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Aims: T-follicular helper (TFH) cells are effector T-cells that are crucial for B-cell selection and differentiation. T-cell lymphomas derived from TFH cells have distinct characteristics. Additionally, in the World Health Organization (WHO) classification 5th edition, three lymphomas were introduced as independent disease entities with TFH cell origin. We aimed to investigate the clinicopathological features of adult T-cell leukemia/lymphoma (ATLL) with a TFH phenotype (TFHP)., Methods and Results: We performed TFH immunohistochemistry analysis of five biomarkers for the biopsy specimen, with TFHP being indicated by a positive result for more than two markers. Among 75 cases of ATLL, 37.3% of them showed TFHP. Compared with cases of ATLL without TFHP, cases of ATLL with TFHP showed higher C-reactive protein levels (p = 0.0219) and increased high endothelial venule proliferation (p = 0.024). However, there were no significant between-group differences in overall survival as well as other clinical and morphological findings. Furthermore, there was no significant between-group difference in TFH markers and FOXP3 expression., Conclusion: Some patients with ATLL may present a TFHP, which should not preclude the diagnosis of ATLL. Although presenting a TFHP does not affect prognosis, it is important to identify cases of ATLL with a TFHP since it may inform future treatment strategies., (© 2024 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

The prognosis of aggressive adult T-cell leukemia/lymphoma (ATL) is poor, and allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment. In order to identify favorable prognostic patients after intensive chemotherapy, and who therefore might not require upfront allo-HSCT, we aimed to improve risk stratification of aggressive ATL patients aged <70 years. The clinical risk factors and genetic mutations were incorporated into risk modeling for overall survival (OS). We generated the m7-ATLPI, a clinicogenetic risk model for OS, that included the ATL prognostic index (PI) (ATL-PI) risk category, and non-silent mutations in seven genes, namely TP53, IRF4, RHOA, PRKCB, CARD11, CCR7, and GATA3. In the training cohort of 99 patients, the m7-ATLPI identified a low-, intermediate-, and highrisk group with 2-year OS of 100%, 43%, and 19%, respectively (hazard ratio [HR] =5.46; P<0.0001). The m7-ATLPI achieved superior risk stratification compared to the current ATL-PI (C-index 0.92 vs. 0.85, respectively). In the validation cohort of 84 patients, the m7-ATLPI defined low-, intermediate-, and high-risk groups with a 2-year OS of 81%, 30%, and 0%, respectively (HR=2.33; P=0.0094), and the model again outperformed the ATL-PI (C-index 0.72 vs. 0.70, respectively). The simplified m7-ATLPI, which is easier to use in clinical practice, achieved superior risk stratification compared to the ATLPI, as did the original m7-ATLPI; the simplified version was calculated by summing the following: high-risk ATL-PI category (+10), low-risk ATL-PI category (-4), and non-silent mutations in TP53 (+4), IRF4 (+3), RHOA (+1), PRKCB (+1), CARD11 (+0.5), CCR7 (-2), and GATA3 (-3).

In the present study, we propose a novel case-based similar image retrieval (SIR) method for hematoxylin and eosin (H&E) stained histopathological images of malignant lymphoma. When a whole slide image (WSI) is used as an input query, it is desirable to be able to retrieve similar cases by focusing on image patches in pathologically important regions such as tumor cells. To address this problem, we employ attention-based multiple instance learning, which enables us to focus on tumor-specific regions when the similarity between cases is computed. Moreover, we employ contrastive distance metric learning to incorporate immunohistochemical (IHC) staining patterns as useful supervised information for defining appropriate similarity between heterogeneous malignant lymphoma cases. In the experiment with 249 malignant lymphoma patients, we confirmed that the proposed method exhibited higher evaluation measures than the baseline case-based SIR methods. Furthermore, the subjective evaluation by pathologists revealed that our similarity measure using IHC staining patterns is appropriate for representing the similarity of H&E stained tissue images for malignant lymphoma., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Adult T cell leukemia-lymphoma (ATL) is clinically heterogeneous and is classified into four subtypes: acute, lymphoma, chronic, and smoldering. Recently, a new prognostic index based on the value of soluble interleukin-2 receptor, denoted the "iATL-PI," has been proposed for patients with smoldering and chronic ATL. To evaluate the effectiveness of the iATL-PI, we re-analyzed our previously published data on 176 patients with smoldering or chronic ATL (76 smoldering, 100 chronic) diagnosed between 2010 and 2011, as well data from the subsequent follow-up study on prognosis between 2016 and 2017. The proportions for the low-, intermediate-, and high-risk iATL-PI groups at the time of ATL diagnosis were 44.7%, 48.7%, and 5% for smoldering ATL; 6.3%, 71.9%, and 21.9% for favorable chronic ATL; and 5.9%, 27.9%, and 66.2% for unfavorable chronic ATL, respectively. The survival of patients with smoldering or chronic ATL as a whole was significantly stratified according to the three iATL-PI groups. Most patients with unfavorable chronic ATL in the low iATL-PI risk group had indolent clinical courses. Our results showed that iATL may become a useful tool to predict the prognosis of smoldering and chronic ATL, which have diverse clinical courses., (© 2022. Japanese Society of Hematology.)

Transforming acidic coiled-coil-containing protein 3 (TACC3) plays an important role in centrosome/microtubule dynamics. Deregulation of centrosomes/microtubules causes mitotic spindle defects, leading to tumorigenesis. However, the correlation between TACC3 and primary central nervous system lymphomas (PCNSLs) is unknown. The present study investigated the association between the immunohistochemical expression of TACC3, p53, and Ki-67, and the clinical factors in 40 PCNSLs. We evaluated the staining of TACC3 based on the histoscore (H-score) that contains a semiquantitative evaluation of both the intensity of staining, and the percentage of positive cells. Expression level of each component was classified as low or high according to the median H-score value. Patients with PCNSLs were divided into groups depending on TACC3 expression levels (no expression and low expression, 18; high expression, 22). Disease-free survival and overall survival of patients with high TACC3 expression were significantly shorter (p < 0.01 and p < 0.05, respectively). These results suggest that elevated expression of TACC3 could reflects aggressiveness of primary central nervous system lymphomas., (© 2022 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

The activities of non-haematopoietic cells (NHCs), including mesenchymal stromal cells and endothelial cells, in lymphomas are reported to underlie lymphomagenesis. However, our understanding of lymphoma NHCs has been hampered by unexplained NHC heterogeneity, even in normal human lymph nodes (LNs). Here we constructed a single-cell transcriptome atlas of more than 100,000 NHCs collected from 27 human samples, including LNs and various nodal lymphomas, and it revealed 30 distinct subclusters, including some that were previously unrecognized. Notably, this atlas was useful for comparative analyses with lymphoma NHCs, which revealed an unanticipated landscape of subcluster-specific changes in gene expression and interaction with malignant cells in follicular lymphoma NHCs. This facilitates our understanding of stromal remodelling in lymphoma and highlights potential clinical biomarkers. Our study largely updates NHC taxonomy in human LNs and analysis of disease status, and provides a rich resource and deeper insights into LN and lymphoma biology to advance lymphoma management and therapy., (© 2022. The Author(s).)

