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Kaposi's sarcoma-associated herpesvirus (KSHV) is the causal agent of all forms of Kaposi's sarcoma (KS), including AIDS-KS, endemic KS, classic KS and iatrogenic KS. Based on Open reading frame (ORF) K1 sequence analysis, KSHV has been classified into seven major molecular subtypes (A, B, C, D, E, F and Z). The distribution of KSHV strains varies according to geography and ethnicity. Xinjiang is a unique region where the seroprevalence of KSHV is significantly higher than other parts of China. The genotyping of KSHV strains in this region has not been thoroughly studied. The present study aimed to evaluate the frequency of KSHV genotypes isolated from KS tissues in Classical KS and AIDS KS patients from Xinjiang, China. ORF-K1 of KSHV from tissue samples of 28 KS patients was amplified and sequenced. Two subtypes of KSHV were identified according to K1 genotyping. Twenty-three of them belonged to subtype A, while five of them were subtype C. More genotype A than genotype C strains were found in both Classical KS and AIDS KS. No significant difference was found in the prevalence of different genotype between Classical KS and AIDS KS.

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causal agent of Kaposi's sarcoma (KS), a common cancer in patients with acquired immunodeficiency syndrome. The risk factors for KSHV infection have been extensively studied for Western countries but remain largely undefined for other parts of the world. Schistosomiasis, caused by Schistosoma japonicum infection, was recently identified as a cofactor for KSHV infection in rural Egypt. In this study, we examined the seroprevalence of KSHV in a population along the Yangtze River in China that has a high incidence of schistosomiasis. KSHV seroprevalence in subjects with schistosomiasis was slightly higher than that in subjects without schistosomiasis, but the difference was not statistically significant (8.4% versus 6.6%; P = 0.204). However, after adjusting for gender, KSHV seroprevalence in men with schistosomiasis was found to be significantly higher than that in men without schistosomiasis (8.4% versus 2.8%; odds ratio [OR], 3.170; 95% confidence interval [CI], 1.501-6.694; P = 0.002). Compared to men, women showed significantly higher seroprevalence of KSHV (5.9% versus 9.3%; OR, 1.621; 95% CI, 1.084-2.425; P = 0.019).

Xinjiang, China is an endemic area for Kaposi's sarcoma (KS) but the seroprevalence of Kaposi's sarcoma-associated herpesvirus (KSHV) and risk factors remain undefined. In this study, antibodies to one KSHV latent protein (ORF73) and two KSHV lytic proteins (ORF65 and ORF-K8.1) were examined in 2,228 subjects from the general population and 37 subjects infected with HIV-1 in Xinjiang, and 560 subjects from the general population in Hubei, a low KS incidence region. The serostatus of a serum sample was defined based on positive results in any one of the three serologic assays. The seroprevalence of KSHV in the general population was higher in Xinjiang than in Hubei (19.2% vs. 9.5%; odds ratios [OR], 2.28; 95% confidence interval [CI], 1.68-3.08; P < 0.001). Among the ethnic groups in Xinjiang, 68 (15.8%) Han, 182 (20.7%) Uygur, 140 (19.9%) Hazakh, 9 (33.3%) Xibo, and 29 (16.8%) Hui were KSHV-seropositive, respectively. Compared to the Han, the latter groups had an increase in the risk of KSHV of 62.2%, 63.8%, 180.1%, and 30.2% (P = 0.003, 0.004, 0.018, and 0.286, respectively). Subjects aged <20, 20-50, and >50 had a seroprevalence of KSHV of 11.8%, 17.9%, and 24.6%, respectively. Compared to subjects aged <20, the latter groups had an increase in the risk of KSHV of 63.3% and 144.5% (P = 0.009 and <0.001, respectively). Subjects infected with HIV-1 in Xinjiang had a seroprevalence of KSHV of 43.2%, and a 220% increase in the risk of KSHV compared to the general population (P < 0.001). Similar results were obtained when the seroprevalence of KSHV was analyzed with any single or two of the three serologic assays alone. Genotyping identified three unique sequences clustered in the A clade. This study indicates that Xinjiang has a high seroprevalence of KSHV. Geographic location, ethnicity, age and HIV-1 infection are risk factors. Serologic and genotyping results suggest the introduction of KSHV into Xinjiang by specific ethnic groups.