Kaposi's sarcoma-associated herpesvirus (KSHV) infection: Endemic strains and cladograms from immunodeficient patients in China

Prevalence and Risk Factors of Kaposi’s Sarcoma-Associated Herpesvirus Infection among Han and Uygur Populations in Xinjiang, China

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), which is endangering human health worldwide, especially in Africa, Europe, the United States, and parts of Asia. The aim of this study was to investigate the prevalence of KSHV in Xinjiang. Three KSHV recombinant proteins (ORF65, ORF73, and K8.1) were used to detect KSHV infection. The serum samples to be tested were detected by an indirect ELISA method. The overall infection rate of KSHV in Xinjiang was 25.60%, with a higher infection rate in the Uygur population of 29.79%. After adjusting for possible confounders, Uygur (OR = 3.95, 95% CI 2.64–6.12, P < 0.001), agriculture and livestock (OR = 1.60, 95% CI 1.20–2.17, P = 0.002), age ≤ 50 years (OR = 1.50, 95% CI 1.13–2.00, P = 0.006), and predominantly meat-based diet (OR = 1.72, 95% CI 1.11–2.78, P = 0.018) were significantly associated with the odds of KSHV seropositivity correlation. Three unique sequences of KSHV were obtained in this study; genotypic analysis showed that the three unique sequences were all subtype A2.

Seroprevalence of human herpesvirus 8 and its impact on the hemoglobin level in patients of end stage of renal diseases

The incidence of Kaposi's sarcoma (KS) is increasing among renal transplant recipients. Patients with end-stage renal disease (ESRD) are immunocompromised and are candidates for renal transplantation, but HHV8 seroprevalence in ESRD patients has not been well documented. A cross-sectional study of 286 ESRD patients and 281 matched subjects without kidney disease was conducted at the First People's Hospital of Huzhou, Zhejiang province to explore the epidemiologic features of HHV8 among ESRD patients in China. Blood samples were collected and HHV8 antibodies and serologic indices were measured. The seroprevalence of HHV8 was 15.3% for ESRD patients and 8.9% for the comparison group. A significant difference in the geometric mean titer (GMT) of the HHV8 antibodies was detected between ESRD patients and the comparison group (617.1 vs 291.7; P = 0.042). The average level of hemoglobin was 11.56 ± 1.78 g/dL for the ESRD group and 13.73 ± 1.42 g/dL for the comparison group, (P > 0.05). Multiple linear regression revealed a negative association between HHV8 infection and plasma hemoglobin concentration (β = -0.682, P = 0.036). We found a higher HHV8 prevalence and a higher level of HHV8 antibody GMT in ESRD patients than the comparison group, which indicate a high risk of posttransplantation KS.

The RBP-Jκ binding sites within the RTA promoter regulate KSHV latent infection and cell proliferation

Kaposi's sarcoma-associated herpesvirus (KSHV) is tightly linked to at least two lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). However, the development of KSHV-mediated lymphoproliferative disease is not fully understood. Here, we generated two recombinant KSHV viruses deleted for the first RBP-Jκ binding site (RTA_1st) and all three RBP-Jκ binding sites (RTA_all) within the RTA promoter. Our results showed that RTA_1st and RTA_all recombinant viruses possess increased viral latency and a decreased capability for lytic replication in HEK 293 cells, enhancing colony formation and proliferation of infected cells. Furthermore, recombinant RTA_1st and RTA_all viruses showed greater infectivity in human peripheral blood mononuclear cells (PBMCs) relative to wt KSHV. Interestingly, KSHV BAC36 wt, RTA_1st and RTA_all recombinant viruses infected both T and B cells and all three viruses efficiently infected T and B cells in a time-dependent manner early after infection. Also, the capability of both RTA_1st and RTA_all recombinant viruses to infect CD19+ B cells was significantly enhanced. Surprisingly, RTA_1st and RTA_all recombinant viruses showed greater infectivity for CD3+ T cells up to 7 days. Furthermore, studies in Telomerase-immortalized human umbilical vein endothelial (TIVE) cells infected with KSHV corroborated our data that RTA_1st and RTA_all recombinant viruses have enhanced ability to persist in latently infected cells with increased proliferation. These recombinant viruses now provide a model to explore early stages of primary infection in human PBMCs and development of KSHV-associated lymphoproliferative diseases.

