The effects of dexmedetomidine on inflammatory mediators after cardiopulmonary bypass.

Cardiac surgery with cardiopulmonary bypass is associated with the development of a systemic inflammatory response that can often lead to dysfunction of major organs. We hypothesised that the highly selective α2-adrenergic agonist, dexmedetomidine, attenuates the systemic inflammatory response. Forty-two patients were randomly assigned to receive dexmedetomidine or saline after aortic cross-clamping). The mean (SD) levels of the nuclear protein plasma high-mobility group box 1 increased significantly from 5.1 (2.2) ng ml(-1) during (16.6 (7.3) ng ml(-1) ) and after (14.3 (8.2) ng ml(-1) ) cardiopulmonary bypass in the saline group. In the dexmedetomidine group, the levels increased significantly only during cardiopulmonary bypass (4.0 (1.9) ng ml(-1) baseline vs. 10.8 (2.7) ng ml(-1) ) but not after (7.4 (3.8) ng ml(-1) ). Dexmedetomidine infusion also suppressed the rise in mean (SD) interleukin-6 levels after cardiopulmonary bypass (a rise of 124.5 (72.0) pg ml(-1) vs. 65.3 (30.9) pg ml(-1)). These suppressive effects of dexmedetomidine might be due to the inhibition of nuclear factor kappa B activation and suggest that intra-operative dexmedetomidine may beneficially inhibit inflammatory responses associated with ischaemia-reperfusion injury during cardiopulmonary bypass.

Production of interleukin 6 from human liver cell lines: production of interleukin 6 is not concurrent with the production of alpha-fetoprotein.

The production of interleukin (IL) 6 from six human liver cell lines, including Chang liver, HLF, HLE, HepG2, PLC/PRF/5, and HuH-7, was investigated using enzyme-linked immunosorbent assay and Northern blot analysis. When cells were cultured in the presence of 12-O-tetradecanoylphorbol-13-acetate, significant amounts of IL6 were detected in the culture supernatants of Chang liver cells, HLF cells, and HLE cells. However, IL6 was not detected in the culture supernatants from HepG2 cells, PLC/PRF/5 cells, or HuH-7 cells which had been treated similarly. To further investigate the production of IL6, expression of the IL6 gene was studied. Results of Northern blot analysis using IL6 complementary DNA as a probe showed that the induction was initiated at the mRNA level. Moreover, IL6 mRNA was also induced by IL1 beta and tumor necrosis factor but not by a calcium ionophore (A23187) or IL6 itself in Chang liver cells. This is the first study to demonstrate the production of human IL6 in liver cells. Furthermore, when the production of alpha-fetoprotein (AFP) from the liver cell lines was examined, the three that were able to produce IL6 failed to produce AFP, whereas the other three cell lines succeeded in producing AFP. These observations may indicate the heterogeneous origin of the liver cell lines.

Granulocyte colony-stimulating factor receptors on human acute leukemia: biphenotypic leukemic cells possess granulocyte colony-stimulating factor receptors.

Granulocyte colony-stimulating factor (G-CSF) receptors on the gated leukemic blast cells from newly diagnosed patients with acute leukemia or crisis of chronic myelogenous leukemia were investigated using flow cytometric detection. Surface marker analysis and cytochemical studies were conducted simultaneously to characterize the blast cells. Among 24 leukemia cases examined, G-CSF receptor-positive blast cells were detected in all 11 cases of acute myeloblastic leukemia even though the percentage range of positive cells was widely variable. On the other hand, they were not detected on the blast cells from patients with peroxidase-negative acute lymphoblastic leukemia with no myeloid surface antigens. However, G-CSF receptors were demonstrated in significant amounts on blast cells from 5 of 8 cases of peroxidase-negative acute leukemia expressing both myeloid and lymphoid surface antigens (biphenotypic leukemia). The percentage of blast cells positive for G-CSF receptors was significantly smaller in biphenotypic cases [33 +/- 14% (SD)] than in acute myeloblastic leukemia cases [65 +/- 22%] (P less than 0.01). The percentage expression of CD13 antigen by blast cells was significantly related to their percentage positivity for G-CSF receptors (rs = 0.50, P less than 0.05). These findings indicate that the distribution of flow cytometrically detectable G-CSF receptors on leukemic cells possessing myeloid characteristics may be related to the maturation process.

