Quantification of Kaposi's sarcoma-associated herpesvirus in blood, oral mucosa, and saliva in patients with Kaposi's sarcoma

Burden of Kaposi sarcoma according to HIV status: A systematic review and global analysis

In 2020, over 34 000 cases of Kaposi sarcoma (KS) were estimated globally, all attributable to KS herpesvirus (KSHV). Prior to the HIV epidemic, KS already existed in KSHV endemic regions, notably in sub-Saharan Africa (SSA). The HIV epidemic has vastly increased the KS burden. We developed a methodology to provide global estimates of KS burden according to HIV status. A systematic review identified studies reporting HIV prevalence in consecutive KS series. Pooled estimates of HIV prevalence, by country or UN subregion, were used to calculate population-attributable fraction (PAF) and these were applied to IARC's GLOBOCAN 2020 to estimate burden and incidence of HIV-attributable and non-HIV-attributable KS. We identified 55 eligible studies, reporting HIV prevalence ranging from ≤5% to ≥95%. Approximately 80% of KS in SSA was estimated attributable to HIV, vs ~50% in the rest of the world. By applying PAFs to national GLOBOCAN estimates, an estimated 19 560 KS cases attributable to HIV were diagnosed in SSA in 2020 (~80% of the worldwide burden), vs 5064 cases of non-HIV-attributable KS (~60% of the worldwide burden). Incidence of HIV-attributable KS was highest in Southern Africa (6.0 cases per 100 000) and Eastern Africa (3.4), which were also the world regions with highest incidence of non-HIV-attributable KS (0.4 and 1.0 cases per 100 000, respectively). This first systematic effort to produce a global picture of KS burden stratified by HIV status highlights the continuing important burden of HIV-attributable KS in SSA, even in the era of combined antiretroviral therapy.

Effect of innate and adaptive immune mechanisms on treatment regimens in an AIDS-related Kaposi's Sarcoma model

Kaposi Sarcoma (KS) is the most common AIDS-defining cancer, even as HIV-positive people live longer. Like other herpesviruses, human herpesvirus-8 (HHV-8) establishes a lifelong infection of the host that in association with HIV infection may develop at any time during the illness. With the increasing global incidence of KS, there is an urgent need of designing optimal therapeutic strategies for HHV-8-related infections. Here we formulate two models with innate and adaptive immune mechanisms, relevant for non-AIDS KS (NAKS) and AIDS-KS, where the initial condition of the second model is given by the equilibrium state of the first one. For the model with innate mechanism (MIM), we define an infectivity resistance threshold that will determine whether the primary HHV-8 infection of B-cells will progress to secondary infection of progenitor cells, a concept relevant for viral carriers in the asymptomatic phase. The optimal control strategy has been employed to obtain treatment efficacy in case of a combined antiretroviral therapy (cART). For the MIM we have shown that KS therapy alone is capable of reducing the HHV-8 load. In the model with adaptive mechanism (MAM), we show that if cART is administered at optimal levels, that is, 0.48 for protease inhibitors, 0.79 for reverse transcriptase inhibitors and 0.25 for KS therapy, both HIV-1 and HHV-8 can be reduced. The predictions of these mathematical models have the potential to offer more effective therapeutic interventions in the treatment of NAKS and AIDS-KS.

Kaposi's Sarcoma-Associated Herpesvirus: Epidemiology and Molecular Biology

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as Human herpesvirus 8 (HHV-8), is a member of the lymphotropic gammaherpesvirus subfamily and a human oncogenic virus. Since its discovery in AIDS-associated KS tissues by Drs. Yuan Chang and Patrick Moore, much progress has been made in the past two decades. There are four types of KS including classic KS, endemic KS, immunosuppressive therapy-related KS, and AIDS-associated KS. In addition to KS, KSHV is also involved in the development of primary effusion lymphoma (PEL) and certain types of multicentric Castleman's disease. KSHV manipulates numerous viral proteins to promote the progression of angiogenesis and tumorigenesis. In this chapter, we review the epidemiology and molecular biology of KSHV and the mechanisms underlying KSHV-induced diseases.

Conceptual Emergence of Human Herpesvirus 8 (Kaposi’s Sarcoma-associated Herpesvirus) as an Oral Herpesvirus

Recognition of the various clinico-epidemiologic forms of Kaposi’s sarcoma, a disease putatively caused by an infectious agent, did not provide ready clues as to how that agent might be transmitted, although fecal and sexual routes were implicated. Application of serologic and genome-detection assays, and cell-culture studies following the identification of human herpesvirus 8 as the causative agent now implicate that virus as one that is orally shed. While oral transmission of the virus might account for the viral endemicity in Africa and Mediterranean countries, why it is particularly prevalent among male homosexuals in the West remains more difficult to explain. Such explanation may be sought from behavioral studies into the role saliva plays in sexual interactions.

