Reactivation of Kaposi's sarcoma-associated herpesvirus by natural products from Kaposi's sarcoma endemic regions

Clinical Significance of Elevated KSHV Viral Load in HIV-Related Kaposi's Sarcoma Patients in South Africa

Kaposi's sarcoma (KS) is an AIDS-defining illness caused by Kaposi's sarcoma-associated herpesvirus (KSHV) predominantly in the context of HIV-related immune suppression. We aimed to explore the usefulness of KSHV DNA viral load (VL) measurement in predicting the severity, response to treatment and outcome of KS. We retrospectively assessed a cohort of KS patients (n = 94) receiving treatment at Groote Schuur Hospital, Cape Town, South Africa. Demographic and clinical data, KS staging and response to treatment were extracted from patient files, while long-term survival was ascertained from hospital records. KSHV serology and VL and hIL-6 were determined empirically from patients' blood. All patients were HIV-positive adults, the majority of whom were on HAART at the time of recruitment. KSHV VL was detectable in 65 patients' blood (median: 280.5/106 cells (IQR: 69.7-1727.3)) and was highest in patients with S1 HIV-related systemic disease (median 1066.9/106 cells, IQR: 70.5-11,269.6). KSHV VL was associated with the S1 stage in a binomial regression controlling for confounders (adjusted odds ratio 5.55, 95% CI: 1.28-24.14, p = 0.022). A subset of six patients identified to have extremely high KSHV VLs was predominantly T1 stage with pulmonary KS, and most had died at follow-up. In our cohort, elevated KSHV VL is associated with systemic HIV-related illness in KS disease. Extremely high KSHV VLs warrant further investigation for patients potentially requiring intensive treatment and investigation for progression or diagnosis of concurrent KSHV lytic syndromes.

Effects of Maternal HIV Infection on Early Kaposi Sarcoma-Associated Herpesvirus Seroconversion in a Kenyan Mother-Infant Cohort

BACKGROUND

We identified whether maternal human immunodeficiency virus (HIV) infection during pregnancy affects transplacental transfer of Kaposi sarcoma-associated herpesvirus (KSHV)-specific antibodies and subsequent infant infection.

METHODS

We followed pregnant Kenyan women through delivery and their infants until age 2 years. Children were classified as HIV-exposed uninfected (HEU) or HIV-unexposed uninfected (HUU) based on maternal HIV status. Maternal venous and cord blood at delivery and child venous blood every 6 months were tested for antibodies to 20 KSHV antigens by multiplex bead-based immunoassay. Multiple comparisons were adjusted using false discovery rate (FDR).

RESULTS

Maternal HIV infection was significantly associated with decreased transplacental transfer of antibodies against all KSHV antigens and lower cord blood levels for 8 antigens at FDR P < .10. Neither birth to 6-month antibody level changes nor 6-month levels differed in HEU and HUU, except for ORF50. By age 24 months, 74% of children KSHV seroconverted but HEU and HUU did not differ in time to seroconversion nor 2-year seropositivity after adjustment for child malaria infection.

CONCLUSIONS

Maternal HIV infection reduced a child's initial KSHV antibody levels but did not affect age of infection. Regardless of HIV exposure in utero, KSHV seroconversion in Kenyan children occurred early; associated factors must be identified.

Distinctive Kaposi Sarcoma-Associated Herpesvirus Serological Profile during Acute Plasmodium falciparum Malaria Episodes

The seroprevalence of Kaposi sarcoma-associated herpesvirus (KSHV) and the incidence of endemic Kaposi sarcoma (KS) overlap with regions of malaria endemicity in sub-Saharan Africa. Multiple studies have shown an increased risk of KSHV seroconversion in children from high malaria compared to low malaria regions; however, the impact of acute episodes of Plasmodium falciparum (P. falciparum) malaria on KSHV's biphasic life cycle and lytic reactivation has not been determined. Here, we examined KSHV serological profiles and viral loads in 134 children with acute malaria and 221 healthy children from high malaria regions in Kisumu, as well as 77 healthy children from low malaria regions in Nandi. We assayed KSHV, Epstein-Barr virus (EBV), and P. falciparum malaria antibody responses in these three by multiplexed Luminex assay. We confirmed that KSHV seroprevalence was significantly associated with malaria endemicity (OR = 1.95, 1.18-3.24 95% CI, p = 0.01) with 71-77% seropositivity in high-malaria (Kisumu) compared to 28% in low-malaria (Nandi) regions. Furthermore, KSHV serological profiles during acute malaria episodes were distinct from age-matched non-malaria-infected children from the same region. Paired IgG levels also varied after malaria treatment, with significantly higher anti-ORF59 at day 0 but elevated ORF38, ORF73, and K8.1 at day 3. Acute malaria episodes is characterized by perturbation of KSHV latency in seropositive children, providing further evidence that malaria endemicity contributes to the observed increase in endemic KS incidence in sub-Saharan Africa.

Kaposi's Sarcoma-Associated Herpesvirus, the Etiological Agent of All Epidemiological Forms of Kaposi's Sarcoma

Simple Summary

Kaposi’s sarcoma-associated herpesvirus (KSHV) is one of the seven oncogenic viruses currently recognized by the International Agency for Research on Cancer. Its presence for Kaposi’s sarcoma development is essential and knowledge on the oncogenic process has increased since its discovery in 1994. However, some uncertainties remain to be clarified, in particular on the exact routes of transmission and disparities in KSHV seroprevalence and the prevalence of Kaposi’s sarcoma worldwide. Here, we summarized the current data on the KSHV viral particle’s structure, its genome, the replication, its seroprevalence, the viral diversity and the lytic and latent oncogenesis proteins involved in Kaposi’s sarcoma. Lastly, we reported the environmental, immunological and viral factors possibly associated with KSHV transmission that could also play a role in the development of Kaposi’s sarcoma.

Abstract

Kaposi’s sarcoma-associated herpesvirus (KSHV), also called human herpesvirus 8 (HHV-8), is an oncogenic virus belonging to the Herpesviridae family. The viral particle is composed of a double-stranded DNA harboring 90 open reading frames, incorporated in an icosahedral capsid and enveloped. The viral cycle is divided in the following two states: a short lytic phase, and a latency phase that leads to a persistent infection in target cells and the expression of a small number of genes, including LANA-1, v-FLIP and v-cyclin. The seroprevalence and risk factors of infection differ around the world, and saliva seems to play a major role in viral transmission. KSHV is found in all epidemiological forms of Kaposi’s sarcoma including classic, endemic, iatrogenic, epidemic and non-epidemic forms. In a Kaposi’s sarcoma lesion, KSHV is mainly in a latent state; however, a small proportion of viral particles (<5%) are in a replicative state and are reported to be potentially involved in the proliferation of neighboring cells, suggesting they have crucial roles in the process of tumorigenesis. KSHV encodes oncogenic proteins (LANA-1, v-FLIP, v-cyclin, v-GPCR, v-IL6, v-CCL, v-MIP, v-IRF, etc.) that can modulate cellular pathways in order to induce the characteristics found in all cancer, including the inhibition of apoptosis, cells’ proliferation stimulation, angiogenesis, inflammation and immune escape, and, therefore, are involved in the development of Kaposi’s sarcoma.

