Establishment of Epstein-Barr virus-associated lymphoma cell line SUBL with t(2;3)(p11;q27) from a liver transplant patient

Increased neoplasm development due to immunosuppressive treatment with FK-506 in BALB/C mice persistently infected with the mouse herpesvirus (MHV-72)

BALB/c mice were infected with the lymphotropic mouse gammaherpesvirus (MHV-72). At late (7-12 months) post-infection intervals the latent virus was detected in the cells of lymphatic system (peripheral blood, lymphocytes and macrophages, thymocytes, lymph nodes, bone marrow, and peritoneal macrophages,) and in the spleen, lungs, liver, and kidney by cocultivation as well as by explantation. The MHV-72 infected mice, in which latency had been established, were treated with the immunosuppressive (IS) drug FK-506 (2 mg/kg/mouse for 30 days). This treatment increased the probability of virus reactivation by over two-fold. During the post-treatment observation period of 19 months, the incidence of lymphomas and the development of MHV-related lymphoproliferative and hemoblastic disorders raised to nearly five-fold in the drug treated mice as compared to untreated animals.

Detection of GB virus-C/hepatitis G virus genome in peripheral blood mononuclear cells and liver tissue

The replication site for the GB virus-C/hepatitis G virus (GBV-C/HGV) was investigated by using polymerase chain reaction (PCR)-based assays and in situ hybridisation. A total of 28 patients with consecutive GBV-C/HGV infection were enrolled in this study: Nine patients were being treated with immunosuppressive therapy after liver transplantation, and the remaining 19 patients were not receiving such treatment. GBV-C/HGV RNA was detected by using reverse transcriptase-polymerase chain reaction (RT-PCR) and was quantitated by using competitive RT-PCR in all patients. Positive and negative strands of GBV-C/HGV RNA in liver tissue were detected with in situ hybridisation by using RNA probes that were specific for the GBV-C/HGV genome. Concentrations of GBV-C/HGV RNA in serum were significantly higher (P=0.003) in the nine patients who were receiving immunosuppression (median, 10(7) copy/ml; range, 10(5)-10(7)) than in the 19 patients who were not receiving immunosuppressive therapy (median, 10(4) copy/ml; range, 10(2)-10(7)). In situ hybridisation of GBV-C/ HGV RNA was performed on paraffin-embedded liver tissue that was obtained from six patients with GBV-C/HGV infection. Two of those six patients were receiving immunosuppressive therapy, and four were not. Significant positive signals were observed in the samples from two of the six patients who were infected with GBV-C/HGV, but such signals were not observed in any of the six patients who were without the infection. The two patients with positive signals (both were undergoing immunosuppressive therapy) showed both positive and negative strands of GBV-C/HGV RNA in mononuclear cells that infiltrated into portal areas, but neither of the strands was observed in hepatocytes. Moreover, the GBV-C/HGV replication was analysed in peripheral blood mononuclear cells by using strand-specific PCR (conventional RT-PCR and rTth method). Two of the six patients were positive for negative-strand GBV-C/HGV RNA by using conventional RT-PCR. In conclusion, GBV-C/HGV replication was active under an immunosuppressive state, and it is suggested that GBV-C/HGV replicates in mononuclear cells.

Effects of immunotherapy on experimental immunodeficiency-related lymphoproliferative disease

BACKGROUND

Human lymphokine-activated cells (LAK cells) and interferon alpha (IFN-alpha) have been used clinically in the therapy of posttransplant lymphoproliferative disease (PTLD). However, the efficacy of such therapy has not been extensively tested under controlled experimental conditions.

METHODS

A B-cell line, derived from PTLD tissue and clonally related to the parent lesion, was tested for its response to IFN-alpha in vitro. The effects of LAK cells and IFN-alpha therapy were examined in a severe combined immunodeficiency disease (SCID) mouse model in vivo.

RESULTS

The PTLD cell line studied showed a 30% decrease in the rate of growth upon incubation with 500 U/ml of IFN-alpha. This in vitro response was also reproduced in vivo, in tumor therapy studies conducted in SCID mice. The magnitude of this inhibitory effect in vivo was a function of tumor burden and dose of IFN-alpha. In parallel experiments, LAK cells reduced the tumorigenicity of a lymphoblastoid cell line derived from the peripheral blood of a patient with PTLD, and prolonged the survival of SCID-beige mice with established lymphoproliferative disease. In contrast with two prior studies, in which the use of autologous cytotoxic T cells was found to be necessary, we found the administration of third-party non-HLA-matched LAK cells also to be effective in reducing tumor burden.

CONCLUSIONS

These observations demonstrate the efficacy of immunotherapy for lymphoproliferative disease under controlled experimental conditions, and validate currently ongoing efforts exploring the utility of such therapy in the clinical setting.

