CNA.42, a new monoclonal antibody directed against a fixative-resistant antigen of follicular dendritic reticulum cells.

A new monoclonal antibody (MAb), CNA.42, was generated using the CEM T-cell line. It recognizes a 120-kd formalin-resistant glycosylated antigen that is mainly expressed by follicular dendritic reticulum cells (FDRCs). This antigen is also expressed by a few mononuclear cells in the paracortical area of reactive lymph nodes and by some cortical thymocytes. Two hundred and eighty-nine cases of hematopoietic tumors of various types were tested with this antibody. They showed either intact FDRC networks or FDRC networks dispersed among malignant cells. In follicular lymphomas, the follicular pattern was highlighted by CNA.42 MAb. Expanded FDRC networks were found in angioimmunoblastic T-cell lymphomas. Neoplastic cells were positive in 43.6% (24/55) of T-cell and 4.6% (6/129) of B-cell lymphomas. The highest percentage of cases with positive neoplastic cells was found in anaplastic large-cell lymphomas (62.5%; 15/24). In Hodgkin's disease, FDRC networks, sometimes encasing Hodgkin and Reed-Sternberg (HRS) cells, were found. HRS cells were also stained by this antibody in 23 (21.9%) of the 105 cases examined. A variety of normal nonlymphoid tissues and nonhematopoietic tumors, such as some neurogenic tumors, carcinoma, and occasional sarcomas, were found to be positive. Analysis of the reactivity of CNA.42 antibody with FDRCs of lymphoid tissue from different animal species showed similar reactivity to that observed in humans, suggesting widespread evolutionary conservation of the antigen recognized by this antibody. In daily diagnostic practice, CNA.42 MAb seems to be a suitable FDRC marker and possibly has an auxiliary role in recognizing T-cell lymphomas.

Polymerase chain reaction on cerebrospinal fluid cells in the detection of leptomeningeal involvement by B-cell lymphoma and leukaemia: a novel strategy and its implications.

In the search of B-cell lymphoma/leukaemia dissemination to cerebrospinal fluid (CSF), we used the highly sensitive semi-nested PCR (snPCR) for the analysis of IgH gene rearrangements. This method detects a rearranged IgH gene from a single B lymphocyte which may or may not represent the neoplastic B-cell population. We therefore performed multiple snPCR (three to five) experiments on the same CSF sample, postulating that the detection of a band of the same size and sequence in different PCR runs was highly indicative of a clonal population. 17 consecutive cases with a differential diagnosis of primary (PCNSL) (n=10) or secondary (SCNSL) (n=7) CNS lymphoma or leukaemia were investigated by the new strategy. The clonal nature of the B-cell population was confirmed in 3/10 of suspected PCNSL, and in six other cases the PCR study was indicative of reactive lymphocytosis. One case revealed a clonal B-cell population in the clinical context of an autoimmune disorder. Evidence of clonal B-cell population was found in 4/7 of suspected SCNSL. In one of these cases the detected band and its sequence proved identical to that of the primary nodal lymphoma. We believe that the evaluation of B-cell clonality in CSF requires multiple snPCR amplification on the same sample to compare the size of the products and, if necessary, the DNA sequences to ascertain the diagnosis of malignancy in equivocal cytologic and clinical findings.

Anaplastic large cell lymphoma of maternal origin involving the placenta: case report and literature survey.

Non-Hodgkin's lymphoma (NHL) occasionally involves the placenta, and information of such occurrence should be useful for management of the mother and fetus. We report the first case of anaplastic large cell lymphoma (ALCL) disseminated to the placenta. The diagnosis was made via excisional biopsy of cervical lymphadenopathy in a 20-year-old woman at 27 weeks' gestation. Involvement of the placenta was noted on gross examination after cesarean section delivery of a girl at 30 weeks' gestation. The ALCL was microscopically confined to intervillous spaces in a manner similar to previous reports of other NHLs. The immunophenotype was characteristic (CD30+, EMA+, BNH9+), and the now frequently associated t(2;5)(p23;q35) translocation with this lymphoma was detected by the recently produced monoclonal antibody ALK1 against the nucleophosmin/anaplastic lymphoma kinase (NPM/ALK) chimeric protein. Complete remission was induced in the mother after delivery. Both mother and child are healthy at 10 years' follow-up. The case is reported in light of the sparse literature on lymphomatous involvement of the placenta.