Identification of Human Herpesvirus 8 Sequences in Conjunctiva Intraepithelial Neoplasia and Squamous Cell Carcinoma of Ugandan Patients

The incidence of squamous cell carcinoma of the conjunctiva is particularly high in sub-Saharan Africa with temporal trends similar to those of Kaposi sarcoma (KS). Human herpesvirus type 8 (HHV8), has not yet been investigated in conjunctiva tumors. In this study biopsies and PBMCs of conjunctiva neoplasia patients along with nonneoplastic conjunctiva tissues have been analyzed for HHV8 sequences by PCR targeting ORF26. All amplimers were subjected to nucleotide sequencing followed by phylogenetic analysis. HHV8 DNA has been identified in 12 out of 48 (25%) HIV-positive, and in 2 out of 24 (8.3%) HIV-negative conjunctiva neoplastic tissues and in 4 out of 33 (12.1%) PBMC samples from conjunctiva neoplasia diseased patients as well as in 4 out of 60 (6.7%) nontumor conjunctiva tissues. The viral load ranged from 1 to 400 copies/10⁵ cells. Phylogenetic analysis showed that the majority of HHV8 ORF26 amplimers clustered with subtypes R (n = 11) and B2 (n = 6). This variant distribution is in agreement with that of HHV8 variants previously identified in Ugandan KS cases. The presence of HHV8 in conjunctiva tumors from HIV-positive patients warrants further studies to test whether HHV8 products released by infected cells may have paracrine effects on the growth of conjunctiva lesions.

A MATHEMATICAL MODEL FOR THE TREATMENT OF AIDS-RELATED KAPOSI'S SARCOMA

We formulate a mathematical model to study the dynamics of HIV-1 related Kaposi's Sarcoma (KS) pathogenesis. KS progression is modeled as a dual process involving the primary infection of B cells, which sustains HHV-8 replication and the secondary infection of progenitor cells by HHV-8, which sustains the KS cell replication. We incorporate the pharmacodynamics of highly active antiretroviral therapy (HAART), or combination therapy (HAART plus KS therapy) and consider how each treatment strategy alters the disease progression. Our results indicate that administration of HAART to individuals co-infected with the HIV-1 and HHV-8 viruses can greatly amplify the therapeutic response of low-dose KS therapies. We have found that adherence levels above 85% can significantly reduce the risk of KS and HIV for a treatment periods under 1 year. For longer treatment periods, however, at least 90% adherence level is recommended.

Risk factors for Kaposi's sarcoma among HIV-positive individuals in a case control study in Cameroon

BACKGROUND

Individuals co-infected with Kaposi's sarcoma herpesvirus (KSHV) and Human Immunodeficiency Virus (HIV) are at greatly increased risk of developing Kaposi's sarcoma (KS). The objective of the current analysis is to identify risk cofactors for KS among HIV-positive individuals.

METHODS

We conducted a case-control study of KS in Cameroon on 161 HIV-positive and 14 HIV-negative cases and 680 HIV-positive and 322 HIV-negative controls. Participants answered a physician-administered questionnaire and provided blood and saliva specimens. Antibodies against KSHV lytic, K8.1, and latent, ORF73, antigens were measured by ELISA to determine KSHV serostatus. Conditional logistic regression was performed to determine multivariate odds ratios (OR) and 95% confidence intervals (CI) for risk factors associated with KS among HIV-positive cases and controls.

RESULTS

Overall, 98% (158) of HIV-positive cases, 100% (14) of HIV-negative cases, 81% (550) of HIV-positive controls, and 80% (257) of HIV-negative controls were KSHV seropositive. Risk factors for KS among HIV-positive individuals included KSHV seropositivity (OR=9.6; 95% CI 2.9, 31.5), non-use of a mosquito bed net (OR 1.9; 95% CI 1.2, 2.9), minority ethnicity (OR=3.1; 95% CI 1.1, 9.3), treatment from a traditional healer (OR=2.3; 95% CI 1.5, 3.7), history of transfusion (OR=2.4; 95% CI 1.5, 3.9), and family history of cancer (OR=1.9; 95% CI 1.1, 3.1).

CONCLUSION

KSHV seroprevalence of ≥80% indicates a high prevalence in the general population in Cameroon. Among HIV-positive individuals, the strong association of KS with non-use of mosquito nets and treatment from traditional healers are compelling findings, consistent with recently reported data from East Africa.

High prevalence of early childhood infection by Kaposi's sarcoma-associated herpesvirus in a minority population in China

In China, KSHV seroprevalence varies considerably among different regions and ethnicities. But in Xinjiang province, located in the northwestern China, there is a very high seroprevalence of KSHV in adults of Kazak and Ughur ethnicities. However, KSHV prevalence in children and the risk factors associated with the acquisition of infection are currently not known. The aim of this study was to investigate the prevalence of KSHV infection and identify associated socioeconomic or behavioural risk factors and the humoral immune response among children in this population. This is a cross-sectional study (N = 178) to screen children and their caregivers from Xinjiang for total KSHV antibodies, KSHV neutralizing antibodies and HIV infection. Structured questionnaires were utilized to investigate risk factors associated with KSHV prevalence. KSHV seroprevalence in children and caregivers in Xinjiang was 48.3% and 64.7%, respectively. Neutralizing antibody was detected in most seropositive caregivers (93.8%) but was detected in only 5.8% of the infected children. A significant association was observed between child KSHV seroprevalence and sharing of food among family members. These results suggest that similar to other endemic areas in Africa, KSHV infection in the minority populations of Xinjiang is likely to be occurring during early childhood, probably via horizontal transmission through saliva, and results in high seroprevalence in the adult population.

