Detection of several types of human papilloma viruses in AIDS-associated Kaposi's sarcoma

Towards Better Understanding of KSHV Life Cycle: from Transcription and Posttranscriptional Regulations to Pathogenesis

Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8 (HHV-8), is etiologically linked to the development of Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. These malignancies often occur in immunosuppressed individuals, making KSHV infection-associated diseases an increasing global health concern with persistence of the AIDS epidemic. KSHV exhibits biphasic life cycles between latent and lytic infection and extensive transcriptional and posttranscriptional regulation of gene expression. As a member of the herpesvirus family, KSHV has evolved many strategies to evade the host immune response, which help the virus establish a successful lifelong infection. In this review, we summarize the current research status on the biology of latent and lytic viral infection, the regulation of viral life cycles and the related pathogenesis.

Presence of Betapapillomavirus in Kaposi sarcoma lesions

Human herpes virus 8 (HHV 8) is recognized as the necessary cause of Kaposi sarcoma (KS) and in the recent past the human papillomavirus (HPV) has been linked to the development of cutaneous basal cell and squamous cell carcinomas. In a cross sectional study investigating Beta-HPV infections in skin lesions, an unexpected occurrence of HPV DNA was found in KS lesions of HIV infected individuals. Of the 18 KS cases included in the study 16 (89%) had HPV DNA detected. The most common Betapapillomavirus types were HPV14 [15 cases (83.3%)], HPV12 [8 cases (44.4%)], and HPV24 [7 cases (39%)]. Multiple Beta-HPV types were detected in 10 (62.5%) of the participants with HPV DNA positive lesions; of these 7 had a CD4+ count below 350 cells/µl and 3 had CD4+ counts above 350 cells/µl. The presence of Beta-HPV DNA in KS lesions is a newly described phenomenon. Further studies to elucidate the role of Beta-HPV in KS need to be conducted as it is possible that HHV 8 may not be the solitary viral carcinogen in KS tumorigenesis.

Human herpesvirus 6 activates lytic cycle replication of Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is a gamma-herpesvirus consistently identified in Kaposi's sarcoma (KS), primary effusion lymphoma, and multicentric Castleman's disease. KSHV infection appears to be necessary, but not be sufficient for development of KS without other co-factors. However, factors that facilitate KSHV to cause KS have not been well defined. Because patients with KS are often immunosuppressed and susceptible to many infectious agents including human herpesvirus 6 (HHV-6), we investigated the potential of HHV-6 to influence the replication of KSHV. By co-culturing HHV-6-infected T cells with KSHV-latent BCBL-1 cell line, infecting BCBL-1 cells with HHV-6 virions, and generating heterokaryons between HHV-6-infected T cells and BCBL-1 cells, we showed that HHV-6 played a critical role in induction of KSHV replication, as determined by production of lytic phase mRNA transcripts and viral proteins. We confirmed and extended the results by using a luciferase reporter assay in which KSHV ORF50 promoter, the first promoter activated during KSHV replication, drove the luciferase expression. Besides HHV-6, we also found that cytokines such as interferon-gamma partially contributed to induction of KSHV replication in the co-culture system. These findings suggest that HHV-6 may participate in KS pathogenesis by promoting KSHV replication and increasing KSHV viral load.

Raf promotes human herpesvirus-8 (HHV-8/KSHV) infection

Human herpesvirus-8 (HHV-8/KSHV) is etiologically associated with Kaposi's sarcoma (KS) and other tumors. Constitutive activation of the mitogen-activated protein kinase (MAPK) signaling pathway has been associated with a variety of tumors, including AIDS-related KS. The oncoprotein Raf is situated at a pivotal position in regulating the MAPK pathway. Hence, we analysed the effect of oncoprotein Raf on HHV-8 infectious entry into target cells. Here we report Raf expression to significantly enhance HHV-8 infection of target cells. These findings implicate a role for Raf not only in the infectious entry of HHV-8 but also in modulating KS pathogenesis.

Establishment of proliferative cell nuclear antigen gene as an internal reference gene for polymerase chain reaction of a wide range of archival and fresh mammalian tissues

Polymerase chain reaction (PCR) from paraffin-embedded tissues provides a powerful tool to amplify DNA from a variety of recent and archival material. Because DNA from paraffin-embedded samples is more degraded than from fresh material, the amplification of reference genes is essential to exclude false-negative results. This study describes the use of the proliferative cell nuclear antigen (PCNA) gene as a reference gene in a range of animal species and in humans. The PCNA-PCR to amplify a fragment extending from exon 5 through exon 6 and including the intervening intron 6 gave a reproducible pattern, with a 280-base pair (bp) band from canine, equine, bovine, ovine, and caprine samples showing high sequence homology. Porcine, guinea pig, tiger, and lion samples, however, gave an additional fragment of approximately 197 bp. The whole intron 6 from these fragments is missing, possibly representing a pseudogene. In feline samples only the 197-bp fragment could be detected. This study shows that the PCNA gene is highly conserved across a broad range of animal species and is well suited as an internal control for PCR analysis in veterinary medicine.

