Search for HHV-8 associated diseases reservoir and spread paths of HHV-8 in Russia

Summarized in the paper are study results of human herpesvirus type 8 (HHV-8) and of its association with Kaposi's sarcoma (KS). The data obtained denotes that the share of individuals producing the antibodies to HHV-8 in a majority of studied patients was low and ranged form 0 to 5.5%, which is indicative of a low degree of the virus spread in population. At the same time, a high share of persons with antibodies to HHV-8 was detected among HIV-infected homosexuals (71.4%), kidney recipients (26.0%) and among AIDS-KS patients (78.6%). It was also unexpectedly high among patients with T- and B-cell lymphomas (50%), encephalopathy (27.3%) and with stomach cancer (41.8%): the appropriate parameters were 7-12-fold higher versus healthy subjects. The HHV-8 markers, i.e. virus specific antibodies and/or nucleotide sequences of the virus, were detected in blood serum and ejaculate of a significant number of patients with different pathologies of the prostate. Such detection of viral markers in the above categories of patients is suggestive of that sexual contacts with such patients are decisive for the HHV-8 spread in population.     

HHV-8 infection in African children

Human herpesvirus 8 (HHV-8) is prevalent in Africa and parts of southern Europe, but less common elsewhere. It is analogous to its distant relative, the Epstein-Barr virus, in that it rarely causes disease in the immunocompetent host but is highly oncogenic when associated with immunosuppression or HIV-1 infection. HHV-8 infection is endemic in sub-Saharan Africa, where high seroprevalence rates of up to 58% in young children were found in Ghana, Tanzania, Cameroon, Uganda and Egypt. Paediatric HHV-8 transmission has been studied in various African populations. Frequent detection of the virus from oral secretions suggests the horizontal route is the most common way to acquire the virus during childhood. A clinical presentation characterized by a self-limited maculopapular rash and fever was associated with HHV-8 primary infection in Egyptian children.     

Antiviral agents active against human herpesviruses HHV-6, HHV-7 and HHV-8

A series of antiviral compounds were examined for their activity against human herpesvirus type 6 (HHV-6), type 7 (HHV-7) and type 8 (HHV-8). They were selected either because they are already approved for clinical use in the treatment of herpesvirus infections (acyclovir, valaciclovir, penciclovir, famciclovir, ganciclovir, brivudin, foscarnet and cidofovir) or have demonstrated marked activity against herpesviruses (lobucavir, H2G, A‒5021, D /L -cyclohexenyl G and S2242). In view of their host cell specificity, different cells and assays had to be used for determining antiviral activity against these three viruses. The most potent compounds with the highest antiviral selectivity index were: (i) for HHV-6; foscarnet, S2242, A-5021 and cidofovir; (ii) for HHV-7; S2242, cidofovir and foscarnet; and (iii) for HHV-8; S2242, cidofovir and ganciclovir. As mycophenolic acid has been shown to enhance significantly the activity of acyclic guanosine analogues (such as acyclovir, penciclovir and ganciclovir) in vitro against HSV-1, HSV-2, VZV and HCMV, it would seem worth evaluating whether mycophenolic acid also potentiates the activity of these acyclic guanosine analogues against HHV-6, -7 and -8. Copyright © 2001 John Wiley & Sons, Ltd.     

HHV-8 and multiple myeloma

Recently, a new member of the gamma-herpesvirus family, human herpesvirus 8 (HHV-8), was identified in a case of Kaposi's sarcoma. This virus has also been found in the nonmalignant dendritic cells of the bone marrow from myeloma patients. In addition, HHV-8 is also detectable in the peripheral blood of most patients although its absence suggests earlier stage disease. By contrast, this virus is undetectable in the blood of family members and sexual partners of myeloma patients. Sequencing of HHV-8 open reading frames from myeloma patients show interpatient differences as well as consistent differences in the myeloma samples compared to HHV-8 in other malignancies associated with HHV-8 infection. Consistent expression of both the viral homologues of interferon regulatory factor and IL-8 receptor suggest a possible role for these transforming viral genes in the pathogenesis of myeloma. The latter gene is known to induce angiogenesis and preliminary studies show the abundance of vascular endothelial cells in the bone marrow of myeloma patients.     