IgH and TcR-gamma gene rearrangements identified in Hodgkin's disease by PCR demonstrate lack of correlation between genotype, phenotype, and Epstein-Barr virus status.

Analysis of IgH and TcR-gamma genes using consensus primers identifying junctional regions of rearranged genes by polymerase chain reaction (PCR) was performed on tissues involved by Hodgkin's disease (HD) in 90 cases and was correlated with the immunophenotype of Hodgkin and Reed-Sternberg (HRS) cells and the presence of Epstein-Barr virus (EBV) within these cells. Clonal IgH gene rearrangements were found in 1/5 cases of lymphocyte predominance (LP) subtype and none was positive for EBV. In 85 cases of classic HD, no IgH or TcR-gamma gene rearrangements were found in 51 (60 per cent) cases. A similar percentage, but not the same cases, were of null (non-B, non-T) phenotype. Of 30 cases where a B phenotype was assigned to HRS cells, nine had IgH gene rearrangements, three had TcR-gamma gene rearrangements, and two had both genes rearranged. None of the five cases assigned to T phenotype of HRS cells showed rearrangement of TcR-gamma genes, but two cases showed rearranged IgH genes. Among 41 cases of null phenotype, ten had IgH gene rearrangements, five had TcR-gamma gene rearrangements, and three cases had both genes rearranged. Whereas EBV was detectable in HRS cells in 17/43 classic HD cases of assigned B phenotype, EBV was also detectable in 2/5 cases of assigned T phenotype and in 21 cases with the null phenotype. Furthermore, there was no correlation of EBV with the presence or lack or IgH or TCR-gamma gene rearrangements. Of the remainder, half (30 per cent) expressed antigens associated with lymphocytes without an appropriate genotype. The results confirm lymphocyte-lineage committed cells at the origin of HRS cells in 40 per cent of cases. Any hypothesis of a non-lymphocytic origin of HRS cells will require the inducibility of CD30 on candidate precursors and the methodology for probing genetic events in such cells to be addressed.

The interface of Hodgkin's disease and anaplastic large cell lymphoma.

We reviewed 18 cases in which morphology was intermediate between Hodgkin's disease (HD) and anaplastic large cell lymphoma (ALCL). Eight cases exhibited the usual CD30+, CD15+/-, null cell phenotype of classic HD but were rich in neoplastic cells with sinusoidal infiltrating pattern. In this group, there was no expression of antigens (EMA, BNH9, CBF78) associated with ALCL, and only two were positive for Epstein-Barr virus (EBV). Ten EBV negative cases fit the description of HD like ALCL by variable expression of antigens unassociated with HD. EMA was clearly and strongly expressed in all ten, whereas antigens recognized by BNH9 and CBF78 were expressed in four and three cases, respectively. Focal expression of CD45 and CD43 was observed in half of these cases. In only one case was the t(2.5) translocation detected with the new monoclonal antibody, ALK1. Therefore, the expression of EMA, BNH9 and CBF78, often in concert without CD15 and without the specific translocation, appears currently to be the most probable phenotype and genotype of HD like ALCL. There was a tendency for aggressive behaviour of the disease considered HD like ALCL. Whether such patients will benefit from a therapeutic strategy that takes into account both phenotype and genotype remains to be discovered.

Telomerase activity in reactive and neoplastic lymphoid tissues: infrequent detection of activity in Hodgkin's disease.

We used the recently described sensitive and rapid detection assay called telomeric repeat amplification protocol (TRAP) to detect telomerase activity in lymphoblastoid (n = 5) and lymphoma cell lines (n = 7), hyperplastic lymph nodes (n = 6) and tonsils (n = 5), and tissues involved by non-Hodgkin's lymphoma (NHL) (n = 43) and Hodgkin's disease (HD) (n = 14). Clearly evident telomerase activity was found in all lymphoblastoid and lymphoma cell lines, and in 34 of 43 cases (80%) of NHL. These results were expected because of the proliferative and immortal nature of the cell lines and most malignant cells. However, positive results were obtained with the TRAP assay in all hyperplastic lymph nodes and tonsils, which raises the issue of derepression of telomerase activity during an immune response. Telomerase activity alone therefore does not distinguish malignant lymphoid proliferations from reactive states. Telomerase activity was detected in only 1 of 14 cases (7%) of lymphoid tissues involved by HD. Eight of the 13 negative cases were considered to be interpretable because of the lack (3 of 13 cases) or low level (5 of 13 cases) of telomerase inhibition. The five remaining cases could not be evaluated because of their telomerase inhibitor content. The findings imply either transient or very low levels of telomerase activity in HD or that HD for the greater part is a telomerase-independent neoplasm. Microdissection studies are needed to identify subsets of cells carrying telomerase activity in both reactive and neoplastic lymphoid tissues.