Multiple sclerosis and Kaposi's sarcoma--chronic diseases associated with new human herpesviruses?

Two diseases that for many years have been suspected to be of viral origin are multiple sclerosis (MS) and Kaposi's sarcoma (KS). With the use of a new technique called representational difference analysis both these diseases have recently been associated with new lymphotropic herpesviruses, i.e. human herpesviruses (HHV) 6 and 8. HHV-6 is a ubiquitous virus and the etiological agent of exanthema subitum. Viral neuroinvasion occurs frequently in primary HHV-6 infection, and meningitis, encephalitis and demyelination have been described as rare complications. A relation with MS has been suggested for HHV-6, as the virus has been detected in MS plaques in the brain. Data from different studies are, however, conflicting and a definitive role for HHV-6 in MS pathogenesis has not been established. HHV-8 is believed to be the causative agent of KS, and is also associated with some rare hematological malignancies. The viral genome contains several potential oncogenes that are believed to have been picked up from the human genome during evolution. The role of HHV-8 in healthy, immunocompetent individuals is however uncertain. In conclusion, the full spectrum of human diseases associated with these new viruses is not yet understood, and rapid developments in molecular biology will continue to shed new light on the interactions between herpesviruses and their hosts.

Human herpesvirus-8 and Kaposi's sarcoma: relationship with the multistep concept of tumorigenesis

Kaposi's sarcoma (KS) develops through discrete inflammatory-angiogenic stages of polyclonal nature (early-stage lesions) to monomorphic nodules of spindle-shaped cells that can be clonal (late-stage lesions) and resemble true sarcomas. Molecular and epidemiological studies indicate that development of KS is tightly associated with infection by the human herpesvirus-8 (HHV-8). However, only individuals with specific conditions of immunodysregulation develop KS. In these individuals the systemic and tissue increase of Th-1-type cytokines (IC) reactivate HHV-8 infection, leading to increased viral load, antibody titers, and an expanded cell tropism that precedes the clinical appearance of KS. Recruitment of the virus into tissues by infected monocytes and other cell types is facilitated by the endothelial cell activation due to IC. In clinical lesions, HHV-8 infection increases with lesion stage and in late-stage lesions most of the spindle cells are latently infected, whereas only few lyrically infected cells are present, suggesting that latent genes may have a role in the transformation of the early inflammatory-hyperplastic lesion into a real sarcoma. The development of tumors, however, is regulated through a multistep process based on the acquisition by cells of several different capabilities leading to malignant growth. Here we review the available data on the expression of HHV-8-encoded genes in primary KS lesions and, in view of their biological activity, analyze their potential function in different steps of tumorigenesis. By this pragmatic approach interesting insights into potential key functions of HHV-8-encoded genes are found and steps of potential cooperativity with other viral factors (HIV-1-Tat) in the pathogenesis of KS are identified.

Activation of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) lytic replication by human cytomegalovirus

The majority of Kaposi's sarcoma-associated herpesvirus (KSHV)-infected cells identified in vivo contain latent KSHV, with lytic replication in only a few percent of cells, as is the case for the cells of Kaposi's sarcoma (KS) lesions. Factors that influence KSHV latent or lytic replication are not well defined. Because persons with KS are often immunosuppressed and susceptible to many infectious agents, including human cytomegalovirus (HCMV), we have investigated the potential for HCMV to influence the replication of KSHV. Important to this work was the construction of a recombinant KSHV, rKSHV.152, expressing the green fluorescent protein (GFP) and neo (conferring resistance to G418). The expression of GFP was a marker of KSHV infection in cells of both epithelial and endothelial origin. The rKSHV.152 virus was used to establish cells, including human fibroblasts (HF), containing only latent KSHV, as demonstrated by latency-associated nuclear antigen expression and Gardella gel analysis. HCMV infection of KSHV latently infected HF activated KSHV lytic replication with the production of infectious KSHV. Dual-color immunofluorescence detected both the KSHV lytic open reading frame 59 protein and the HCMV glycoprotein B in coinfected cells, and UV-inactivated HCMV did not activate the production of infectious KSHV-GFP. In addition, HCMV coinfection increased the production of KSHV from endothelial cells and activated lytic cycle gene expression in keratinocytes. These data demonstrate that HCMV can activate KSHV lytic replication and suggest that HCMV could influence KSHV pathogenesis.