Both granulocyte-macrophage colony-stimulating factor and monocytic colony-stimulating factor are produced by the human T-cell line, HUT 102.

We present the first report of a T-helper cell line, HUT 102, constitutively producing both granulocyte-macrophage colony-stimulating factor (GM-CSF) and monocytic colony-stimulating factor (M-CSF), as detected by sensitive enzyme-linked immunosorbent assays and Northern blot analysis. However, neither amplification nor structural change of the GM-CSF and M-CSF genes was detected by Southern blot analysis. In the case of HUT 102, in which human T-lymphotropic leukemia virus type I (HTLV-I) is integrated, the viral protein, which acts as a trans-acting transcriptional activator, may induce the production of both GM-CSF and M-CSF.

Amplification and expression of a decoy receptor for fas ligand (DcR3) in virus (EBV or HTLV-I) associated lymphomas.

The recently identified decoy receptor 3 (DcR3) binds to FasL and inhibits FasL-induced apoptosis, and is considered to play a role in the immune escape system of neoplastic cells. To examine the involvement of DcR3 in the immune evasions of virus-associated lymphoma, we analyzed the amplification and expression of DcR3, using dot blot and in situ hybridization (ISH), in 45 cases, which included 17 cases with Epstein-Barr virus (EBV)-associated lymphoma (seven pyothorax-associated B-cell lymphomas (PAL); ten natural killer lymphoma (NKL)), seven cases with adult T-cell leukemia lymphoma (ATLL), 13 Hodgkin's disease (eight EBV-associated cases; five non-EBV-associated cases), and eight control cases (three reactive lymphadenopathy; five non-EBV-associated-B-cell lymphoma). EBV-associated PAL and NKL exhibited DcR3 amplification and expression in lymphoma cells. ATLL also showed DcR3 expression and amplification. The cases with DcR3 amplification showed DcR3 expression; however, the expression was confined in the neoplastic cells, but not in the reactive cells. In Hodgkin's disease (HD), DcR3 was expressed only in Hodgkin and Reed-Sternberg giant (H-RS) cells. However, DcR3 was not expressed or amplified in reactive lymphadenopathy. Non-EBV-associated B-cell lymphoma also rarely expressed DcR3, and showed no amplification except in two cases, in which rare expression was present. Our results suggest that EBV and HTLV-I probably use DcR3 to escape from the immune system during lymphomagenesis, or virus-infected lymphoma cells with DcR3 expression might be selected in the multistep tumorigenesis.

Mutation analysis of mitotic checkpoint genes (hBUB1 and hBUBR1) and microsatellite instability in adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a neoplasm of T-lymphocytes, and human T-cell lymphotropic virus type-I (HTLV-I) is etiologically considered as the causative virus of ATLL. The karyotypes of ATLL are very complex in both number and structure, although no specific karyotype abnormalities have been identified. HTLV-I is thought to integrate its provirus into random sites in host chromosomal DNA and induces chromosomal instability. The BUB gene is a component of the mitotic checkpoint in budding yeast. Recently, human homologues of the BUB were identified and mutant alleles of hBUB1 and hBUBR1 were detected in two colorectal tumor cell lines, which showed microsatellite instability (MIN). In vitro, BUB proteins form a complex of monomers. These proteins interact with the human MAD1 gene product, a target of the HTLV-1 tax oncogene. We examined the role of checkpoint gene in the chromosomal abnormalities of ATLL by investigating mutations of hBUB1 and hBUBR1, and MIN of replication errors of BAX, insulin-like growth factor, and transforming growth factor beta type II. We analyzed ten cases with ATLL and eight B-cell lymphomas (five diffuse large cell lymphomas, three follicular lymphomas). Complex chromosomal abnormalities were detected in ATLL, while B-cell lymphomas showed only simple or minimal chromosomal abnormalities. Significant mutations/deletion of hBUB1 or hBUBR1 were detected in four of ten cases with ATLL, including two heterozygous point mutations, one homozygous point mutation, and one with a 47 bp deletion. In contrast, only one of eight B-cell lymphomas showed nonsense mutation of hBUBR1. None of the ATLL and B-cell lymphomas showed MIN. In the multistage process of leukemogenesis of ATLL, our findings indicate that mutations of mitotic checkpoint genes may play an important role in the induction of complex chromosomal abnormalities.

