湖州地区献血人群隐匿性乙型肝炎病毒感染的血清学特征及分子机制研究

正全球约有3亿人感染乙型肝炎病毒(hepatitis B virus,HBV),我国为HBV高流行区,HBV感染率约占33%~(1])。虽随乙肝疫苗接种的普及,HBV母婴传播减少,人群乙型肝炎表面抗原(hepatitis B surface antigen,HBs Ag)携带率降低,

Serological characteristics and molecular mechanism of occult hepatitis B virus infection in blood donors in Huzhou

Objective To understand occult hepatitis B virus (HBV) infection (OBI), serological characteristics and gene mutation characteristics of S region in blood donors in Huzhou, so as to provide reference for the prevention of OBI. Methods During the period from January 2018 to September 2019 in central blood station of Huzhou, blood samples with negative hepatitis B surface antigen (HBsAg) in initial examination and re-examination, and with positive HBsAg in nucleic acid amplification test (NAT) were enrolled as OBI group, while blood samples with positive HBsAg in initial examination and re-examination, and with positive HBsAg in NAT were enrolled as positive control group. The five serum makers of hepatitis B were detected. The serum viral DNA was extracted. HBV DNA quantification was detected by real-time quantitative polymerase chain reaction (PCR). HBV S gene region was amplified by nested PCR for sequencing, which was compared with standard sequence. The gene variation was observed to find variation sites that might be related to OBI. Results Amongthe the 109, 560 blood specimens from January 2018 to September 2019 in central blood station of Huzhou, there were 30 cases with negative HBsAg in initial examination and re-examination, and with positive HBsAg in NAT, with detection rate of 0.027% (30/109, 560). In OBI serological mode: 12 cases (40.00%) with anti-HBc(+)/anti-HBs(-), 8 cases (26.67%) with anti-HBs(+)/anti-HBc(+), 3 cases (10.00%) with anti-HBs(+)/Anti-HBc(-), 7 cases (23.33%) with anti-HBc(-)/anti-HBs(-). Of the 30 OBI specimens, interval of HBV-DNA viral load was 8-1751 (median: 268.33) IU/mL and ALT range was within 10-36 (median: 18.13) U/L. Of the 30 OBI blood donation samples, there were 29 (96.67%) cases with successful amplification in S region, 2 (6.67%) cases with successful amplification of whole genotype, 23 (76.67%) cases with successful amplification of BCP/PC, and 22 (73.33%) cases with successful amplification in S region and BCP/PC. In terms of genotype: 23 cases (76.67%) with type B, 5 cases (16.67%) with type C and 2 cases (6.67%) not clearly determined. In terms of serotype: 24 cases (80.00%) with adw, 5 cases (16.67%) with adr and 1 case (3.33%) with ayr. HBV genotypes in both OBI group and positive control group were dominated by type B. There was no significant difference in the distribution of genotypes between the two groups (P>0.05). In OBI group, there were 18 cases (62.07%) in small S area with varying degrees of amino acid mutations and 2 cases (6.90%) with OBI forming stop codons early. In positive control group, there were 10 cases (33.33%) in small S area with varying degrees of amino acid mutations and 1 cases (3.33%) with OBI forming stop codons early. The mutation rate of S region in OBI group was higher than that in positive control group (P<0.05). Conclusion The detection rate of OBI among blood donors in Huzhou is 0.027%. The infection rate of OBI among anti-HBc-positive blood donors is relatively higher. The genotype is mainly on type B. The gene mutation of HBV in S region may be the key molecular mechanism of OBI.