Human herpesvirus-8 in Peruvian blood donors: a population with hyperendemic disease?

Evidence for altered host genetic factors in KSHV infection and KSHV-related disease development

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), the most common AIDS-related malignancy. It also causes other rare, but certainly underreported, KSHV-associated pathologies, namely primary effusion lymphoma, multicentric Castleman disease and KSHV inflammatory cytokine syndrome. Epidemiology and pathogenicity studies point to the potential for host genetic predisposition to KSHV infection and/or the subsequent development of KSHV-associated pathologies partly explaining the peculiar geographic and population-specific incidence of KSHV and associated pathologies and discrepancies in KSHV exposure and infection and KSHV infection and disease development. This review consolidates the current knowledge of host genetic factors involved in the KSHV-driven pathogenesis. Studies reviewed here indicate a plausible connection between KSHV susceptibility and host genetic factors that affect either viral access to host cells via entry mechanisms or host innate immunity to viral infection. Subsequent to infection, KSHV-associated pathogenesis, reviewed here primarily in the context of KS, is likely influenced by an orchestrated concert of innate immune system interactions, downstream inflammatory pathways and oncogenic mechanisms. The association studies reviewed here point to interesting candidate genes that may prove important in achieving a more nuanced understanding of the pathogenesis and therapeutic targeting of KSHV and associated diseases. Recent studies on host genetic factors suggest numerous candidate genes strongly associated with KSHV infection or subsequent disease development, particularly innate immune system mediators. Taken together, these contribute toward our understanding of the geographic prevalence and population susceptibility to KSHV and KSHV-associated diseases.

Lymphotropic Viruses EBV, KSHV and HTLV in Latin America: Epidemiology and Associated Malignancies. A Literature-Based Study by the RIAL-CYTED

The Epstein-Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV) and human T-lymphotropic virus (HTLV-1) are lymphomagenic viruses with region-specific induced morbidity. The RIAL-CYTED aims to increase the knowledge of lymphoma in Latin America (LA), and, as such, we systematically analyzed the literature to better understand our risk for virus-induced lymphoma. We observed that high endemicity regions for certain lymphomas, e.g., Mexico and Peru, have a high incidence of EBV-positive lymphomas of T/NK cell origin. Peru also carries the highest frequency of EBV-positive classical Hodgkin lymphoma (HL) and EBV-positive diffuse large B cell lymphoma, not otherwise specified (NOS), than any other LA country. Adult T cell lymphoma is endemic to the North of Brazil and Chile. While only few cases of KSHV-positive lymphomas were found, in spite of the close correlation of Kaposi sarcoma and the prevalence of pathogenic types of KSHV. Both EBV-associated HL and Burkitt lymphoma mainly affect young children, unlike in developed countries, in which adolescents and young adults are the most affected, correlating with an early EBV seroconversion for LA population despite of lack of infectious mononucleosis symptoms. High endemicity of KSHV and HTLV infection was observed among Amerindian populations, with differences between Amazonian and Andean populations.

Kaposi sarcoma

Kaposi sarcoma (KS) gained public attention as an AIDS-defining malignancy; its appearance on the skin was a highly stigmatizing sign of HIV infection during the height of the AIDS epidemic. The widespread introduction of effective antiretrovirals to control HIV by restoring immunocompetence reduced the prevalence of AIDS-related KS, although KS does occur in individuals with well-controlled HIV infection. KS also presents in individuals without HIV infection in older men (classic KS), in sub-Saharan Africa (endemic KS) and in transplant recipients (iatrogenic KS). The aetiologic agent of KS is KS herpesvirus (KSHV; also known as human herpesvirus-8), and viral proteins can induce KS-associated cellular changes that enable the virus to evade the host immune system and allow the infected cell to survive and proliferate despite viral infection. Currently, most cases of KS occur in sub-Saharan Africa, where KSHV infection is prevalent owing to transmission by saliva in childhood compounded by the ongoing AIDS epidemic. Treatment for early AIDS-related KS in previously untreated patients should start with the control of HIV with antiretrovirals, which frequently results in KS regression. In advanced-stage KS, chemotherapy with pegylated liposomal doxorubicin or paclitaxel is the most common treatment, although it is seldom curative. In sub-Saharan Africa, KS continues to have a poor prognosis. Newer treatments for KS based on the mechanisms of its pathogenesis are being explored.

Letter to the editors regarding the paper: Prognostic factors in HIV-positive patients with non-Hodgkin lymphoma: a Peruvian experience

Non-Hodgkin Lymphoma (NHL) is a neoplasm associated with a group of malignancies called AIDs-Defining Malignancies (ADMs) in Human-Immunodeficiency Virus (HIV) -patients. Similar to the case of NHL in Latin America, particularly in Peru, the amount of research done on others ADMs is limited, especially in the case of Kaposi's Sarcoma (KS). Prior investigations have talked about the great potential risk that represents this illness in latin american population, but topics as prognosis factors are yet to be well defined. In this letter, we address the importance of investigation in this area and include previously reported data that may enlighten the current national standpoint.