A retrospective survey of mucocutaneous manifestations of HIV infection in Malaysia: analysis of 182 cases

A retrospective analysis of 182 HIV positive Malaysians was done in two centers, the University Hospital Kuala Lumpur (UHKL) and the General Hospital Kuala Lumpur (GHKL) from March 1997 to February 1998. Demographic and clinical data were analyzed. The analysis showed that 130 out of 182 patients had mucocutaneous disorders (71.4%). In the study there were 125 males (96.2%) and 5 females (3.8%). The majority of the patients were in the age group from 20 to 50 years. The patients who presented with mucocutaneous disease also had low CD4+ T lymphocyte counts, and most of them had AIDS defining illnesses. The number of cases with generalized hyperpigmentation was very high (35.7%), followed by papular eruptions (29.1%) and xerosis (27.5%). Seborrheic dermatitis was seen in 19.2% of the cases and psoriasis in 7.7%. The most common infections were oral candida 35.7%, tinea corporis and onychomycosis 9.9%, and herpes infection 4.3%. However, mucocutaneous manifestations of Kaposi's sarcoma were rare. The results suggested that mucocutaneous findings are useful clinical predictors of HIV infection or a sign of the presence of advanced HIV infection.

Human herpesvirus 8: is it a tumor virus?

Human herpesvirus 8 (HHV-8), also termed Kaposi's sarcoma-associated herpesvirus, was identified in Kaposi's sarcoma (KS) biopsy specimens in 1994. The epidemiological data available to date indicate a strong association of HHV-8 with KS. It appears that HHV-8 is necessary for KS development. HHV-8 DNA is invariably found in all epidemiological forms of KS and primary effusion lymphomas. In contrast, HHV-8 DNA is rarely found in various tumor and nontumor tissues from patient groups not at risk of KS. Although current serology does not allow us to assess the HHV-8 prevalence in the general population, high titers of HHV-8 antibodies are almost exclusively found in KS risk groups. In addition, HHV-8 seroconversion has been shown to precede KS development. The mechanisms and genes involved in HHV-8 pathogenesis are less clear. HHV-8 belongs to a family of transforming viruses, and several candidate oncogenes have been identified by using rodent fibroblast transformation assays. However, expression of most of these genes could not be shown in latently infected tumor cells. As the HHV-8 genome encodes several cytokines and cytokine receptor homologues, HHV-8 may also promote KS pathogenesis through paraendocrine mechanisms.

Penile intraepithelial neoplasia overlying Kaposi's sarcoma lesions: role of viral synergy?

Several viral agents have been detected in the lesional tissue of Kaposi's sarcoma (KS). Their precise oncogenic role remains to be determined. A 32-year-old heterosexual man with acquired immunodeficiency syndrome (AIDS) who had penile lesions of KS with overlying epithelial changes characteristic of intraepithelial neoplasia associated with concurrent infection by human papillomavirus (HPV) and human herpesvirus 8 (HHV-8) is reported. The absence of viral DNA from uninvolved skin suggests that this coinfection is more than coincidental and may involve synergy between these viruses, as has already been suggested for HPV and herpes simplex 2 virus.

The role of HHV-8 in Kaposi's sarcoma

The epidemiology of Kaposi's sarcoma (KS) amongst North American and Northern European patients with AIDS suggests that an infectious agent other than HIV is involved in its pathogenesis. Several lines of evidence indicate that human herpesvirus 8 (HHV-8), also termed Kaposi's sarcoma associated herpesvirus, is the sought after agent. DNA of HHV-8 is invariably found in all forms of KS where the virus is present in the KS spindle cell. In contrast, HHV-8 DNA is not regularly detected in most other malignancies. Antibodies against HHV-8 are more frequently found in groups at risk of KS, and HHV-8 seroconversion precedes KS development. Several HHV-8 genes have been identified that exhibit transforming potential in cell culture systems. In addition, the virus encodes and induces several cytokines and angiogenic factors. This is of particular interest as models of KS pathogenesis developed before the discovery of HHV-8 emphasized the importance of inflammatory cytokines. Although the expression pattern of viral genes in KS is not certain yet, it appears likely that the pathogenetic role of HHV-8 in KS may be rather complex and differs from other virus-induced malignancies. 1999 Academic Press.