Recent advances in Kaposi sarcoma herpesvirus-associated multicentric Castleman disease

PURPOSE OF REVIEW

The discovery of Kaposi sarcoma herpesvirus (KSHV) led to recognition of KSHV-associated multicentric Castleman disease (MCD) as a distinct lymphoproliferative disorder. The pathogenesis of KSHV-MCD is attributed to proliferation of KSHV-infected B cells, production of KSHV-encoded viral interleukin 6 by these cells, and dysregulation of human interleukin 6 and interleukin 10. This article reviews advances in the field of disease pathogenesis and targeted therapies.

RECENT FINDINGS

Our understanding of the pathogenesis of KSHV-MCD has increased in recent years and improved therapies have been developed. Recent studies demonstrate that the anti-CD20 monoclonal antibody, rituximab, as well as virus-activated cytotoxic therapy using high-dose zidovudine and valganciclovir, can control symptoms and decrease adenopathy. With treatment, 1-year survival now exceeds 85%. Interestingly, even in the absence of pathologic findings of MCD, KSHV-infected patients may have inflammatory symptoms, excess cytokine production, and elevated KSHV viral load similar to KSHV-associated MCD. The term KSHV-associated inflammatory cytokine syndrome has been proposed to describe such patients.

SUMMARY

Recent advances in targeted therapy have improved outcomes in KSHV-MCD, and decreased need for cytotoxic chemotherapy. Improved understanding of the pathogenesis of KSHV-MCD and KSHV-associated inflammatory cytokine syndrome is needed, and will likely lead to additional advances in therapy for these disorders.

In vivo and in vitro evidence for an association between the route-specific transmission of HHV-8 and the virus genotype

The study was performed to determine if there is an association between the genotype and transmission of HHV-8 types A and C. These HHV-8 subtypes are prevalent in the area of North of Sardinia, which is an island off west Italy's mainland that has a high HHV-8 seroprevalence (35%). Blood and saliva samples from 30 patients with classic Kaposi's sarcoma who were lifetime residents of North Sardinia were analyzed to identify the HHV-8 genotype and quantitate the viral load. Genotype A, especially A1 subtype, was found more frequently (9/30 patients) and had a significantly higher viral load in saliva compared to blood (P = 0.029), where type C was found more frequently but with a viral load lower than 10(3)  copies/ml. To determine if there is a correlation between the viral genotype and cellular tropism, type A1 and C3 HHV-8 viral particles were obtained from cell lines BCBL1 and BC3 infected chronically with HHV-8 A1 and C3 genotypes respectively and used to infect HEK293 epithelial origin cells and PBMCs in vitro. The data indicate that the A1 HHV-8 genotype is tropic and replicates at higher levels in the epithelial cell lines.

KSHV DNA viremia correlates with low CD4+ cell count in Italian males at the time of diagnosis of HIV infection

To evaluate the relevance and the virological and immunological markers of Kaposi sarcoma herpesvirus 8 (KSHV) viremia in Italian male patients at the time of diagnosis of infection with HIV-1, 481 men infected with HIV were recruited consecutively. The presence of KSHV DNA was evaluated in peripheral blood mononuclear cells (PBMCs) and in plasma and correlated with demographic and viro-immunological parameters. Seventy-four patients had KSHV DNA detected in PBMCs. By univariate analysis, the presence of KSHV DNA was associated significantly with unprotected homosexual relationships (P=0.003) and it was significantly higher in patients with CD4+ cell <350 (P=0.025). By multivariate analysis, homosexual relationships were associated independently with KSHV DNA in PBMCs (OR: 3.25; 95% CI: 1.1-9.7; P=0.035). Among the 74 patients with KSHV DNA detected in PBMCs, plasma samples from 60 were analyzed and 33 were positive for KSHV DNA. The CD4+ cell counts and percentages were significantly lower in patients with KSHV DNA in both PBMCs and plasma as compared to patients with only KSHV DNA in PBMCs (P=0.006 and P=0.019, respectively). Among the patients with KSHV DNA detected in PBMCs, all 13 patients with CD4+ cells count <200 had detectable levels of KSHV in their plasma. By multivariate analysis adjusted for the epidemiologic and virological parameters, low CD4+ cell count was the only independent variable associated with the presence of KSHV DNA in plasma (OR, 0.001; 95% CI: <0.001-0.001; P=0.03). In HIV-positive antiretroviral therapy-naïve males, KSHV active replication as detected by KSHV DNA in plasma was associated significantly with low CD4+ cell count.

