Addressing controversies over Kaposi's sarcoma.
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Animals↗
Biomedical subjects
C Boshoff
Publications and source records attributed to C Boshoff.
KSHV-encoded CC chemokine vMIP-III is a CCR4 agonist, stimulates angiogenesis, and selectively chemoattracts TH2 cells.
Kaposi's sarcoma-associated herpesvirus (KSHV) encodes 3 genes that are homologous to cellular chemokines. vMIP-III, the product of open reading frame K4.1, is the most distantly related to human chemokines and has yet to be characterized. We have examined the interaction of vMIP-III with chemokine receptors, its expression in KS lesions, and its in ovo angiogenic properties. We show expression of vMIP-III in KS lesions and demonstrate the stimulation of angiogenesis by this chemokine, like vMIP-I and vMIP-II, in the chick chorioallantoic membrane assay. vMIP-III does not block human immunodeficiency virus entry through the coreceptors CCR3, CCR5, or CXCR4. However, vMIP-III is an agonist for the cellular chemokine receptor CCR4. CCR4 is expressed by TH2-type T cells. Consistent with this, vMIP-III preferentially chemoattracts this cell type. Because of these biologic properties and because it is expressed in KS lesions, vMIP-III may play an important role in the pathobiology of KS. (Blood. 2000;95:1151-1157)
Allantois↗
HHV-8 is associated with a plasmablastic variant of Castleman disease that is linked to HHV-8-positive plasmablastic lymphoma.
Castleman disease (CD) is a lymphoproliferative disorder of unknown etiology that is associated with the development of secondary tumors, including B-cell lymphoma. Human herpesvirus 8 (HHV-8) (Kaposi's sarcoma-associated herpesvirus) sequences have been described in some cases of multicentric Castleman disease (MCD). Using a monoclonal antibody against an HHV-8-latent nuclear antigen, we show that HHV-8 is specifically associated with a variant of MCD in which HHV-8-positive plasmablasts that show lambda light-chain restriction localize in the mantle zone of B-cell follicles and coalesce to form microscopic lymphomas in some cases. Furthermore, we show that the frank plasmablastic lymphoma that develops in patients with this plasmablastic variant of MCD is also positive for HHV-8 and lambda light chain. Plasmablastic lymphoma associated with MCD is a new disease entity associated with HHV-8 infection. (Blood. 2000;95:1406-1412)
Adolescent↗
The latent nuclear antigen of Kaposi sarcoma-associated herpesvirus targets the retinoblastoma-E2F pathway and with the oncogene Hras transforms primary rat cells.
Kaposi sarcoma-associated herpesvirus (KSHV) is involved in the etiopathogenesis of Kaposi sar-coma and certain lymphoproliferative disorders. Open reading frame (ORF) 73 encodes the main immunogenic latent nuclear antigen (LNA-1) of KSHV. LNA-1 maintains the KSHV episome and tethers the viral genome to chromatin during mitosis. In addition, LNA-1 interacts with p53 and represses its transcriptional activity. Here we show that LNA-1 also interacts with the retinoblastoma protein. LNA-1 transactivated an artificial promoter carrying the cell cycle transcription factor E2F DNA-binding sequences and also upregulated the cyclin E (CCNEI) promoter, but not the B-myb (MYBL2) promoter. LNA-1 overcame the flat-cell phenotype induced by retinoblastoma protein in Saos2 cells. In cooperation with the cellular oncogene Harvey rat sarcoma viral oncogene homolog (Hras), LNA-1 transformed primary rat embryo fibroblasts and rendered them tumorigenic. These findings indicate that LNA-1 acts as a transcription co-factor and may contribute to KSHV-induced oncogenesis by targeting the retinoblastoma protein-E2F transcriptional regulatory pathway.
Animals↗
Detection of antibodies to human herpesvirus 8 in Italian children: evidence for horizontal transmission.
Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma associated herpesvirus (KSHV), has been shown to be the causative agent for Kaposi's sarcoma (KS) and to be more prevalent in populations or risk groups at increased risk for KS. HHV-8 infection is rare in children from the US and the UK, but has been reported in African children. In this study we examine HHV-8 infection in children from Italy, a country with an elevated prevalence of HHV-8 in adults and high socio-economic conditions.