We generated dual-antigen receptor (DR) T cells from induced pluripotent stem cells (iPSCs) to mitigate tumor antigen escape. These cells were engineered to express a chimeric antigen receptor (CAR) for the antigen cell surface latent membrane protein 1 (LMP1; LMP1-CAR) and a T cell receptor directed to cell surface latent membrane protein 2 (LMP2), in association with human leucocyte antigen A24, to treat therapy-refractory Epstein-Barr virus-associated lymphomas. We introduced LMP1-CAR into iPSCs derived from LMP2-specific cytotoxic T lymphocytes (CTLs) to generate rejuvenated CTLs (rejTs) active against LMP1 and LMP2, or DRrejTs. All DRrejT-treated mice survived >100 days. Furthermore, DRrejTs rejected follow-up inocula of lymphoma cells, demonstrating that DRrejTs persisted long-term. We also demonstrated that DRrejTs targeting CD19 and LMP2 antigens exhibited a robust tumor suppressive effect and conferred a clear survival advantage. Co-operative antitumor effect and in vivo persistence, with unlimited availability of DRrejT therapy, will provide powerful and sustainable T cell immunotherapy., Competing Interests: Declaration of interests H.N. is a co-founder of and an advisor to Century Therapeutics. The remaining authors declare no competing interests., (Copyright © 2021 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

Adult T-cell leukemia/lymphoma (ATL) cells frequently exhibit chromosomal abnormalities, including numerical aberrations and structural defects. However, no studies have examined the correlation between these abnormalities and survival in patients with ATL after allogeneic HSCT (allo-HSCT). In this study, 300 patients with ATL (median age, 55 years; range, 24-74) who were registered in a Japanese nationwide registry database were analyzed. The majority (n = 183) had acute ATL. Specimens for chromosomal analysis were collected from bone marrow (n = 166), lymph nodes (n = 86), peripheral blood (n = 41), and other locations (n = 7). In survival analyses, breakpoints at 2q (hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.12-2.38; P = .012) and 5q (HR, 2.18; 95% CI, 1.25-3.80; P = .006) were significantly poor prognostic factors for overall survival (OS). In terms of ATL-related death, loss of chromosome 14 and breakpoints at 3p, 1q, 5q, and 6q were extracted as significantly poor prognostic factors. Moreover, complex karyotypes were associated with ATL-related death. This study of the survival impact of chromosomal abnormalities in patients with ATL after allo-HSCT demonstrated that several structural breakpoints were independent risk factors for OS and ATL-related death., (© 2021 by The American Society of Hematology.)

Adult T-cell leukemia/lymphoma (ATLL) is a malignancy caused by the human T-cell leukemia virus type 1. Aggressive ATLL is refractory to conventional chemotherapy and has a poor prognosis. Better therapeutic approaches, including cancer immunotherapy, are required to improve survival and prognosis. The genetic landscape of ATLL reveals frequent genetic alterations in genes associated with immune surveillance, including major histocompatibility complex (MHC) class I, CD58 antigen, and programmed cell death ligand 1. Clinicopathological investigations also revealed tumor immunity mechanisms in ATLL, including immune checkpoint molecules, MHC molecules, tumor-associated macrophages, and chemokines. However, the tumor microenvironment of ATLL remains complex because ATLL itself originates from T-cells, usually expressing regulatory T-cell markers. In this review, we discuss the recent literature describing the tumor microenvironment of ATLL.

A pathological evaluation is one of the most important methods for the diagnosis of malignant lymphoma. A standardized diagnosis is occasionally difficult to achieve even by experienced hematopathologists. Therefore, established procedures including a computer-aided diagnosis are desired. This study aims to classify histopathological images of malignant lymphomas through deep learning, which is a computer algorithm and type of artificial intelligence (AI) technology. We prepared hematoxylin and eosin (H&E) slides of a lesion area from 388 sections, namely, 259 with diffuse large B-cell lymphoma, 89 with follicular lymphoma, and 40 with reactive lymphoid hyperplasia, and created whole slide images (WSIs) using a whole slide system. WSI was annotated in the lesion area by experienced hematopathologists. Image patches were cropped from the WSI to train and evaluate the classifiers. Image patches at magnifications of ×5, ×20, and ×40 were randomly divided into a test set and a training and evaluation set. The classifier was assessed using the test set through a cross-validation after training. The classifier achieved the highest levels of accuracy of 94.0%, 93.0%, and 92.0% for image patches with magnifications of ×5, ×20, and ×40, respectively, in comparison to diffuse large B-cell lymphoma, follicular lymphoma, and reactive lymphoid hyperplasia. Comparing the diagnostic accuracies between the proposed classifier and seven pathologists, including experienced hematopathologists, using the test set made up of image patches with magnifications of ×5, ×20, and ×40, the best accuracy demonstrated by the classifier was 97.0%, whereas the average accuracy achieved by the pathologists using WSIs was 76.0%, with the highest accuracy reaching 83.3%. In conclusion, the neural classifier can outperform pathologists in a morphological evaluation. These results suggest that the AI system can potentially support the diagnosis of malignant lymphoma.

Human T cell leukemia virus type 1 (HTLV-1) is the etiologic agent of a T cell neoplasm and several inflammatory diseases. A viral gene, HTLV-1 bZIP factor (HBZ), induces pathogenic Foxp3-expressing T cells and triggers systemic inflammation and T cell lymphoma in transgenic mice, indicating its significance in HTLV-1-associated diseases. Here we show that, unexpectedly, a proinflammatory cytokine, IL-6, counteracts HBZ-mediated pathogenesis. Loss of IL-6 accelerates inflammation and lymphomagenesis in HBZ transgenic mice. IL-6 innately inhibits regulatory T cell differentiation, suggesting that IL-6 functions as a suppressor against HBZ-associated complications. HBZ up-regulates expression of the immunosuppressive cytokine IL-10. IL-10 promotes T cell proliferation only in the presence of HBZ. As a mechanism of growth promotion by IL-10, HBZ interacts with STAT1 and STAT3 and modulates the IL-10/JAK/STAT signaling pathway. These findings suggest that HTLV-1 promotes the proliferation of infected T cells by hijacking the machinery of regulatory T cell differentiation. IL-10 induced by HBZ likely suppresses the host immune response and concurrently promotes the proliferation of HTLV-1 infected T cells., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)

Ghrelin and its receptor, growth hormone secretagogue receptor (GHS-R), have been found in a variety of malignant tumor tissues, suggesting a biological function of the ghrelin/GHS-R axis in tumor growth and progression. Among central nervous system tumors, primary central nervous system lymphomas (PCNSLs) are relatively rare and characterized by a rapid progression and poor prognosis. In order to clarify ghrelin expression and its functional role in promoting tumor growth and progression in PCNSLs, we undertook an immunohistochemical investigation for ghrelin and GHS-R expression in 43 patients and tested the effect of ghrelin inhibition on lymphoma cells. Furthermore, we investigated the expression of CD105, a marker for tumor angiogenesis, to explore its association with the ghrelin/GHS-R axis. The Kaplan-Meier method and Cox's proportional hazards regression model were used to determine the association of ghrelin/GHS-R expression with overall survival rate. The immunohistochemical study showed moderate/strong immunostaining of cells for ghrelin and GHS-R in 40 patients (93.0%) and 39 patients (90.7%), respectively. A ghrelin inhibitor did not affect tumor cell proliferation in vitro. Expression levels of ghrelin and GHS-R were divided into high and low groups by the rate of moderate-strong staining cells to tumor cells. The survival rate was significantly lower in patients with high GHS-R expression (P = 0.0368 by log-rank test; P = 0.0219 by Wilcoxon test). In addition, multivariate analysis of overall survival using Cox's proportional hazards regression model indicated that GHS-R was a significant independent prognostic factor (P = 0.0426). CD105 expression on tumor vessels was positive in 33 patients (33/37, 89.2%). There was a positive correlation between the moderate-strong staining rate of ghrelin and CD105-positive vessel count. These results indicated that the ghrelin/GHS-R axis plays a potential role in promoting tumor growth and progression through neoangiogenesis, rather than the proliferation of tumor cells., (© 2020 Japanese Society of Neuropathology.)