Global epidemiology of human herpesvirus 8 in men who have sex with men: A systematic review and meta-analysis

Men who have sex with men (MSM) were highly vulnerable to HIV/AIDS and Human herpes virus 8 (HHV8), while the epidemiologic features of HHV8 among MSM remain obscure. We therefore performed a systematic review and meta-analysis to assess the burden of HHV8 in MSM. Electronic databases were searched for publications on HHV8 epidemiologic characteristics among MSM. Random-effect meta-analysis was applied to combine the HHV8 seroprevalence in MSM and odds ratios (ORs) for associated risk factors. Meta-regression and stratified analyses were performed to detect the potential sources of heterogeneity. The pooled HHV8 seroprevalence in MSM was 33.0% (95%CI 29.2%-37.1%). Significant factors associated with HHV8 included HIV (OR 3.70, 95%CI 2.93-4.67), STDs (OR 2.32, 95%CI 1.82-2.97), and high risk sexual behaviors (OR 1.50, 95%CI 1.17-1.92). Race (OR 1.44, 95%CI 0.94-2.12) and multiple sexual partners (OR 1.61, 95%CI 0.95-2.72) were also associated with HHV8 (P < 0.10). We found no significant association between IDU and HHV8 (OR 1.44, 95%CI 0.06-32.47). HHV8 is highly prevalent among MSM and the high risk behaviors may facilitate the transmission of this virus. This situation could be of significant public health importance, especially in the context of HIV coinfection.

Diversity of human herpesvirus 8 genotypes in patients with AIDS and non-AIDS associated Kaposi's sarcoma, Castleman's disease and primary effusion lymphoma in Argentina

HHV-8 genotypes are distributed heterogeneously worldwide. The variable K1 gene and the conserved ORF26E region serve to genotype. The aim of the study was to characterize HHV-8 isolates from patients with AIDS, classical, and iatrogenic KS, primary effusion lymphoma and Castleman's disease and one organ donor from Argentina by analysis of ORFK1 and ORF26E regions. DNA was extracted from fresh or paraffin embedded biopsies, blood, and saliva samples and submitted to HHV-8 PCR. Phylogenetic analyses of ORFK1 showed that subtypes C (C1, C2, and C3), B1 and A (A1, A2, and A3) were present in 70.8%, 16.7%, and 12.5% of cases, respectively. Analyses of ORF26E fragment revealed that most strains (45.8%) were subtype A/C while the remaining fall into K, J, B2, R, and D subtypes. Linkage between ORFK1-ORF26E subtypes corresponded to reported relationships, except for one strain that clustered with B1 (K1 African) and D (ORF26E Asian-Pacific) subtypes. This research reveals predominance of subtype C, a broad spectrum of HHV-8 genotypes and reports the first isolation of the African B genotype in Argentina.

Viral immunology. Comprehensive serological profiling of human populations using a synthetic human virome

The human virome plays important roles in health and immunity. However, current methods for detecting viral infections and antiviral responses have limited throughput and coverage. Here, we present VirScan, a high-throughput method to comprehensively analyze antiviral antibodies using immunoprecipitation and massively parallel DNA sequencing of a bacteriophage library displaying proteome-wide peptides from all human viruses. We assayed over 10(8) antibody-peptide interactions in 569 humans across four continents, nearly doubling the number of previously established viral epitopes. We detected antibodies to an average of 10 viral species per person and 84 species in at least two individuals. Although rates of specific virus exposure were heterogeneous across populations, antibody responses targeted strongly conserved "public epitopes" for each virus, suggesting that they may elicit highly similar antibodies. VirScan is a powerful approach for studying interactions between the virome and the immune system.

Human herpesvirus 8 genotype E in patients with Kaposi sarcoma, Peru

To determine human herpesvirus 8 (HHV-8) K1 genotypes in patients with Kaposi sarcoma (KS) from Peru, we characterized HHV-8 in 25 KS biopsy samples. Our findings of 8 A, 1 B, 14 C, and 2 E subtypes showed high HHV-8 diversity in these patients and association between E genotype and KS development.

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.

