Diagnostic accuracy of imprint cytology in the assessment of Hodgkin's disease in Japan

Our objective was to evaluate the usefulness of cytomorphologic assessment in the accuracy of diagnosis of Hodgkin's disease (HD), using imprint cytological preparations over a 18-yr period. Imprint materials from 34 HD cases were reviewed using cytomorphological and immunocytochemical studies. Twenty-six cases (76.5%) were diagnosed to be HD and 6 cases (17.6%) were suspected to be HD, but 2 cases (5.9%) were cytologically diagnosed as reactive lesions, because of an insufficient number of Reed-Sternberg (RS) cells. The 6 suspected cases were definitively diagnosed as HD, using immunocytochemistry. Immunophenotyping of RS cells in 32 cases (excluding the two cases of reactive lesions) showed CD30+ in 31 (96.9%) cases, CD15+ in 22 (68.8%) cases and CD20+ in 12 (37.5%) cases. RS cells were immunophenotypically classified into five groups: A, (CD 30+, 15+, 20-) 15 (46.9%); B, (CD30+, 15-, 20-) 5 (15.6%); C, (CD 30+, 15+, 20+) 6 (18.8%); D, (CD30+, 15-, 20+) 5 (15.6%); and E, (CD30-, 15+, 20+) 1 (3.1%). Cytomorphologic differences in RS cells were identified between group D and other groups (CD15+ and/ or CD20-). The former had a low polymorphic shape (like popcorn), and the latter had a more classical polymorphic shape. Epstein-Barr virus (EBV)-latent membrane protein-1(LMP-1) was identified in 16 (50%) cases. LMP-1 expression was found not only in classic RS cells, but also in smaller variants. These variants did not match the morphologic criteria of RS cells, but expressed the common phenotype (CD30+, CD15+/-) of RS cells, suggesting the same cellular origin as RS cells. This study demonstrated that imprint cytology from lymph node biopsies can be a useful tool for the diagnosis and the evaluation of the cellular biology of HD.     

Comparison of fascin expression in anaplastic large cell lymphoma and Hodgkin disease

Diagnostic difficulties sometimes arise in distinguishing anaplastic large cell lymphoma (ALCL) from Hodgkin disease (HD), especially the syncytial variant. Study of the biologic features of diagnostic Reed-Sternberg cells in HD, in search of specific markers for Reed-Sternberg cells, has suggested fascin as a relatively specific and sensitive marker. We studied the frequency of fascin expression in 30 ALCLs and 34 cases of classic HD, including 17 cases of the syncytial variant. Staining with CD30 and anaplastic lymphoma kinase (ALK)-1 also was performed in all cases. All ALCL and HD cases showed membranous and Golgi zone CD30 positivity. Fascin stained all HD cases but also stained 67% (20/30) of the ALCLs in a cytoplasmic pattern. Fascin positivity was observed in 59% (10/17) of T-cell ALCLs and 77% (10/13) of null-cell ALCLs; ALK-1-positive ALCLs, regardless of origin, were usually fascin-positive (91% [10/11]). In conclusion, fascin shows strong positivity in all cases of classic HD but also is positive in the majority of ALCLs, including ALK-1-positive and ALK-1-negative cases. Positive staining for fascin is not useful for distinguishing ALCL from HD. In some cases, fascin negativity may help rule out classic HD.     

Differential expression of thymus and activation regulated chemokine and its receptor CCR4 in nodal and cutaneous anaplastic large-cell lymphomas and Hodgkin's disease.