This study provides an overview of the epidemiology and secular trends of malignant lymphoma in Japan. Using data from clinics and hospitals throughout Japan, we analyzed 9426 cases of malignant lymphoma diagnosed in 2007-2014. We show that the proportion of follicular lymphoma and methotrexate-associated lymphoproliferative disorder increased during this time, as did the onset age for follicular lymphoma and diffuse large B-cell lymphoma. Significant increases in onset age for follicular lymphoma and diffuse large B-cell lymphoma were observed in both men and women (all P values <0.0001 except for P = 0.0448 for the latter disease in women). Further studies are required to determine the reasons for the higher proportion of and onset age for these lymphomas. Additionally, we believe that continued observation of these trends is necessary., (© 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

It has been shown that high expression of certain immune checkpoint molecules, including those of the programmed death protein 1/programmed death ligand 1 (PD-1/PD-L1) axis, can be utilized to regulate immunosuppression in the microenvironment of malignant neoplasms. For the purpose of clarifying the immune-escape mechanism of primary central nervous system lymphomas (PCNSLs), particularly in Epstein-Barr virus (EBV)-positive cases, markers for PD-1, PD-L1, tumor-associated macrophages (TAMs), and tumor-infiltrating lymphocytes (TILs) in 39 surgical specimens of PCNSLs (17 EBV-positive, 22 EBV-negative) were investigated by immunohistochemistry. Staining for PD-L1 was scored as follows: (-), no staining; (1+), 0-30% positive cells; (2+), 30-60% positive cells; and (3+), >60% positive cells. In EBV-positive cases, PD-L1 was detected in both lymphoma cells and TAMs in 12/17 cases, and in TAMs only in 4/17 cases. The mean number of PD-1, TIA-1 (a marker for cytotoxic T-cells), and FOXP3 (a marker for regulatory T-cells)-positive TILs in EBV-positive cases was 36.4 ± 45.9, 390 ± 603, and 9.88 ± 15.1, respectively. In EBV-negative cases, PD-L1 was detected in both lymphoma cells and TAMs in 11/22 cases, and in TAMs only in 4/22 cases. The mean of PD-1, TIA-1 and FOXP3-positive lymphocytes in EBV-negative cases was 67.3 ± 82.0, 158 ± 206 and 9.32 ± 17.5, respectively. We found no significant difference in the number of FOXP3-positive, lymphocytes between EBV-positive and negative cases. However, there were significantly higher numbers of PD-1-positive lymphocytes in the former, and significantly higher numbers of TIA-1-positive lymphocytes in the latter (P < 0.05). The combined data indicate that expression of PD-L1 by lymphoma cells and TAMs mediate the trafficking of TILs, which may explain the immune-escape process of PCNSLs. In addition, EBV infection appears to affect the trafficking mechanism of TILs, and may thus play an important role in the microenvironment immunity of these tumors., (© 2017 Japanese Society of Neuropathology.)

Primary central nervous system lymphoma (PCNSL) is a distinct subtype of extranodal lymphoma with aggressive clinical course and poor outcome. As increased IL-10/IL-6 ratio is recognized in the cerebrospinal fluid (CSF) of PCNSL patients, we hypothesized that PCNSL might originate from a population of B cells with high IL-10-producing capacity, an equivalent of "regulatory B cells" in mice. We intended in this study to clarify whether Tim-1, a molecule known as a marker for regulatory B cells in mice, is expressed in PCNSL. By immunohistochemical analysis, Tim-1 was shown to be positive in as high as 54.2% of PCNSL (26 of 58 samples), while it was positive in 19.1% of systemic diffuse large B-cell lymphoma (DLBCL) samples (17 of 89 samples; P < 0.001). Tim-1 expression positively correlated with IL-10 expression in PCNSL (Cramer's V = 0.55, P < 0.001), and forced expression of Tim-1 in a PCNSL cell line resulted in increased IL-10 secretion, suggesting that Tim-1 is functionally linked with IL-10 production in PCNSL. Moreover, soluble Tim-1 was detectable in the CSF of PCNSL patients, and was suggested to parallel disease activity. In summary, PCNSL is characterized by frequent Tim-1 expression, and its soluble form in CSF may become a useful biomarker for PCNSL., (© 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Although primary diffuse large B-cell lymphomas of the CNS are designated as primary CNS lymphomas according to the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissue in 2008, a variety of other lymphomas (Burkitt lymphomas, EBV-positive diffuse large B-cell lymphoma of the elderly) and related diseases (lymphomatoid granulomatosis) that are also found in the CNS have been spotlighted in recent years. The histopathology of primary CNS Burkitt lymphomas mimics that of primary diffuse large B-cell lymphomas of the CNS after steroid administration. Therefore, for correct diagnosis of the involved lymphoma, comprehensive fluorescent in situ hybridization analysis for c-MYC and BCL2 is recommended in all primary CNS lymphoma cases with aggressive clinical course, multifocal involvement of the CNS, and a high proliferation index. The pathological characteristics of primary CNS EBV-positive diffuse large B-cell lymphoma of the elderly have similarities with those of the latency phenotype III, EBV lymphoproliferative disorders that arise in the setting of immunodeficiency. These age-related lymphomas usually occur in elderly immunocompetent patients, and the incidence of this disease was estimated to range from 4.0% to 13.6% of all primary CNS lymphomas. Shorter overall survival has been reported for patients with this disease. Lymphomatoid granulomatosis (LYG) is a systemic, EBV-driven, angiocentric and angiodestructive lymphoproliferative disorder. Primary LYG that shows distinct clinicopathological features compared with systemic LYG was recently reported. Finally, this review focuses on the relationship between primary CNS lymphomas and demyelinating diseases, and the concomitant use of intraoperative cytology and frozen sections that are helpful in rapid intraoperative diagnosis., (© 2015 Japanese Society of Neuropathology.)

Chemokines are peptides that function as chemoattractant cytokines in cell activation, differentiation and trafficking. Endothelin B receptor (ETBR) is a receptor for endothelin, which is known to function as a vasoconstrictor. In the present study, to clarify the immune escape mechanism of primary central nervous system lymphomas (PCNSLs), the expression of ETBR and of subsets of chemokines (CXCL12, 13) in 24 PCNSLs was investigated. CXCL12 was expressed by lymphoma cells in different resident brain cell populations in 22/24 cases. CXCL13 expression was identified in tumor cells in 19/24 cases, but was only expressed by tumor cells and by proliferating vascular endothelial cells. In addition, tumor-infiltrated lymphocytes (TILs) accumulated in areas with expression of chemokines, particularly of CXCL13. ETBR expression was detected in 12/24 cases. Positive ETBR cases were associated with a paucity of TILs, particularly of cytotoxic T cells, whereas negative ETBR cases were associated with an abundance of TILs. The combined data indicate that CXCL12 and CXCL13 up-regulation may be differently linked to the development of PCNSLs and to the accumulation of TILs. In addition, ETBR expression by lymphoma and endothelial cells may mediate trafficking of TILs, which may explain the immune escape processes of PCNSLs.

