + cytolytic cells by immunohistochemistry. Distribution of T cell subsets and NK cells were also quantified. Cells expressing TIA-1 antigen was observed in all the cases, seen as a strong granular cytoplasmic signal. Results indicate significantly higher number of TIA-1 cytolytic cells outside (periphery of the follicle and interfollicular areas) than within the neoplastic follicle in follicular lymphomas (p<0.001). In small lymphocytic lymphomas, cytolytic cells were mainly seen as uniformly scattered single cells, distributed throughout the tumor environment. In mantle cell and diffuse large B-cell lymphomas these were most often seen as small clusters and less frequently as singly scattered cells. Higher numbers of CD4 + than the CD8 + T cells were observed in most cases. Contrary to the follicles in follicular hyperplasia, CD57 + NK cells were predominantly observed outside the neoplastic follicle in follicular lymphomas (FLs). These results outline specific interactions between the potential anti-tumoral cytolytic and the malignant cells of B-cell NHLs.

Nijmegen breakage syndrome-associated T-cell-rich B-cell lymphoma: case report

In 1981 Weemaes et al. first described the Nijmegen breakage syndrome (NBS), a rare autosomal recessive disorder characterized by stunted growth, microcephaly, immunodeficiency, spontaneous chromosome instability, and a peculiar predisposition to cancer development. Most NBS-related malignancies are lymphomas, but their pathologic features have rarely been specified. We report here the case of a northern Italian 8-year-old child who, 2 years after the diagnosis of NBS, developed a diffuse large B-cell lymphoma (T cell-rich B-cell lymphoma variant). The histological and immunobiological features of the lymphoma population are analyzed and discussed in detail.

Better-surviving liver grafts by the injection of anti-CD2 antibody: the important roles of host CD8+ and CD2+CD28+ T cells in chronic graft rejection and beta type platelet-derived growth factor receptor (PDGFR-beta) expression on apoptotic liver grafts

Syngeneic liver grafts were implanted in the livers of 22 LEW/Sea strain rats. To prolong the graft survival, anti-CD2 monoclonal antibody (MAb) or anti beta type platelet-derived growth factor receptor (PDGFR-beta) antibody (Ab) was injected, or splenectomy was performed in the rats which were then followed until 10 to 11 weeks posttransplantation. The 22 rats with chronic graft rejection showed increased CD8a-like antigen (probably Fas ligand) on the peripheral blood T cells. All the liver grafts had both necrosis and apoptosis. The liver graft apoptosis was indicated by histopathological abnormalities, and by DNA strand breaks and hemosiderin depositions in the cytoplasm. PDGFR-beta expression in the apoptotic liver graft was demonstrated immunohistochemically. Among the 17 rats injected with anti-CD2 MAb, CD2 signaling on host T cells was effectively suppressed by the injection of anti-CD2 MAb in 4 rats with better-surviving liver grafts. In these 4 rats, CD28 antigen on thymic lymphocytes was down-modulated and high numbers (136-233-positive cells per lobe) of the epithelial reticular cells with apoptotic lymphocytes were counted. Anti-PDGFR-beta Ab caused high pulmonary secretions of growth factors and reticular fibrosis in the lungs of 5 rats injected with the Ab. Anti-PDGFR-beta Ab injection reduced the host cell apoptosis in the lung and thymus, but did not prolong the survival of liver grafts. In the 9 rats with both splenectomy and anti-CD2 MAb injection, pulmonary apoptosis was induced with the 6-16% reductions of CD4+ lymphocytes. Prolonged graft survival was observed in only one of the 9 rats. Anti-CD2 MAb was effective for prolonging the liver graft survival with suppressed CD28 antigen, but anti-PDGFR-beta Ab and splenectomy were not.