Seroprevalence of Kaposi's sarcoma-associated herpesvirus among HIV-infected Uygurs in Xinjiang, China

Role of the Killer Immunoglobulin-like Receptor and Human Leukocyte Antigen I Complex Polymorphisms in Kaposi Sarcoma-Associated Herpesvirus Infection

Background

Kaposi sarcoma, caused by the pathogen Kaposi sarcoma-associated herpesvirus (KSHV), is the most common neoplasm for patients with AIDS. Susceptibility to KSHV has been associated with several different genetic risk variants. The purpose of this study was to test whether variants of killer cell immunoglobulin-like receptors (KIRs) and their human leukocyte antigen (HLA-I) ligands influence the risk of KSHV infection.

Methods

A case-control study was performed in Xinjiang, a KSHV-endemic region of China. We recruited 299 individuals with HIV, including 123 KSHV-seropositive persons and 176 KSHV-seronegative controls. We used logistic regression and the MiDAS package to evaluate the association between KIR/HLA-I polymorphisms and KSHV infection.

Results

HLA-A*31:01, HLA-C*03:04, and HLA-C*12:03 were found to be associated with KSHV infection, with A*31:01 showing a protective effect under 3 different models (dominant: 0.30 [95% confidence interval {CI}, .08-.82], P = .031; additive: 0.30 [95% CI, .09-.80], P = .030; overdominant: 0.31 [95% CI, .09-.88], P = .042). The effect of A*31:01 might cause the variants of amino acid at HLA-A position 56, with individuals carrying an arginine having a lower KSHV infection risk. The increased homozygous KIR2DL3 was associated with a relatively high KSHV viral load (16.30% vs 41.94%, P = .010).

Conclusions

This study provides further insight into the link between HLA-I alleles and KIR genes and KSHV infection, highlighting KSHV-susceptible variants of HLA-I and KSHV replication caused by specific KIR genotype, and revealing a potential role of KIR-mediated natural killer cell activation in anti-KSHV infection.

Environmental risk factors and genetic markers of Kaposi's sarcoma associated herpesvirus infection among Uygur population in Xinjiang, China

OBJECTIVES

Kaposi sarcoma-associated herpesvirus (KSHV) is endemic in Xinjiang, China. Determinants of KSHV seropositivity among high-risk groups are not well understood. We seek to identify genetic and environmental predisposing factors for KSHV infection among Uygurs in this endemic region.

METHODS

A cross-sectional study was performed among Uygur population in Xinjiang, China. KSHV-antibodies were detected using immunofluorescence assay (IFA) and human leukocyte antigen (HLA) alleles were genotyped. Univariate and multivariate logistic regression analysis were applied to explore the environmental and genetic risk factors of KSHV seropositivity.

RESULTS

A total of 721 participants were included. The seroprevalence of KSHV was 24.1% among this population. Sweet-food preference (OR 1.85, 95%CI 1.03-3.34), and coronary heart disease (OR 1.91, 95 %CI 1.24-2.94) were statistically correlated with KSHV infection. HLA-DQB1*06:09 were found to significantly increase the risk of KSHV infection under all 3 models (OR_Allelic =4.06; OR_Dominant =3.27; OR_Recessive =8.06). Six SNPs (SNP0260, SNP0361, SNP0797, SNP0852, SNP1159, SNP1375) in the DQB1 and DRB1 region and haploid type GTCTAACTAATC in block 17 were statistically associated with KSHV infection.

CONCLUSION

We demonstrated that genetic variations in HLA-DQB1/DRB1 and environmental risk factors were strongly associated with KSHV infection among this population. This article is protected by copyright. All rights reserved.

Seroprevalence of human herpesvirus 8 in Ireland among blood donors, men who have sex with men, and heterosexual genitourinary medicine and infectious diseases clinic attendees

Human herpesvirus 8 (HHV-8) seroprevalence varies geographically and between subpopulations. High seroprevalence rates have been ascribed to men who have sex with men (MSM), African migrants, and HIV-infected individuals. The objective of this study was to determine the seroprevalence of HHV-8 in an Irish population, including specific risk groups. A cross-sectional study of 200 blood donors and 200 genitourinary medicine (GUM) and infectious diseases (ID) clinic patients was performed, with testing for Immunoglobulin G (IgG) antibodies to HHV-8 lytic antigens using a commercial indirect fluorescence assay (Scimedx Corp.). Verification was performed at the Centers for Disease Control and Prevention (CDC). All 200 blood donor samples were negative for HHV-8 IgG antibodies. 21% of GUM and ID patients were positive for HHV-8 IgG antibodies. One hundred of these patients were MSM, 35% of whom were HHV-8 seropositive (46% of HIV-positive MSM and 24% of HIV-negative MSM). Of 100 heterosexual patients, only 7% were HHV-8 seropositive. The absence of seropositivity in 200 Irish blood donors may suggest that Ireland has a low overall population HHV-8 seroprevalence. The proportion of HHV-8 seropositivity in the MSM population was significantly higher than in the heterosexual population and most marked in HIV-positive MSM.