Recent Advances in Developing Treatments of Kaposi's Sarcoma Herpesvirus-Related Diseases

Kaposi-sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV-8) is the causative agent of several malignancies, including Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). Active KSHV replication has also been associated with a pathological condition called KSHV inflammatory cytokine syndrome (KICS), and KSHV may play a role in rare cases of post-transplant polyclonal lymphoproliferative disorders. Several commonly used herpesviral DNA polymerase inhibitors are active against KSHV in tissue culture. Unfortunately, they are not always efficacious against KSHV-induced diseases. To improve the outcome for the patients, new therapeutics need to be developed, including treatment strategies that target either viral proteins or cellular pathways involved in tumor growth and/or supporting the viral life cycle. In this review, we summarize the most commonly established treatments against KSHV-related diseases and review recent developments and promising new compounds that are currently under investigation or on the way to clinical use.

Risk Factors for Kaposi's Sarcoma-Associated Herpesvirus DNA in Blood and in Saliva in Rural Uganda

BACKGROUND

Detectable Kaposi's sarcoma-associated herpesvirus (KSHV) DNA in blood and increased antibody titres may indicate KSHV reactivation, while the transmission of KSHV occurs via viral shedding in saliva.

METHODS

We investigated the risk factors for KSHV DNA detection by real-time polymerase chain reaction in blood and by viral shedding in saliva, in 878 people aged 3 to 89 years of both sexes in a rural Ugandan population cohort. Helminths were detected using microscopy and the presence of malaria parasitaemia was identified using rapid diagnostic tests. Regression modelling was used for a statistical analysis.

RESULTS

The KSHV viral load in blood did not correlate with the viral load in saliva, suggesting separate immunological controls within each compartment. The proportions of individuals with a detectable virus in blood were 23% among children aged 3-5 years and 22% among those 6-12 years, thereafter reducing with increasing age. The proportions of individuals with a detectable virus in saliva increased from 30% in children aged 3-5 years to 45% in those aged 6-12 years, and decreased subsequently with increasing age. Overall, 29% of males shed in saliva, compared to 19% of females (P = .008).

CONCLUSIONS

Together, these data suggest that young males may be responsible for much of the onward transmission of KSHV. Individuals with a current malaria infection had higher levels of viral DNA in their blood (P = .031), compared to uninfected individuals. This suggests that malaria may lead to KSHV reactivation, thereby increasing the transmission and pathogenicity of the virus.

Variation in KSHV prevalence between geographically proximate locations in Uganda

Kaposi's sarcoma-associated herpesvirus (KSHV) transmission within endemic areas may vary. KSHV seroprevalence has been studied by different groups of researchers using different methods, making it difficult to make direct comparisons. Here we show results on KSHV seroprevalence using the same laboratory method from four different but geographically proximate populations in Uganda. Blood samples from the urban Entebbe Mother and Baby Study (EMaBS), the rural General Population Cohort (GPC), the fishing community Lake Victoria Island Intervention Study on Worms and Allergy related Diseases (LaVIISWA) and the high-risk sexual behaviour Good Health for Women Project (GHWP), were tested for IgG antibody levels to K8.1 and ORF73 recombinant proteins using ELISA. All adult participants of the EMaBS study and the GHWP were women, while the GPC (54% female) and LaVIISWA (52% female) studies had both males and females. EMaBS children were all 5 years of age while their mothers were 14 to 47 years of age. GHWP women were 15 to 45 years old, LaVIISWA participants were 1 to 72 years old while GPC participants were 1 to 103 years old. KSHV seropositivity varied in the different populations. In children aged 5 years, EMaBS had the lowest prevalence of 15% followed by GPC at 35% and LaVIISWA at 54%. In adult women, seropositivity varied from 69% (EMaBS) to 80% (LaVIISWA) to 87% (GPC) to 90% (GHWP). The reasons for the variation in prevalence are unclear but may reflect differences in the prevalence of cofactors between these four geographically proximate populations.

Mutual detection of Kaposi's sarcoma-associated herpesvirus and Epstein-Barr virus in blood and saliva of Cameroonians with and without Kaposi's sarcoma

Kaposi's sarcoma-associated herpesvirus (KSHV) and Epstein-Barr virus (EBV) are prevalent in sub-Saharan Africa, together with HIV; the consequent burden of disease is grave. The cofactors driving transmission of the two viruses and pathogenesis of associated malignancies are not well understood. We measured KSHV and EBV DNA in whole blood and saliva as well as serum antibodies levels in 175 Cameroonians with Kaposi's sarcoma and 1,002 age- and sex-matched controls with and without HIV. KSHV seroprevalence was very high (81%) in controls, while EBV seroprevalence was 100% overall. KSHV DNA was detectable in the blood of 36-46% of cases and 6-12% of controls; EBV DNA was detected in most participants (72-89%). In saliva, more cases (50-58%) than controls (25-28%) shed KSHV, regardless of HIV infection. EBV shedding was common (75-100%); more HIV+ than HIV- controls shed EBV. Cases had higher KSHV and EBV VL in blood and saliva then controls, only among HIV+ participants. KSHV and EBV VL were also higher in HIV+ than in HIV- controls. Cases (but not controls) were more likely to have detectable KSHV in blood if they also had EBV, whereas shedding of each virus in saliva was independent. While EBV VL in saliva and blood were modestly correlated, no correlation existed for KSHV. Numerous factors, several related to parasitic coinfections, were associated with detection of either virus or with VL. These findings may help better understand the interplay between the two gammaherpesviruses and generally among copathogens contributing to cancer burden in sub-Saharan Africa.

Role of iron in cancer development by viruses

Increased levels of iron in body are attributed to higher cancer risk. Given the fact that 16% of all human cancers are caused by viral infections, iron is suggested to play an important role in carcinogenesis particularly those induced by viral infections. The present study provides an updated summary of the literature and the plausible mechanisms of iron involvement in cancer development by viruses. Our understanding about the interplay between viral infections and iron in different settings particularly cancer development is yet to be improved as it may shed a new light in development of new therapeutic strategies.

Polymorphisms in KSHV-encoded microRNA sequences affect levels of mature viral microRNA in Kaposi Sarcoma lesions

Background

We previously reported Kaposi sarcoma-associated herpesvirus (KSHV) microRNA sequence variants in clinical samples correlated with increased risk of multicentric Castleman's disease (MCD). We then demonstrated that microRNAs with variant sequence have different maturation and mature microRNA expression in vitro. Here, we illustrate the association between microRNA sequence and changes in mature microRNA levels within Kaposi sarcoma (KS) lesions.

Methods

KSHV microRNA sequences were determined from 20 KS lesions and 4 control skin biopsies from individuals evaluated for KS. Levels of mature KSHV microRNAs were measured with 21 custom small RNA qRT-PCR assays using RNA RNU6B as endogenous control.

Results

The levels of 13 KSHV-encoded microRNAs were elevated in KS lesions compared to control biopsies. MicroRNA 9-5p was strongly down regulated in South African vs. US biopsies. Low levels of K12-9-5p were associated with single nucleotide polymorphisms (SNPs) in miR-K12-9-5p, 4-5p, 5-3p, 7-3p and pri-miR-K12-3. One SNP in pri-miR-K12-3 resulted in down regulation of miR-K12-6-3p, 8-3p, 10-3p, 12-5p and the upregulation of 5-5p, illustrating sequence variants outside pre-microRNAs were also associated with changes in mature microRNA levels.

Conclusions

The levels of mature KSHV-encoded microRNAs in KS lesions correlate with sequence variation reflecting changes in secondary and tertiary RNA structure.