Assessment of the methods for the detection of Epstein-Barr virus nucleic acids and related gene products in Hodgkin's disease.

BACKGROUND: Epstein-Barr virus (EBV) is present in the pathogenic cells of a significant number of cases of Hodgkin's disease, particularly of the mixed cellularity subtype. EBV remains latent and the incidence of detection rate of the genomes and gene products varies greatly with the methods employed. EXPERIMENTAL DESIGN: From a pool of 137 cases of Hodgkin's disease previously studied by cold in situ hybridization (ISH) for the presence or absence of EBV DNA and the immunohistochemical reactivity with anti-latent membrane protein 1 antibody, we selected 24 cases (12 EBV DNA-positive, 12 EBV DNA-negative) for Southern blotting, as well as for study with nonisotopic EBER and BHLF1 oligonucleotide probes and amplification of DNA by polymerase chain reaction. EBV positive cases were further tested with anti-ZEBRA (BZLF1) antibody. RESULTS: The EBV DNA detection rate was found to be lower with Southern blotting compared to ISH and IHC methods because 8 of the 12 EBV positive cases were positive with BamHI W probe and only 7 (of the 8) with XhoI 1.9 kb probe. These 7 cases contained monoclonal episomal circular EBV genomes. All EBV DNA-positive cases showed EBER gene transcription by ISH. EBER probes also reacted with small lymphocytes in all EBV DNA+ and 9 EBV DNA- cases. These EBER-positive small lymphocytes were detected neither by BamHI W DNA probe nor by immunohistochemical methods with anti-latent membrane protein 1 and anti-EBNA2 antibodies. Polymerase chain reaction produced a positive result in all EBV DNA+ cases and 2 (of the 9) EBV DNA- cases containing EBER+ small lymphocytes. This discrepancy was attributed to amplification of EBV in reactive lymphocytes. Anti-ZEBRA antibody was positive in 2 cases (one BHLF1+) suggesting infrequent viral replication and probable abortive lytic cycle. CONCLUSIONS: ISH and immunohistochemical methods are more sensitive than Southern blot for detecting EBV in Hodgkin and Reed-Sternberg cells of Hodgkin's disease. Polymerase chain reaction appears to be very sensitive but is less sensitive and specific (amplification of EBV DNA of non-neoplastic lymphocytes) than ISH with non-isotopic EBER oligoprobes, which often detects and localizes EBV in pathogenic cells even when they are in small numbers and also in a few small lymphocytes. In addition, this method offers the advantage of being applied to routinely processed tissue sections.

High incidence of Epstein-Barr virus detection in Hodgkin's disease and absence of detection in anaplastic large-cell lymphoma in children.

By in situ hybridization with EBER oligonucleotides and immunohistochemistry with anti-latent membrane protein 1 (LMP1) antibody, we compared the detection rate of Epstein-Barr virus (EBV) in Hodgkin's disease and anaplastic large-cell lymphomas in children. Among the 13 cases of Hodgkin's disease tested, 7 (54%) were found to be EBV associated (EBER transcripts +, LMP1 +). None of the 11 cases of ALC lymphomas was found to contain EBV genomes or gene products. This may indicate that EBV is not a pathogenic agent in anaplastic large-cell lymphomas in children in comparison to Hodgkin's disease.

Demonstration of Epstein-Barr virus replication in Reed-Sternberg cells of Hodgkin's disease.