Recent studies demonstrated that Hodgkin/Reed-Sternberg (H/RS) cells in Hodgkin's disease (HD) express thymus and activation-regulated chemokine (TARC), whereas reactive lymphocytes surrounding H/RS cells express its ligand, CC-chemokine receptor 4 (CCR4). Because in vitro studies showed that CCR4 expression is a marker for lymphocytes bearing a T-helper 2 (Th2) phenotype, it was suggested that expression of TARC is a new immune escape mechanism in HD. To find out whether this mechanism might also be operative in CD30+ malignant lymphomas other than HD, TARC and CCR4 expression was investigated by immunohistochemistry on paraffin and frozen-tissue sections of 39 nodal CD30+ anaplastic large cell lymphomas (ALCL), including 27 ALK-negative and 12 ALK-positive ALCL, 25 primary cutaneous CD30+ ALCL, including 11 patients with lymphomatoid papulosis, and 31 cases of HD. TARC was expressed by the neoplastic cells in 12/27 (44%) nodal ALK-negative ALCL and all cases of classic HD, but not in nodal ALK-positive ALCL (0/12) and only rarely in primary cutaneous CD30+ ALCL (3/25). In contrast, CCR4 was expressed by the neoplastic cells in 9/9 cutaneous CD30+ ALCL, and in 9/15 (60%) nodal ALK-negative ALCL, but only in 1/4 (25%) nodal ALK-positive ALCL and not by the H/RS cells in HD (0/8). Apart from three cases of HD showing 10 to 15% CCR4-positive lymphocytes surrounding TARC-positive H/RS cells, CCR4-positive reactive T cells were few (<5%) in all other cases studied. Our results demonstrate a differential expression of TARC and CCR4 in different types of CD30+ malignant lymphomas. The small number of CCR4-positive reactive T cells in most cases studied argues against an important role of TARC expression in the evasion of antitumor responses.     

Fine-needle aspiration cytology and immunocytochemistry of Hodgkin's disease,suppurative type

We describe 3 cases of Hodgkin's disease (HD) of unusual suppurative type, which were diagnosed on fine-needle aspirates. The smears were dominated by neutrophils, macrophages, and cellular debris. Only a few large, atypical cells of Hodgkin and Reed-Sternberg type were observed. The differential diagnoses of such smears include infectious mononucleosis, tuberculosis, metastatic lymph node involvement, non-Hodgkin's large-cell anaplastic Ki-1-positive lymphomas, T-cell-rich B-cell lymphomas, and peripheral T-cell lymphomas of mixed type. Immunocytochemistry identified the large atypical cells as CD 30 (BerH2)-positive and negative for CD 45 (LCA) in cytospin material from 2 patients, which allowed a conclusive diagnosis of HD. Diagn. Cytopathol. 1998;18:437–440.© 1998 Wiley-Liss, Inc.     

Proliferating cell nuclear antigen (PCNA) expression in Hodgkin's disease.

Previous studies of the proliferating cell fraction in Hodgkin's disease (HD) have been directed towards the classical Hodgkin and Reed-Sternberg cells (HRS) to the exclusion of the background population and have not included cases of nodular lymphocyte predominant Hodgkin's disease (NLPHD). Using an antibody to proliferating cell nuclear antigen (PCNA), we have determined the growth fraction of HRS cells and L&H cells in paraffin sections of 15 cases of classical HD [12 nodular sclerosis (NS), 3 mixed cellularity (MC)] and eight cases of NLPHD. By double staining with anti-PCNA and antibodies to B cells (CD20) and T cells (CD45RO), we also determined the growth fraction and immunophenotype of the background population in each case. In classical HD, 50.4 per cent of HRS cells were PCNA-positive and judged to be proliferating, which is comparable to previous studies, while in NLPHD 76.9 per cent of L&H cells were PCNA-positive. In both classical HD and NLPHD, the majority of PCNA-positive cells in the background were T cells, which showed a growth fraction of 57.8 and 68.5 per cent, respectively; in comparison, only 4 per cent of B cells were PCNA-positive in each type of HD. L&H cells are widely accepted to be B cells and there is growing evidence that HRS cells are also B cell-derived. Our results underline a relationship between classical HD and NLPHD and suggest that the characteristic histological features of both diseases may be caused by the production and release of cytokines from altered B cells.     