Detection of human herpesviruses HHV-6, HHV-7 and HHV-8 in whole blood by real-time PCR using the new CMV, HHV-6, 7, 8 R-gene kit

Human herpesviruses 6 (HHV-6), 7 (HHV-7) and 8 (HHV-8) are lymphotropic herpesviruses that may cause opportunistic diseases in immunosuppressed patients such as transplant or AIDS patients. The new commercial CMV HHV-6, 7, 8 R-gene kit (Argene, Varilhes, France) for the simultaneous quantitation of HHV-6 and qualitative detection of HHV-7 and HHV-8 was evaluated using whole blood samples (respectively, n=175, 100 and 161) and using different extraction and real-time PCR platforms in two Centers A and B. In comparison with HHV-6 in-house real-time PCR the commercial kit showed agreements of 96% (n=75) and 85% (n=100) in A and B, respectively, with significant Spearman's correlation between both techniques (in A: r=0.97 [p<0.001]; in B: r=0.70 [p<0.001]). The Bland-Altman test results and prospective monitoring of patients confirmed the accuracy of these HHV-6 real-time PCR techniques. The agreement between the in-house HHV-7 PCR and commercial kit was of 86% (n=100). In comparison with in-house HHV-8 real-time PCRs, the commercial kit showed agreements of 100% (n=61) and 93.7% (n=96) in A and B, respectively. These results demonstrate that the new commercial CMV HHV-6, 7, 8 R-gene kit was an efficient and reliable tool for the diagnosis of herpesvirus 6, 7, 8 infections.     

Prevalence of HHV-8 in systemic autoimmune diseases

BackgroundEpidemiological data suggest that some viruses may be linked to the development of autoimmunity.ObjectivesThe objective of this work was to determine the presence of HHV-8 viral DNA in whole blood from patients suffering from different systemic autoimmune diseases (SAD). We also aimed at testing the prevalence of patients showing antibodies against an HHV-8 orfK8.1 peptide.Study designTwo hundred and eighty SAD patients and 50 healthy blood donor controls were included. Molecular analyses were performed by nested PCR from DNA obtained from whole blood and an enzyme immunoassay was developed in order to test for the presence of antibodies directed against a synthetic peptide derived from the HHV-8 orfK8.1 protein.ResultsOnly 2 out of the 280 samples analyzed yielded the specific HHV-8 PCR product. Antibodies against orfK8.1 were detected in 2 SLE patients, 1 patient suffering from Sjögren's syndrome and 2 patients with vasculitis.ConclusionsWe conclude that HHV-8 is usually not present in blood neither from autoimmune patients nor from healthy controls. Furthermore, HHV-8 antibodies against the HHV-8 orfK8.1 peptide were rarely detected. It leads us to infer that HHV-8 is not involved on the development of these disorders. It does not rule out the possibility that other environmental and microbiological triggers may account for their etiopathogenesis.     

HHV-8 infection and multiple myeloma.

Human herpes virus 8 (HHV-8) also known as Kaposi's sarcoma-associated herpes virus has been strongly implicated in the pathogenesis of Kaposi's sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease. Recently, this gamma-herpes virus was also found in the nonmalignant bone marrow dendritic cells of the majority of myeloma patients. In addition, HHV-8 is also detectable in the peripheral blood of most myeloma patients. In contrast, this virus is rarely detected in close contacts of myeloma patients or healthy subjects. Furthermore, only about one-third of patients with monoclonal gammopathy of undetermined significance (MGUS) are infected with HHV-8. Sequencing of HHV-8 DNA isolated from myeloma patients shows both interpatient differences and conserved differences unique to myeloma compared to HHV-8 in other malignancies. Consistent expression of both the viral homologs of interferon regulatory factor and interleukin-8 receptor in myeloma suggests a possible role for these transforming viral genes in the pathogenesis of this disease.     

Localisation of HHV-8 in AIDS related lymphadenopathy.