To study the advantages and pitfalls of intraoperative rapid diagnosis (IRD) of primary central nervous system lymphomas (PCNSL), pathology reports and frozen sections in our institution were reviewed. We examined 27 cases of PCNSL, one case of anaplastic glioma, and one case of metastatic brain tumor that were diagnosed on neuroimaging. Fifteen cases of intraoperative cytological preparations were also reviewed in a correlative manner. Among the 27 cases initially diagnosed as PCNSL, 18 were also diagnosed as PCNSL by IRD. However, IRD identified four of the 27 cases as gliosis, two as demyelination, one as atypical epithelial cells, one as malignant glioma and anaplastic astrocytoma. In addition, the case identified as metastatic brain tumor on neuroimaging was corrected to a diagnosis of PCNSL based on IRD. The final accuracy of IRD in the present study was 89.6% (26/29). After postoperative definitive diagnosis, two cases of anaplastic astrocytoma and one case of PCNSL by IRD were corrected to PCNSL, anaplastic oligodendroglioma and demyelination, respectively. PCNSL were sometimes histologically indistinguishable from malignant gliomas or demyelinating diseases in the present study, particularly in frozen sections. Notably, all cases for which both intraoperative cytology and frozen section were performed concomitantly were correctly diagnosed in the present study. In particular, lymphoglandular bodies were highly characteristic cytological findings of PCNSL. Both intraoperative cytology and frozen sections should therefore be performed concomitantly when PCNSL are suspected., (© 2014 Japanese Society of Neuropathology.)

From a clinicopathological conference on nine elderly patients with Epstein-Barr virus (EBV)-associated T/natural killer (NK)-cell lymphoma, we have addressed the patients' backgrounds, clinical manifestations, histopathological findings, cytogenesis, complications and prognoses. Among these elderly patients (>65 years old), seven patients had extranodal NK/T-cell lymphoma, nasal type (ENKL) with an NK-cell phenotype, and two patients had EBV(+) T-cell lymphomas or lymphoproliferative disorders (LPD) with cutaneous lesions mimicking pityriasis lichenoides et varioliformis acuta (PLEVA) or hydroa vacciniforme (HV). No patients had a previous episode of EBV-related symptoms such as infectious mononucleosis, chronic active EBV infection, HV or hypersensitivity to mosquito bites. Elderly patients with ENKL may show the centroblastoid variant. EBV(+) CD8(+) CD56(+/-) lymphocytes may be responsible for the development of PLEVA or HV-like cutaneous lesions in the elderly., (© 2014 Japanese Dermatological Association.)

Evidence is accumulating that hematologic malignancies develop following acquisition of multiple genetic changes. Despite providing many insights into the way by which given genetic changes contribute to the development of disease, the generation of animal models is often laborious. We show a simplified method that allows the retroviral transduction of genes of interest into mouse B or T cells, thus leading to the rapid generation of models of lymphoid neoplasm in mice. Specifically, germinal center B cells induced in vitro from naive mouse B cells and infected with retroviruses for Myc and Bcl2 rapidly developed a neoplasm of immunoglobulin-expressing mature B cells in transplanted mice. Likewise, T cells induced in vitro from immature hematopoietic cells and infected with retroviruses for Myc, Bcl2, and Ccnd1 rapidly developed CD4(+)CD8(-) and CD4(+)CD8(+) T cell neoplasm in transplanted mice. These findings support the use of our simplified method as a versatile tool for lymphoma research., (Copyright © 2013 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc. All rights reserved.)

NK cell neoplasms are lymphoid malignancies with an aggressive clinical course. In the present study, we analyzed gene expression profiling of NK cell neoplasms and attempted to identify important molecular pathways and new effective drugs. Pathway analysis of gene expression profiles suggested the important roles of the JAK-STAT pathway, NF-κB pathway or Wnt pathways in NK cell neoplasms. Notably, western blot analysis revealed that STAT3 was expressed and phosphorylated at a higher level in NK cell lines than in normal NK cells or other cell lines. These findings indicate the occurrence of JAK-STAT activation in NK cell neoplasms. Connectivity Map (CMAP) analysis of gene expression profiles identified candidate drugs against NK cell neoplasms. Among the drugs suggested by CMAP analysis, we focused on puromycin, phenoxybenzamine, LY294002, wortmannin, vorinostat and trichostatin A because they exhibited high enrichment scores. We added these drugs to NK cell lines and other cell lines. Among the drugs, vorinostat suppressed NK cell line proliferation at a significantly lower concentration compared to other cell lines. Suppression of the JAK-STAT pathway appeared to contribute to this effect. Vorinostat may be a good candidate for use in the therapy against NK cell neoplasms., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

To evaluate the incidence and risk factors for secondary solid tumors in Japan after allogeneic hematopoietic SCT (allo-HSCT), 2062 patients who had received allo-HSCT between 1984 and 2005 were retrospectively analyzed. Twenty-eight patients who developed 30 solid tumors were identified a median of 5.6 years after transplantation. The risk for developing tumors was 2.16-fold higher than that of the age- and sex-adjusted general population. The cumulative incidence of solid tumors at 10 years after allo-HSCT was 2.4%. The risk was significantly higher for tumors of the skin, oral cavity and esophagus (standard incidental ratio 40.23, 35.25 and 10.73, respectively). No increase in gastric, colon or lung cancer, despite being the most prevalent neoplasm in the Japanese, was observed. In multivariate analysis, occurrence of chronic GVHD and malignant lymphoma as a primary disease was associated with a higher risk for developing solid tumors. Eighteen patients are still alive, and their 5-year probability of survival since diagnosis of solid tumors is 59.7%. Our data suggest that the incidence and risk factors of secondary solid tumors in Japanese allo-HSCT recipients are comparable to those reported in Western countries and emphasize that the early detection of solid tumors has a crucial role in improving OS.

The World Health Organization classification was used to conduct an analysis of geographic, age, sex, and lesion primarily biopsied/resected distribution of 2260 lymphoid neoplasms diagnosed during 2001-2006 throughout Japan. B-cell neoplasms accounted for 65% of all lymphoid neoplasms, T/natural killer (T/NK)-cell neoplasms for 25% and Hodgkin lymphoma for 7%. The most common type was diffuse large B-cell lymphoma (DLBCL, 33%), followed by follicular lymphoma (18%), and adult T-cell leukemia/lymphoma (ATLL, 10%). The high rate of 18% for follicular lymphoma was similar to that in Western countries (11-33%). T/NK-cell neoplasms accounted for a higher percentage of lymphoid neoplasms in Kyushu (30%) and Okinawa (38%) compared with other areas of Japan (18-20%). Among T/NK-cell neoplasms, ATLL was the most common type in Okinawa (54%) and Kyushu (59%). Extranodal NK/T cell lymphoma was the second most common type of T/NK-cell neoplasms in Okinawa (15%). This epidemiological study shows that the distribution patterns of malignant lymphoma differ especially in Kyushu and Okinawa, the endemic area of human T-cell leukemia/lymphoma virus type 1.