Seroprevalence of human herpesvirus 8 infection in individuals from health care centers in Mozambique: potential for endemic and epidemic Kaposi's sarcoma

Human herpesvirus 8 (HHV-8) infection is common in sub-Saharan Africa, but its prevalence in Mozambique is unknown. The seroprevalence of HHV-8 in a cohort of individuals seen at public health centers in Northern (n = 208), Central (n = 226), or Southern (n = 318) Mozambique was examined. All individuals were interviewed to obtain socioeconomic, demographic and clinical data and were tested for serum anti-HHV-8 antibodies using an immunofluorescence assay. The overall frequency of HHV-8 antibodies was 21.4% and, in spite of the diversity of epidemiological characteristics of the tested individuals, did not differ significantly among regions: 18.7%, 24.3% and 21.4% in the North, Center, and South, respectively (chi(2), 2.37; P = 0.305). The variables that were associated significantly with the presence of HHV-8 antibodies were gender, age, level of education, number of siblings and HIV serostatus, but these differed across the regions. In the North, although tested individuals lived under poor socioeconomic conditions, no association between HHV-8 infection and household variables was detected, with the exception of the number of siblings (P = 0.042). In the Central region, HHV-8 infection was associated with gender (P = 0.010), the number of household members (P = 0.031), and the place of attendance (P = 0.021). In the South, HHV-8 infection was associated with the number of siblings (P = 0.023) and HIV status (P = 0.002). The overall prevalence of HHV-8 seropositivity increased with age. These results demonstrate that Mozambique is another country in Africa with endemic HHV-8 infection, and, because of the AIDS epidemic, continued access to antiretroviral treatment is necessary to avert an outbreak of AIDS-Kaposi's sarcoma.

Human herpesvirus-8 in northwestern China: epidemiology and characterization among blood donors

Background

Human herpes virus 8 (HHV-8) is the etiologic agent associated with development of classical, AIDS-related, iatrogenic, and endemic Kaposi's sarcoma (KS). Several studies provide strong evidence that HHV-8 can be transmitted by blood transfusion. We evaluated the seroprevalence and potential risk factors of HHV-8 infection in blood donors in one region. We surveyed HHV-8 infection among 4461 blood donors in Xinjiang, China, a unique endemic area for HHV-8 and KS.

Results

The HHV-8 seroprevalence was higher in local minority groups which comprise most KS cases in China, than in Han people. HHV-8 prevalence was 18.6% in the Han ethnic group, 25.9% in Uygur subjects, 29.2% in Kazak subjects, 36.8% in Mongolian subjects, and 21.9% in other ethnic groups. In several subgroups, the time of donation of whole blood seemed to be a risk factor. In HHV-8-seropositive subjects, a larger fraction of local minorities (23.9%) had high HHV-8 titers than that of Han subjects (9.2%). HHV-8 infection was associated with ethnicity and residence.

Conclusion

HHV-8 seroprevalence was significantly high among blood donors in Xinjiang, where the prevalence of KS correlates with HHV-8 prevalence and titers in Uygur and Kazak ethnic groups. Blood exposure represented by the frequency of blood donation indicated a possible blood-borne transmission route of HHV-8 in Xinjiang. Detecting anti-HHV-8 antibodies before donation in this region is therefore important.

Prevalence and correlates of human herpesvirus 8 infection among Peruvian men who have sex with men

BACKGROUND

Infection with human herpesvirus 8 (HHV-8) is common among men who have sex with men (MSM) in North America and Europe and is also found to be endemic in some regions of South America. Little is known about HHV-8 prevalence and its correlates among MSM in the Andean region.

METHODS

We assessed HHV-8 seroprevalence among 497 MSM recruited for the 2002 Peruvian HIV sentinel surveillance program using a combined HHV-8 enzyme immunoassay and immunofluorescence assay algorithm. Logistic regression analysis was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs) to determine the association between selected covariates and HHV-8 seropositivity.

RESULTS

One hundred thirty-one (66.5%, 95% CI 63.1% to 69.9%) of 197 HIV-infected and 80 (26.7%, 95% CI 24.4% to 29.0%) of 300 HIV-uninfected MSM had serologic evidence of HHV-8 infection. Factors independently associated with HHV-8 infection were education<12 years (OR 1.7, 95% CI 1.1 to 2.7), anal receptive sex with the last partner (OR 2.0, 95% CI 1.2 to 3.3), self-reported sexually transmitted infection symptoms during the last year (OR 1.9, 95% CI 1.2 to 3.0), coinfection with HIV (OR 4.2, 95% CI 2.8 to 6.4) and chronic hepatitis B (OR 4.9, 95% CI 1.5 to 15.8). MSM with long-standing HIV infection were more likely to have serologic evidence of HHV-8 infection when compared with men with recently acquired HIV (OR 3.8, 95% CI 1.7 to 9.1).

CONCLUSIONS

HHV-8 infection is common among both HIV-infected and HIV-negative MSM in Lima, Peru. HHV-8 seropositivity is correlated with anal receptive sex, self-reported sexually transmitted infection symptoms, and HIV infection among these MSM and thus seems to be sexually transmitted. HHV-8 infection seems to be acquired after HIV infection, suggesting that future studies should evaluate the mode of HHV-8 transmission and prevention strategies among HIV-uninfected MSM.