BACKGROUND: Many lymph node abnormalities have been described in AIDS. These include opportunistic infections that sometimes result in spindle cell pseudotumours, Kaposi's sarcoma (KS), malignant lymphoma (Hodgkin's and non-Hodgkin's), and florid reactive hyperplasia. Among these, reactive hyperplasia is the most common manifestation of AIDS related lymphadenopathy. AIM: To examine whether human herpesvirus 8 (HHV-8), the aetiological agent of KS, can be localised in AIDS related lymphadenopathy and whether its appearance in such nodes is predictive of Kaposi's sarcoma development. METHODS: A series of human immunodeficiency virus (HIV) positive men (n = 21) with AIDS related lymphadenopathy who at the time of presentation had KS or subsequently developed KS (n = 5) were examined. The prevalence of HHV-8 was assessed in these patients using solution phase polymerase chain reaction (PCR), real time TaqMan quantitative PCR, and in cell amplification techniques (PCR in situ hybridisation (PCR-ISH) and labelled primer driven in cell amplification). RESULTS: Using standard solution phase PCR in a nested format, only two of the 21 patients with AIDS related lymphadenopathy were positive for HHV-8. The lymph node of one of these patients contained KS lesions. Three HHV-8 positive patients were identified using TaqMan PCR (the original two positive patients and one additional patient). All of the positive patients either subsequently developed KS (n = 2) or had KS at the time of diagnosis (n = 1). Two additional patients subsequently developed KS, but were negative for HHV-8 by solution phase PCR and TaqMan PCR. Using PCR-ISH, HHV-8 amplicons were identified in some lymphoid cells (in one patient) and in spindle cells of the KS lesion in another. The positive lymphoid cells were predominantly concentrated in B cell areas of the affected lymph nodes, confirming the B cell tropism exhibited by HHV-8. CONCLUSIONS: The presence of HHV-8 in AIDS related lymphadenopathy is predictive of KS development and probably represents seeding of HHV-8 infected B cells from the peripheral blood. These findings support a role for HHV-8 in the pathobiology of KS.     

Expression of human herpesvirus 8 (HHV-8)-encoded immediate early protein, open reading frame 50, in HHV-8-associated diseases.

OBJECTIVES: To investigate the expression of the open reading frame (ORF) 50 protein, a human herpesvirus 8 (HHV-8)-encoded immediate early protein, in HHV-8-associated diseases. STUDY DESIGN/METHODS: We developed a rabbit anti-ORF50 protein polyclonal antibody, and investigated the ORF50 protein expression by immunohistochemistry using primary effusion lymphoma (PEL) cell lines and tissue sections of Kaposi's sarcoma (KS), HHV-8-associated solid lymphoma, and multicentric Castleman's disease (MCD). RESULTS: Western blot analysis revealed that this antibody reacted with a 110-kd protein in the lysate of phorbolester-stimulated HHV-8-infected PEL cell lines. Immunohistochemistry revealed that a very small population of cells expressed the ORF50 protein in KS and HHV-8-associated solid lymphoma cells, and almost all these cells expressed HHV-8-encoded latency-associated nuclear antigen. The ORF50 protein expression was also rare in the cells of PEL cell lines, and the staining pattern was diffuse or dot-like in the nuclei, overlapping partially with that of promyelocytic leukemia protein. In MCD, however, the ORF50 protein was expressed in some cells of the mantle zone of the lymphoid follicle. CONCLUSIONS: The ORF50 protein expression in vivo was considerably rare in KS, HHV-8-associated solid lymphoma, and PEL, but was more frequent in MCD. Rare expression of this transactivator protein in HHV-8-associated malignancies causes low expression levels of other lytic proteins and may play a role in the maintenance of the latent infection. This is the first report describing the expression of an immediate early protein of HHV-8 in cases of HHV-8-associated diseases.     

Assessment of a combined testing strategy for detection of antibodies to human herpesvirus 8 (HHV-8) in persons with Kaposi's sarcoma,persons with asymptomatic HHV-8 infection,and persons at low risk for HHV-8 infection

The performance of a human herpesvirus 8 (HHV-8) enzyme immunoassay (EIA) and selective subsequent use of an HHV-8 immunofluorescence assay (IFA) was tested in persons unlikely to be infected with HHV-8 and those who had HHV-8 detected in their saliva. The IFA was performed on samples within a range of EIA optical densities (0.15 to 0.35) where there was considerable overlap between HHV-8-infected and uninfected individuals. The sensitivity of the testing strategy was 88%, with a specificity of 97%.     

Absence of HHV-8 DNA sequences in malignant mesothelioma.