Cyclooxygenase (COX) is the rate-limiting enzyme that catalyzes the initial step in biosynthesis of prostaglandins (PGs) from arachidonic acid. COX-2 has been associated with inflammatory processes and tumorigenesis. In order to investigate the correlation between VEGF, COX-2 expression, and tumorigenesis in primary central nervous system lymphomas (PCNSLs), the present study assessed 26 cases of PCNSL by immunostaining for VEGF and COX-2. Immunohistochemical studies were evaluated as follows: (-), no staining; (1+), 0-30% positive cells; (2+), 30-60% positive cells; (3+), >60% positive cells. VEGF expression was detected in 21 of 26 cases; of these, 14, 1 and 6 were scored as 3+, 2+ and 1+, respectively. COX-2 expression was detected in 22 of 26 cases; of these, 14, 4 and 4 were scored as 3+, 2+ and 1+, respectively. For double immunofluorescence, 20 of 26 cases that were detected with both VEGF and COX-2 were examined and almost all tumor cells coexpressed both VEGF and COX-2 in the examined cases. However, COX-2 and VEGF expression in PCNSLs did not correlate with neoangiogenesis and patient survival in the present study, in contrast to previous findings in systemic lymphomas. It is suggested that the high frequency of COX-2 and VEGF coexpression in PCNSLs may be associated with tumorigenesis of PCNSLs and could possibly lead to a future therapeutic trial of PCNSLs with selective COX-2 inhibitor therapy.

Neoplasms putatively originating from precursor and mature natural killer (NK) cells are rare, and their clinical features are unclear. A nationwide survey was performed in Japan to clarify the clinical features of these neoplasms diagnosed between 1994 and 1998, and data for 237 patients who met the criteria for putative NK cell-lineage neoplasms were analyzed. Among them, 11 had myeloid/NK-cell precursor acute leukemia, 15 blastic NK-cell lymphoma, 21 precursor NK-cell acute lymphoblastic leukemia, 22 aggressive NK-cell leukemia/lymphoma, 149 nasal-type NK-cell lymphoma (123 nasal and 26 extranasal) and 19 chronic NK lymphocytosis. The median overall survival time of patients with aggressive NK-cell leukemia/lymphoma was 2 months, which for chronic NK lymphocytosis was more than 8 years, and that for the other types of NK-cell neoplasms was between 6 and 22 months. Nasal NK-cell lymphoma and extranasal NK-cell lymphoma share the same histology. The age of affliction was the same, but the sex was different with males predominantly having nasal NK-cell lymphoma and females extranasal NK-cell lymphoma. Patients with extranasal NK-cell lymphoma had the tendency to exhibit a more advanced state of disease, with significantly higher International Prognostic Index and LDH levels, and significantly lower hemoglobin and platelet levels. The overall survival, however, did not differ significantly. Precursor NK-cell acute lymphoblastic leukemia and blastic NK-cell lymphoma were arbitrarily defined by the presence or absence of 30% or more of blastic cells in the bone marrow or peripheral blood, but there were no significant differences for affected age, gender, involved sites or prognosis. Aggressive NK-cell leukemia/lymphoma and extranasal NK-cell lymphoma were arbitrarily defined by the presence or absence of 30% or more of large granular lymphocytes in the bone marrow or peripheral blood and it is possible that aggressive NK-cell leukemia/lymphoma is a leukemic phase of extranasal NK-cell lymphoma. The incidence of skin involvement, however, was significantly higher for extranasal NK-cell lymphoma, suggesting that the two diseases are different. In nasal NK-cell lymphoma, Epstein-Barr virus in tumor cells was detected in all patients tested, suggesting its causative role.

Interleukin (IL)-15 plays an important role in the survival of human natural killer (NK) cells. We investigated IL-2/15 signaling in NK cell neoplasms from five patients and in five cell lines (NK-92, KHYG-1, SNK-6, HANK1 and MOTN-1) compared to mature peripheral NK cells from 10 healthy subjects. Apoptosis of NK cell lines was prevented by addition of IL-15 in vitro. Blocking IL-2/15Rbeta on IL-2-stimulated NK-92 cells resulted in reduced expression of Bcl-X(L) and phosphorylated Stat5, which paralleled early apoptosis without altering Bcl-2 expression. These data add IL-2/15Rbeta to the list of factors important for the survival of NK cell neoplasms.

Aim: To study the clinicopathological and immunohistochemical features of 143 cases of primary small and large intestinal non-Hodgkin's lymphoma (NHL) in Japanese patients who presented between 1981 and 2000., Methods and Results: The new World Health Organization (WHO) classification was used to classify NHL. The patients included 109 males and 34 females, with an average age of 54.1 years. Tumour sites were as follows: ileocaecal (n = 51, 35.7%), ileum (n = 29, 20.3%), rectum (n = 13, 9.1%), and duodenum (n = 11, 7.7%). Macroscopically, 124 cases (86.7%) were classified as tumorous type, 12 (8.4%) as diffuse infiltration type (erosion, superficial ulceration), five (3.5%) as polyposis type, and only two cases (1.4%) as ulceration type. Immunohistochemically, 122 lesions (85.3%) were of B-cell phenotype and 21 lesions (14.7%) were of T-cell phenotype. According to the WHO classification, of the B-cell lymphomas, 84 cases (68.9%) were large cell, 16 (13.1%) were Burkitt, 10 (8.2%) were marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT), and seven (5.7%) were mantle cell tumours. Among the T-cell lymphomas, 15 (71.4%) were of unspecified type, two (9.5%) were natural killer type, two were anaplastic large-cell lymphomas, one was lymphoblastic, and one was an adult T-cell leukaemia lymphoma. The survival rate for T-cell lymphomas was poorer than for B-cell lymphomas. Among the B-cell lymphomas, mantle cell lymphoma tended to have a poorer prognosis, whereas MALT lymphomas had a better prognosis than other B-cell tumour types., Conclusions: Our retrospective study of patients with primary malignant lymphomas in the small and large intestines has illustrated the clinical features and outcomes of patients with this disease.

We treated a 73-year-old man who developed a pyothorax-associated pleural lymphoma after a 52-year history of tuberculous pleuritis. The lymphoma was classified histologically as a diffuse large, B-cell type. Epstein-Barr virus (EBV) was identified in the tumor by immunocytochemical and molecular methods. Chemotherapy both without and with the addition of rituximab was only minimally effective, but adding radiotherapy to chemotherapy reduced the tumor size, resulting in a partial remission. The EBV load measured by a quantitative real-time polymerase chain reaction correlated well with the tumor size and the serum lactate dehydrogenase concentration. Monitoring the EBV load may be useful in the management of pyothorax-associated lymphoma., (Copyright 2003 Wiley-Liss, Inc.)