Adolescent↗
Continuous low dose Thalidomide: a phase II study in advanced melanoma, renal cell, ovarian and breast cancer.
To grow and metastasize, solid tumours must develop their own blood supply by neo-angiogenesis. Thalidomide inhibits the processing of mRNA encoding peptide molecules including tumour necrosis factor-alpha (TNF-alpha) and the angiogenic factor vascular endothelial growth factor (VEGF). This study investigated the use of continuous low dose Thalidomide in patients with a variety of advanced malignancies. Sixty-six patients (37 women and 29 men; median age, 48 years; range 33-62 years) with advanced measurable cancer (19 ovarian, 18 renal, 17 melanoma, 12 breast cancer) received Thalidomide 100 mg orally every night until disease progression or unacceptable toxicity was encountered. Three of 18 patients with renal cancer showed partial responses and a further three patients experienced stabilization of their disease for up to 6 months. Although no objective responses were seen in the other tumour types, there were significant improvements in patients' sleeping (P < 0.05) and maintained appetite (P < 0.05). Serum and urine concentrations of basic fibroblast growth factor (bFGF), TNF-alpha and VEGF were measured during treatment and higher levels were associated with progressive disease. Thalidomide was well tolerated: Two patients developed WHO Grade 2 peripheral neuropathy and eight patients developed WHO grade 2 lethargy. No patients developed WHO grade 3 or 4 toxicity. Further studies evaluating the use of Thalidomide at higher doses as a single agent for advanced renal cancer and in combination with biochemotherapy regimens are warranted.
Adult↗
Kaposi's sarcoma-associated herpesvirus: from cell biology to pathogenesis.
Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8) is linked to the etiopathogenesis of Kaposi's sarcoma, a plasma-blastic variant of Castleman's disease and primary effusion lymphoma. KSHV is related to a number of non-human primate viruses. Only a limited number of KSHV proteins are expressed in tumor cells. Here we discuss the putative role of these proteins in KSHV pathogenesis.
Castleman Disease↗
Seroprevalence of human herpesvirus 8 and its association with Kaposi sarcoma in Brazil.
BACKGROUND: Epidemiologic studies have indicated that human herpesvirus 8 is implicated in the development of Kaposi sarcoma in different geographic areas worldwide. GOAL: To provide information on the prevalence of human herpesvirus 8 in Brazil and its association with Kaposi sarcoma. STUDY DESIGN: An immunofluorescence assay was performed to test 1,044 serum samples from 747 blood donors, 73 patients presenting to casualty departments, and 224 patients attending sexually transmitted disease/AIDS clinics. The sexually transmitted disease group was composed of 88 patients with HIV (40 Kaposi sarcoma positive, 48 Kaposi sarcoma negative) and 136 patients without HIV. RESULTS: Antibodies to human herpesvirus 8-latent nuclear antigens were found in 34 blood donors (4.6%), and in seven casualty patients (9.6%). The highest frequency of human herpesvirus 8 antibodies was found in the sexually transmitted disease group: 32 HIV-positive patients with Kaposi sarcoma (80%) and seven patients without Kaposi sarcoma (14.6%). CONCLUSION: The presence of human herpesvirus 8 in patients with HIV was strongly associated with Kaposi sarcoma (odds ratio, 23.4; 95% CI, 7.7-71.4), male gender, homosexual or bisexual orientation, and hepatitis B virus infection, but not with the other sexually transmitted diseases that were investigated.
Adult↗
Early peripheral lymph node involvement of human herpesvirus 8-associated, body cavity-based lymphoma in a human immunodeficiency virus-negative patient.