EPHA2 sequence variants are associated with susceptibility to Kaposi's sarcoma-associated herpesvirus infection and Kaposi's sarcoma prevalence in HIV-infected patients

BACKGROUND

To determine if variations exist in the KSHV host receptor EPHA2's coding region that affect KSHV infectivity and/or KS prevalence among South African HIV-infected patients.

METHODS

A retrospective candidate gene association study was performed on 150 patients which were randomly selected from a total of 756 HIV-infected patients and grouped according to their KS status and KSHV serodiagnosis; namely group 1: KS+/KSHV+; group 2: KS-/KSHV+; group 3: KS-/KSHV-. Peripheral blood DNA was used to extract DNA and PCR amplify and sequence the entire EPHA2 coding region, which was compared to the NCBI reference through multiple alignment.

RESULTS

100% (95% CI 92.9-100%) of the KS positive patients, and 31.6% (95% CI 28.3-35.1%) of the KS negative patients were found to be KSHV seropositive. Aggregate variation across the entire EPHA2 coding region identified an association with KS (OR = 6.6 (95% CI 2.8, 15.9), p = 2.2 × 10-5). This was primarily driven by variation in the functionally important protein tyrosine kinase domain (Pkinase-Tyr; OR = 4.9 (95% CI 1.9, 12.4), p = 0.001) and the sterile-α-motif (SAM; OR = 13.8 (95% CI 1.7, 111.6), p = 0.014). Mutation analysis revealed two novel, non-synonymous heterozygous variants (c.2254 T > C: OR undefined, adj. p = 0.02; and c.2990 G > T: OR undefined, adj. p = 0.04) in Pkinase-Tyr and SAM, respectively, to be statistically associated with KS; and a novel heterozygous transition (c.2727C > T: OR = 6.4 (95% CI 1.4, 28.4), adj. p = 0.03) in Pkinase-Tyr to be statistically associated with KSHV.

CONCLUSIONS

Variations in the KSHV entry receptor gene EPHA2 affected susceptibility to KSHV infection and KS development in a South African HIV-infected patient cohort.

Chromatin remodeling controls Kaposi's sarcoma-associated herpesvirus reactivation from latency

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of three human malignancies, the endothelial cell cancer Kaposi's sarcoma, and two B cell cancers, Primary Effusion Lymphoma and multicentric Castleman's disease. KSHV has latent and lytic phases of the viral life cycle, and while both contribute to viral pathogenesis, lytic proteins contribute to KSHV-mediated oncogenesis. Reactivation from latency is driven by the KSHV lytic gene transactivator RTA, and RTA transcription is controlled by epigenetic modifications. To identify host chromatin-modifying proteins that are involved in the latent to lytic transition, we screened a panel of inhibitors that target epigenetic regulatory proteins for their ability to stimulate KSHV reactivation. We found several novel regulators of viral reactivation: an inhibitor of Bmi1, PTC-209, two additional histone deacetylase inhibitors, Romidepsin and Panobinostat, and the bromodomain inhibitor (+)-JQ1. All of these compounds stimulate lytic gene expression, viral genome replication, and release of infectious virions. Treatment with Romidepsin, Panobinostat, and PTC-209 induces histone modifications at the RTA promoter, and results in nucleosome depletion at this locus. Finally, silencing Bmi1 induces KSHV reactivation, indicating that Bmi1, a member of the Polycomb repressive complex 1, is critical for maintaining KSHV latency.

Determinants of Gammaherpesvirus Shedding in Saliva Among Ugandan Children and Their Mothers

Background

Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) are transmitted via saliva, but factors associated with salivary shedding are unknown.

Methods

We measured the DNA load of both viruses in saliva specimens collected from approximately 500 Ugandan mothers and their 6-year-old children, testing all participants for EBV and KSHV-seropositive individuals for KSHV.

Results

EBV and KSHV were shed by 72% and 22% of mothers, respectively, and by 85% and 40% of children, respectively; boys were more likely than girls to shed KSHV (48% vs 30%) but were equally likely to shed EBV. Children shed more KSHV and EBV than mothers, but salivary loads of EBV and KSHV were similar. KSHV shedding increased with increasing anti-KSHV (K8.1) antibodies in mothers and with decreasing antimalarial antibodies both in mothers and children. Among mothers, 40% of KSHV shedders also shed EBV, compared with 75% of KSHV nonshedders; among children, EBV was shed by 65% and 83%, respectively.

Conclusions

In summary, in this population, individuals were more likely to shed EBV than KSHV in saliva. We identified several factors, including child's sex, that influence KSHV shedding, and we detected an inverse relationship between EBV and KSHV shedding, suggesting a direct or indirect interaction between the two viruses.

Kaposi sarcoma herpesvirus pathogenesis

Kaposi sarcoma herpesvirus (KSHV), taxonomical name human gammaherpesvirus 8, is a phylogenetically old human virus that co-evolved with human populations, but is now only common (seroprevalence greater than 10%) in sub-Saharan Africa, around the Mediterranean Sea, parts of South America and in a few ethnic communities. KSHV causes three human malignancies, Kaposi sarcoma, primary effusion lymphoma, and many cases of the plasmablastic form of multicentric Castleman's disease (MCD) as well as occasional cases of plasmablastic lymphoma arising from MCD; it has also been linked to rare cases of bone marrow failure and hepatitis. As it has colonized humans physiologically for many thousand years, cofactors are needed to allow it to unfold its pathogenic potential. In most cases, these include immune defects of genetic, iatrogenic or infectious origin, and inflammation appears to play an important role in disease development. Our much improved understanding of its life cycle and its role in pathogenesis should now allow us to develop new therapeutic strategies directed against key viral proteins or intracellular pathways that are crucial for virus replication or persistence. Likewise, its limited (for a herpesvirus) distribution and transmission should offer an opportunity for the development and use of a vaccine to prevent transmission.

This article is part of the themed issue ‘Human oncogenic viruses’.

Egr-1 regulates RTA transcription through a cooperative involvement of transcriptional regulators

Kaposi's sarcoma associated herpesvirus (KSHV) regulates the host cellular environment to establish life-long persistent infection by manipulating cellular signaling pathways, with approximately 1- 5% of cells undergoing lytic reactivation during the course of infection. Egr-1 (Early Growth Response Factor-1) is one such cellular transcription factor, which gets phosphorylated during the lytic phase of viral life cycle to perpetrate its function. This study demonstrates the mechanism of how Egr-1 mediates transcription of the immediate early gene, RTA (Replication and transcription activator), which is the lytic switch gene of KSHV. Egr-1 depleted KSHV infected cells exhibited reduced expression of RTA. Also, an increase in Egr-1 phosphorylation led to a higher virion production, which was suppressed in the presence of p38 and Raf inhibitors. Reporter assays showed that coexpression of Egr-1 and CBP (CREB-binding protein) enhances RTA promoter activity as compared to the expression of either Egr-1 or CBP alone. Binding of Egr-1 and CBP at RTA promoter was analyzed by chromatin immunoprecipitation assay (ChIP), which showed an enhanced accumulation during viral reactivation. Mutation in Egr-1 binding site of the RTA promoter eliminated Egr-1 response on promoter activation. Furthermore, de novo infection of THP-1 (monocytic) and HUVECs (endothelial) cells showed an upregulation of Egr-1 phosphorylation, whereas depletion of Egr-1 reduced the mRNA levels of RTA during primary infection. Together, these results demonstrate a cooperative role of Egr-1 and CBP in mediating RTA transcription, which significantly improves our understanding of the involvement of cellular factors controlling RTA transcription in KSHV pathogenesis.