Cytologic criteria for subclassification of Hodgkin's disease using fine-needle aspiration

Hodgkin's disease (HD) is increasingly being evaluated by fine-needle aspiration (FNA); however, criteria to subclassify HD into its four subtypes--nodular sclerosis (NS), mixed-cellularity (MC), lymphocyte-depleted (LD), and lymphocyte-predominant (LP)--has not been established. In order to evaluate criteria for subclassification, all FNA cases of HD obtained over a 5-yr period at Indiana University Medical Center that had confirmatory surgical biopsies were reviewed. The number of Reed-Sternberg (RS) cells was quantitated in each cytologic case and statistically analyzed by subgroup, using analysis of variance (ANOVA). LD had the highest mean (means) number of RS cells (means = 51) with NS and MC having similar means (means = 7 and 6, respectively). Only one case of LP was identified and therefore could not be analyzed statistically. Fibrosis and the presence of RS variants were qualitatively assessed and were not helpful in distinguishing the subtypes of HD. Although the quantitation of RS cells may be used to identify LD types of Hodgkin's disease, MC and NS cannot be separated reliably on this criterion alone. Although FNA can be used to diagnose HD, stage a patient, or assess efficacy of chemotherapy, subtyping of HD should still be done on histologic sections of excised lymph nodes.     

Bone marrow and peripheral blood natural killer cell activity in lymphomas. Its response to IL-2.

Natural killer (NK) cytotoxic activity was simultaneously investigated in bone marrow mononuclear cells (BMMC) and peripheral blood lymphocytes (PBL) from nine Hodgkin's disease (HD) and 15 non-Hodgkin lymphoma (NHL) untreated patients. Twenty-five PBL samples and seven bone marrow specimens from healthy individuals were also included as control group (C). NK cell activity was evaluated in basal condition and post-stimulation with human recombinant IL-2 (rIL-2). Data were expressed in K values (number of BMMC or PBL needed to lyse 50% of the target cells). In basal condition, both HD and NHL patients showed a NK cell activity comparable to the C group, both in BMMC (HD, K = 2.48 +/- 1.3; NHL, K = 3.8 +/- 2.0; C, K = 3.2 +/- 0.7) and PBL (HD, K = 2.0 +/- 1.0; NHL, K = 2.3 +/- 1.0; C, K = 2.2 +/- 0.2). Stimulation with rIL-2 induced a significant and comparable enhancement of the NK activity in PBL from HD, NHL and C while the response to rIL-2 of the BMMC in most of the HD and NHL patients was significantly greater than the C group. Responder cells were characterized by negative selection with specific MoAb plus complement as a CD3-, CD16+, CD56+ cytotoxic cell and further confirmed by flow cytometry. We postulate that IL-2 activation of bone marrow NK cell precursors, in addition to enhancing the activity of circulating NK, may be of value for the therapeutic rationale of IL-2 in patients with lymphoma.     

PCR-mismatch analysis of p53 gene mutation in Hodgkin's disease

Expression of the p53 protein can be detected by immunohistochemistry in Reed-Sternberg (RS) cells, the presumed neoplastic component of Hodgkin's disease (HD) lesions. At present, there is no clear molecular evidence that p53 positive immunostaining in HD correlates with the presence of mutations or other structural alterations of the p53 gene. To address this question, 49 cases of HD have been investigated for p53 expression by immuno-histochemistry, using the DO1 monoclonal antibody on paraffin sections. Thirty-seven out of 49 cases (75 per cent) exhibited positive immunostainining restricted to RS cells and variants. Among these 37 positive cases, ten cases were selected on the basis of a rich content of RS cells showing virtually 100 per cent DO1 positivity. A PCR-mismatch strategy was chosen for the detection of p53 mutations. The threshold level of sensitivity was assessed on positive cell-line controls. A proportion of 10–15 per cent p53 mutated cells mixed in a normal population could be identified. Total genomic DNA was extracted from the ten selected HD cases and PCR amplification of exons 5–8 of the p53 gene was performed. Heteroduplex mismatch analysis revealed no structural alterations of the p53 gene in any case. In view of these findings, it appears unlikely that the sensitivity of the method by itself can fully explain the negative results, although this possibility cannot be completely ruled out. Thus, it is conceivable that p53 positive immunostaining in HD may not necessarily imply genomic alterations in the classic ‘hot spot’ regions and may be related to another mechanism of p53 protein stabilization.     