Mucocutaneous manifestations of HIV infection: a retrospective analysis of 145 cases in a Chinese population in Malaysia

BACKGROUND

Mucocutaneous lesions directly related to human immunodeficiency virus (HIV) infection usually present as initial manifestations of immune deficiency. The most common mucocutaneous lesions are Kaposi's sarcoma, histoplasmosis, oro-esophageal candidiasis, oral hairy leukoplakia, and, in Asia, Penicillium marneffei infection. Non-HIV-related skin lesions, such as psoriasis, seborrheic dermatitis, and nodular prurigo, may be the initial presentation among HIV infected patients attending outpatient clinics.

METHODS

A retrospective analysis was performed on 145 HIV-positive Malaysians of Chinese descent from two centers at the University Hospital Kuala Lumpur (UHKL) and the General Hospital Kuala Lumpur (GHKL) from March 1997 to February 1998. Demographic data and clinical data were analyzed.

RESULTS

The analysis showed that 104 out of 145 patients had mucocutaneous disorders (71.7%). In the study, there were 100 men (96.2%) and four women (3.8%). The majority of patients were in the age group 20-50 years. The patients who presented with mucocutaneous disease also had low CD4+ T-lymphocyte counts and most had acquired immunodeficiency syndrome (AIDS) defining illness. The number of cases with generalized hyperpigmentation was very high in the group (35.9%), followed by nodular prurigo (29.7%) and xerosis (27.6%). Seborrheic dermatitis was seen in 20.7% of cases, with psoriasis in 8.3%. The most common infections were oral candidiasis (35.9%), tinea corporis and onychomycosis (9.7%), and herpes infection (5.5%); however, mucocutaneous manifestations of Kaposi's sarcoma were rare.

CONCLUSIONS

The results suggest that mucocutaneous findings are useful clinical predictors of HIV infection or signs of the presence of advanced HIV infection.

PCR assay fails to detect molluscum contagiosum virus-related sequences in AIDS-related Kaposi's sarcoma

Previous PCR-based studies have demonstrated the presence of various viral DNA or RNA sequences in Kaposi's sarcoma (KS) tissues. To date, only human herpesvirus 8 (HHV-8) DNA sequences are found consistently in KS. The putative role of this agent in KS pathogenesis remains, however, to be determined; HHV-8 could infect populations endemically and could be reactivated in patients with KS. A close association between AIDS-related KS and molluscum contagiosum occurrence was found and this study was conducted primarily to search for the presence of molluscum contagiosum virus DNA sequences in KS. Frozen KS samples were examined for the presence of both HHV-8 and molluscum contagiosum virus DNA sequences by PCR. Despite a high rate of co-infection, no molluscum contagiosum virus (MCV) DNA sequence could be found in the KS samples whereas HHV-8 was uniformly detected. These results suggest that the high prevalence of MCV in AIDS patients with KS relies on a mode of transmission common for HHV-8 and molluscum contagiosum virus rather than on a multiviral etiology of KS. They may also indicate a particular susceptibility of the host to viral reactivation. If this is so, the failure to detect MCV DNA sequences in KS tissues by PCR indicates that locally produced or released cyotokines are not involved in the latter process.

Detection and typing of human papillomavirus in biopsy and cytological specimens by polymerase chain reaction and restriction enzyme analysis: a method suitable for semiautomation

Screening for high-risk human papillomavirus (HPV) types allows the detection of women at a high risk of cervical squamous carcinomas, thereby defining a subset of patients targeted for more intensive screening and follow-up. Thirty-four cervical biopsy specimens and isolated cells from cervical smears of normal women or women diagnosed with high-grade intraepithelial lesion (HGSIL) were screened for the presence of HPV by in situ hybridization (ISH) and/or by polymerase chain reaction (PCR). The exact HPV type was determined using a novel restriction typing method. The detection of HPV was facilitated greatly by the use of a PCR-enzyme-linked immunosorbent assay (ELISA)-based method. HPV was detected by PCR in 32% of the biopsy specimens, whereas only 23% had a positive staining by ISH. In one case, a double infection was detected by ISH as well as by PCR. In two cases, the presence of HPV was detected by both methods but the exact type was different. Analyzing cells isolated from cervical smears by the PCR-ELISA technique or by PCR followed by agarose gel electrophoresis, HPV was detected only in patients with HGSIL and not in the control group. The PCR system is more sensitive than conventional ISH, and the PCR-ELISA system presented in this study is efficient in screening large series of cytological samples. Furthermore, this system allows exact HPV typing on the microtiter plate. These innovations may allow the application of HPV detection and typing as a routine screening method to identify patients with a high risk of developing cervical neoplasia.