Beral et al's 1990 paper on Kaposi's sarcoma among persons with AIDS: demonstrating the power of descriptive epidemiology

Here we discuss the impact of Beral et al's 1990 paper "Kaposi's sarcoma among persons with AIDS: a sexually transmitted infection?" Not only did this paper galvanise research into the underlying infectious cause of Kaposi's sarcoma, it also demonstrated the power of observational epidemiology in pointing the way towards major discoveries.

Kaposi Sarcoma-associated Herpesvirus: mechanisms of oncogenesis

Kaposi Sarcoma-associated Herpesvirus (KSHV, HHV8) causes three human malignancies, Kaposi Sarcoma (KS), an endothelial tumor, as well as Primary Effusion Lymphoma (PEL) and the plasma cell variant of Multicentric Castleman's Disease (MCD), two B-cell lymphoproliferative diseases. All three cancers occur primarily in the context of immune deficiency and/or HIV infection, but their pathogenesis differs. KS most likely results from the combined effects of an endotheliotropic virus with angiogenic properties and inflammatory stimuli and thus represents an interesting example of a cancer that arises in an inflammatory context. Viral and cellular angiogenic and inflammatory factors also play an important role in the pathogenesis of MCD. In contrast, PEL represents an autonomously growing malignancy that is, however, still dependent on the continuous presence of KSHV and the action of several KSHV proteins.

The discovery of novel antifungal scaffolds by structural simplification of the natural product sampangine

Structural simplification of the natural product sampangine led to the discovery of two novel antifungal compounds with excellent activity and low toxicity.

Rituximab plus liposomal doxorubicin in HIV-infected patients with KSHV-associated multicentric Castleman disease

Kaposi sarcoma (KS) herpesvirus-associated multicentric Castleman disease (KSHV-MCD) is a lymphoproliferative disorder, most commonly seen in HIV-infected patients, that has a high mortality if untreated. Concurrent KS is common. Although rituximab has reported activity in KSHV-MCD, its use is often associated with KS progression. Within a natural history study of KSHV-MCD, we prospectively evaluated rituximab 375 mg/m(2) combined with liposomal doxorubicin 20 mg/m(2) (R-Dox) every 3 weeks in 17 patients. Patients received a median of 4 cycles (range 3-9). All received antiretroviral therapy, 11 received consolidation interferon-α, and 6 received consolidation high-dose zidovudine with valganciclovir. Using NCI KSHV-MCD response criteria, major clinical and biochemical responses were attained in 94% and 88% of patients, respectively. With a median 58 months' potential follow-up, 3-year event-free survival was 69% and 3-year overall survival was 81%. During R-Dox therapy, cutaneous KS developed in 1 patient, whereas 5 of 6 patients with it had clinical improvement. R-Dox was associated with significant improvement in anemia and hypoalbuminemia. KSHV viral load, KSHV viral interleukin-6, C-reactive protein, human interleukin-6, and serum immunoglobulin free light chains decreased with therapy. R-Dox is effective in symptomatic KSHV-MCD and may be useful in patients with concurrent KS. This trial was registered at www.clinicaltrials.gov as #NCT00092222.

Epidemiology and transmission of Kaposi's sarcoma-associated herpesvirus

This review summarizes the current knowledge pertaining to Kaposi sarcoma-associated herpesvirus (KSHV) epidemiology and transmission. Since the identification of KSHV twenty years ago, it is now known to be associated with Kaposi's sarcoma (KS), primary effusion lymphoma, and multicentric Castleman's disease. Many studies have been conducted to understand its epidemiology and pathogenesis and their results clearly show that the worldwide distribution of KSHV is uneven. Some geographical areas, such as sub-Saharan Africa, the Mediterranean region and the Xinjiang region of China, are endemic areas, but Western Europe and United States have a low prevalence in the general population. This makes it imperative to understand the risk factors associated with acquisition of infection. KSHV can be transmitted via sexual contact and non-sexual routes, such as transfusion of contaminated blood and tissues transplants, or via saliva contact. There is now a general consensus that salivary transmission is the main route of transmission, especially in children residing in endemic areas. Therefore, there is a need to better understand the sources of transmission to young children. Additionally, lack of animal models to study transmission, gold standard serological assay and the lack of emphasis on endemic KS research has hampered the efforts to further delineate KSHV transmission in order to design effective prevention strategies.

Vascular endothelial growth factor A polymorphism and risk of Kaposi's sarcoma herpesvirus viremia in kidney allograft recipients

BACKGROUND

Kaposi's sarcoma herpesvirus (KSHV) causes Kaposi's sarcoma (KS), primary effusion lymphoma, and multicentric Castleman's disease in immunocompromised patients including allograft recipients. Detection of KSHV DNA in blood, as well as host genetic polymorphisms has been found to be associated with an increased risk for KS. We investigated an association between single nucleotide polymorphisms (SNPs) in vascular endothelial growth factor A (VEGFA) gene region and KSHV viremia in kidney transplant recipients (KTR) in Saudi Arabia.

METHODS

In total, 152 KTR who have survived kidney transplantation for at least 6 months were included in the study. KSHV viremia was determined by real-time polymerase chain reaction (PCR). Genotyping of SNPs in the VEGFA region was performed by PCR and direct sequencing, as well as by restriction fragment length polymorphism.

RESULTS

KSHV DNA was detected in 28.9% (n = 44) of the study population. The A-allele at position C172A VEGFA gene promoter region was found to be associated with KSHV viremia (odd ratio [OR] = 4.8, P = 0.005). In addition, the G-allele at position C+405G in the 5'-untranslated region was associated with KSHV viremia in women, but not in men (OR = 3.98, P = 0.004).

CONCLUSIONS

Our results suggest an association of VEGFA polymorphisms with KSHV viremia among KTR in this study population. A limitation of our study is that the results can only be predicated for patients 6 months after kidney transplantation and should be validated in another cohort with larger sample size.

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.

A Review of Human Herpesvirus 8, the Kaposi's Sarcoma-Associated Herpesvirus, in the Pediatric Population

Human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma (KS)-associated herpesvirus, is the etiologic agent responsible for all types of KS. Although the majority of pediatric KS cases occur in sub-Saharan Africa, a rise in pediatric transplant KS has been reported in developed countries. In addition, HHV-8 is increasingly described as an infectious cause of hemophagocytic lymphohistiocytosis in children. Transmission of HHV-8 among children is poorly understood; however, the literature strongly suggests that horizontal transmission plays a critical role. Acute infection with HHV-8 and progression to KS in children may be different than in adults, and diagnosis may be overlooked. Currently, neither adult nor pediatric treatment guidelines exist. This review provides an overview of HHV-8 disease in children as it relates to epidemic KS, transplant KS, and other disease manifestations. The current state of the literature is reviewed and knowledge gaps are identified for future exploration.