Epstein-Barr virus (EBV) is detectable in approximately 40% of cases of Hodgkin's disease (HD). The viral genomes remain latent but positive staining with anti-ZEBRA antibody in a small fraction of Reed-Sternberg (RS) cells of some cases of HD would suggest possible activation of EBV replication within these cells. We report the investigation of 40 cases of EBV-associated HD (including 5 human immunodeficiency virus [HIV]-positive cases) using anti-ZEBRA antibodies. Positive staining was found in only three (HIV-negative) cases. One of these three cases showed approximately 1% of ZEBRA-positive tumor cells, whereas the other two cases showed rare positive cells. In the case with 1% ZEBRA-positive cells, a strong signal was obtained with anti-EA-R antibody and BHLF1 oligoprobes, which indicated early gene expression. EBV replication could be shown in this case by nonisotopic in situ DNA-DNA hybridization, which showed markedly increased numbers of EBV genomes in a few RS cells. Viral replication was confirmed using reverse transcriptase and polymerase chain reaction that detected transcripts from the BLLF1 gene encoding for the membrane antigen gp350/220. EBV replication in RS cells seems to be an exceptional event but may provide clues to mechanisms of control of viral latency and assume clinical implications in the future.

Relation of follicular dendritic reticulum cells to Reed-Sternberg cells of Hodgkin's disease with emphasis on the expression of CD21 antigen.

Based on observations of 66 cases, in which tissues were specially processed to optimize the simultaneous preservation of cell membrane antigens and morphology, we provide evidence in favor of a relationship between follicular dendritic reticulum cells (FDRC) and Reed-Sternberg (RS) cells of Hodgkin's disease (HD) other than the lymphocyte predominance subtype. RS cells were intimately related to the FDRC network (75% of cases), and the expression of CD21 antigen was frequent (41% of cases). Exclusive expression of CD21 antigen was found in 11 cases of HD, while the expression of other B-cell-associated markers (CD19, CD20, CD22) was both variable and inconsistent. The expression of T-cell antigens (CD3, CD4, CD8) was rare. Null phenotype of RS cells was observed in 27 of 66 cases (41%). Epstein-Barr virus (EBV) nucleic acids were found in 34 of 66 (51.5%) cases. Double labeling techniques showed the presence of EBV-positive RS cells within the FDRC network. A non-B-cell origin of RS cells was supported by the differential expression of EBV latent antigens in HD (latent membrane protein+, EB nuclear antigen 2-), which is unusual in EBV-driven lymphoblastoid cell lines and EBV-positive B-cell lymphomas. FDRC and RS cells are known to share morphological traits (binucleated cells), and both cell types possess Fc receptor for IgG. The hypothesis is further backed by the findings of CD15 antigen expression by occasional RS-like dysplastic FDRC in Castleman's disease (five cases), which is characterized by hyperplasia of FDRC. Whether FDRC might be the only cells involved in the conversion to RS cells by the loss or gain of antigens remains to be determined.

Comparison of in situ hybridization using different nonisotopic probes for detection of Epstein-Barr virus in nasopharyngeal carcinoma and immunohistochemical correlation with anti-latent membrane protein antibody.

BACKGROUND: The detection of Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC) may be of diagnostic importance, particularly in cases from nonendemic areas. For cellular localization of viral genomes, cold in situ hybridization methods for the demonstration of EBV-associated NPC remain difficult and relatively insensitive for routinely processed tissues. EXPERIMENTAL DESIGN: The aim of the present study was to assess the importance of tissue processing and the hybridization targets to improve the sensitivity of the cold in situ hybridization method. In situ hybridization was performed in six cases of NPC using three biotinylated EBV cDNA probes (BamHI W/IR1, BamHI Y/EBNA2, XhoI/latent membrane protein) and two cocktails of EBER and BHLF1 oligonucleotides labeled with fluorescein isothiocyanate on routinely fixed and paraffin embedded sections. In two cases, in situ hybridization was also performed on specially processed (ModAMeX) sections. Immunohistochemistry was used to detect EBV-induced antigens using monoclonal antibodies against latent membrane protein, EBNA2 and ZEBRA (BZLF1). RESULTS: All cases showed EBV nucleic acids regardless of the tissue preparation with the three cDNA probes and on routinely processed sections with EBER oligonucleotides. By using cDNA probes, the best EBV DNA signal was obtained with BamHI W without heating of slides in tissue sections processed by ModAMeX, which probably gives rise to large amounts of single stranded DNAs. All cases positive with cDNA probes were found to be positive with EBER oligonucleotides and negative with BHLF1. However, on routinely processed paraffin sections, the signals with EBER oligonucleotides were stronger than with BamHI W cDNA probe. Dual labeling with in situ hybridization and immunohistochemistry showed that the hybridization signals were restricted to malignant epithelial cells. Latent membrane protein expression was detectable in four of six EBV nucleic acid-positive cases on both ModAMeX and routinely processed sections. The anti-EBNA2 and anti-ZEBRA antibodies were found to be negative on the two cases processed by ModAMeX. CONCLUSIONS: Cold in situ hybridization, in particular with EBER oligonucleotides, appears to be more reliable than immunohistochemistry with anti-latent membrane protein antibody to detect EBV in NPC in routine pathology. These findings confirm a distinctive phenotype (latent membrane protein +/-, EBNA2-, ZEBRA-) of EBV-positive NPC. The negative staining for BHLF1 oligonucleotides further supports the viral latency.