Intrafamiliar transmission of Kaposi's sarcoma-associated herpesvirus and seronegative infection in family members of classic Kaposi's sarcoma patients

The link between Kaposi's sarcoma-associated herpesvirus (KSHV or human herpesvirus 8) and Kaposi's sarcoma has been proven, but the transmission routes, especially in the heterosexual population, are not yet completely understood. To assess the intrafamilial patterns of transmission among first-degree relatives of Italian classic Kaposi's sarcoma (cKS) patients, KSHV seroprevalence and the presence of viral DNA in blood and saliva were evaluated in 18 families (32 cKS patients and 35 family members), comparing the results with those obtained in 200 elderly healthy controls without known exposure to KSHV. The KSHV genotype of variable region VR1 of the hypervariable ORF K1 gene was subsequently analysed in all KSHV-positive samples. The results showed that KSHV infection was significantly higher in relatives of cKS patients (11/35 cases) than in healthy controls (17/200 cases; P=0.001). The 11 infected relatives included spouses (n=3), siblings (n=2) and offspring (n=6) of the cKS patients; the same KSHV genotype was shared within the same family in the majority of cases (85%), indicating the presence of person-to-person transmission within families. Viral DNA was mostly observed in the saliva of infected relatives (45.4%); detection of DNA in blood was less frequent (27.3%). Notably, KSHV DNA was present in saliva and/or blood of three KSHV-infected relatives with indeterminate or negative serostatus. Thus, the risk of KSHV infection is greatly enhanced within families of cKS patients, where close contacts (horizontal and/or sexual) can contribute to the spread of KSHV.

LANA-1, Bcl-2, Mcl-1 and HIF-1alpha protein expression in HIV-associated Kaposi sarcoma

Human herpesvirus 8 (HHV8) is necessary for Kaposi sarcoma (KS) to develop, but whether the tissue viral load is a marker of KS progression is still unclear. Little is known about the level of expression of apoptosis-regulating proteins and of hypoxia-inducible factors (HIFs) in KS tumour cells relative to HHV8 expression. We therefore investigated the expression of the latency-associated nuclear antigen (LANA-1) of HHV8, Bcl-2, Mcl-1, Bax, Bcl-xL, caspase 3 and HIF-1alphain KS tissue specimens at different stages of the disease. The expression of these proteins was evaluated immunohistochemically using tissue microarrays (TMAs) in tissue specimens from 245 HIV-positive patients at different stages of the disease. Both LANA-1 and HIF-1alpha were expressed in KS biopsies taken at different stages, but their level increased throughout tumour progression. Additionally, the levels of Bcl-2 and Mcl-1 were higher in visceral KS lesions compared to levels observed in cutaneous and mucosal KS. This study demonstrates that late tumour stages of KS in tissues from HIV-positive patients are associated with high levels of LANA-1, HIF-1alpha and of the anti-apoptotic proteins, Bcl-2 and Mcl-1. Finally, the expression of these proteins can be potentially used as a tissue biomarker in defining patients with a higher risk of disease progression.

HHV8 a subtype is associated with rapidly evolving classic Kaposi's sarcoma

The link between human herpesvirus 8 (KSHV) and Kaposi's sarcoma (KS) has been proven, but many important aspects including risk factors, genetic predisposition to tumor development, transmission of KSHV, and the pathogenic potential of different genotypes remain to be elucidated. Possible associations between clinical parameters and antibody levels, viral load fluctuations, and viral genotype were analyzed by quantitative real-time PCR, an in-house developed IFA assay, and sequence analysis of ORF K1-VR1 in blood, serum and saliva of 38 subjects with classic KS (cKS). KSHV lytic antibodies were significantly increased in stage IV compared to stage I and II patients (p = 0.006 and p = 0.041, respectively). KSHV blood, serum, and saliva viral load was comparable in all stages. The highest viral loads were detected in saliva, and they decreased in stages III-IV compared to stages I-II patients. Higher concentrations of lytic antibodies and higher viral loads were observed in fast progressing cKS patients, in whom KSHV detection from blood was also more frequent. Type A KSHV strain was almost exclusively present in rapid progressors (12/17 cases), while C type was mainly present in slow progressing patients (6/7 cases). Finally, detection of type A KSHV strain associated with higher blood viral loads. KSHV lytic antibody levels and viral load can be used to monitor clinical evolution of cKS. Infection supported by KSHV A subtype is associated with more rapid progressive disease. Careful monitoring and aggressive therapeutic protocols should be considered in patients with KSHV A-supported infection.