Comparison between the monoclonal antibodies Ki-67 and PC 10 in 125 malignant lymphomas

The monoclonal antibody (MAb) Ki-67 detects a nuclear proliferation-associated antigen which corresponds to a non-histone protein with a molecular weight of 395 and 345 kD. Its prognostic relevance has been assessed in both lymphoid and non-lymphoid tumours. The MAb PC10 picks up the proliferating cell nuclear antigen (PCNA), which is a 36 kD nuclear protein associated with the cell cycle Whereas Ki-67 works only in fresh material. PC10 detects a fixation-resistant epitope of PCNA. Preliminary data have revealed a linear relationship between Ki-67 and PC 10 reactivity in normal lymphoid tissue and in non-Hodgkin's lymphomas (NHLs). We applied Ki-67 and PC 10 to frozen and routine sections, respectively, from 25 examples of Hodgkin's disease (HD) (14 nodular sclerosis, 6 lymphocyte predominance, 5 mixed cellularity) and 100 NHLs (corresponding to the main varieties of the updated Kiel classification). The results obtained can be summarized as follows: (1) both MAbs gave rise to extremely variable results within the same category of NHLs; (2) most Hodgkin and Reed-Stern berg cells (50-98 per cent) were labelled by the reagents; (3) Ki-67 and PC10 stained a similar ratio of neoplastic cells in 65 and 76 per cent of NHL and HD cases, respectively; in the remaining instances, no correspondence was observed, the PC10-positive elements usually outnumbering the Ki-67-positive ones significantly. These discrepancies, which might be due to low PCNA catabolism and/or PCNA expression by quiescent cells, underline the need for further kinetic and clinico-pathologic studies in order to define the specific relevance of PC 10.     

Presence of Epstein-Barr virus harbouring small and intermediate-sized cells in Hodgkin'S disease. Is there a relationship with Reed-Sternberg cells?

Forty-four cases of Hodgkin's disease (HD), mostly of the nodular sclerosing type, were investigated for the presence of Epstein-Barr virus (EBV) by polymerase chain reaction (PCR) and DNA and RNA in situ hybridization (DISH, RISH), as well as by immunohistochemistry for the detection of latent membrane protein-1 (LMP-1) of EBV. in situ hybridization (ISH) was combined with immunohistochemistry to correlate the presence and activity of the virus at the cellular level. In 18/34 (53 per cent) cases, EBV-DNA sequences could be detected with the PCR method. In 12/18 positive cases, DISH and RISH were also positive. In the remaining six EBV-PCR positive cases, two were also positive with RISH and LMP-1, whereas no positive signal with DISH could be obtained. All DISH and/or RISH positive cases were also positive for LMP-1. With RISH, not only the Reed-Sternberg cells and their mononuclear variants (RS cells) stained positive, but also small and intermediate cells frequently reacted with the EBV-specific probes (EBER-1 and -2). Double staining with cellular markers (CD3, CD20, CD45, CD45RO, CD68, and the lectin PNA) revealed that most of the smaller EBER-positive cells frequently did not express T, B, or histiocytic markers, but that they, as well as the RS cells, showed cytoplasmic and membranous staining with PNA. These smaller EBER-positive cells were not found in EBV-PCR negative HD. EBER-positive RS cells were almost always LMP-1 positive, as well as a substantial proportion of the intermediate-sized cells, whereas the majority of the small EBER-positive cells remained LMP-1 negative. In EBV-PCR positive non-malignant lymph nodes, only a few EBER-1 and -2 positive cells could be observed. As in infectious mononucleosis, these cells frequently expressed the B-cell marker CD20. Although we cannot exclude the fact that the majority of the smaller EBV-positive cells in HD belong to reactive EBV-infected lymphocytes, our data favour the hypothesis that at least some of these smaller cells may belong to the reservoir of neoplastic cells in HD.     

Persistence of Epstein-Barr virus in Reed-Sternberg cells throughout the course of Hodgkin's disease.

Non-isotopic in situ hybridization employing digoxigenin-labelled DNA probes has been used to localize Epstein-Barr virus (EBV) in 55 cases of Hodgkin's disease (HD). The virus was found in Reed-Sternberg (RS) and mononuclear Hodgkin's cells in nine patients (16 per cent). Further samples taken at different times from three patients also showed the presence of EBV in the malignant cell population. Estimations of the number of EBV genomes present per cell suggested wide variations between different patients, but relatively constant amounts in different samples from the same patient. These findings are compatible with a stable infection of the neoplastic cells and support the notion that EBV may play a role in the development of HD in these patients. We also found evidence for the presence of EBV in a small percentage of non-neoplastic cells in 8 of the 55 samples. This suggests that isolation of EBV from HD tissue does not always signify a pathogenetic role for the virus. Furthermore, it is apparent that a high percentage of HD tissues do not contain demonstrable EBV, and the virus is therefore unlikely to be a causative agent for all cases of HD.     