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

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

Role of Pattern Recognition Receptors in KSHV Infection

Kaposi’s sarcoma-associated herpesvirus or Human herpesvirus-8 (KSHV/HHV-8), an oncogenic human herpesvirus and the leading cause of cancer in HIV-infected individuals, is a major public health concern with recurring reports of epidemics on a global level. The early detection of KSHV virus and subsequent activation of the antiviral immune response by the host’s immune system are crucial to prevent KSHV infection. The host’s immune system is an evolutionary conserved system that provides the most important line of defense against invading microbial pathogens, including viruses. Viruses are initially detected by the cells of the host innate immune system, which evoke concerted antiviral responses via the secretion of interferons (IFNs) and inflammatory cytokines/chemokines for elimination of the invaders. Type I IFN and cytokine gene expression are regulated by multiple intracellular signaling pathways that are activated by germline-encoded host sensors, i.e., pattern recognition receptors (PRRs) that recognize a conserved set of ligands, known as ‘pathogen-associated molecular patterns (PAMPs)’. On the contrary, persistent and dysregulated signaling of PRRs promotes numerous tumor-causing inflammatory events in various human cancers. Being an integral component of the mammalian innate immune response and due to their constitutive activation in tumor cells, targeting PRRs appears to be an effective strategy for tumor prevention and/or treatment. Cellular PRRs are known to respond to KSHV infection, and KSHV has been shown to be armed with an array of strategies to selectively inhibit cellular PRR-based immune sensing to its benefit. In particular, KSHV has acquired specific immunomodulatory genes to effectively subvert PRR responses during the early stages of primary infection, lytic reactivation and latency, for a successful establishment of a life-long persistent infection. The current review aims to comprehensively summarize the latest advances in our knowledge of role of PRRs in KSHV infections.

Prevalence of Kaposi's sarcoma-associated herpesvirus in Uygur and Han populations from the Urumqi and Kashgar regions of Xinjiang, China

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the infectious etiologic agent associated with Kaposi’s sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease. It has been shown that high KSHV prevalence and high incidence of both classic KS and AIDSassociated KS are found mostly among people of Uygur ethnicity in Xinjiang, while people of Han ethnicity in Xinjiang have a higher KSHV seroprevalence than those of other Han populations in mainland China. However, it is still unclear why there is such geographical and population variation in KSHV distribution in China. In this work, we focused on the populations in the Kashgar region and Urumqi area, where a total of 1294 research subjects were randomly selected to investigate the potential correlation between KSHV prevalence and different ethnicities in endemic areas of Xinjiang, and to determine risk factors that may affect KSHV infection rates or KS incidence. We identified a high seroprevalence of KSHV and high peripheral blood DNA infection in the general Uygur and Han populations in both Urumqi and Kashgar regions of Xinjiang, and determined that advancing age, low education level, and stationary population status affect KSHV infection rates. Further, KSHV-positive Uygur participants were shown to have higher prevalence of neutralizing antibodies and neutralizing antibody titers than KSHV-positive Han participants.

Prevalence of Kaposi's sarcoma-associated herpesvirus among intravenous drug users: a systematic review and meta-analysis

Intravenous drug users (IDUs) have been demonstrated to be highly vulnerable to HIV/AIDS. Nevertheless, the prevalence of Kaposi's sarcoma associated herpesvirus (KSHV), an important co-infected agent with HIV, among this population remained obscure. We conducted a systematic review on the epidemiological features of KSHV among IDUs worldwide. Eligible studies were retrieved from 6 electronic databases (PubMed, EMBASE, Web of Science, CBM, CNKI and Wanfang). We calculated the pooled prevalence and 95% confidence interval (CI) overall and among subgroups using either random-effects model or fixed-effects model depending on between-study heterogeneity. The potential publication bias was assessed by the Egger's test. A meta-regression analysis was performed to explore the sources of heterogeneity. Finally, twenty-two studies with a total sample of 7881 IDUs were included in the analysis. The pooled prevalence of KSHV was 14.71% (95% CI 11.12%-19.46%) among IDUs. Specifically, KSHV prevalence was 10.86% (95% CI 6.95%-16.96%) in HIV-negative IDUs, and 13.56% (95% CI 10.57%-17.38%) in HIV-positive IDUs. Moreover, prevalence among IDUs from the three continents involved in the current study was similar: 16.10% (95%CI 7.73%-33.54%) in Asia; 14.22% (95%CI 8.96%-22.57%) in Europe and 14.06% (95%CI 11.38%-17.37%) in America. Globally, IDUs are at higher risk of the KSHV infection when compared with the general population, regardless of geographical region or HIV-infection status.