Early childhood infection by human herpesvirus 8 in Zambia and the role of human immunodeficiency virus type 1 coinfection in a highly endemic area

Kaposi's sarcoma occurs at high incidence among Zambian adults and children, but there is a paucity of data on human herpesvirus 8 (HHV-8) incidence and routes of infection, especially in children. Between 1998 and 2004, the authors conducted a prospective study of viral transmission in a cohort of 684 children in Lusaka, Zambia, to estimate the annual incidence of HHV-8 from birth through 48 months of age. Maternal and pediatric human immunodeficiency virus type 1 (HIV-1) infection status was also determined. The results, based on 1,532 child-years of follow-up, showed that HHV-8 seroconversion occurs early in life. The incidence rate of HHV-8 seroconversion was 13.8 infections per 100 child-years by 48 months of age. HIV-1-infected children were at substantially higher risk for HHV-8 seroconversion (adjusted hazard ratio = 4.60, 95% confidence interval: 2.93, 7.22). Maternal HIV-1 and HHV-8 infection status were not independently associated with risk of HHV-8 seroconversion in the child. HHV-8 antibody titers in children followed at all consecutive time points revealed sero-reversion of HHV-8 antibodies, with undetectable titers in some children at one or more time points after seroconversion. These results demonstrate that cross-sectional serologic screening probably underestimates true HHV-8 seroprevalence in young Zambian children because of fluctuations in detectable antibody titers.

Kaposi's sarcoma in HIV-negative men having sex with men

BACKGROUND

Four epidemiologic forms of Kaposi's sarcoma have been described, all of which are associated with the human herpesvirus-8. In western countries, human herpesvirus-8 is more prevalent in homosexual men than in the general population, and anecdotal cases of Kaposi's sarcoma in HIV-negative homosexual men have been reported.

PATIENTS AND METHODS

We included HIV-negative homosexual and bisexual male patients with histologically proven Kaposi's sarcoma in a retrospective study. Clinical data were collected using a standardized form. Risk factors for human herpesvirus-8 infection and for the development of Kaposi's sarcoma were systematically recorded.

RESULTS

Between 1995 and 2007, 28 men met the defined inclusion criteria. Mean age at first symptoms of Kaposi's sarcoma was 53 years. Clinical presentation resembled classical Kaposi's sarcoma, with limited disease in most patients. No cellular or humoral immunodeficiency was observed. Serologic tests for human herpesvirus-8 (latent immunofluorescence assay) were positive in 88% of patients, and only two patients displayed human herpesvirus-8 viremia at the time of Kaposi's sarcoma diagnosis. Three patients developed lymphoproliferative disorders (Castleman disease, follicular lymphoma and Burkitt lymphoma). In this population, alpha-interferon was well tolerated and gave a complete response, but most patients require only local treatment, if any.

CONCLUSION

Kaposi's sarcoma may develop in homosexual or bisexual men without HIV infection. This type of Kaposi's sarcoma has clinical features in common with classical Kaposi's sarcoma but occurs in younger patients. Its prognosis is good, as Kaposi's sarcoma is generally limited, but clinicians should be aware of the association with lymphoproliferative diseases, which may affect prognosis.

Human herpesvirus 8 load and progression of AIDS-related Kaposi sarcoma lesions

INTRODUCTION

Human herpesvirus 8 (HHV8) is necessary for Kaposi sarcoma (KS) to develop, but whether peripheral blood viral load is a marker of KS burden (total number of KS lesions), KS progression (the rate of eruption of new KS lesions), or both is unclear. We investigated these relationships in persons with AIDS.

METHODS

Newly diagnosed patients with AIDS-related KS attending Mulago Hospital, in Kampala, Uganda, were assessed for KS burden and progression by questionnaire and medical examination. Venous blood samples were taken for HHV8 load measurements by PCR. Associations were examined with odds ratio (OR) and 95% confidence intervals (CI) from logistic regression models and with t-tests.

RESULTS

Among 74 patients (59% men), median age was 34.5 years (interquartile range [IQR], 28.5-41). HHV8 DNA was detected in 93% and quantified in 77% patients. Median virus load was 3.8 logs10/10(6) peripheral blood cells (IQR 3.4-5.0) and was higher in men than women (4.4 vs. 3.8 logs; p=0.04), in patients with faster (>20 lesions per year) than slower rate of KS lesion eruption (4.5 vs. 3.6 logs; p<0.001), and higher, but not significantly, among patients with more (>median 20 KS lesions) than fewer KS lesions (4.4 vs. 4.0 logs; p=0.16). HHV8 load was unrelated to CD4 lymphocyte count (p=0.23).

CONCLUSIONS

We show significant association of HHV8 load in peripheral blood with rate of eruption of KS lesions, but not with total lesion count. Our results suggest that viral load increases concurrently with development of new KS lesions.

Human herpesvirus 8 presence and viral load are associated with the progression of AIDS-associated Kaposi's sarcoma

OBJECTIVE

We present the largest longitudinal study to date that examines the association between Kaposi's Sarcoma (KS) disease progression and the presence and viral load of human herpesvirus 8 (HHV-8).

METHODS

Ninety-six men were enrolled at HIV clinics in Atlanta, Georgia, who had KS (n = 47) or were without KS but seropositive for HHV-8. Visits occurred at 6-month intervals for 2 years at which the patient's KS status was evaluated and oral fluid and blood were collected for quantification of HHV-8 DNA and antibodies.