Kaposi's sarcoma: etiology and pathogenesis, inducing factors, causal associations, and treatments: facts and controversies

Kaposi's sarcoma (KS), an angioproliferative disorder, has a viral etiology and a multifactorial pathogenesis hinged on an immune dysfunction. The disease is multifocal, with a course ranging from indolent, with only skin manifestations to fulminant, with extensive visceral involvement. In the current view, all forms of KS have a common etiology in human herpesvirus (HHV)-8 infection, and the differences among them are due to the involvement of various cofactors. In fact, HHV-8 infection can be considered a necessary but not sufficient condition for the development of KS, because further factors (genetic, immunologic, and environmental) are required. The role of cofactors can be attributed to their ability to interact with HHV-8, to affect the immune system, or to act as vasoactive agents. In this contribution, a survey of the current state of knowledge on many and various factors involved in KS pathogenesis is carried out, in particular by highlighting the facts and controversies about the role of some drugs (quinine analogues and angiotensin-converting enzyme inhibitors) in the onset of the disease. Based on these assessments, it is possible to hypothesize that the role of cofactors in KS pathogenesis can move toward an effect either favoring or inhibiting the onset of the disease, depending on the presence of other agents modulating the pathogenesis itself, such as genetic predisposition, environmental factors, drug intake, or lymph flow disorders. It is possible that the same agents may act as either stimulating or inhibiting cofactors according to the patient’s genetic background and variable interactions.

Treatment guidelines for each form of KS are outlined, because a unique standard therapy for all of them cannot be considered due to KS heterogeneity. In most cases, therapeutic options, both local and systemic, should be tailored to the patient’s peculiar clinical conditions.

Bioactive activities of natural products against herpesvirus infection

More than 90% of adults have been infected with at least one human herpesvirus, which establish long-term latent infection for the life of the host. While anti-viral drugs exist that limit herpesvirus replication, many of these are ineffective against latent infection. Moreover, drug-resistant strains of herpesvirus emerge following chemotherapeutic treatment. For example, resistance to acyclovir and related nucleoside analogues can occur when mutations arise in either HSV thymidine kinase or DNA polymerases. Thus, there exists an unmet medical need to develop new anti-herpesvirus agents with different mechanisms of action. In this Review, we discuss the promise of anti-herpetic substances derived from natural products including extracts and pure compounds from potential herbal medicines. One example is Glycyrrhizic acid isolated from licorice that shows promising antiviral activity towards human gammaherpesviruses. Secondly, we discuss anti-herpetic mechanisms utilized by several natural products in molecular level. While nucleoside analogues inhibit replicating herpesviruses in lytic replication, some natural products can disrupt the herpesvirus latent infection in the host cell. In addition, natural products can stimulate immune responses against herpesviral infection. These findings suggest that natural products could be one of the best choices for development of new treatments for latent herpesvirus infection, and may provide synergistic anti-viral activity when supplemented with nucleoside analogues. Therefore, it is important to identify which natural products are more efficacious anti-herpetic agents, and to understand the molecular mechanism in detail for further advance in the anti-viral therapies.

Quantitative determinations of anti-Kaposi sarcoma-associated herpesvirus antibody levels in men who have sex with men

Infection with Kaposi sarcoma-associated herpesvirus (KSHV; also called human herpesvirus-8) is common among men who have sex with men (MSM). Here, quantitative anti-KSHV antibody levels were measured using luciferase immunoprecipitation systems (LIPS) in an MSM cohort with and without HIV from the NIH Clinical Center. Antibodies were detected using a mixture of 4 KSHV antigens in the MSM cohort and in Kaposi sarcoma (KS) patients. Along with HIV status, these results were compared with K8.1 and ORF73 ELISA, PCR virus detection, and additional LIPS testing. LIPS revealed that 25% (76/307) of the MSM cohort were KSHV seropositive, including 59 HIV+ and 17 HIV- subjects. The anti-KSHV antibody levels detected by LIPS were not statistically different between the KSHV+/HIV+ and KSHV+/HIV- subgroups but were lower than the KS patients (P < 0.0001). ELISA analysis of the MSM cohort detected a 35.5% frequency of KSHV infection and showed agreement with 81% of the samples evaluated by LIPS. Further LIPS testing with v-cyclin, a second ORF73 fragment and ORF38 reconciled some of the differences observed between LIPS and the ELISA immunoassays, and the revised LIPS seroprevalence in the MSM cohort was increased to 31%. Additional quantitative antibody analysis demonstrated statistically lower KSHV antibody levels in MSM compared to KS patients, but no difference was found between KSHV infected with and without HIV coinfection. These findings also suggest that antibodies against v-cyclin and ORF38 are useful for identifying patients with asymptomatic KSHV infection.

Dangerous liaisons: molecular basis for a syndemic relationship between Kaposi's sarcoma and P. falciparum malaria

The most severe manifestations of malaria (caused by Plasmodium falciparum) occur as a direct result of parasitemia following invasion of erythrocytes by post-liver blood-stage merozoites, and during subsequent cyto-adherence of infected erythrocytes to the vascular endothelium. However, the disproportionate epidemiologic clustering of severe malaria with aggressive forms of endemic diseases such as Kaposi's sarcoma (KS), a neoplasm that is etiologically linked to infection with KS-associated herpesvirus (KSHV), underscores the significance of previously unexplored co-pathogenetic interactions that have the potential to modify the overall disease burden in co-infected individuals. Based on recent studies of the mechanisms that P. falciparum and KSHV have evolved to interact with their mutual human host, several new perspectives are emerging that highlight a surprising convergence of biological themes potentially underlying their associated co-morbidities. Against this background, ongoing studies are rapidly constructing a fascinating new paradigm in which the major host receptors that control parasite invasion (Basigin/CD147) and cyto-adherence (CD36) are, surprisingly, also important targets for exploitation by KSHV. In this article, we consider the major pathobiological implications of the co-option of Basigin/CD147 and CD36 signaling pathways by both P. falciparum and KSHV, not only as essential host factors for parasite persistence but also as important mediators of the pro-angiogenic phenotype within the virus-infected endothelial microenvironment. Consequently, the triangulation of interactions between P. falciparum, KSHV, and their mutual human host articulates a syndemic relationship that points to a conceptual framework for prevalence of aggressive forms of KS in malaria-endemic areas, with implications for the possibility of dual-use therapies against these debilitating infections in resource-limited parts of the world.

Oral HIV-Associated Kaposi Sarcoma: A Clinical Study from the Ga-Rankuwa Area, South Africa

Background. Kaposi sarcoma (KS) is one of the most common neoplasms diagnosed in HIV-seropositive subjects. Oral involvement is frequent and is associated with a poor prognosis. The aim of this study was to characterize the features of oral HIV-KS in patients from Ga-Rankuwa, South Africa. Methods. All cases with confirmed oral HIV-KS treated at the oral medicine clinic in Ga-Rankuwa from 2004 to 2010 were included in this retrospective study. Differences between males and females with oral HIV-KS in relation to HIV infection status, to oral KS presentation and to survival rates were statistically analysed. Results. Twenty (54%) of the 37 patients in the study were females and 17 (46%) were males. In 21 patients (57%), the initial presentation of HIV-KS was in the mouth. Other than the fact that females presented with larger (≥10 mm) oral KS lesions (P = 0.0004), there were no statistically significant gender differences. Significantly more patients presented with multiple oral HIV-KS lesions than with single lesions (P = 0.0003). Nine patients (24%) developed concomitant facial lymphoedema, and these patients had a significantly lower CD4+ T-cell count (28 cells/mm(3)) compared to the rest of the group (130 cells/mm(3)) (P = 0.01). The average CD4+ T-cell count of the patients who died (64 cells/mm(3)) was significantly lower (P = 0.0004), there were no statistically significant gender differences. Significantly more patients presented with multiple oral HIV-KS lesions than with single lesions (P = 0.016) at the time of oral-KS presentation than of those who survived (166  cells/mm(3)).