A novel human lymphoma cell line (Deglis) with dual B/T phenotype and gene rearrangements and containing Epstein-Barr virus genomes.

We report a new and apparently unique human lymphoma cell line termed Deglis. The line was established from a polymorphic centroblastic lymphoma. The cell line and its source carry a dual B-cell and T-cell phenotype and Epstein-Barr virus (EBV) genomes. Simultaneous expression of B-cell (CD19+, CD20+, CD23+, CD37+) and T-cell (CD2+, CD3+/-, CD7+, CD43+) antigens, activation antigens (CD30+, CDw70+) as well as CD68+, a macrophage-associated antigen, was observed on the cell line and its source. Genotypic studies of the cell line showed dual gene rearrangements. JH (on both primary tumor and the cell line) and C kappa were rearranged without expression of cytoplasmic or surface immunoglobulins. T-cell receptor-alpha (TCR-alpha) and TCR-beta genes were rearranged, but TCR-delta and TCR-gamma genes were in germline configuration. Apparently, functional transcripts of TCR-alpha and truncated transcripts for TCR-beta and TCR-delta were observed. EBV-encoded proteins (LMP and EBNA2) were expressed by the parent tumor and the cell line. Southern blot analysis showed the same clonal EBV genomes in the primary tumor and the cell line. Karyotypic analysis of the cell line showed several chromosomal abnormalities but normal chromosomal number. The characteristics of this cell line suggest that neoplastic transformation has occurred in a precursor cell broadly committed to lymphoid lineage. Further studies on this cell line may help resolve some issues in the physiopathology of lymphoid tumors.

Hairy cell leukemia. Diagnosis of bone marrow involvement in paraffin-embedded sections with monoclonal antibody DBA.44.

The new monoclonal antibody DBA.44 recognizes an unknown fixation-resistant B-cell differentiation antigen expressed by mantle zone lymphocytes, reactive immunoblasts, monocytoid B cells, and a small proportion of high- and low-grade lymphomas. Among node-based lymphomas, the strongest membrane staining was observed in centroblastic, immunoblastic, and monocytoid B-cell lymphomas. In studying bone marrow biopsy specimens from 166 patients with hairy cell leukemia, strong positive staining of surface membrane 'hairy' features of leukemic cells was observed in routinely fixed and decalcified bone marrow biopsy specimens of nearly all cases. The antibody distinguished hairy cell leukemia from the more common B-cell chronic lymphocytic leukemia and bone marrow infiltrates of typical lymph node-based lymphomas by immunomorphologic criteria. DBA.44 was valuable to (1) confirm the diagnosis of hairy cell leukemia, (2) estimate the bone marrow density of hairy cell leukemia before and after treatment, and (3) make the diagnosis of hairy cell leukemia in ambiguous cases, which are all properties that indicate its usefulness in the practice of diagnostic hematopathology.

Correlation of the expression of Epstein-Barr virus latent membrane protein and in situ hybridization with biotinylated BamHI-W probes in Hodgkin's disease.