RESULTS

The presence of HHV-8 DNA in blood was more common (P < 0.001) and the viral load higher (P < 0.001) in men with KS in comparison with men without KS. Mean HHV-8 viral loads in blood and oral fluids were associated with disease status, being highest among patients with progressing KS, intermediate among patients with stable KS, and lowest among patients with regressing KS. Consistent with our previous report high antibody titers to HHV-8 orf 65 were inversely associated with HHV-8 shedding in oral fluid.

CONCLUSIONS

We observed a significant association between changes in KS disease severity and the presence and viral load of HHV-8. HHV-8 viral load in blood may provide useful information to clinicians for assessment of the risk of further disease progression in patients with KS.

Kaposi's sarcoma herpesvirus load in biopsies of cutaneous and oral Kaposi's sarcoma lesions

OBJECTIVES

To evaluate human herpesvirus 8/Kaposi's sarcoma associated herpesvirus (HHV-8/KSHV) viral load in diagnostic, (formalin fixed, paraffinised) biopsies and patient serum during tumour progression of oral and cutaneous AIDS-related Kaposi's sarcoma (AKS), and endemic Kaposi's sarcoma (EKS) by a sensitive and specific quantitative real time polymerase chain reaction (qRT-PCR) assay.

STUDY DESIGN

Eighty six biopsies of both AKS (oral and cutaneous AKS, 68) and EKS (cutaneous EKS, 18) were evaluated by qRT-PCR and immunohistochemistry (IHC). The viral load in human tumour tissue and serum of some individual patients were compared.

RESULTS

Higher viral load as well as frequency of latency-associated nuclear antigen (LANA)+ tumour spindle cells (SC) and number of LANA granules per SC was found in oral AKS compared to cutaneous AKS. Although few cases were available, serum viral load appeared to decrease compared to tumour tissue during KS progression.

CONCLUSIONS

The higher viral load in oral rather than cutaneous AKS is consistent with the well recognised reservoir function of the oral mucosa. Decrease of serum HHV-8 load during KS progression may indicate decreased virus release and/or increased virus clearance.

Relationship between human herpesvirus 8 loads and disease stage in classic Kaposi sarcoma patients

Human herpesvirus 8 (HHV-8), also known as Kaposi sarcoma (KS)-associated herpesvirus, is causally implicated in all forms of KS, including the classic form. Our objective was to investigate the relationship between HHV-8 load in peripheral blood mononuclear cells (PBMCs) and the stage of the disease in classic KS (CKS) patients. HHV-8 loads were measured in 41 PBMC samples from CKS patients with different Krigel-based classification stages using a quantitative real-time polymerase chain reaction assay. Low HHV-8 DNA loads reaching a maximum of 75.5 copies/10(5) cells were detected in 73.2% of the patients. HHV-8 loads in patients with stages I and II were similarly distributed. An increased detection rate of HHV-8 DNA, although not statistically significant, was evident in patients diagnosed with CKS stages III and IV. We conclude that the measurements of HHV-8 load in PBMCs provide a limited correlation with the clinical stage of KS.

Prognostic Significance of Immune Subset Measurement in Individuals With AIDS-Associated Kaposi's Sarcoma

Purpose

A prognostic index for AIDS-associated Kaposi's sarcoma (KS) diagnosed in the era of highly active antiretroviral therapy (HAART) was based on routine clinical and laboratory characteristics. Because immune subset measurement is often performed in HIV-positive individuals, we examined whether these were predictive of mortality independently of the prognostic index, or could predict time to progression of KS.

Patients and Methods

We performed univariate and multivariate Cox regression analyses on a data set of 326 individuals with AIDS-associated KS to identify immune subset covariates predictive of overall survival and time to progression. Adaptive (CD8 T cell and CD19 B cell) and innate (CD16/56 natural-killer cell) immune parameters were studied by flow cytometry.

Results

In univariate analyses, all three immune subsets had significant effects on overall survival (P < .025). In multivariate analyses including the prognostic index, only CD8 counts remained significant (P = .026), although its effect on the overall prognostic index is small. An increase of 100 cells/mm3 in the CD8 count confers a 5% improvement in overall survival. Individuals with a higher CD8 count did not have an increased time to progression. Patients who were already on HAART at the time of KS diagnosis did not have a shorter time to progression than those who were antiretroviral naïve at KS diagnosis.

Conclusion

The CD8 count appears to provide independent prognostic information in individuals with AIDS-associated KS. Measurement of the CD8 count is clinically useful in patients with KS.

Transmission of human herpesvirus 8: an update

PURPOSE OF REVIEW

Human herpesvirus 8 is associated with neoplastic diseases in the immunocompromised host, including Kaposi's sarcoma, multicentric Castleman disease and primary effusion lymphoma. Acquisition and control of human herpesvirus 8 infection have not yet been fully elucidated. This review focuses on the most recent findings on human herpesvirus 8 transmission.

