Virological and molecular characterization of Kaposi’s sarcoma-associated herpesvirus strains from Xinjiang, China

K1 gene transformation activities in AIDS-related and classic type Kaposi's sarcoma: Correlation with clinical presentation

Kaposi's sarcoma-associated herpesvirus (KSHV) causes both AIDS-related Kaposi's sarcoma (KS) and classic KS, but their clinical presentations are different, and respective mechanisms remain to be elucidated. The KSHV K1 gene is reportedly involved in tumorigenesis through the immunoreceptor tyrosine-based activation motif (ITAM). Since we found the sequence variations in the K1 gene of KSHV isolated from AIDS-related KS and classic KS, we hypothesized that the transformation activity of the K1 gene contributes to the different clinical presentations. To evaluate our hypothesis, we compared the transformation activities of the K1 gene between AIDS-related KS and classic KS. We also analyzed ITAM activities and the downstream AKT and NF-κB. We found that the transformation activity of AIDS-related K1 was greater than that of classic K1, and that AIDS-related K1 induced higher ITAM activity than classic K1, causing more potent Akt and NF-κB activities. K1 downregulation by siRNA in AIDS-related K1 expressing cells induced a loss of transformation properties and decreased both Akt and NF-κB activities, suggesting a correlation between the transformation activity of K1 and ITAM signaling. Our study indicates that the increased transformation activity of AIDS-related K1 is associated with its clinical aggressiveness, whereas the weak transformation activity of classic type K1 is associated with a mild clinical presentation and spontaneous regression. The mechanism of spontaneous regression of classic KS may provide new therapeutic strategy to cancer.

Was Kaposi's sarcoma-associated herpesvirus introduced into China via the ancient Silk Road? An evolutionary perspective

Kaposi's sarcoma-associated herpesvirus (KSHV) has become widely dispersed worldwide since it was first reported in 1994, but the seroprevalence of KSHV varies geographically. KSHV is relatively ubiquitous in Mediterranean areas and the Xinjiang Uygur Autonomous Region, China. The origin of KSHV has long been puzzling. In the present study, we collected and analysed 154 KSHV ORF-K1 sequences obtained from samples originating from Xinjiang, Italy, Greece, Iran and southern Siberia using Bayesian evolutionary analysis in BEAST to test the hypothesis that KSHV was introduced into Xinjiang via the ancient Silk Road. According to the phylogenetic analysis, 72 sequences were subtype A and 82 subtype C, with C2 (n = 56) being the predominant subtype. The times to the most recent common ancestors (tMRCAs) of KSHV were 29,872 years (95% highest probability density [HPD], 26,851-32,760 years) for all analysed sequences and 2037 years (95% HPD, 1843-2229 years) for Xinjiang sequences in particular. The tMRCA of Xinjiang KSHV was exactly matched with the time period of the ancient Silk Road approximately two thousand years ago. This route began in Chang'an, the capital of the Han dynasty of China, and crossed Central Asia, ending in the Roman Empire. The evolution rate of KSHV was slow, with 3.44 × 10-6 substitutions per site per year (95% HPD, 2.26 × 10-6 to 4.71 × 10-6), although 11 codons were discovered to be under positive selection pressure. The geographic distances from Italy to Iran and Xinjiang are more than 4000 and 7000 kilometres, respectively, but no explicit relationship between genetic distance and geographic distance was detected.

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

Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi's sarcoma (KS), which primarily affects human immunodeficiency virus (HIV)-infected adults with advanced immunodeficiency. Xinjiang province in China is an endemic area for Kaposi's sarcoma (KS), however, currently, only limited data for KSHV infection among HIV-infected individuals living in this endemic area is available. A cross-sectional study of 86 HIV positive participants was conducted in Xinjiang, China from 2014 through 2015. Plasma samples were collected and screened for KSHV and HIV infection. HIV pol gene and KSHV ORF-K1 gene were amplified and sequenced, genotypes were determined by phylogenetic analysis. Over all, prevalence was 48.9% (42/86; 95%CI 38.4-59.3%) for KSHV. Only CRF07_BC subtype has been identified among all these HIV positive individuals, while the subtype A and C of KSHV were detected in the participants. Meanwhile, we found that those with high CD4 counts (>500) showed a lower anti-KSHV titer, compared with other groups. Our study indicated a high prevalence of KSHV among HIV positive individuals in Xinjiang, China. Thus, management of HIV/AIDS patients should include KSHV screen and should consider the risk of KSHV-associated malignancies.

One hundred and five Kaposi sarcoma patients: a clinical study in Xinjiang, Northwest of China

BACKGROUND

Kaposi's sarcoma (KS) is an unusual illness that may be associated with human herpes virus 8 (HHV-8) infections, and appears mainly in Jews, Italians and Greeks. There is a lack of patient data in Xinjiang regarding the clinical characteristics of KS.

OBJECTIVES

To review the clinical characteristics of a series of patients with KS in Xinjiang, Northwest China, over 16-year period.

METHODS

A retrospective analysis of patients referred to a Xinjiang hospital in Northwest China with classic KS (CKS) and AIDS-associated KS (AIDS-KS) between January 1997 and April 2013 was performed. Reviewed information included demographics, clinical features, histopathological traits, treatment and presence of HHV-8 infection.

RESULTS

During the study period, 105 patients with a diagnosis of KS, including 77 CKS and 28 AIDS-KS, were referred to our hospital. Mean age at diagnosis was 55.8 ± 16.8 years (range: 25-85 years). There were 70 (90.9%) males and 7 (9.1%) females (male-to-female ratio: 10 : 1) having CKS and 21 (75.0%) males and 7 (25.0%) females (male-to-female ratio: 3 : 1) with AIDS-KS. Most of the patients were Uyghur, including 67 CKS and 24 AIDS-KS. The rate of multifocal lesions at diagnosis was 98.1% (103/105). The most common area of lesions was between 1% and 5% of CKS and AIDS-KS. The main types of lesions were nodules, patches and plaques. The lower extremity and foot were the most common locations for CKS and AIDS-KS. In addition to skin damage, the penis, mouth, lymph nodes and interstitial lung tissues were involved in some cases. No second primary malignancy was diagnosed. Systemic chemotherapy and radiotherapy were effective treatments for CKS. The HHV-8 positivity rate was 98.98% in 98 KS cases.

CONCLUSIONS

In Xinjiang, most CKS and AIDS-KS patients were older Uyghur men. AIDS-KS was found predominantly among 30-year-old Uyghur patients, compared with 60 years for those having CKS. The latter exhibited certain characteristics such as disseminated skin disease; in some patients, the condition was accompanied by lymphedema, visceral or lymph node involvement, but no secondary malignancies. In addition, the HHV-8 positivity rate associated with KS was very high.