New insights into the pathogenesis of lymphoid malignancies have been gained through novel genetic, molecular and immunological techniques. A new classification system for lymphoid malignancies, known as the new World Health Organization (WHO) classification, has been proposed recently based on these findings. The relative incidence of the subtypes of malignant lymphoma is known to differ according to geographic location. Adult T-cell leukemia/lymphoma (ATLL) is a human malignancy associated with human T-cell leukemia virus type 1 (HTLV-1), and the Kyushu islands are an HTLV-1 endemic area. To clarify the relationship between the histological classification and prognosis of lymphoid malignancies, we reclassified previous cases in our department and summarized our previous reports using the WHO classification. Of 933 cases of lymphoid malignancies, 471 (50%) were B-cell lymphoma, 396 (42%) T/natural killer (NK)-cell lymphoma and 41 (4%) Hodgkin lymphoma (HL). Analysis of clinical outcome showed favorable prognosis for HL, intermediate for B-cell lymphoma and poor prognosis for T-cell lymphoma. Among B-cell lymphomas, the commonest type was diffuse large B-cell lymphoma (n = 281; 60%). Marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) was diagnosed in 82 cases (17%), follicular lymphoma in 52 (11%) and mantle cell lymphoma in 24 (5%). Other less common lymphomas were Burkitt lymphoma (n = 9; 2%) and lymphoblastic lymphoma (n = 5; 1%). Using overall survival rates, the various B-cell lymphoma types could be divided into three broad groups for prognostic purposes: (i) low-risk group comprising follicular lymphoma and MALT; (ii) intermediate-risk group comprising diffuse large B-cell lymphoma and Burkitt lymphoma; and (iii) high-risk group comprising mantle cell lymphoma and lymphoblastic lymphoma. Among the T/NK-cell lymphomas, the commonest type was ATLL (n = 191; 48%), followed by peripheral T-cell lymphoma, unspecified (n = 83; 21%), angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) (n = 38; 10%), anaplastic large cell lymphoma (ALCL) (n = 22; 6%). Less common types were lymphoblastic lymphoma (n = 17; 4%), nasal and nasal-type NK/T-cell lymphoma (n = 17; 4%), mycosis fungoides (MF) (n = 9; 2%) and other rare types. With respect to clinical prognosis, T/NK-cell lymphomas fell into three groups: (i) relative low-risk group comprising ALCL, AILD, MF and lymphoblastic lymphoma; (ii) relative intermediate-risk group comprising NK/T-cell lymphoma and unspecified lymphoma; and (iii) extremely high-risk group comprising ATLL. Among the lymphoblastic lymphomas, B-cell type and T-cell type lymphomas exhibited different clinical outcomes. We conclude that the histological, phenotypic and genotypic classification of the new WHO system should be beneficial for the clinical approach to these tumors.

Aims: Pyothorax-associated lymphoma (PAL) develops in the pleural cavity of patients with a long history of pyothorax. Epstein-Barr virus (EBV) is also involved in PAL, similar to lymphomas in immunodeficient patients. Here we examined T-lymphocyte subsets as well as c-myc and REL gene amplification in PAL tissues., Methods and Results: We determined the number and distribution of CD4+ and CD8+ T-lymphocytes, to evaluate T-cells in the host immune reaction in seven cases of PAL. As controls, we also studied 10 cases of extranodal diffuse large B-cell lymphoma (DLBL) and 10 cases of nodal DLBL. Chromosomal imbalances in PAL were determined by using comparative genomic hybridization (CGH) analysis. The mean numbers of CD4+ and CD8+ and their ratio were significantly lower in PAL than in nodal DLBL. CGH analysis of PAL showed amplification of the 8q24 chromosomal region. In addition, c-myc amplification was found in four cases of PAL by Southern blot analysis., Conclusions: Our results suggest that the development of PAL may involve a local immunosuppressive environment and that amplification of c-myc might promote tumour progression, as has been described in the development of Burkitt's lymphoma.

Aims: Epstein-Barr virus (EBV) is associated with numerous reactive and neoplastic lymphoproliferative disorders. In vitro, EBV infection can transform B-lymphocytes and induce phenotypic alterations. This study presents the clinicopathological features of four cases with malignant lymphoma, which showed phenotypic and/or genotypic alterations during the course of the disease., Methods and Results: To determine the type of EBV genotype, we performed polymerase chain reaction (PCR) for lymphocyte-defined membrane antigen (LYDMA) of EBV, subtype A/B and latent membrane protein (LMP)-1 deletion. In addition, we analysed the terminal repeat (TR) band of EBV and receptor genes (T-cell receptor gene, TCR; immunoglobulin gene heavy chain, IgH) for EBV-infected cell clonality. Double staining of cell markers (B, T-lymphocytes; histiocytes), and in-situ hybridization (ISH) for EBV were performed using tissues obtained during the course of the disease. The first case showed genotypic and phenotypic alterations of T-cell type to B-cell type. The first TCR rearrangement and T-cell markers (CD3+, CD4+, CD8-) were lost and IgH rearrangement and B-cell markers (CD19+, CD20+) were identified. During the course of the disease, EBV-TR bands changed in size; however, the EBV genotype type B, LMP1 deletion type, and single LYDMA band remained the same. The initial T-cell lymphoma clone was considered to be different from the latter B-cell lymphoma clone. The second case showed phenotypic alterations. The first B-cell marker (CD19+, CD20+, CD68-) changed to histiocytic markers (CD19-, CD20-, CD68+). However, IgH rearrangement and EBV-TR bands remained the same throughout the course of the disease and EBV genotype type A, LMP1 deletion type, and single LYDMA band remained unchanged. The third case showed phenotypic alterations. The B-cell marker (CD20+) was lost; however, IgH rearrangement of PCR and EBV genotype remained the same. In the second and third cases, the initial lymphoma clones were considered to be same as the latter clones. The last case showed lineage alterations from Hodgkin's disease to natural killer (NK) cell leukaemia. However, EBV genotype did not change. The second case and Hodgkin's disease showed LMP expression, but the first and third cases showed no LMP, and EBNA2 was not detected in all cases., Conclusions: We report the genotypic and/or phenotypic alterations in four patients with EBV-associated lymphoma/leukaemia. However, EBV genotype did not change in all four. These findings suggest that EBV might induce the cell marker and lineage alteration in vivo, as in vitro.

Cytotoxic cells include natural killer (NK) cells and cytotoxic alpha beta and gamma delta T lymphocytes (CTLs). These cells express cytotoxic molecules of T-cell restricted intracellular antigen (TIA-1), and activated cytotoxic molecules of perforin, granzyme B, and FasL. Recent studies suggest that most extranodal T-cell lymphomas are derived from CTLs, and that NK cell lymphomas are extranodal. However, only a few nodal NK and cytotoxic lymphomas have been described so far. We present here the clinicopathological features of seven cases of nodal cytotoxic T and NK cell lymphomas. The study excluded anaplastic large-cell lymphomas expressing cytotoxic molecules. The neoplastic cells of all cases contained activated cytotoxic molecules of TIA-1, granzyme B, Fas ligand, and/or perforin. Phenotypically and genotypically, four cases showed alpha beta T cell type [CD2+, CD3+, T-cell receptor (TCR)-delta-1-, beta F1+, and TCR gene rearrangement], two cases showed gamma delta cell type [CD2+, CD3+, T-cell receptor (TCR) delta-1+, beta F1-, and TCR gene rearrangement], and one case showed NK cell type [CD2+, CD3-, CD56+, T-cell receptor (TCR) delta-1-, beta F1-, and TCR gene germline]. Using Southern blot analysis, Epstein-Barr virus (EBV) sequences were detected in six cases, and monoclonal terminal repeat proliferation was confirmed. In addition, in situ hybridization (ISH) studies for EBV showed EBV infection in almost all neoplastic cells. Clinically, all patients presented with peripheral lymphadenopathy in high clinical stages and showed an aggressive course. Hepatosplenomegaly was detected in six cases. During the course of the disease, bone marrow and extranodal invasion were noted in five cases. The nodal type showed an aggressive clinical course in all cases but one, as did the extranodal type. The nodal type varied in phenotype, but was closely associated with EBV infection.