Human herpesvirus 8 (HHV-8), or Kaposi sarcoma-associated herpesvirus, is a gamma herpesvirus first detected in a specimen of Kaposi sarcoma from a human immunodeficiency virus (HIV)-positive patient. Human herpesvirus 8 is also found in an unusual clinicopathologic form of body cavity-based B-cell lymphoma, which has been named primary effusion lymphoma (PEL) and occurs primarily in HIV-positive patients. PEL is characterized by the formation of lymphomatous effusions, without obvious lymphadenopathy, tumor masses, or bone marrow involvement. Only a few cases of PEL in HIV-seronegative patients have been reported. We describe a case of an HHV-8-associated lymphoma, with ascites, pleural effusion, and axillary lymphadenopathy in an HIV-negative patient. The patient was a 68-year-old Jewish man of North African extraction, with a previous history of coronary bypass surgery and multiple blood transfusions. The pleural fluid contained large atypical lymphoid cells and was suggestive of lymphoma but could not provide a conclusive diagnosis of PEL. The lymph node contained groups of large anaplastic lymphoid cells. Polymerase chain reaction for HHV-8 performed on the lymph node specimen was positive, establishing the diagnosis of PEL. Polymerase chain reaction for Epstein-Barr virus was negative. Results of a gallium scan were normal. The patient did not respond to combination chemotherapy with cyclophosphamide, doxorubicin, vincristine sulfate, and prednisone and progressively developed, massive intra-abdominal solid tumor formation. To our knowledge, this is the first report of a case of PEL that demonstrates peripheral lymph node involvement at diagnosis and the first report of PEL in an Israeli patient.
Aged↗
Comparison of a maedi-visna virus CA-TM fusion protein ELISA with other assays for detecting sheep infected with North American ovine lentivirus strains.
A maedi-visna virus CA-TM fusion protein ELISA (MVV ELISA) was evaluated for the detection of antibody in sheep infected with North American ovine lentivirus (OvLV). The results of the MVV ELISA were compared with other assays for OvLV antibody and with viral infection in an intensively studied group of 38 sheep with a high prevalence of OvLV infection and disease. The sensitivity, specificity, and concordance of assays for OvLV antibody (MVV ELISA, indirect ELISA, Western blot, and AGID), virus (virus isolation, PCR, antigen ELISA), and OvLV-induced disease in each animal were compared with OvLV infection status as defined by a positive result in two or more of the assays. Five sheep met the criteria for absence of OvLV infection. The sensitivity of the MVV ELISA in detecting OvLV infected sheep was 64%, whereas the sensitivity of the other three tests for antibody ranged from 85 to 94%. All the antibody assays were 100% specific in this group of animals. Of the assays for virus, the PCR test had the highest sensitivity and the best concordance with OvLV infection, but it also had the lowest specificity of any of the virus or antibody assays. Among the antibody tests, the concordance of the MVV ELISA compared most favorably with the AGID test for detecting OvLV-infected sheep. Analysis of serum samples from 28 lambs experimentally-infected with one of three North American strains of OvLV suggested that there were no significant strain differences detectable by antibody assay. Twenty virus-inoculated lambs were positive by both the MVV ELISA and the AGID test, five lambs were MVV ELISA negative and AGID test positive, and three lambs were MVV ELISA positive and AGID test negative. No pre-inoculation samples were positive by either assay. In a longitudinal study involving seven lambs, antibodies to OvLV were detected by AGID 3-5 weeks post-inoculation, but were not detected by MVV ELISA until 5-10 weeks post-inoculation. Among 128 naturally and experimentally-infected sheep that were seropositive in the AGID test, the overall sensitivity of the MVV ELISA was higher in the naturally infected sheep (84%) than in the experimentally infected sheep (69%). The data indicated that the MVV ELISA represents a less sensitive, but specific alternative for the detection of OvLV antibodies.
Animals↗
Antibodies against human herpesvirus 8 in black South African patients with cancer.