Kaposi's sarcoma-associated herpesvirus (KSHV) is tightly linked to at least two lymphoproliferative disorders, primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD). The life cycle of KSHV consists of latent and lytic phase. RTA is the master switch for viral lytic replication. In this study, we first show that recombinant viruses deleted for the RBP-Jκ sites within the RTA promoter have a decreased capability for lytic replication, and thus enhanced colony formation and proliferation of infected cells. Interestingly, the recombinant viruses show greater infectivity in human peripheral blood mononuclear cells (PBMCs). The recombinant viruses also infected CD19+ B cells and CD3+ T cells with increased efficiency in a time-dependent manner and now provide a model which can be used to explore the early stages of primary infection in human PBMCs, as well as the development of KSHV-associated lymphoproliferative diseases.

Prevalence of human herpesvirus 8 and hepatitis C virus in a rural community with a high risk for blood-borne infections in central China

Illegal blood donation in the past decade has caused human immunodeficiency virus (HIV) outbreaks in some rural areas in China. Other HIV-associated virus infections, such as those caused by human herpesvirus 8 (HHV8), in such areas are still not well defined. In order to explore HHV8 and hepatitis C virus (HCV) seroprevalence and potential risk factors in such areas, a cross-sectional study with 305 HIV-positive and 315 HIV-negative subjects recruited from a rural county in Shanxi province was conducted, in which illegal blood collection was reported. Interview questionnaires and serum testing were carried out with these participants. HCV and HHV8 seroprevalence were found to be higher in the HIV-positive than in the HIV-negative group (76.4% vs. 2.5% and 15.4% vs. 4.8%, respectively), whereas the difference in HBV seroprevalence was not significant. Co-infection with HCV and HHV8 was also more prevalent in the HIV-positive group. HIV status (OR 2.71; 95% CI 1.16-6.30) and HBV status (OR 2.56; 95% CI 1.14-5.75) were independently associated with HHV8 infection. HIV status (OR 23.03; 95% CI 9.95-53.27) and blood/plasma selling history (OR 14.57; 95% CI 7.49-28.23) were strongly associated with HCV infection. These findings demonstrate that both HHV8 and HCV infections are prevalent in this community. HIV infection is an important risk factor for both HHV8 and HCV infection. HBV infection is associated with HHV8 infection but not with HCV infection. It is possible that HHV8 and hepatitis B virus, but not HCV, have similar modes of transmission in this population.

Update on KSHV epidemiology, Kaposi Sarcoma pathogenesis, and treatment of Kaposi Sarcoma

Much has been learned since the discovery of KSHV in 1994 about its epidemiology and pathology but much of what has been learned has yet to be translated into clinical practice. In this review, we survey the current state of knowledge on KSHV epidemiology and KS pathogenesis and highlight therapeutic opportunities in both the developed and developing world.

Generation and application of polyclonal antibody against replication and transcription activator of Kaposi's sarcoma-associated herpesvirus

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi's sarcoma, the most common neoplasm in untreated HIV-1-infected individuals, and several B cell disorders. KSHV infection goes through lytic and latent phases, and the switch from latency to lytic replication is governed by viral replication and transcription activator (RTA). RTA consists of 691 amino acids, containing an N-terminal DNA-binding and a C-terminal activation domain. In the present study, polyclonal antibody against RTA was generated and evaluated. The C-terminal region of RTA (E482 approximately D691) was expressed in Escherichia coli, purified by affinity chromatography, and utilized to raise polyclonal antibody in BALB/c mice. High-affinity antisera were obtained, which successfully detected the antigen at a dilution of 1:13,500 for ELISA and 1:20,000 for Western blot analysis. The antibody can specifically recognize full-length RTA expressed in both E. coli and mammalian cells. Furthermore, endogenous RTA can be detected with the antibody in TPA-induced BCBL-1 cells under various conditions. These results suggested that the antibody is valuable for the investigation of biochemical properties and biological functions of RTA.