The Study Of Occult Hepatitis B Virus Infection,genotype Of Virus And Mutation Among Blood Donors In Fuzhou

Objective:To investigate the prevalence of the occult hepatitis B virus infection( OBI) in blood donors in Fuzhou,and the distribution of genotype of virus and the mutation of amino-acid sequence in S region of viral genome.Method:A total of 102866 samples were collecting from Nov.2011 to Mar.2013. All samples were tested by Serologic testing of HBs Ag and nucleic acid testing, Then the HBs Ag- and HBV DNA + samples were testing by Serologic screening for HBV antigen and antibody.After eliminate the samples which were in HBV infection window periods.The OBI samples were performed by Real-time fluorescent quantitative PCR detection,nest-PCR on S region of viral genome,then using MEGA5.0 software to analyse the genotype and the mutation of the viral strains on the sequences.Result:(1)75 in 102866 donations were HBsAg- and HBV DNA +,9 samples were identified as HBV antigen and antibody markers negetive by serologic tests.66 samples were selected as OBI samples.The prevence in Fu Zhou is 0.064%(66/102 866),and the infection rates were not all the same in the areas among Xia Men,Shang Hai,Shen Zhen,Fu Zhou(P < 0.001),while the prevence in Xiamen was larger than other areas(P < 0.001),and in the other three areas were not significant difference(P>0.05).(2) 62 in 66(93.9%)OBI samples were anti- HBc positive(with or without anti- HBs positive),in which 37 samples were just only anti- HBc positive, accounting for 56.1%(37/66); 4 samples were anti-HBs postive and other antibody markers negetive, accounting for 6.1%(4/66).(3) 66 OBI plasma samples were testing by Real-time fluorescent quantitative PCR, only 12 samples could detected HBV DNA. The average of the whole cycle threshold(CT) values of samples was 40,the DNA copies were between 13 to 302 IU/ml, only one sample DNA copies greater than 200 IU/m L.(4) Then the 12 samples were selected to perform nest-PCR on S region of viral genome,and the genotype and the mutation of the viralstrains were analyzed based on the sequences.10 samples(83.3%) could be amplified S region sequences with nest-PCR,7 was B genotype,6 in 7(85.7%) have mutation in S region of viral genome, while 3 was B genotype,1 in 3 have mutation in S region of viral genome.There are 6 samples,which main mutations occurred in the major hydrophilic region( MHR) of S antigen.Conclusion:(1) The prevalence of OBI in blood donors in Fuzhou was 0.064%(66/102866),which was similar to Shang Hai and shenzhen(P>0.05), but significantly lower than Xiamen(P<0.001).These differences may be related to the composition of the donors in different areas or HBV infection status in different groups.(2) The majority OBI samples were anti- HBc positive(with or without anti-HBs positive),we could filter out part of OBI cases through screening anti- HBc in the blood samples.(3)The Viral loads of OBI were very low, HBV DNA quantitative results usually < 200 IU/ml,it is difficult to detect the OBI samples.(4) In our study, we found it was mainly B genotypes in Fu Zhou,comparing with other cities in china(5) In our study,we found the mutations in MHR of S region could be one of the factors for OBI occurrence.