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Occult Hepatitis B Virus Infection in Nigerian Blood Donors and Hepatitis B Virus Transmission Risks.

Oluyinka OO, Tong HV, Bui Tien S, Fagbami AH, Adekanle O, Ojurongbe O, Bock CT, Kremsner PG, Velavan TP - PLoS ONE (2015)

Bottom Line: Occult hepatitis B virus infection (OBI) characterized by the absence of detectable HBsAg remains a potential threat in blood safety.The L217R polymorphism in the reverse transcriptase domain of the HBV polymerase gene was observed significantly higher in OBI compared with HBsAg positive individuals (P<0.0001).High incidence of OBI is relevant in high endemic areas worldwide and is a general burden in blood safety.

View Article: PubMed Central - PubMed

Affiliation: Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; Deparment of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomosho, Nigeria.

ABSTRACT

Background: Occult hepatitis B virus infection (OBI) characterized by the absence of detectable HBsAg remains a potential threat in blood safety. We investigated the actual prevalence, viral factors and genotype of OBI infections in Nigerian blood donors.

Methods: Serum collected from two blood banks were reconfirmed as HBsAg seronegative by ELISA. Forty HBsAg positive samples were employed as controls. HBV-DNA was amplified from all donors and viral loads were determined using quantitative real-time PCR. Antibodies to the HBV core, surface and HBe antigen (anti-HBc,anti-HBs,HBeAg) were measured. The PreS/S and PreC/C regions of the HBV genome were sequenced.

Results: Of the 429 blood donors, 72(17%) were confirmed as OBI by DNA detection in different reference labs and excluded the concern of possible contamination. Of the 72 OBI samples, 48(67%) were positive for anti-HBc, 25(35%) positive for anti-HBs, and 2(3%) positive for HBeAg. Of the 72 OBI samples, 31(43%) were seropositive for either anti-HBc, anti-HBs or HBeAg, 21 (30%) positive for both anti-HBc and anti-HBs,one positive for both anti-HBc and HBeAg. None of the OBI samples were positive for all three serological markers. The viral load was <50copies/ml in the OBI samples and genotype E was predominant. The L217R polymorphism in the reverse transcriptase domain of the HBV polymerase gene was observed significantly higher in OBI compared with HBsAg positive individuals (P<0.0001).

Conclusion: High incidence of OBI is relevant in high endemic areas worldwide and is a general burden in blood safety. This study signifies the high prevalence of OBI and proposes blood donor samples in Nigeria should be pre-tested for OBI by nucleic acid testing (NAT) and/or anti-HBc prior to transfusion to minimize the HBV infection risk.

No MeSH data available.


Related in: MedlinePlus

Reconstructed phylogenetic tree of preS/S region of the HBV genome.Phylogenetic analysis inferred from distance analysis (Kimura 2 parameters model) and neighbor-joining reconstruction from preS/S region of OBI sample sequences showing that the HBV sequences clustered in the HBV genotype E branch. HBV sequences are referred to as “number”, i.e., “016”. The HBV sequences were compared to HBV reference sequences gathering the 8 HBV genotypes (NCBI-Genbank accession numbers are denoted). The numbers at the nodes indicate bootstrapping values in percentage of 1000 replicates.
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pone.0131912.g001: Reconstructed phylogenetic tree of preS/S region of the HBV genome.Phylogenetic analysis inferred from distance analysis (Kimura 2 parameters model) and neighbor-joining reconstruction from preS/S region of OBI sample sequences showing that the HBV sequences clustered in the HBV genotype E branch. HBV sequences are referred to as “number”, i.e., “016”. The HBV sequences were compared to HBV reference sequences gathering the 8 HBV genotypes (NCBI-Genbank accession numbers are denoted). The numbers at the nodes indicate bootstrapping values in percentage of 1000 replicates.