CONCLUSIONS

In Ga-Rankuwa, South Africa where HIV-KS is prevalent, oral KS affects similarly males and females. A low CD4+ T-cell count at the time of oral HIV-KS diagnosis and the development of facial lymphoedema during the course of HIV-KS disease portends a poor prognosis.

Parasite infection is associated with Kaposi's sarcoma associated herpesvirus (KSHV) in Ugandan women

Background

Immune modulation by parasites may influence susceptibility to bacteria and viruses. We examined the association between current parasite infections, HIV and syphilis (measured in blood or stool samples using standard methods) and antibodies against Kaposi's sarcoma herpesvirus (KSHV), measured by ELISA, in 1915 stored plasma samples from pregnant women in Entebbe, Uganda.

Results

Seroprevalence of KSHV was higher in women with malaria parasitaemia (73% vs 60% p = 0.01), hookworm (67% vs 56% p = 0.001) and Mansonella perstans (69% vs 59% p = 0.05); seroprevalence increased with increasing intensity of hookworm infection (p < 0.001[trend]). No associations were found for HIV, five other parasites or active syphilis. These effects were not explained by socioeconomic status or education.

Conclusions

Specific parasite infections are associated with presence of antibodies against KSHV, perhaps mediated via their effect on immune function.

Molecular epidemiology of human herpesvirus 8 variants in Kaposi's sarcoma from Iranian patients

Kaposi's sarcoma (KS) is a rare cancer in Iran and there is no epidemiological and molecular information about HHV-8 variants circulating among the Iranian population. In this study HHV-8 sequences have been analyzed in 43 cutaneous KS biopsies from Iranian patients mainly affected by classic KS. DNA samples were subjected to PCR amplification of HHV-8 ORF26, T0.7 and K1 followed by direct nucleotide sequencing and phylogenetic analysis. The analysis of ORF26 showed that 30 (69.8%) and 13 (30.2%) samples belonged to subtypes A/C and K, respectively. In general, the clustering of HHV-8 T0.7 variants paralleled that of ORF26. Genotyping of K1 sequences showed that the majority of samples (39 out of 41) fall into the large C clade with only 2 belonging to the A clade. In conclusion, HHV-8 variants identified among classic Iranian KS are largely related to Eurasian genotypes previously identified in KS from Mediterranean, Middle East, and East Asian regions.

High-dose zidovudine plus valganciclovir for Kaposi sarcoma herpesvirus-associated multicentric Castleman disease: a pilot study of virus-activated cytotoxic therapy

Kaposi sarcoma herpesvirus (KSHV)-associated multicentric Castleman disease (MCD) is a lymphoproliferative disorder most commonly observed in HIV-infected patients. It is characterized by KSHV-infected plasmablasts that frequently express lytic genes. Patients manifest inflammatory symptoms attributed to overproduction of KSHV viral IL-6, human IL-6, and human IL-6. There is no standard therapy and no established response criteria. We investigated an approach targeting 2 KSHV lytic genes, ORF36 and ORF21, the protein of which, respectively, phosphorylate ganciclovir and zidovudine to toxic moieties. In a pilot study, 14 HIV-infected patients with symptomatic KSHV-MCD received high-dose zidovudine (600 mg orally every 6 hours) and the oral prodrug, valganciclovir (900 mg orally every 12 hours). Responses were evaluated using new response criteria. A total of 86% of patients attained major clinical responses and 50% attained major biochemical responses. Median progression-free survival was 6 months. With 43 months of median follow-up, overall survival was 86% at 12 months and beyond. At the time of best response, the patients showed significant improvements in C-reactive protein, albumin, platelets, human IL-6, IL-10, and KSHV viral load. The most common toxicities were hematologic. These observations provide evidence that therapy designed to target cells with lytic KSHV replication has activity in KSHV-MCD. This trial was registered at www.clinicaltrials.gov as #NCT00099073.

Kaposi sarcoma and quinine: a potentially overlooked triggering factor in millions of Africans

Kaposi sarcoma (KS)-associated herpesvirus, also known as human herpesvirus 8, is necessary but not sufficient for the development of KS. Lytic reactivation of human herpesvirus 8 may be important in KS pathogenesis. KS and its causative agent, KS-associated herpesvirus, have distinctive largely unexplained geographic distributions. We note the recent "oncoweed" hypothesis of biologic plants in the environment accounting for this reactivation. We believe that quinine and its derivatives might better explain the epidemiology of KS than oncoweeds. Indeed, we propose an "oncodrug" hypothesis, specifically with regard to quinine and its derivatives, a linkage first advanced by one of us (V. R.) and associates in 1984.

Mechanisms of Kaposi's Sarcoma-Associated Herpesvirus Latency and Reactivation

The life cycle of Kaposi's sarcoma-associated herpesvirus (KSHV) consists of latent and lytic replication phases. During latent infection, only a limited number of KSHV genes are expressed. However, this phase of replication is essential for persistent infection, evasion of host immune response, and induction of KSHV-related malignancies. KSHV reactivation from latency produces a wide range of viral products and infectious virions. The resulting de novo infection and viral lytic products modulate diverse cellular pathways and stromal microenvironment, which promote the development of Kaposi's sarcoma (KS). The mechanisms controlling KSHV latency and reactivation are complex, involving both viral and host factors, and are modulated by diverse environmental factors. Here, we review the cellular and molecular basis of KSHV latency and reactivation with a focus on the most recent advancements in the field.

Risk of classic Kaposi sarcoma with exposures to plants and soils in Sicily

Background

Ecologic and in vitro studies suggest that exposures to plants or soil may influence risk of Kaposi sarcoma (KS).

Methods

In a population-based study of Sicily, we analyzed data on contact with 20 plants and residential exposure to 17 soils reported by 122 classic KS cases and 840 sex- and age-matched controls. With 88 KS-associated herpesvirus (KSHV) seropositive controls as the referent group, novel correlates of KS risk were sought, along with factors distinguishing seronegatives, in multinomial logistic regression models that included matching variables and known KS cofactors - smoking, cortisone use, and diabetes history. All plants were summed for cumulative exposure. Factor and cluster analyses were used to obtain scores and groups, respectively. Individual plants and soils in three levels of exposure with P_trend ≤ 0.15 were retained in a backward elimination regression model.

Results

Adjusted for known cofactors, KS was not related to cumulative exposures to 20 plants [per quartile adjusted odds ratio (OR_adj) 0.96, 95% confidence interval (CI) 0.73 - 1.25, P_trend = 0.87], nor was it related to any factor scores or cluster of plants (P = 0.11 to 0.81). In the elimination regression model, KS risk was associated with five plants (P_trend = 0.02 to 0.10) and with residential exposure to six soils (P_trend = 0.01 to 0.13), including three soils (eutric regosol, chromic/pellic vertisol) used to cultivate durum wheat. None of the KS-associated plants and only one soil was also associated with KSHV serostatus. Diabetes was associated with KSHV seronegativity (OR_adj 4.69, 95% CI 1.97 - 11.17), but the plant and soil associations had little effect on previous findings that KS risk was elevated for diabetics (OR_adj 7.47, 95% CI 3.04 - 18.35) and lower for current and former smokers (OR_adj 0.26 and 0.47, respectively, P_trend = 0.05).

Conclusions

KS risk was associated with exposure to a few plants and soils, but these may merely be due to chance. Study of the effects of durum wheat, which was previously associated with cKS, may be warranted.