Aims: Two molecular mechanisms of T/natural killer (NK) cell-mediated cytotoxicity, one perforin based and the other Fas based, have been demonstrated, and both systems induce cytotoxicity in the target cells. The Fas-based mechanism involves the transducing molecule Fas and its ligand (FasL). In addition, perforin and/or FasL are also expressed in the cytotoxic T/NK cells. This study was thus designed to investigate the Fas and perforin pathways of the cytotoxic T/NK lymphoma cells in the nasal cavity., Methods and Results: Eight patients with nasal lymphoma were analysed using immunohistochemical staining methods. Two cases were CD3+ CD56+ (T/NK cell) type, and six were CD3- CD56+ (NK cell) type. All cases showed Epstein-Barr virus genomes by in-situ hybridization. In addition, all cases showed the expression of TIA-1 (GMP-17), which is a marker of cytotoxic T and NK cells. FasL was expressed in the majority of the lymphoma cells and some histiocytes, while Fas was found in lymphoma cells and many non-neoplastic cells. In addition, the expression of perforin was detected in almost all lymphoma cells. In the double stainings, lymphoma cells expressed both FasL and perforin. Based on these findings, both the perforin- and Fas-based pathway of the cytotoxic T/NK lymphoma cells are thus considered to play an important role in the clinical features., Conclusions: Tissue damage is a common morphological feature in nasal T/NK cell lymphoma. The above findings therefore support the theory that tissue damage is due to both the cytotoxicity of T/NK lymphoma cells as well as to angiocentricity.

An extremely rare case of primary gastrointestinal T-cell lymphoma involving the stomach and intestine is reported. Radiographic and endoscopic examinations showed multiple polypoid lesions covered by a normal-appearing mucosa in the stomach, duodenal bulb, and terminal ileum and numerous small aphthoid lesions throughout the entire colorectum. Histopathologic, immunohistochemical, and polymerase chain reaction studies were performed using paraffin-embedded or fresh-frozen specimens from endoscopic biopsies and endoscopic mucosal resections. All lesions were composed of small, atypical lymphoid cells, which were classified as low-grade pleomorphic lymphoma. The tumor cells expressed CD3, CD4, and the T-cell receptor gamma gene phenotype as well as human mucosal lymphocyte 1 antigen, suggesting that the lymphoma cells were derived from intraepithelial T lymphocytes. This is the first description of primary gastrointestinal T-cell lymphoma with expression of human mucosal lymphocyte 1 antigen and a novel morphology resembling multiple lymphomatous polyposis.

Epstein-Barr virus (EBV), a DNA virus of the herpes virus family can infect and transform resting human B lymphocytes in vitro. EBV was originally considered to be a possible causative agent of African Burkitt's lymphoma and nasopharyngeal lymphoepithelioma. Recently, using highly sensitive methods, such as the polymerase chain reaction (PCR) and in situ hybridization (ISH), EBV has been found to be also present in numerous human lymphoproliferative disorders, including Hodgkin's disease, anaplastic large cell lymphoma, B cell lymphoma in immunocompromised patients, peripheral T cell lymphoma, adult T cell leukemia/lymphoma, nasal lymphoma, AILD-T cell lymphoma, pyothorax-associated pleural lymphoma, and angiocentric T/NK cell lymphoma. However, the EBV infection pattern and the role of EBV in each disease is not the same. We introduce the relationship between EBV and each disease found in our department, using Southern blot analysis, PCR, ISH and immunological staining.

We used the polymerase chain reaction (PCR) in situ hybridization (ISH) (PCR-ISH) on sections of malignant lymphoma and nonspecific lymphadenitis to detect small amounts of Epstein-Barr virus (EBV), a DNA virus of the herpes virus family. We first surveyed the EBV DNA by Southern blot analysis and PCR, and then compared results of the two PCR/ISH methodologies with the results of simplified/sensitive ISH for the positive cases. The target of the simplified in situ (DNA-ISH) was a few copies of EBV DNA per cell, and the target of the sensitive in situ (RNA-ISH) was as many as 10(7) copies of EBV RNA per cell. When EBV DNA was detected by Southern blot, DNA-ISH, RNA-ISH and PCR-ISH all revealed EBV genomes. When PCR revealed only amplified EBV DNA, DNA-ISH showed no EBV genomes, but PCR-ISH and RNA-ISH showed EBV genomes in a few cells. When PCR showed no detectable amplified EBV DNA, all of DNA-ISH, RNA-ISH and PCR-ISH showed no genomes. These findings indicate that PCR-ISH consistently detected a few copies of the EBV virions. The PCR-ISH was as sensitive as RNA-ISH. The RNA-ISH could not detect virus if RNA was not expressed, but the PCR-ISH could detect virus without such expression. The ability to detect a single copy of a specific gene in situ has many advantages and multiple applications in molecular biology, pathology, and cell biology.

The Epstein-Barr virus (EBV) has been shown to be associated with numerous human malignancies including Burkitt's lymphoma and nasopharyngeal lymphoepithelioma. In addition, some typical gastric adenocarcinomas were also recently reported to demonstrate EBV relevance. The present study was designed to detect EBV in primary gastric lymphoma, using the in situ hybridization (ISH) method, in which oligonucleotide probes for the EBER1 RNA and the EBV DNA W region have been used. Of the 49 cases of primary gastric lymphoma studied, which all showed B cell immunophenotype, EBER1 sequences could only be found in four cases, including two low-grade cases and two high-grade cases of histological subtypes while the number of positive cells was less than 50% of the tumor cells. In one case of low-grade mucosa associated lymphoid tissue (MALT) lymphoma, the EBER1-positive neoplastic cells were found in the regional lymph node, but the primary site of the stomach showed no positive signals. The EBV presence was further confirmed by the EBV DNA ISH. Using the ISH method, rare or occasional positive lymphoid cells (probably non-tumorous bystander cells) could be detected in 10 other cases including all histological subtypes. The present study shows that only a small proportion of primary gastric lymphoma is associated with EBV, and such positive cases could be found in both high- and low-grade histological subtypes. It is also suggested that the EBV presence in the neoplastic cells of some cases of primary gastric lymphoma is most likely a secondary phenomenon.

The transition between atypical hyperplasia and lymphoma with angioimmunoblastic lymphadenopathy and dysproteinaemia (AILD) was studied in serial lymph node biopsy specimens from five patients using DNA analysis with Southern blot analysis, polymerase chain reaction, chromosomal analysis, and immunophenotyping. The chromosomal analysis showed additional abnormalities as the disease progressed to those present initially, and immunological staining showed a corresponding increase in the numbers of CD4- and Ki67-positive cells. In the first biopsy from each patient a diagnosis of atypical hyperplasia with AILD was made and lymphoma excluding by the finding of only a few atypical lymphoid cells and the preservation of follicles with germinal centres. DNA analysis of lymph nodes at this stage showed either germ lines or oligoclonal rearrangements of the T-cell receptor (TCR) and immunoglobulin heavy chain genes. In the final biopsy, when a diagnosis of lymphoma with AILD was made, either a monoclonal rearrangement of the TCR was observed or one of the rearranged bands had increased in density. These results suggest selective proliferation of a clone of abnormal cells may account for the progression of atypical hyperplasia to lymphoma with AILD.

We investigated three patients suffering from angiocentric lymphoma with granulomatous panniculitis in the skin. All three patients presented with multiple purple subcutaneous nodules. Immunohistologically, the lymphoma cells in all three patients expressed CD2 (T-11), CD56 (neural cell adhesion molecule), and Mik-beta 1 (interleukin-2 beta receptor). CD3s (CD3, Leu-4)-positive lymphoma cells were found in two patients. A pore-forming protein (perforin) was detected in the lymphoma cells of all three patients. Perforin-possessing lymphoid cells were focally scattered in 2 of 15 patients with CD56-negative cutaneous lymphomas who served as controls. By the Southern blot method, one patient showed a rearranged T-cell receptor (TcR)beta gene in the biopsied specimen, and the other two patients had germ-line configurations of TcRs and immunoglobulin heavy chain genes. One patient had serum anti-human T-cell lymphotropic virus (HTLV)-I antibody, but showed no integration of its proviral DNA. Ultrastructurally, membrane-bound azurophilic granules were detected in the atypical lymphoid cells of all three patients. Angiocentric lymphoma with panniculitis in three patients showed the characteristics of natural killer and large granular T-cells. The histological features might be due to the characteristics of the neoplastic cells with azurophilic granules and perforin.