Charcoal hemoperfusion in the treatment of phenytoin overdose.

In the case of phenytoin, a drug that is generally highly protein bound, there is a lack of consensus on the use of charcoal hemoperfusion in cases of overdose. We performed charcoal hemoperfusion on a phenytoin-overdosed patient to assess the effectiveness of this treatment. The plasma concentrations of total and free phenytoin fell rapidly, from 40.0 microg/mL and 3.6 microg/mL to 16.2 microg/mL and 1.5 microg/mL, respectively, after 3 hours of hemoperfusion. The total phenytoin elimination half-life was 3.9 hours. The fraction of protein-bound phenytoin was constant (90.8% +/- 0.5%) before, during, and after the procedure. The relations between the in vitro protein binding and adsorption of phenytoin to activated charcoal were also examined. Interestingly, bound phenytoin was found to dissociate from plasma proteins in the presence of activated charcoal and subsequently became adsorbed to the activated charcoal. Considering that phenytoin is bound to albumin with a large number of binding sites (n = 6) and a small binding constant (K = 6 x 10(3/)mol/L), the extent of adsorption to activated charcoal may depend on the magnitude of the binding constant of the drug to plasma proteins. The current results suggest that charcoal hemoperfusion is effective for the removal of drugs that bind to plasma proteins with a low binding constant.

Production of macrophage colony-stimulating factor by human lymphoblastoid cell lines.

The in vitro production of macrophage colony-stimulating factor (M-CSF) was studied in 14 human lymphoblastoid cell lines and their lineages were ascertained by surface phenotype analysis. M-CSF gene transcripts were detected in a T-lymphocyte-derived cell line (CCRF-CEM) and 3 B-lymphoblastoid cell lines (IM-9, BALL-1, and CCRF-SB) by Northern-blot analysis. The secretion of M-CSF protein into the culture supernatant by each cell line was also studied using an enzyme-linked immunosorbent assay for M-CSF. The 4 cell lines which expressed the M-CSF gene secreted considerable amounts of M-CSF into their culture supernatants, while the 10 cell lines without M-CSF gene expression did not do so. The cell lines which constitutively produced M-CSF were then subjected to Southern-blot analysis of the M-CSF gene structure, and all 14 cell lines were examined for infection by the Epstein-Barr virus. Neither structural changes nor amplification of the M-CSF gene were detected, and Epstein-Barr virus infection was found to be not directly related to M-CSF production.

Bcl10 expression, rearrangement and mutation in MALT lymphoma: correlation with expression of nuclear factor-kappaB.

Mucosa-associated lymphoid tissue (MALT) lymphomas usually involve extranodal sites, especially the stomach, lung and salivary glands. The Bcl10 gene was recently isolated from the breakpoint region of t(1;14) (p22;q32) in MALT lymphomas, and considered to be an apoptosis-associated gene, and involves a caspase recruitment domain (CARD)-containing protein that activates NF-kappaB. We investigated the role of Bcl10 in MALT lymphoma by analyzing its expression, rearrangement and somatic mutation, by immunostaining, reverse transcriptase-polymerase chain reaction (RT-PCR), Southern blot and PCR in 20 cases of MALT lymphoma. Expression of NF-kappaB was studied by immunostaining. Five cases of reactive lymphadenitis (RLA) were used as the control. Bcl10 rearrangement was detected in 8 of 20 (40%) MALT lymphomas, but in none of RLA. Significant Bcl10 mutation was detected only in 1 case (5%) with MALT, but not in RLA. RT-PCR showed higher density bands of Bcl10 in MALT lymphomas than in RLA. Immunostaining showed a weak Bcl10 expression in the germinal center and very weak expression in the marginal zone B-cells in RLA, which was limited to the cytoplasm. In contrast, Bcl10 was strongly expressed in MALT lymphomas, and was mainly detected in the cytoplasm, as well as in the nuclei. Bcl10 expression did not correlate with Bcl10 mutation and re-arrangements. NF-kappaB was expressed in nuclei of MALT lymphoma cells, but not in RLA. Bcl10 expression in MALT lymphoma correlated closely with NF-kappaB expression. Our results suggest that activation of Bcl10 and NF-kappaB may be important in MALT lymphomagenesis, and that nuclear localization of Bcl10 may be important in the progression of MALT.