Patterns of antibodies against latent and lytic antigens of human herpesvirus 8 in an endemic population and patients with Kaposi's sarcoma in Mozambique

The patterns of antibodies against latent and lytic antigens of human herpesvirus 8 (HHV-8) were assessed using immunofluorescence assays of samples from 155 persons seropositive for HHV-8 seen at public health centers and 24 patients with Kaposi's sarcoma (KS) from Mozambique. Of the 155 persons without KS, 48 (31%) had antibodies against latent antigens only, 29 (18.7%) had antibodies against lytic antigens only, and 78 (50.3%) had antibodies against both types of antigen. The HHV-8 antibody titer tended to increase with age until age 40, after which it began to decrease. High titers of antibodies against latent and lytic antigens of HHV-8 were detected mostly in persons co-infected with HIV, and these increased titers could have a predictive value. All patients with KS except four patients who were seronegative for HHV-8 had elevated titers of HHV-8 antibodies, predominantly against latent antigens. The data suggest the potential for an increase in the development of KS in this endemic area for HHV-8.

HLA polymorphisms and detection of kaposi sarcoma-associated herpesvirus DNA in saliva and peripheral blood among children and their mothers in the uganda sickle cell anemia KSHV Study

Kaposi sarcoma-associated herpesvirus (KSHV, also called Human herpesvirus 8 or HHV8) is a γ-2 herpesvirus that causes Kaposi sarcoma. KSHV seroprevalence rates vary geographically with variable rates recorded in different sub Sahara African countries, suggesting that effects of genetic and/or environmental factors may influence the risk of infection. One study conducted in South Africa, where KSHV seroprevalence is relatively low, found that carriage of human leukocyte antigen (HLA) alleles HLA-A*6801, HLA-A*30, HLA-A*4301, and HLA-DRB1*04 was associated with increased shedding of KSHV DNA in saliva. Confirmation of those results would strengthen the hypothesis that genetic factors may influence KSHV distribution by modulating KSHV shedding in saliva. To explore these associations in another setting, we used high resolution HLA-A, B, and DRB1 typing on residual samples from the Uganda Sickle Cell Anemia KSHV study, conducted in a high KSHV seroprevalence region, to investigate associations between HLA and KSHV shedding in saliva or peripheral blood among 233 children and their mothers. HLA-A and HLA-DRB1 alleles were not associated with KSHV shedding in our study, but our study was small and was not adequately powered to exclude small associations. In exploratory analyses, we found marginal association of KSHV DNA shedding in saliva but not in peripheral blood among children carrying HLA- B*4415 and marginal association of KSHV DNA shedding in peripheral blood but not in saliva among children carrying HLA- B*0801 alleles. The contribution of individual HLA polymorphisms to KSHV shedding is important but it may vary in different populations. Larger population-based studies are needed to estimate the magnitude and direction of association of HLA with KSHV shedding and viral control.

MDM2 and CDKN1A gene polymorphisms and risk of Kaposi's sarcoma in African and Caucasian patients

A single-nucleotide polymorphism in the MDM2 promoter (SNP309; rs2279744) causes elevated transcription of this major negative regulator of p53 in several cancer types. We investigated MDM2 SNP309 and CDKN1A (p21/Waf1/Cip1) codon 31 (rs1801270) polymorphisms in 86 cases of cutaneous Kaposi's sarcoma (KS) from African and Caucasian patients, and 210 healthy controls. A significant increase of the MDM2 SNP309 T/G genotype was observed among classic KS cases (odds ratio 2.38, 95% confidence interval 1.0-5.5). Frequencies of CDKN1A codon 31 genotypes were not significantly different between cases and controls. The results suggest that the MDM2 SNP309 G allele may act as a susceptibility gene for the development of classic KS in Caucasian patients.

Sex and geographic patterns of human herpesvirus 8 infection in a nationally representative population‐based sample in Uganda

BACKGROUND

Human herpesvirus 8 (HHV8), the infectious cause of Kaposi sarcoma, varies dramatically across Africa, suggesting that cofactors correlated with large-area geographic or environmental characteristics may influence risk of infection. Variation in HHV8 seropositivity across small-area regions within countries in Africa is unknown. We investigated this issue in Uganda, where Kaposi sarcoma distribution is uneven and well described.

METHODS

Archival samples from individuals aged 15-59 years randomly selected from a nationally representative 2004-2005 human immunodeficiency virus-AIDS serobehavioral survey were tested for HHV8 seropositivity with use of enzyme immunoassays based on synthetic peptides from the K8.1 and orf65 viral genes. Adjusted odds ratios and 95% confidence intervals (CIs) of association of HHV8 seropositivity with demographic risk factors were estimated.

RESULTS

Among 2681 individuals tested, HHV8 seropositivity was 55.4%. HHV8 seropositivity was lower in female than in male persons (adjusted odds ratio, 0.82 [95% CI, 0.69-0.97]) and increased 2.2% (95% CI, 1.0%-3.6%) in female persons and 1.2% (95% CI, 1.0%-2.3%) in male persons per year of age. HHV8 seropositivity was inversely associated with education ( P = .01, for trend) and was elevated in the West Nile region, compared with the Central region (adjusted odds ratio, 1.49 [95% CI, 1.02-2.18]) but not with other regions.

CONCLUSIONS

Our findings suggest that HHV8 seropositivity in Uganda may be influenced by cofactors correlated with small-area geography, age, sex, and education.

Kaposi's Sarcoma Associated-Herpes Virus (KSHV) Seroprevalence in Pregnant Women in South Africa

Background

Factors previously associated with Kaposi's sarcoma-associated herpesvirus (KSHV) transmission in Africa include sexual, familial, and proximity to river water. We measured the seroprevalence of KSHV in relation to HIV, syphilis, and demographic factors among pregnant women attending public antenatal clinics in the Gauteng province of South Africa.

Methods

We tested for antibodies to KSHV lytic K8.1 and latent Orf73 antigens in 1740 pregnant women attending antenatal clinics who contributed blood to the "National HIV and Syphilis Sero-Prevalence Survey - South Africa, 2001". Information on HIV and syphilis serology, age, education, residential area, gravidity, and parity was anonymously linked to evaluate risk factors for KSHV seropositivity. Clinics were grouped by municipality regions and their proximity to the two main river catchments defined.

Results

KSHV seropositivity (reactive to either lytic K8.1 and latent Orf73) was nearly twice that of HIV (44.6% vs. 23.1%). HIV and syphilis seropositivity was 12.7% and 14.9% in women without KSHV, and 36.1% and 19.9% respectively in those with KSHV. Women who are KSHV seropositive were 4 times more likely to be HIV positive than those who were KSHV seronegative (AOR 4.1 95%CI: 3.4 - 5.7). Although, women with HIV infection were more likely to be syphilis seropositive (AOR 1.8 95%CI: 1.3 - 2.4), no association between KSHV and syphilis seropositivity was observed. Those with higher levels of education had lower levels of KSHV seropositivity compared to those with lower education levels. KSHV seropositivity showed a heterogeneous pattern of prevalence in some localities.

Conclusions

The association between KSHV and HIV seropositivity and a lack of common association with syphilis, suggests that KSHV transmission may involve geographical and cultural factors other than sexual transmission.

An interleukin-6-related systemic inflammatory syndrome in patients co-infected with Kaposi sarcoma-associated herpesvirus and HIV but without Multicentric Castleman disease

BACKGROUND

Kaposi sarcoma-associated herpesvirus (KSHV) is the causal agent for Kaposi sarcoma (KS) and multicentric Castleman disease (MCD) in human immunodeficiency virus (HIV)-infected patients. Patients with KSHV-MCD develop fevers, wasting, hypoalbuminemia, cytopenias, and hyponatremia that are related to overproduction of KSHV-encoded viral interleukin (IL)-6 (vIL-6) and human IL-6 (hIL-6).