BACKGROUND: Infection with human herpesvirus 8 (HHV-8) has been consistently linked to Kaposi's sarcoma, but its mode of transmission, association with other cancers, and interaction with the human immunodeficiency virus type 1 (HIV-1) are largely unknown. METHODS: Between January 1992 and December 1997, we interviewed 3591 black patients with cancer in Johannesburg and Soweto, South Africa. Blood was tested for antibodies against HIV-1 and HHV-8 in 3344 of the patients. Antibodies against HHV-8 were detected with an indirect immunofluorescence assay. The intensity of the fluorescent signal correlated well with the titers of antibodies (P<0.001). The relations among the presence of anti-HHV-8 antibodies, sociodemographic and behavioral factors, type of cancer, and the presence or absence of coexistent HIV infection were examined with the use of unconditional logistic-regression models. RESULTS: Among the 3293 subjects with cancers other than Kaposi's sarcoma, the standardized seroprevalence of antibodies against HHV-8 was 32 percent, which did not differ significantly from the standardized seroprevalence among black blood donors. Among these 3293 patients, the prevalence of antibodies against HHV-8 increased with increasing age (P<0.001) and an increasing number of sexual partners (P=0.05) and decreased with increasing years of education (P=0.007); it was not strongly associated with HIV-1 infection. Anti-HHV-8 antibodies were more frequent among black than white blood donors (P<0.001). Among the 51 patients with Kaposi's sarcoma, the standardized seroprevalence of antibodies against HHV-8 was 83 percent, significantly higher than the prevalence among those without Kaposi's sarcoma (P<0.001). For 16 other specific types of cancer, including multiple myeloma (108 cases) and prostate cancer (202 cases), the variation in the standardized seroprevalence of antibodies against HHV-8 was not remarkable. At a given intensity of fluorescence of anti-HHV-8 antibodies, Kaposi's sarcoma was more frequent among HIV-1-positive patients than among those who were HIV-1-negative (P<0.001). CONCLUSIONS: Among black patients with cancer in South Africa, the seroprevalence of anti-HHV-8 antibodies is high and is specifically associated with Kaposi's sarcoma, particularly at high titers.
Adolescent↗
Increasing probability of mother-to-child transmission of HHV-8 with increasing maternal antibody titer for HHV-8.
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Adolescent↗
Transcriptional analysis of human herpesvirus-8 open reading frames 71, 72, 73, K14, and 74 in a primary effusion lymphoma cell line.
We examined the transcription and splicing of open reading frames (ORFs) 71 (K13)-74 of human herpesvirus-8 (HHV-8) in the primary effusion lymphoma cell line BCP-1 (latently infected with HHV-8), using a combination of NORTHERN blot analysis, RT-PCR, and rapid amplification of cDNA ends (PCR-RACE). The three genes encoded by ORFs 71, 72, and 73 [viral FLICE inhibitory protein (v-FLIP), v-cyclin, latent nuclear antigen (LNA)] are transcribed from a common transcription start site in BCP-1 cells uninduced (latent) or induced (lytic) with n-butyrate. The resulting transcript is spliced to yield a 5.32-kb message encoding LNA, v-cyclin, and v-FLIP and a 1.7-kb bicistronic message encoding v-cyclin and v-FLIP. The two genes encoded by ORFs K14 and 74 (v-Ox2 and v-GPCR) are transcribed as a 2.7-kb bicistronic transcript that is induced with n-butyrate. A small (149-bp) intron is spliced from the intragenic noncoding region immediately before the v-GPCR initiating codon. Examination of sequence elements in the promoter of the LNA/v-cyclin/v-FLIP operon revealed TAATGARAT and Octamer binding motifs characteristic of herpesvirus immediate-early genes. Sequence elements in the v-Ox2/v-GPCR promoter included AP1 and Zta-like (EBV Zebra transactivator) binding motifs consistent with the n-butyrate induction of this operon.
Base Sequence↗
Distribution of human herpesvirus-8 latently infected cells in Kaposi's sarcoma, multicentric Castleman's disease, and primary effusion lymphoma.