Human herpesvirus 8 (HHV-8) associated primary effusion lymphomas arise and grow in the body cavities as effusions, but it is not known whether the lining of body cavities and mesothelium derived malignancies are potential targets of HHV-8 infection. We examined a series of 13 diffuse malignant mesotheliomas and four mesothelial cell rich effusion samples of non-neoplastic aetiology from non-immunodepressed patients using the polymerase chain reaction to detect HHV-8 specific sequences. HHV-8 amplification products were absent in diffuse malignant mesotheliomas and in non-neoplastic effusions samples. These results suggest that HHV-8 has a selective tropism among body cavity based tumours, being confined to primary effusion lymphomas.     

Prevalence trend and correlates of HHV-8 infection in HIV-infected patients

To assess the circulation of human herpesvirus (HHV)-8 infection over the years, two seroprevalence surveys were conducted, which tested sera from HIV-infected individuals recruited 10 years apart (206 individuals from 1986 to 1988 and 177 individuals from 1997 to 1998). For all patients, antibodies to hepatitis C virus (HCV), hepatitis B virus (HBV), and HHV-8 lytic and latent antigens were evaluated.HHV-8 seroprevalence was higher among individuals recruited in the 1990s (31.6% for anti-lytic, 8.5% for anti-latent antibodies) compared with similar findings in those seen in the late 1980s (14.6% and 3.4% for anti-lytic and anti-latent antibodies, respectively), with a twofold increase of the risk of HHV-8 infection. However, the increase was observed only among injecting drug users, whereas seroprevalence tended to slightly increase among those infected by sexual contact. At univariate analysis, time of recruitment and being homosexual men were factors associated with HHV-8 infection, an association that remained after adjusting for age. HBV infection was significantly associated with HHV-8 infection (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.3-3.6), whereas those infected with HCV had a lower probability of having HHV-8 antibodies (OR, 0.3; 95% CI, 0.20-0.6). After controlling for age and gender, time of recruitment remained independently associated with HHV-8 infection among injecting drug users.In conclusion, HHV-8 seroprevalence appears to be increased during 10 years among HIV-infected injection drug users but not among homosexual men, who remain those at the highest risk of infection.     

Lymphotropic herpes virus (EBV, HHV-6, HHV-8) DNA sequences in HIV negative Castleman''s disease

Aim—To evaluate the possible involvement of lymphotropic herpes viruses in Castleman's disease.     

Proliferation in HHV-8-positive primary effusion lymphomas is associated with expression of HHV-8 cyclin but independent of p27(kip1)

Primary effusion lymphoma (PEL) develops in immunodeficient patients, selectively localizes to the serous body cavities, and harbors infection by human herpesvirus type-8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus. HHV-8 encodes a viral (v)-cyclin homologous to cellular D-type cyclins, a class of positive cell-cycle regulators that are physiologically modulated by the p27(Kip1) cell cycle inhibitor. The aims of the present study were: 1) to establish the expression pattern of p27(Kip1) in PEL; and 2) to address the relationship between p27(Kip1) expression, proliferation index, and expression of cellular cyclin D1 and v-cyclin in PEL. Expression of p27(Kip1) was detected in all (n = 18) PEL samples analyzed by both immunocytochemistry and Western blot. All PELs displayed a high proliferation index as assessed by Ki-67 staining. Expression of cellular cyclin D1 was absent in all PELs tested, which conversely expressed (14 out of 14 samples) v-cyclin by immunocytochemistry and/or Western blot. In contrast to PELs, HHV-8-negative lymphomatous effusions secondary to a tissue-based lymphoma generally failed to express p27(Kip1). Overall, these data show that PELs consistently express p27(Kip1) protein despite the high proliferative rate of the lymphoma clone, suggesting that p27(Kip1) may be unable to drive cell-cycle arrest in PEL cells. The co-existence of p27(Kip1) expression and high proliferative index is a selective feature of PEL among lymphomas involving the serous body cavities, because lymphomatous effusions secondary to a tissue-based lymphoma generally display the inverse relationship between p27(Kip1) positivity and growth fraction observed in normal lymphoid tissues and in most other lymphomas. Expression of p27(Kip1) in PEL associates with expression of HHV-8 v-cyclin, but not of cellular cyclin D1. The fact that HHV-8 v-cyclin is resistant to p27(Kip1)-modulated inhibition, whereas cellular cyclin D1 is sensitive, may explain, at least in part, the co-existence of p27(Kip1) expression and high proliferative index observed in PEL.