Castleman's disease

Castleman's disease (CD) is a rare atypical lymphoproliferative disorder whose morphology, soon after the original presentation of Castleman et al., has been definitely subdivided in a hyaline vascular (HV) and plasma cell (PC) histopathological pattern, with intermediate variants. The former occurs much more frequently than the latter and is usually localized to the mediastinum or pulmonary hilum. The latter involves lymph nodes separately or in aggregations and often displays multicentricity with systemic symptoms including autoimmune phenomena and aggressive course. Infections are the most frequent causes of patient demise in these cases, followed by malignancies such as Kaposi's sarcoma, malignant lymphoma or epithelial neoplasia. Increase of follicular dendritic reticulum cells (FDRC), often dysplastic, in the germinal center (GC) and marginal zone (MZ), broad MZ expansion with prominence of immunophenotypically aberrant B cells (Ki B3-negative, CD5-positive), possible predominance of paracortical plasma cells often with clusters of clonal l-light chain restricted plasma cells, increase of paracortical plasmacytoid monocytes, represent common hallmarks of CD. However, small hyalinized and hypervascular GCs with hypervascular interfollicular stroma and sinus effacement are common features of the HV variant, whereas hyperplastic GCs with plasma cell aggregates in lymph node paracortex and partially spared sinuses are characteristic features of the PC variant. The frequent concomitance of the HV and PC types at separate sites, together with transient morphological patterns from one type to the other and from the localized to multicentric form during the course of the disease, along with B and T cell impaired functions, with frequent development of autoantibodies, have suggested that CD is a single disorder related to immune dysregulation. A key event in the pathogenesis of CD has been recently suggested to be an abnormal production of a B cell growth factor, such as IL-6, leading to lymphoproliferation and plasma cell differentiation and being involved in the oncogenesis of plasmacytoma. In this event, Kaposi's sarcoma associated virus (HHV-8), which has been found in many cases of CD, especially in the multicentric form, could play a crucial role both in producing IL-6 and releasing angiogenic factors. A possible differentiation block may lead to the development of a malignant lymphoma. Kaposi's sarcoma or other malignant neoplasias can be supposed to be consequences of the immunodeficiency typical of CD.     

CD26/dipeptidyl peptidase IV expression in human lymphomas is restricted to CD30-positive anaplastic large cell and a subset of T-cell non-Hodgkin's lymphomas

CD26 is identical to the cell surface ectoenzyme dipeptidyl peptidase IV (DPPIV). is associated with T-cell activation and proliferation and also may function as an auxiliary adhesion factor. Although has been previously studied on lymphoid populations and on leukemias/lymphomas of B- and T-cell phenotype, little is known about its expression and functional role in some specific types of lymphomas, such as CD30-positive anaplastic large cell (ALC) lymphomas and Hodgkin's disease (HD). A series of 81 lymphoma samples, including 23 cases of HD, 17 cases of CD30-positive ALC lymphomas, 41 cases of other non-Hodgkin's lymphomas (NHL), and a panel of HD- or ALC lymphoma-derived human cell lines were evaluated for expression by enzyme histochemistry and immunohistochemistry on frozen sections and cell smears. protein was expressed on neoplastic cells in 12 of 17 (71%) ALC lymphomas irrespective of their antigenic phenotype and in seven of 15 (47%) T-cell NHLs. In contrast, we did not detect expression in tumor cells from 26 cases of B-cell NHL other than ALC lymphomas or in Reed Sternberg (RS) cells and variants of 21 of 23 HD cases. Accordingly, expression was maintained on the CD30-positive ALC lymphoma cell line Karpas 299, but the molecule was not detected on HD-derived cell lines of B, T, or non-B non-T phenotype. These results may support a new potential tool for the phenotypic separation of ALC lymphomas from HD based on the differential expression of the molecule. Moreover, given the demonstration that is identical to the human adenosine deaminase (ADA) binding protein, it could be speculated that also may function by interacting with ADA to regulate the growth of expressing neoplastic cells in ALC lymphomas.     