Gene expression of cytokines suppressing hematopoietic progenitor cells in lymphoid malignancies.

The expression of cytokine genes for tumor necrosis factor alpha (TNF alpha), lymphotoxin and transforming growth factor beta (TGF beta), all of which are known to suppress normal hematopoiesis, was investigated in 32 patients with lymphoid malignancies using Northern blot analysis. Messenger RNA (mRNA) for TNF alpha, lymphotoxin and TGF beta was detected in 9 cases, 2 cases and 7 cases, respectively. When the relationship between cytokine gene expression and surface phenotype was analyzed, the expression of CD19 correlated significantly with expression of the TNF alpha gene (P less than 0.05). This suggests that B cell malignancies are likely to produce TNF alpha. When the hematological parameters of patients expressing and not expressing the gene were compared, the expression of TNF alpha mRNA was found to correlate with more profound anemia in acute lymphoblastic leukemia (P less than 0.05). Both granulocyte and platelet counts were lower in patients expressing TNF alpha mRNA; however, the decreases were not significant. Neither lymphotoxin nor TGF beta gene expression correlated significantly with any hematological parameter.

CD7-positive acute myeloid leukemia: further evidence of cellular immaturity.

Among 63 cases of acute myeloid leukemia (AML), 14 were found to express the CD7 antigen, a cell surface marker usually found at an early stage during T lineage differentiation. The CD7-positive AML cases consisted of 5 cases of M1, 3 cases of M2, 3 cases of M4, 1 case of M5, 1 case of M6 and 1 case of M7. Among these 63 cases, the proportion of blast cells expressing the CD34 antigen was examined. The proportion of CD34-stained cells among the CD7-positive AML cases, although varying, was significantly larger than that among the CD7-negative AML cases (P less than 0.05). As the CD34 antigen was expressed on hematopoietic progenitor cells and was considered to reflect an early hematopoietic stage, the high proportion of cells expressing CD34 among the CD7-positive AML cases may support the notion that CD7-positive AML cells are immature.

Clinical, immunohistochemical and phenotypic features of aggressive nodal cytotoxic lymphomas, including alpha/beta, gamma/delta T-cell and natural killer cell types.

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.

Absence of cytotoxic molecules in CD8- and/or CD56-positive adult T-cell leukaemia/lymphoma.

Adult T-cell leukaemia/lymphoma (ATLL) cells usually exhibit a CD4+ (helper/inducer) phenotype (CD4+/8-/56-), and only a minority of tumours express the CD8 (cytotoxic/suppressor) or CD56 (natural killer [NK]-associated) antigens. TIA-1 is a cytotoxic granule-associated protein expressed in NK cells and cytotoxic T lymphocytes (CTLs). Granzyme B, perforin and Fas ligand (FasL) are also expressed in activated CTLs and NK cells. To clarify the cytotoxic potential of ATLL cells, immunohistochemistry was performed in CD8+ and/or CD56+ ATLL cells, using anti-TIA-1, anti-granzyme B, anti-perforin and anti-FasL antibodies. We studied nine cases of CD8+ and/or CD56+ ATLL, all of which exhibited monoclonal integration of human T-cell leukaemia virus type 1 (HTLV-1) proviral DNA. Four cases exhibited a CD8+/CD56- phenotype, four others had a CD8-/CD56+ phenotype, and one was CD8+/CD56+. All but one case also expressed the surface antigens CD3, TCR alpha beta, and CD4. Expression of granzyme B and TIA-1 were demonstrated in three and two cases, respectively, but none expressed perforin or FasL. In the control study, 10 cases with typical CD3+/4+/8-/56- ATLL demonstrated no expression of those cytotoxic-associated proteins. Our findings suggest that CD8 and/or CD56 positivity probably confer(s) no cytotoxic function on ATLL cells, and it is possible that CD8 and CD56 may be simply aberrant surface markers in ATLL.

Cerebral mass lesions associated with adult T-cell leukemia/lymphoma.

