Pathogenesis Research On Human Herpesvirus 8 (HHV-8) Of Xinjiang And Epidemiology Study In Blood Donors

Objective: To understand the seroprevalence and risk factors of HHV-8 in blood donors in Xinjiang through large-scale wellcontrolled cross-sectional epidemiology study. To investigate the genotypes, viral load and expression profiles of HHV-8, subsequently constructing relationship with clinical phenotype of Kaposi's Sarcoma. Methods: Research subjects consisted of three parts as follows: 1) 4461 blood donors with complete questionaire information had been collected with cooperation from province blood centre from 08/2006 to 05/2007. 2) 51 comfirmed KS tissue samples of our hospital from 1980 to 2007 and 3) 2 matched pairs of KS ledion and paracancerous tissue. Mixed-antigens ELISA was used to detect anti-HHV-8 antibodies. Multivariate logistic regression model was employed for analysis. HHV-8 K1 gene from 23 KS patients was compared with homologenous strains from Genbank and drawed phylogenetic tree by mega 3.0 and phylip 23.63 after amplification and sequencing. Real-time fluorescent PCR was constructed and possessed to detect HHV-8viral load. cDNA microarrays was used to analyze the discrepency of expression profiles between KS lesion/normal shin and two samples. Results: The sensitivity and specificity of mixed-antigens ELISA are 81.8% and 97.9%, respectively. Overall seroprevalence of HHV-8 in 4461 Xinjiang blood donors was 20.4%. Ethnic minority background was the only identified risk factor (p, 0.000; OR, 1.8; 95% CI, 1.1-4.2) ultimately, also confirmed by anti-HHV-8-antibody and M-H analysis. 3 and 20 local KS are divided into A and C respectively, and A5, C6 and C7 subtype was first isolated in China. The characteristics of local HHV-8 genotype distribution presented cluster joining and common origining. Most reference strains were from Africa, Russia and Middle-east area. C type was mainly distributed in shorter course (p, 0.046). The standard curve showed that the Ct value of ORF26 andβ-actin had a good 1inear re1ationship (r2=0.996) with the standard samples and good reproducibility. Viral load between individual cases showed substantial difference about 107. Viral load in AIDS-KS was significantly lower than other types of KS (p, 0.025), in concordance with distribution of anti-HHV-8 antibodies. The common up/down regulated genes between two samples were 117, mainly related with HIV, hyperplasia, skin cancer, inflamation and melanoma those known factors attributed to HHV-8 infection or KS pathogenesis. Conclusions: HHV-8 mixed-antigens ELISA was strong technique platform for large scale epidemiology research. The seroprevalence of HHV-8 in blood donors from Xinjiang was great higher than same population in other provinces. Thus to detect anti-HHV-8 antibodies before donation became necessary. Ethnic minority background was the most crucial risk factor resulting in HHV-8 infection and high titre antibodies. The genotype of local HHV-8 and its distribution closely related with ethnic origin and evolution of local minorities. Different genotype of HHV-8 could have different pathogenesis mechanism, thus provided foundation for subsequently genetic susceptibility research. Highly sensitive and specific real-time fluorescent PCR for HHV-8 detection was contructed successfully, being good candidate for suspicious cases confirmation. HHV-8 viral load in local AIDS-KS cannot be used to predict the tumor progression. The inportance of the index should be evaluated differently among AIDS-KS/Classic KS/transplantion-associated KS. Gene expression profiling showed endoplasmic reticulum stress signal pathway make critical role during KS pathogenesis.