METHODS

We identified 6 HIV-infected patients with KS or serological evidence of KSHV infection who had severe inflammatory MCD-like symptoms but in whom we could not diagnose MCD, and we hypothesized that these symptoms resulted from vIL-6 overproduction. Serum vIL-6 levels were assessed in these 6 patients and compared with levels in 8 control patients with symptomatic KSHV-MCD and 32 control patients with KS. KSHV viral load, serum hIL-6 level, and human IL-10 level were also evaluated.

RESULTS

Patients with inflammatory MCD-like symptoms but without MCD had elevated vIL-6 levels, comparable with levels in patients with symptomatic KSHV-MCD, and had levels that were significantly greater than those in control patients with KS (P = .003). Elevated hIL-6, IL-10, and KSHV viral loads were also comparable to patients with symptomatic KSHV-MCD and significantly greater than those with KS.

CONCLUSIONS

A subset of patients with HIV and KSHV co-infection, but without MCD, can develop severe systemic inflammatory symptoms associated with elevated levels of KSHV vIL-6, IL-6, and KSHV viral loads. Excess lytic activation of KSHV, production of the lytic gene product vIL6, and associated immunologic dysregulation may underlie the pathophysiology of these symptoms. This IL-6-related inflammatory syndrome is important to consider in critically ill patients with HIV and KSHV co-infection.

Socio-economic and other correlates of Kaposi sarcoma-associated herpesvirus seroprevalence among older adults in Sicily

The virus that causes Kaposi sarcoma, KS-associated herpesvirus (KSHV, also known as human herpesvirus 8) has an unusual distribution and poorly characterized modes of transmission. To clarify these issues, socio-demographic correlates of KSHV seroprevalence were examined in a population-based study. In 1,154 randomly sampled adults (aged 32- 92, mean 71 years) throughout Sicily, KSHV antibodies were detected with four assays and a conservative algorithm. Seroprevalence was re-weighted to the population. Odds ratios with 95% confidence intervals (OR, CI) from multivariate logistic regression were used to estimate associations of seroprevalence with interview data. KSHV seroprevalence was 8.5%, including 5.3% among men (N = 848) and 11.5% among women (N = 306, P = 0.22). Seroprevalence was higher with residence in a smaller community during childhood (P(trend) = 0.03) and working with plants/soil during adulthood (OR 2.9, CI 1.1-7.9); these were especially strong among women. Among men, seroprevalence was significantly associated with lower education (OR 2.6, CI 1.1-5.9) and migration to a larger community (OR 0.3, CI 0.1-0.9). Other demographic and household variables were unrelated to seroprevalence. From these data, KSHV in Sicily appears to be related to low socio-economic status, but micro-endemicity in small communities cannot be excluded.

Distribution of 'promoter' sandflies associated with incidence of classic Kaposi's sarcoma

The patchy geographical distributions of classic Kaposi's sarcoma (KS) and human herpesvirus type 8 (HHV-8), better known as Kaposi's sarcoma-associated herpesvirus (KSHV) remain unexplained. It has been proposed that certain species of bloodsucking insects ('promoter arthropods') promote the reactivation of HHV-8/KSHV and facilitate both HHV-8/KSHV transmission and KS development. This hypothesis was tested by sampling the presence and density of human-biting Diptera with CDC light traps in two areas of Sardinia with contrasting incidence rates of classic KS. In total, 11,030 specimens (99.9% sandflies and 0.1% mosquitoes) belonging to 10 species were collected from 40 rural sites. Five of these species are considered to be possible promoter arthropods because of the irritation their bites cause: Phlebotomus perniciosus Newstead; Phlebotomus perfiliewi Parrot (Diptera: Psychodidae); Aedes berlandi Seguy; Culiseta annulata (Schrank) and Culex theileri Theobald (Diptera: Culicidae). Five species are probable 'non-promoters' because their bites are not particularly irritating: Culiseta longiareolata (Macquart); Culex pipiens s.l.; Anopheles algeriensis Theobald; Anopheles maculipennis s.l., and Anopheles plumbeus Stephens. A significant correlation was found between the geographical distribution of promoter arthropods and incidence rates of KS (Spearman's r = 0.59,P < 0.01). Promoter arthropods were more likely to be caught in areas with cutaneous leishmaniasis and a past high prevalence of malaria, and in areas of limestone, acid volcanic soil and cereal cultivation. The study supports the association between promoter arthropods and classic KS, which may explain the geographic variability of KS and HHV-8/KSHV, and highlights the links with a number of variables previously associated with the incidence of KS.

Kaposi sarcoma-associated herpesvirus (KSHV) seroprevalence in population-based samples of African children: evidence for at least 2 patterns of KSHV transmission

BACKGROUND

Kaposi sarcoma-associated herpesvirus (KSHV) infection is endemic among adult populations in Africa. A prevailing view is that childhood transmission is primarily responsible for the high seroprevalence of KSHV among adults that is observed throughout the continent. However, few studies have directly examined children, particularly in locations where KS is not commonly endemic.

METHODS

Participants were children aged 1.5-8.9 years, including 427 children from a population-based sample in South Africa, 422 from a population-based sample in Uganda, and 567 from a clinic-based sample in Uganda. All serum specimens were tested by the same laboratory for KSHV antibodies with use of 2 enzyme immunoassays (against K8.1 and ORF65) and 1 immunofluorescence assay.

RESULTS

KSHV seroprevalence was 7.5%-9.0% among South African children and was not associated with age. In contrast, in the Ugandan population-based sample, KSHV seroprevalence increased from 10% among 2-year-old children to 30.6% among 8-year-old children (P(trend) < .001). In the Ugandan clinic-based sample, seroprevalence increased from 9.3% among 2-year-old children to 36.4% among 8-year-old children (P(trend) < .001).

CONCLUSION

Two distinct relationships between age and KSHV infection among children imply that KSHV transmission among children is not uniform throughout Africa and is therefore not always responsible for the high seroprevalence observed in adults. There are at least 2 patterns of KSHV transmission in Africa.

Seroprevalence and risk factors for human herpesvirus 8 infection, rural Egypt

Seroprevalence and Risk Factors for Human Herpesvirus 8 Infection, Rural Egypt, Salivary and nosocomial transmission are possible.

To determine whether human herpesvirus 8 (HHV-8) is associated with schistosomal and hepatitis C virus infections in Egypt, we surveyed 965 rural household participants who had been tested for HHV-8 and schistosomal infection (seroprevalence 14.2% and 68.6%, respectively, among those <15 years of age, and 24.2% and 72.8%, respectively, among those ≥15 years of age). Among adults, HHV-8 seropositivity was associated with higher age, lower education, dental treatment, tattoos, >10 lifetime injections, and hepatitis C virus seropositivity. In adjusted analyses, HHV-8 seropositivity was associated with dental treatment among men (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.1–5.2) and hepatitis C virus seropositivity among women (OR 3.3, 95% CI 1.4–7.9). HHV-8 association with antischistosomal antibodies was not significant for men (OR 2.1, 95% CI 0.3–16.4), but marginal for women (OR 1.5, 95% CI 1.0–2.5). Our findings suggest salivary and possible nosocomial HHV-8 transmission in rural Egypt.