Three patients with adult T-cell leukemia/lymphoma (ATLL) accompanied by cerebral mass lesions in their courses are reported. The findings of cerebrospinal fluid and their history suggested that those three cerebral involvements were the mass lesions derived from ATLL. Two of the three patients had acute type and the other one had chronic type ATLL. During the same period in which these three patients were observed, we experienced 17 other patients with ATLL. Although this group included 12 lymphoma type and five acute type ATLL, involvement of the central nervous system (CNS) was not observed in these 17 patients. The incidence of CNS involvement was 3/20 (15%). The prognoses of the three patients after the occurrence of CNS involvement was 1, 4, and 8 months, respectively. In these three patients, cerebral lesions became the cause of death for two patients although they continued to be in complete remission hematologically. Cerebral lesions, once occurring, are very hard to cure and spoil the quality of life for sufferers. From these points, prophylactic therapy against central nervous system involvement seems necessary not only for acute leukemias, but also for ATLL patients.

Apoptosis and prognostic factors in myelodysplastic syndromes.

The myelodysplastic syndromes (MDS) are a group of disorders characterized by peripheral pancytopenia despite normo- or hyper-cellular bone marrow. This is thought to be due to apoptosis of hematopoietic bone marrow cells, resulting in ineffective hematopoiesis. Several studies have confirmed the presence of a high apoptotic rate and proliferative state in the bone marrow of MDS. However, MDS is a heterogeneous disease from the point of view of prognosis. Some patients develop only anemia and show long survival with or without maintenance therapy, while others develop fatal pancytopenia or leukemic changes and therefore show a poor prognosis. This review focuses on the relationship between prognosis and apoptotic or proliferative processes affecting hematopoietic cells in the bone marrow of patients with MDS.

Cytoplasmic cytokines in lymphoproliferative disorders: multiple cytokine production in angioimmunoblastic lymphadenopathy with dysproteinemia.

Cytokines play an important role in the pathogenesis of lymphomas via autocrine or paracrine mechanisms, or both. Here we determined the proportion of CD3-positive T lymphocytes containing various types of cytokines in enlarged lymph nodes. Lymph nodes were obtained from 16 patients with various lymphoproliferative disorders, including 3 cases with angioimmunoblastic lymphadenopathy with dysproteinemia (AILD), 3 cases with adult T cell leukemia/lymphoma (ATLL), 2 cases with T-cell nonspecific malignant lymphoma (T-ML), 3 cases with B-cell diffuse large malignant lymphoma (BDL), 3 cases with histiocytic necrotizing lymphadenitis (HNL), and 2 cases with non-specific lymphadenitis (NSL). The percentages of T lymphocytes positive for cytoplasmic cytokines IL-2, IL-4, IL-5, IL-6, IL-13, TNF-alpha, and INF-gamma were determined. The percentage of INF-gamma positive T lymphocytes was high in reactive lymphadenopathy of NSL and HNL. AILD showed a high proportion of TNF-alpha positive T-lymphocytes, and in addition, the percentages of IL-2, IL-4, IL-5, IL-6, IL-13 and INF-gamma positive T-lymphocytes were relatively higher than in other diseases. Our results supported the state of multiple hypercytokinemia typically seen in AILD and suggested that the source of the cytokines is the lymph nodes. Our results also suggested that multiple cytokine networks play an important role in the clinical and histopathological features of AILD. Modulation of the cytokine network may be the logical objective in future therapeutic strategies designed for AILD.

Prognostic value of Bcl 10 rearrangement in diffuse large B-cell lymphoma.

The role of bcl 10, a recently cloned apoptosis-associated gene, in diffuse large B-cell lymphoma (DLBL) is unknown. Here we determined the role of bcl 10 gene rearrangement on prognosis. Bcl 10 rearrangement was examined by Southern blot. Bcl 10 rearrangement was detected in 20 of 137 (14.6%) samples of DLBL. The frequency of bcl 10 rearrangement was higher in extranodal (eight of 38 cases, 21%) than in nodal (12 of 99, 12%) DLBL. The survival rate in patients with bcl 10 rearrangement tended to be better than in those with germ-line bcl 10, albeit statistically insignificant probably due to the small population sample. The superior prognosis in patients with bcl 10 rearrangement might be due to bcl 10-induced enhanced apoptosis.

Rearrangements of bcl-1, bcl-2, bcl-6, and c-myc in diffuse large B-cell lymphomas.