The detection of Epstein-Barr virus (EBV) nucleic acids by in situ hybridization (ISH) with biotinylated BamHI-W probes was correlated with the expressions of EBV latent membrane protein (LMP) and EB nuclear antigen 2 (EBNA2), in 107 cases of Hodgkin's disease (HD) of different immunomorphologic subtypes. Epstein-Barr virus nucleic acids were present and restricted to the pathogenic cells in 4 of 40 (10%) cases of nodular sclerosis (NS) and 33 of 55 (60%) cases of mixed cellularity (MC), but were undetectable in other subtypes. Of the 37 cases positive for EBV nucleic acids, 35 (95%) showed the expression of LMP. Epstein-Barr virus nucleic acids and LMP were restricted to Reed-Sternberg cells and variants. Only 1 case (MC) showed LMP expression in the absence of EBV detection. The correlation was strengthened by the finding of LMP expression at first diagnosis in 6/7 EBV positive cases at relapse (14-126 months) (5/5 EBV negative cases at relapse were LMP negative at first diagnosis). EBNA2 was absent in all 13 (NS, 2; MC, 11) EBV+ and LMP+ cases tested. Both LMP and EBNA2 were expressed in control EBV-positive tissues and cell lines. EBV serology in MC HD was indicative of latent EBV infection, but neither serology nor clinical parameters correlated with the presence or the absence of EBV, over a short-term follow-up (median, 20 months). The findings, although not proving EBV as the etiologic agent of HD, suggest that: 1) LMP expression alone may be adequate for identifying EBV-associated HD, 2) the MC subtype has a stronger relation with EBV presence, and 3) the regulation of EBV genes in HD is different from other EBV-associated disorders. The clinical implications still remain to be discovered.

Quantitative study of KI-67 antibody staining in 46 T-cell malignant lymphomas using image analysis.

Image analysis with a SAMBA 2005 (ALCATEL-TITN, Co) was used to quantify the Ki-67 stained area percentage in 46 T-cell malignant lymphomas (T-ML), classified according to the updated Kiel classification. This parameter demonstrated correlation with the number of Ki-67-positive cellular profiles (r = 0.88, P less than 0.001) and was more reproducible than cell counting. A significant difference was found between low and high grade T-ML (mean values +/- SEM respectively of 10.20 +/- 1.82 per cent and 25.63 +/- 3.15 per cent). The most interesting findings were that: (1) AILD-type T-ML showed an intermediate proliferation rate (15.55 +/- 2.72 per cent) between pleomorphic T-ML with medium and with large cells (respectively 12.53 +/- 3.64 per cent and 22.43 +/- 3.46 per cent), both of which belong to the high grade malignancy group. This finding is in accordance with the poor prognosis of this subtype despite its classification in the low grade malignancy group. (2) Subclassification of the pleomorphic MLs according to the predominance of small, medium or large cells, demonstrated significant differences between these three subtypes. However, the great overlap of values between pleomorphic T-ML with medium and with large cells, seems to indicate that the subclassification of these two subtypes is less valid. (3) A wide range of values with overlap was observed in AILD-type ML, in pleomorphic with medium or large cells and in lymphoblastic T-ML: for these T-ML with variable survival courses, the Ki-67 area percentage, one parameter of proliferative activity, appears worth studying as a prognostic factor.

Large B-cell lymphoma rich in T-cells and simulating Hodgkin's disease.

Unusual clinicopathological features drew our attention to nine of 208 cases diagnosed as Hodgkin's disease. Lymph node biopsy specimens in these cases were immunostained with monoclonal antibodies against B-cell, T-cell and Reed-Sternberg cell associated antigens and epithelial membrane antigen (EMA). Reed-Sternberg-like and other atypical large cells were dispersed in a diffuse, small lymphocyte-rich background, consistent more often with the initial diagnosis of diffuse, lymphocyte predominance Hodgkin's disease. The clinical stage in these cases was unusually advanced (stages III and IV). Splenomegaly was a common feature (six of nine cases), the male to female ratio was 7:2 and the median age was 55 years (range 25-77). Response to recognized regimes for Hodgkin's disease treatment was poor in most cases, and three patients died early of their disease. Large cells were B-lymphocytes expressing EMA--an immunophenotype similar to nodular, lymphocyte predominance Hodgkin's disease. Reed-Sternberg cell and T-cell associated antigens were absent on large cells. Mature T-cells, with nuclear irregularities in some instances, predominated in the background. A more appropriate diagnostic category is, therefore, T-cell-rich B-cell lymphoma. The cases represent a 4-5% erroneous diagnosis of Hodgkin's disease and further suggest that there is a need for revision of criteria for the diagnosis of the diffuse, lymphocyte predominance variant.