Induction of interleukin-1 and glucocorticoid hormones by HIV promotes viral replication and links human chromosome 2 to AIDS pathogenesis: genetic mechanisms and therapeutic implications

Human immunodeficiency virus may regulate its replication by stimulating the synthesis of interleukin-1. Interleukin-1, in turn, has the ability to stimulate the human immunodeficiency virus enhancer region. The human genes responsible for interleukin-1 and interleukin-1 receptor antagonist synthesis are located on the long arm of chromosome 2. Coincidentally, the trans-activation responsive ribonucleic acid element in the R region of the long terminal repeat of human immunodeficiency virus-1 has been found to interact directly with a factor present on the long arm of chromosome 2 to facilitate transactivation by the human immunodeficiency virus Tat protein. The human CD26 gene is also located on the long arm of chromosome 2. CD26 is a lymphocyte cell surface antigen that is stimulated by interleukin-1 and serves with CD4 as a coreceptor that interacts with the V3 loop in gp120 of human immunodeficiency virus. The human immunodeficiency virus-induced interleukin-1 excess, thus, serves human immunodeficiency virus by enhancing replication, and by increasing human immunodeficiency virus infectivity via activation of CD26. IL-1 also adversely affects acquired immune deficiency syndrome-related Kaposi's sarcoma. Several genetic treatments for human immunodeficiency virus infection are proposed.

Fluorescence in situ hybridization identifies new chromosomal changes involving 3q27 in non-Hodgkin's lymphomas with BCL6/LAZ3 rearrangement

Twelve B-cell non-Hodgkin's lymphomas with BCL6/LAZ3 rearrangement selected from a series of 30 lymphomas with cytogenetically detectable 3qter abnormalities were characterized at the histological, clinical, and cytogenetic levels, including fluorescence in situ hybridization (FISH) analysis, which was performed in all cases but one. A classical t(3;14) and t(3;22) were found in three patients (25%). In the remaining cases, eleven different 3q27 abnormalities were demonstrated and characterized with the use of chromosome painting. Seven of twelve "variant" rearrangements identified in our series affecting 1p32, 1p34, 3p14, 6q23, 12p13, 14q11, and 16p13 have not been reported before. Moreover, involvement of both homologs of chromosome 3 in distinct translocations was detected as an unexpected result in two cases and was confirmed via FISH in a third case. The putative bichromosomal rearrangements of the 3q27 region were evidenced by Southern analysis in one of these cases. In another case, FISH with a cosmid spanning the 3q27 breakpoint region demonstrated the involvement of BCL6/LAZ3 only in one of two t(3q27). In our series, which was selected on cytogenetic and molecular criteria, 50% (6 of 12) of cases with BCL6/LAZ3 rearrangement were diagnosed as diffuse, large B-cell lymphomas (DLCL). Another 33% (4 of 12) of cases were diagnosed as follicular center lymphomas (FL), with t(14;18)/BCL2 rearrangement in all but one case. Furthermore, in three follicular lymphoma cases in which multiple samples were analyzed, the disease showed no evidence of histological progression during a follow-up period of 3-14 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Epstein-Barr virus-associated post-transplant non-Hodgkin's lymphoma: establishment and characterization of a new cell line

A new human lymphoma cell line derived from pulmonary non-Hodgkin's lymphoma that developed in a renal transplant recipient was established from the patient's pleural effusion and designated PTLC-1. PTLC-1 grew aggressively in suspension, forming very loose clumps with a doubling time of about 18.9 h. The morphological, chromosomal, and immunophenotypic characteristics of the patient's tumor cells and PTLC-1 cells were very similar. PTLC-1 showed a monoclonal rearrangement of IgH gene and was highly tumorigenic in athymic nude mice. In situ hybridization, Southern blot hybridization and polymerase chain reaction demonstrated the presence of Epstein-Barr virus (EBV) genome in the patient's tumor and PTLC-1. PTLC-1 has been maintained in culture for over 60 months. Since EBV has been implicated in the pathogenesis of post-transplant lymphoma, this new cell line should serve as a useful experimental model for studying the etiology and biology of lymphoma developing in organ transplant recipients.

Variant translocation of the BCL6 gene to immunoglobulin kappa light chain gene in B-cell lymphoma

A lymphoma cell line with a variant type of translocation, t(2;3)(p11;q27), was established from a patient who had received liver transplantation. To elucidate the molecular mechanism of the t(2;3)(p11;q27) chromosomal translocation, we compared the structures of both derivative (der) chromosomal breakpoints with those of their germline predecessors. We noted that the BCL6 gene on chromosome 3 was juxtaposed with the immunoglobulin kappa light chain (Ig kappa) gene on chromosome 2 in a head-to-head configuration. The breakpoint of the BCL6 gene was within a previously reported breakpoint cluster region. The breakpoint on chromosome 2 was within the intron between the leader (L) and variable (V) sequences of one of the V kappa genes, which was fused to the J kappa 3 (J = joining) segment. At chromosomal junctures, a direct repeat duplication of chromosome 3 sequences and a deletion of chromosome 2 sequences were discovered. These results are consistent with a translocation model with illegitimate pairing of staggered double-stranded DNA breaks at 3q27 and 2p11, repair, and ligation to generate der(3) and der(2) chromosomes.