Human herpesvirus 8 (HHV-8, also called KSHV) is linked to the etiopathogenesis of Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL). The universal presence of HHV-8 in early KS has not yet been shown. We used a mAb (LN53) against latent nuclear antigen-1 (LNA-1) of HHV-8 encoded by ORF73 to study the distribution of the cell types latently infected by HHV-8 in patch, plaque, and nodular KS, MCD, and PEL. In early KS, HHV-8 is present in <10% of cells forming the walls of ectatic vessels. In nodular KS, HHV-8 is present in cells surrounding slit-like vessels and in >90% of spindle cells, but not in normal vascular endothelium. In addition, HHV-8 colocalizes with vascular endothelial growth factor receptor-3 (VEGFR-3), a marker of lymphatic and precursor endothelium. In early KS lesions, VEGFR-3 is more extensively expressed than LNA-1, indicating that HHV-8 is not inducing the proliferation of VEGFR-3-positive endothelium directly. In MCD, HHV-8 is present in mantle zone large immunoblastic B cells. No staining for LNA-1 is seen in samples from multiple myeloma, prostate cancer, and angiosarcoma, supporting the absence of any etiological link between these diseases and HHV-8.
Antigens, CD↗
Degradation of p27(Kip) cdk inhibitor triggered by Kaposi's sarcoma virus cyclin-cdk6 complex.
The Kaposi's sarcoma-associated human herpesvirus 8 (KSHV/HHV8) encodes a protein similar to cellular cyclins. This cyclin is most closely related to cellular D-type cyclins, but biochemically it behaves atypically in various respects. Complexes formed between the viral cyclin and the cyclin-dependent kinase subunit, cdk6, can phosphorylate a wider range of substrates and are resistant to cdk inhibitory proteins. We show here that the KSHV-cyclin-cdk6 complex phosphorylates p27(Kip) on a C-terminal threonine that is implicated in destabilization of this cdk inhibitor. Expression of the viral cyclin in tissue culture cells overcomes a cell cycle block by p27(Kip). However, full cell-cycle transit of these cells appears to depend on C-terminal phosphorylation of p27(Kip) and seems to involve transactivation of other cellular cyclin-dependent kinases. A p27(Kip)-phosphorylating cdk6 complex exists in cell lines derived from primary effusion lymphoma and in Kaposi's sarcoma, this indicating that virally induced p27(Kip) degradation may occur in KSHV-associated tumours.
Base Sequence↗
Seroprevalence of human herpesvirus-8 (HHV-8) in countries of Southeast Asia compared to the USA, the Caribbean and Africa.
Seroprevalence of HHV-8 has been studied in Malaysia, India, Sri Lanka, Thailand, Trinidad, Jamaica and the USA, in both healthy individuals and those infected with HIV. Seroprevalence was found to be low in these countries in both the healthy and the HIV-infected populations. This correlates with the fact that hardly any AIDS-related Kaposi's sarcoma has been reported in these countries. In contrast, the African countries of Ghana, Uganda and Zambia showed high seroprevalences in both healthy and HIV-infected populations. This suggests that human herpes virus-8 (HHV-8) may be either a recently introduced virus or one that has extremely low infectivity. Nasopharyngeal and oral carcinoma patients from Malaysia, Hong Kong and Sri Lanka who have very high EBV titres show that only 3/82 (3.7%) have antibody to HHV-8, demonstrating that there is little, if any, cross-reactivity between antibodies to these two gamma viruses.
Adolescent↗
Human herpesvirus 8: seroepidemiology among women and detection in the genital tract of seropositive women.
An indirect IFA to detect antibodies against latent nuclear antigens of human herpesvirus 8 (HHV-8) was used to determine the prevalence of HHV-8 antibodies in 169 women attending a sexually transmitted diseases clinic and a human immunodeficiency virus (HIV) clinic at a London hospital. Nested polymerase chain reaction was used to detect HHV-8 DNA in 93 blood samples and 89 cervical brush scrapes (CBS). Another 96 CBS from women attending a colposcopy clinic were also analyzed. The overall seroprevalence of HHV-8 was 18.3%. The seroprevalence was higher among women born in Africa (24.7%) than among women born elsewhere (11.5%; P=.06) and was independent of HIV serostatus. HHV-8 DNA was detected in 3 CBS and 6 peripheral blood samples from 11 HHV-8-seropositive women but not in CBS from 78 seronegative women, 96 women from the colposcopy clinic, or in blood samples from 82 seronegative women.
Africa↗