Decreased expression of cellular markers in Epstein-Barr virus-positive Hodgkin's disease

Epstein-Barr virus (EBV) has been demonstrated in the Reed–Stenberg cells and their mononuclear variants (Hodgkin cells; H-RS cells) in a substantial number of Hodgkin's disease (HD) cases. Moreover, EBV can modulate both in vivo and in vitro the expression of several cellular genes, including lymphoid differentiation markers. Therefore we investigated, in 64 cases of HD, the relationship between the presence of EBV and the expression of lymphoid (CD45RB), T- (CD3, CD45RO), B- (CD20, MB2 antigen, CDw75), and myeloid-cell lineage markers (CD15), and of activation markers (CD30, EMA, and the 115D8 antigen) on the H-RS cells. EBV-positive cases, as demonstrated by the presence of EBER-1 and -2 RNA and LMP-1 protein expression, showed a significant reduction in the expression on H-RS cells of T-cell lineage (CD3, p<0·02), B-cell lineage (CD20, P<0·005), AND ACTIVATION MARKERS (ema; P<0·002 and the 115D8 antigen; P<0·001) as compared with EBV-negative cases. No differences were found in the expression of CD15, CD30, CD45RO, CD45RB CDw75, or the MB2 antigen on H-RS cells in EBV-positive and EBV-negative HD cases. Interestingly, in 11 cases of EBV-negative HD, B-as well as T-cell lineage markers could be found on some H-RS cells. These data suggest that EBV in H-RS cells is able to down-regulate the expression of T- (CD3) and B- (CD20) cell lineage markers and lymphoid activation markers (EMA and the 115D8 antigen). For this reason, the origin of H-RS cells in HD, as studies by immunohistochemistry, cannot be discussed without taking into account the presence of EBV.     

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.     

In vivo expression of the CTLA4 inhibitory receptor in malignant and reactive cells from Human lymphomas

The CTLA4 receptor is a CD28 homologue which induces inhibitory effect on activated T-cells. Peripheral T-cells proliferate spontaneously in CTLA4-deficient mice. These results led to an analysis of CTLA4 expression in human lymphomas (n=82) including Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NHLs), using immunohistochemistry. CTLA4 was present in neoplastic cells from most (10/11) T-cell malignancies, except for anaplastic and lymphoblastic subtypes (0/4). Malignant B-cells from rare (3/55) B-NHLs (all of follicular subtype) were also CTLA4-positive. Other B-NHLs (52/55) were negative in malignant B-cells and occasionally positive in T-cells. Reactive small lymphocytes, but not Reed–Sternberg cells, from all (12/12) HD cases were strongly CTLA4-positive. The CTLA4 ligands CD80 and CD86 were simultaneously expressed in most CTLA4-negative lymphoma cases. CTLA4 is thus expressed either in the reactive or in the malignant cell populations, depending on the lymphoma subtype. These results provide new insights leading towards therapeutic strategies based either on enhancement of anti-tumour immunity by CTLA4 blockade in reactive lymphocytes or on triggering of a CTLA4-mediated inhibitory pathway in lymphoma cells. © 1997 John Wiley & Sons, Ltd.     

Lymphadenitis mimicking Hodgkin''s disease

A variant of lymphadenitis mimicking interfollicular Hodgkin's disease is described. The morphology, immunohistochemistry and clinical course of 25 cases are reported. The morphology is characterized by changes in the interfollicular region within a well-preserved lymph node architecture. These changes include variegated hyperplasia of the pulp with epithelioid cells, mature eosinophilic granulocytes and immunoblasts occasionally resembling Hodgkin cells. In contrast to Hodgkin's disease no typical Sternberg-Reed cells could be found. Immunohistochemically, neither positive reactions with Hodgkin cell markers (anti-CD15: LeuM1; 3C4; C3D-1) nor B-cell monoclonality could be detected. Transition to malignancy, in particular Hodgkin's disease, did not occur in our cases.     