RECENT FINDINGS

Horizontal transmission by saliva appears the most common route not only in families in endemic regions, but also among high-risk groups in Western countries. Vertical, sexual, and blood and transplant-related transmission, however, remain of significant concern worldwide. Novel approaches to standardize and optimize the assessment of human herpesvirus 8 infection have been reported. New insights on the host immune cell mechanisms devoted to the control of human herpesvirus 8 infection have also been presented.

SUMMARY

The increasing knowledge about the routes of human herpesvirus 8 transmission, which appear now more similar to those of other more ubiquitous human herpesviruses (i.e. Epstein-Barr virus and cytomegalovirus), the growing efforts in improving laboratory diagnosis and the caution in the research of new biological associations are the major recent findings. They constitute a fundamental background for directing more appropriate future research and achieving more stringent evidence useful for the control of human herpesvirus 8 spread and for the management of human herpesvirus 8-related diseases.

Human herpesvirus-6 (HHV-6) DNA in plasma reflects the presence of infected blood cells rather than circulating viral particles

BACKGROUND

The presence of HHV-6 DNA in plasma or serum is considered a good marker of active infection. However, it is ignored whether this DNA corresponds to virus particles produced by lymphoid tissue infection or virus-free DNA released from infected circulating blood cells.

OBJECTIVES

To investigate whether HHV-6 DNA in whole plasma is nonencapsidated and its amount is correlated to cellular and human herpesvirus-7 (HHV-7) DNA loads in plasma subfractions as well as in corresponding peripheral blood mononuclear cells (PBMCs).

STUDY DESIGN

Whole plasma samples from immunocompromised patients were submitted to a DNase-resistance test. Plasma samples from a second group of patients were split up into three subfractions: P1 (pellet of clarification), P2 (pellet of ultracentrifugation), and S (supernatant of ultracentrifugation). HHV-6, HHV-7, and cellular DNA loads were determined in each fraction and PBMCs using specific real-time PCR.

RESULTS

Among 14 whole plasma samples, the majority of HHV-6 DNA detected was unprotected against DNase, i.e. nonencapsidated. The study of 35 other plasma samples revealed that cellular DNA was present in all subfractions from all samples whereas HHV-6 DNA was detected in 13 P1, 12 P2, 10 S fractions, and HHV-7 DNA in only one P1 fraction. Accordingly, median HHV-6 DNA load was significantly higher in P1 than in P2 and S fractions. The detection of HHV-6 DNA in plasma subfractions was statistically associated with a higher HHV-6 viral load in PBMCs (p<or=0.0003).

CONCLUSIONS

Taken together, these data tend to favour the hypothesis of a release of HHV-6 and cellular DNA into plasma following the lysis of infected PBMCs. HHV-6 DNA in plasma does not necessarily reflect the amount of virus produced by the active infection of distant lymphoid tissue and organs.

Human Herpesvirus 8 Oral Shedding in HIV-Infected Men With and Without Kaposi Sarcoma

OBJECTIVES

Two main routes of human herpesvirus 8 (HHV-8) transmission are known: sexual, predominantly in men who have sex with men; and nonsexual, in endemic populations. Both routes implicate saliva, so identifying the factors that influence oral HHV-8 shedding is important.

METHODS

Using polymerase chain reaction and immunohistochemistry, we prospectively analyzed HHV-8 infection of oral epithelial cells in 98 Swiss HIV Cohort Study patients, with mean follow-up of 9.4 years, and correlated data to immune status, HHV-8 serology, and Kaposi sarcoma (KS) history, as well as survival.

RESULTS

Sixty-eight (43.9%) of the 98 men were HHV-8 seropositive, and 33 (33.67%) had a history of KS. In both groups, men who have sex with men were significantly more affected than heterosexuals (P < 0.05). Of 77 patients, 9 (11.6%) were oral HHV-8 polymerase chain reaction positive, and 2 of these were also positive by immunohistochemistry. Oral HHV-8 detection was not influenced by the immune status, but a trend toward higher detection was observed in patients with KS (P = 0.084). Oral HHV-8 shedding had no predictive value either for the development of KS lesions or for survival.

CONCLUSIONS

Human herpesvirus 8 can be present in oral epithelial cells and is shed independent of the patient's immune status, indicating that oral HHV-8 shedding may occur at any time in HHV-8-seropositive individuals.

A prognostic index for AIDS-associated Kaposi's sarcoma in the era of highly active antiretroviral therapy

BACKGROUND

AIDS-associated Kaposi's sarcoma remains common in individuals with HIV-1 infection in the era of highly active antiretroviral therapy (HAART). We developed a simple model for predicting mortality on the basis of clinical characteristics present at the time of diagnosis of Kaposi's sarcoma.

METHODS

Of 5873 individuals with HIV-1 infection, 326 (6%) developed Kaposi's sarcoma; for 262 (80%) this was their first AIDS-defining illness. We did univariate and multivariate Cox regression analyses to identify covariates predictive of overall survival and validated our model with an independent data set of 446 patients with Kaposi's sarcoma.