Diffuse large B-cell lymphoma (DLBL) is characterized by a marked degree of morphologic and clinical heterogeneity. We studied 137 patients with de novo DLBL for rearrangements of the bcl-1, bcl-2, bcl-6 and c-myc oncogenes by Southern blot analysis. Structural alterations of bcl-1, bcl-2, bcl-6, and c-myc were detected in 21 of 137 (15.3%), 8 of 137 (5.8%), 22 of 137 (16.1%), 14 of 137 (10.2%) patients, respectively. Two cases showed a combination of bcl-1 and bcl-6 rearrangements. Chromosomal analysis was performed in 31 cases of the 137 DLBL. 27 of these showed karyotypic abnormalities, and two had translocations 3q27 involving bcl-6. However, one of two cases had no rearrangement of bcl-6. Patients with rearranged bcl-6 and c-myc tended to have poorer survival than patients with germ-line. Furthermore, bcl-1 and bcl-2 rearrangements tended to have a better outcome, although the above differences were not statistically significant. Rearrangements of the bcl-1, 2, 6, and c-myc gene correlated with the clinical outcome in DLBL and may thus serve as prognostic markers in patients with this form of malignant lymphoma. However, other genetic factors are probably involved in determining prognosis.

Nasal lymphomas in Japan: a high prevalence of Epstein-Barr virus type A and deletion within the latent membrane protein gene.

The majority of nasal lymphomas are of the natural killer (NK)/T cell lineage. We analyzed 33 specimens of nasal lymphoma from Japanese patients for Epstein-Barr virus (EBV). Phenotypic and genetic analyses showed 28 cases with NK/T cell type and 5 cases with B cell type. All NK/T lymphomas were of pleomorphic cell type except 2 large cell (centroblastoid) and one lymphoblastic lymphoma. All cases with nasal B cell lymphoma were of large (centroblastoid) cell type. EBV was detected in all cases of NK/T cell type with the exception of one lymphoblastic case, and was monoclonally integrated in all cases examined (14/14 cases). All but one case had subtype A of EBV infection with 30-base paired deleted LMP-1 gene. One case of B cell lymphoma showed the presence of EBV infection with subtype A and deletion of LMP-1. Our results indicate that the majority of nasal lymphomas in Japanese patients are of the nasal NK/T cell type, have pleomorphic morphology, a high prevalence of EBV with a monoclonal integration, subtype A and deleted LMP-1 gene. In contrast, nasal B cell lymphoma showed monomorphic appearance and rare EBV infection.

Possible immortalization of Hodgkin and Reed-Sternberg cells: telomerase expression, lengthening of telomere, and inhibition of apoptosis by NF-kappaB expression.

Telomerase, an enzyme associated with cellular immortality, is expressed on malignant tumor cells. Deregulation of telomerase is thought to facilitate tumorigenesis and cellular immortality by providing cancer cells with unlimited proliferation capacity. Hodgkin and Reed-Sternberg (H&RS) cells are generally considered as neoplastic cells in Hodgkin's disease (HD), however, such cells are only found in a minority of HD lesions. In addition, H&RS cells with mitotic features are rare and mummified forms are occasionally encountered. There are no available data on the relationship between telomerase activity and apoptosis in HD. We studied 14 cases with Hodgkin's disease (mixed cellularity type, nine cases; nodular sclerosis type, five cases) to clarify the relationship between telomerase activity and apoptosis using in situ hybridization of human telomerase reverse transcriptase (hTERT), reverse transcriptase-polymerase chain reaction (RT-PCR) of hTERT, using extracted RNA and immunohistochemistry of nuclear factor-?B (NF-?B), and TdT-mediated dUTP-digoxigenin nick end-labeling (TUNEL) technique for apoptosis. We also analyzed the telomere length, using sorted H&RS cells. TUNEL showed a few apoptotic H&RS cells, but the cells frequently expressed hTERT, as confirmed by ISH and RT-PCR. Lengthening of the telomere of H&RS cells was noted in ten cases. In addition, H&RS cells frequently expressed NF-?B, which is known as an inducible transcription factor and inhibitor of apoptosis. Our findings of telomerase activity in H&RS cells indicate that these cells are neoplastic and are potentially immortal. In addition, NF-?B expression on H&RS cells suggests its possibility in inhibition of apoptosis of these cells.