Low incidence of mbr bcl-2/JH fusion genes in Hodgkin's disease

Lymph node biopsies from 140 cases of Hodgkin's disease (HD) and from 30 non-malignant lesions were screened for the presence of t(14;18) translocations involving the major breakpoint region (mbr) of the bcl-2 gene and the joining region (J)_H of the immunoglobulin heavy chain gene, using a polymerase chain reaction (PCR) assay with subsequent nucleotide sequencing of amplified bcl-2/J_H junctional regions. Expression of the bcl-2 protein within the Hodgkin and Reed-Sternberg (HRS) cells was investigated in 86 cases of HD by immunohistochemistry on cryostat or paraffin sections. Although bcl-2 expression could be found in a proportion of neoplastic cells in up to one-third of HD cases, the frequency of t(14;18) gene fusions detected by PCR was low. We identified such gene fusions in only 3 out of 140 (2 per cent) HD cases, one biopsy of which presented with four clonally distinct bcl-2/J_H sequences. No t(14;18) was found in any of 30 reactive lymph node lesions. All fusion gene sequences were unique regarding the localization of the chromosome 14 and 18 breakpoints and the extranucleotide N-insertions. None of these gene fusions conformed to t(14;18) breakpoint sequences previously characterized in our laboratories. Our findings point to a mere coincidence in some cases of HD lesions and cells carrying a t(14;18) in the same biopsy and argue against a significant role of bcl-2 in the pathogenesis of HD.     

Modulation of interleukin-6 expression in Hodgkin and Reed–Sternberg cells by Epstein–Barr virus

Variable proportions of Hodgkin's disease (HD) cases are associated with the Epstein–Barr virus (EBV), but the role of EBV in HD is not entirely clear. Hodgkin and Reed–Sternberg (HRS) cells of EBV-associated HD are characterized by expression of the EBV gene product LMP1. In other cellular environments, LMP1 has been shown to induce interleukin (IL)-6. In this study, 105 HD cases were tested for differences in IL-6 expression among LMP1-positive and -negative cases. Isotopic in situ hybridization and correlation with the presence of EBV gene products revealed significantly higher proportions of cases with IL-6-expressing tumour cells in LMP1-positive (31 of 37, 84 per cent) as compared with LMP1-negative HD cases (35 of 68, 51 per cent). Thus, although not exclusive to EBV-positive HRS cells, IL-6 expression appears to be upregulated in EBV-associated HD. IL-6 receptor (CD126) expression was tested by in situ hybridization and found in a broad spectrum of cell types, regularly including HRS cells. Superinduction of IL-6 expression may be among the mechanisms by which EBV confers a growth advantage on virus-infected HRS cells and by which the virus may contribute to the morphological and clinical peculiarities of HD. © 1997 John Wiley & Sons, Ltd.     

Cutaneous multicentric Castleman's disease mimicking IgG4-related disease

Castleman's disease, an uncommon lymphoproliferative disorder, can be difficult to differentiate from immunoglobulin (Ig) G4-related disease. The latter is typically characterized by elevated serum IgG4 levels and abundant IgG4-positive cells. However, multicentric Castleman's disease can also have elevated serum IgG4 levels and even fulfill the histological diagnostic criteria for IgG4-related disease. We present a case of cutaneous multicentric Castleman's disease mimicking IgG4-related disease. A 55-year-old Japanese woman developed erythematous and brown plaques on her back. Skin biopsy revealed regressive follicles with interfollicular plasmacytosis, and many plasma cells were positive for IgG4 (mean 263.67 ± 79.19, range 214–355 per high power field). The IgG4-/IgG-positive cell ratios were 35.6%, 36.2%, and 48.4%, respectively, with an average of 40.6%, thus fulfilling the histological diagnostic criteria for IgG4-related disease. Furthermore, serum IgG4 level was significantly elevated (1490 mg/dl; normal range: 4.8–105 mg/dl). However, laboratory findings of anemia, hypoalbuminemia, polyclonal gammaglobulinemia, high C-reactive protein level, and elevated serum interleukin-6 level were consistent with hyper-IL-6 syndrome. Hence, the diagnosis of cutaneous multicentric Castleman's disease was made. In conclusion, IgG4-related disease cannot be differentiated from hyper-IL-6 syndromes on histology alone. Instead, laboratory analyses are necessary to distinguish between the two diseases.