RESULTS

In the primary model, we developed a prognostic score from 0 to 15 starting at 10. Having Kaposi's sarcoma as the AIDS-defining illness (-3 points) and increasing CD4 count (-1 point for every complete 100 cells per mm3) improved prognosis; age of 50 years or older (2 points) and having another AIDS-associated illness at the same time (3 points) conveyed a poorer prognosis. In individuals with prognostic scores of 0, 5, 10, and 15, probability of survival at 1-year was 0.993, 0.967, 0.834, and 0.378, and at 5 years was 0.984, 0.918, 0.631, and 0.084, respectively. Increasing prognostic score by 1 increased 1-year death hazard ratio by 40% (95% CI 28-53%; bootstrapped hazard ratio 1.39, 1.25-1.51). The index had concordance of 76.8% (71.7-82.3).

INTERPRETATION

We identified four prognostic factors that can be used to obtain an accurate prognostic index at diagnosis of AIDS-associated Kaposi's sarcoma. This index is widely applicable and can be used to guide therapeutic options.

Kaposi's sarcoma-associated herpesvirus viremia is associated with the progression of classic and endemic Kaposi's sarcoma

In order to gain further insight on the role of Kaposi's sarcoma-associated herpesvirus (KSHV) in classic and endemic Kaposi's sarcoma (KS) pathogenesis, we aimed to determine (i) whether KSHV is detectable in peripheral blood mononuclear cells (PBMCs), (ii) which PBMCs subpopulation harbor the virus, (iii) which clinical, histologic, and immunologic parameters are associated with KSHV viremia in a population of classic and endemic KS. KSHV viremia and various immunologic parameters were screened on 81 patients. KSHV viremia was positive in 58% of the patients. KSHV was detected in B cells, T cells, and monocytes. CD34+ cells depleted in circulating endothelial cells (CECs) were never infected and 50% of the patients tested had CECs infected by KSHV. We observed a significant increase of IL-2 and IFN-gamma production by CD4 T cells and an increase of IFN-gamma production by CD8 T cells compared to control patients. KS progression (P = 0.001) and KS staging (P = 0.03) were significantly and independently associated with positive KSHV viremia. Our results show that there is no specific immunosuppression in classic or endemic KS. We showed that KSHV can be detected within CECs and that KSHV viremia could be an indicator of circulating mature or precursor spindle cells.

Possible role of human herpesvirus 8 in the lymphoproliferative disorders in common variable immunodeficiency

Patients who have common variable immunodeficiency (CVID) and granulomatous/lymphocytic interstitial lung disease (GLILD) are at high risk for early mortality and B cell lymphomas. Infection with human herpes virus type 8 (HHV8), a B cell lymphotrophic virus, is linked to lymphoproliferative disorders in people who have secondary immunodeficiencies. Therefore, we determined the prevalence of HHV8 infection in CVID patients with GLILD. Genomic DNA isolated from peripheral blood mononuclear cells was screened by nested- and real time-quantitative PCR (QRT-PCR) for the presence of HHV8 genome. It was positive in 6/9 CVID patients with GLILD (CVID-GLILD), 1/21 CVID patients without GLILD (CVID-control), and no patients receiving intravenous gamma globulin (n = 13) or normal blood donors (n = 20). Immunohistochemistry (IHC) demonstrated expression of the latency-associated nuclear antigen-1 (LANA-1) in the biopsies of the lung, liver, and bone marrow of four patients with CVID-GLILD. One CVID-GLILD patient developed a B cell lymphoma during the course of the study. QRT-PCR demonstrated high copy number of HHV8 genome and IHC showed diffuse staining for LANA-1 in the malignant lymph node. HHV8 infection may be an important factor in the pathogenesis of the interstitial lung disease and lymphoproliferative disorders in patients with CVID.

Salivary lactoferrin is recognized by the human herpesvirus-8

Human herpesvirus-8 (HHV-8) is commonly detected in all epidemiologic forms of Kaposi's sarcoma. Despite the broad cellular tropism of HHV-8, studies on mucosal shedding of HHV-8 have shown that infectious particles are restricted to saliva isolated from the oropharynx. We used biotinylated purified HHV-8 particles in a direct binding assay to whole clarified human salivary samples isolated from HHV-8-infected and uninfected individuals. We found that the major binding activity was carried out by a protein of 78-kDa size, which was further characterized as human lactoferrin (hLf) using 2-D electrophoresis and MALDI-ToF analysis. Preliminary comparison of HHV-8 binding activity of 76 salivary samples from HHV-8-infected and uninfected individuals showed that 7.8% of the uninfected population exhibited a form of Lf not recognized by HHV-8. Deglycosylation of hLf by PNGase F did not reduce HHV-8 binding activity, whereas endoproteinase cleavage of native hLf generated a non-glycosylated 8-kDa peptide recognized by HHV-8 particles and was located at the position Ala606-Tyr679 in the native hLf amino acid sequence, corresponding to the C-terminal region of the glycoprotein. This work identify the lactoferrin in saliva as a ligand for HHV-8 and suggests that this glycoprotein could be used as a carrier for the viral particles.