We examined bone marrow specimens from 19 patients with malignant histiocytosis (MH) and/or malignant lymphoma (ML) with concurrent hemophagocytic syndrome (HS) who suffered from high fever, hepatosplenomegaly, liver dysfunction, profound cytopenia, and erythrophagocytosis. There was little lymph-node enlargement or no tumor formation. The neoplastic cells in 3 patients exhibited histiocytes/macrophages phenotype with positive reactions for fluoride-sensitive nonspecific esterase, lysozyme and CD68 (KP1). Twelve other patients showed a T-cell (CD3) phenotype, in which 5 patients expressed CD30 (BerH2) as well. B-cell characteristics with CD20 (L26), CIg. nu lambda and gamma kappa were manifest in 2 patients, but indeterminate markers were found in the 2 remaining patients. Eighteen patients showed an infiltration of large neoplastic cells mainly with noncohesive interstitial growth pattern, ranging from 1.7% to 74.2% of the nucleated cells in the bone marrow. A large number of histiocytes/macrophages and dendritic cells was diffusely observed in 15 patients. Severely decreased hematopoiesis in all three series of hematopoietic cells was found in 16 patients. Bone marrow infiltration by the neoplastic cells and numerous reactive cells with erythrophagocytosis appears to be an important factor of profound cytopenia in patients of MH and/or ML with HS. The infiltrating pattern of the neoplastic and reactive cells in the bone marrow of MH and/or ML with HS was different from that of other types of peripheral T-cell ML, B-cell ML in high grade malignancy, and Hodgkin's disease. Cell characteristics and lineage of the neoplastic cells in MH and/or ML with HS are also discussed in this study.

Ninety cases of malignant lymphoma and 56 cases of reactive lymphadenopathy were studied using Southern blot analysis and the polymerase chain reaction to identify human herpes virus-6 (HHV-6) DNA. This was detected in cases of lymphoid malignancy at a rate which ranged from 50.0% to 68.8%. There were no differences in rates for different types of lymphoid malignancies. Herpes virus-6 DNA was detected by PCR in lymphoid malignancies less frequently than in reactive lymphadenopathies. It was not detected in lymphoid malignancies using Southern blotting. These results suggest that HHV-6 DNA was not related to lymphoid malignancy and was only a latent infection of non-neoplastic cells in tumour tissue.

We analyzed the T-cell receptors and immunoglobulin genes in 140 cases of hematopoietic malignancies, including ALL/LBL, malignant lymphomas, AILDs, Hodgkin's disease, ATL and CLL. In many cases, the findings obtained by immunoassociated gene analysis were in parallel to the phenotypic findings. Gene analysis is useful to determine the clonality and the lineage of malignant cells. However, 10-30% cases appeared bigenotype. In some cases, oligoclonalities were recognized. The relationship to the prognosis in these cases was discussed. The development of gamma delta- and alpha beta-cells on T-cell ontogeny was elucidated. Some T-cell leukemic lines were found to be pre-alpha beta T-cells with some consensus characteristics. We also analyzed the V beta family of 15 alpha beta T-cell leukemia cell lines using six V beta cDNA probes. This approach may be useful to determine the clonality of T-cell malignancies. The method of using a PCR system on immunoassociated genes has been described. The PCR method, using the super variable region as a tumor specific fragment, is valuable in the detection of the residual cells of lymphoma and leukemia at a concentration of 1/10(5) cells.

Human T-cell leukemia virus type I (HTLV-I) is associated with adult T-cell leukemia/lymphoma (ATLL). To examine the relationship between defective HTLV-I proviruses and clinicopathological features, we examined 95 patients with ATLL showing clonal integration of HTLV-I proviral DNA; 77 patients (81%) showed 1 clonal band, 15 (16%) showed 2 clonal bands, and 3 (3%) showed 3 clonal bands. In addition, the defective proviral form was detected in 28 patients (29%): 23 (30%) of the 77 with 1 clonal band, 4(27%) of the 15 with 2 clonal bands, and 1(33%) of the 3 with 3 clonal bands. The numbers of clonal bands had no association with the presence of defective proviruses. We classified the 95 patients with ATLL into four types according to clinicopathological features (smoldering leukemia, chronic leukemia, acute leukemia, and lymphoma types). The distribution of patients with the defective form was not different among these four types. The HTLV-I genomes must have integrated into the human genome DNA and been deleted partially in the cells. The defective form was kept during the clinical stage. All patients with the defective form showed defect of the gag or/and env region. No patient had a defect of the pX region. These data suggest that the pX region of HTLV-I must have played an important role in ATLL genesis.

109 malignant lymphomas were surveyed by Southern blot analysis and polymerase chain reaction (PCR) for Epstein-Barr virus (EBV) DNA and compared with 16 examples of non-neoplastic lymphadenopathy and 4 normal thymuses. In specimens positive by the method of Southern and PCR, in situ hybridization studies were performed on formalin-fixed, paraffin-embedded sections. By Southern blot analysis, two of seven Hodgkin's disease samples (29%) (one of mixed cellularity and the other of lymphocyte predominance type), three of 56 B-cell lymphomas (5.6%) and five of 46 T-cell lymphomas (11%) demonstrated EBV DNA. However, the 16 examples of lymphadenitis and the 4 normal thymuses showed no EBV DNA. With PCR, EBV DNA was identified in one B-cell lymphoma, nine T-cell lymphomas, ten lymphadenitis specimens and two of the normal thymus, in addition to the positive specimens determined by the Southern blotting method. These results indicate that the presence of EBV DNA is not related to lymphoid malignancy, but enhancement of the DNA is demonstrated in some neoplastic conditions. By in situ hybridization, EBV genomes were not detected in all PCR-positive cases, but only in those positive by Southern blot analysis.

We examined an antibody against Ki-1 antigen in 161 cases of malignant lymphoma, four of histiocytic sarcoma, and six of nonspecific lymphadenitis, using monoclonal antibody Ki-1, which is known to react selectively with activated lymphocytes, Reed-Sternberg cells, and Hodgkin's cells. Among them, 12 cases of malignant lymphoma demonstrated a diffuse positive cell membrane and/or cytoplasmic reaction of tumor cells and were categorized as Ki-1-positive lymphoma. Nine of these cases exhibited large cells with indented nuclei, distinct nucleoli, and abundant basophilic or amphophilic cytoplasm. Of the remaining three cases, two were of medium-sized and one of small-cell type. Immunologically, the 12 cases of malignant lymphoma demonstrated T-helper/inducer phenotype in six cases, B-cell in two case, and non-T, non-B in four cases. Tac and HLADR were positive in 9/12 and 4/5, respectively, and markers for histiocytes (lysozyme, alpha-1 anti-chymotrypsin, and OK-M1) were usually negative. Clinically, T-cell Ki-1-positive lymphoma was most likely to occur in the elderly, at extranodal sites, and had a rather poor prognosis (mean survival 35.5 months) as compared with B-cell and non-T, non-B lymphoma (7-52 months survival).