Mentions: The preS/S region of 72 OBI samples were sequenced and phylogenetic analysis revealed that all OBI samples belong to the HBV genotype E (Fig 1). Of the additional 30 HBsAg positive individuals investigated, HBV genotype E and A were observed in 28 (93%) and 2 (7%) individuals, respectively. In addition, the phylogenetic analysis also showed that 2 HBsAg positive samples were HBV sub-genotype A2. Investigation of the RT domain of the HBV polymerase gene of the 72 OBI individuals revealed a number of non synonymous substitutions. The G779 nucleotide substitution that translates L217R amino acid in the RT domain of the polymerase gene was found significantly higher (99%) in OBI compared to HBsAg positive samples (47%) included in this study (P<0.0001) (Table 2). Other mutations were observed in the OBI sequence of the RT domain including L144F, P177R, L179R and K212R substitutions. In addition, the G779 nucleotide substitution also resulted in amino acid change at L209V in the S gene. Consequently, the L209V amino acid substitution was significantly higher in OBI (99%) compared to HBsAg positive samples. Also, the amino acid substitutions R169G and SN204G were observed frequently in OBI (4% and 8%, respectively) but not in HBsAg positive samples. Other OBI specific amino acid substitutions observed were A128V, E164G, S171A and P188L. Of those, the substitutions A128V, E164G are in the major hydrophilic region (MHR) of the S gene (Table 3).


Occult Hepatitis B Virus Infection in Nigerian Blood Donors and Hepatitis B Virus Transmission Risks.

Oluyinka OO, Tong HV, Bui Tien S, Fagbami AH, Adekanle O, Ojurongbe O, Bock CT, Kremsner PG, Velavan TP - PLoS ONE (2015)

Reconstructed phylogenetic tree of preS/S region of the HBV genome.Phylogenetic analysis inferred from distance analysis (Kimura 2 parameters model) and neighbor-joining reconstruction from preS/S region of OBI sample sequences showing that the HBV sequences clustered in the HBV genotype E branch. HBV sequences are referred to as “number”, i.e., “016”. The HBV sequences were compared to HBV reference sequences gathering the 8 HBV genotypes (NCBI-Genbank accession numbers are denoted). The numbers at the nodes indicate bootstrapping values in percentage of 1000 replicates.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492924&req=5

pone.0131912.g001: Reconstructed phylogenetic tree of preS/S region of the HBV genome.Phylogenetic analysis inferred from distance analysis (Kimura 2 parameters model) and neighbor-joining reconstruction from preS/S region of OBI sample sequences showing that the HBV sequences clustered in the HBV genotype E branch. HBV sequences are referred to as “number”, i.e., “016”. The HBV sequences were compared to HBV reference sequences gathering the 8 HBV genotypes (NCBI-Genbank accession numbers are denoted). The numbers at the nodes indicate bootstrapping values in percentage of 1000 replicates.
Mentions: The preS/S region of 72 OBI samples were sequenced and phylogenetic analysis revealed that all OBI samples belong to the HBV genotype E (Fig 1). Of the additional 30 HBsAg positive individuals investigated, HBV genotype E and A were observed in 28 (93%) and 2 (7%) individuals, respectively. In addition, the phylogenetic analysis also showed that 2 HBsAg positive samples were HBV sub-genotype A2. Investigation of the RT domain of the HBV polymerase gene of the 72 OBI individuals revealed a number of non synonymous substitutions. The G779 nucleotide substitution that translates L217R amino acid in the RT domain of the polymerase gene was found significantly higher (99%) in OBI compared to HBsAg positive samples (47%) included in this study (P<0.0001) (Table 2). Other mutations were observed in the OBI sequence of the RT domain including L144F, P177R, L179R and K212R substitutions. In addition, the G779 nucleotide substitution also resulted in amino acid change at L209V in the S gene. Consequently, the L209V amino acid substitution was significantly higher in OBI (99%) compared to HBsAg positive samples. Also, the amino acid substitutions R169G and SN204G were observed frequently in OBI (4% and 8%, respectively) but not in HBsAg positive samples. Other OBI specific amino acid substitutions observed were A128V, E164G, S171A and P188L. Of those, the substitutions A128V, E164G are in the major hydrophilic region (MHR) of the S gene (Table 3).

Bottom Line: Occult hepatitis B virus infection (OBI) characterized by the absence of detectable HBsAg remains a potential threat in blood safety.The L217R polymorphism in the reverse transcriptase domain of the HBV polymerase gene was observed significantly higher in OBI compared with HBsAg positive individuals (P<0.0001).High incidence of OBI is relevant in high endemic areas worldwide and is a general burden in blood safety.

View Article: PubMed Central - PubMed

Affiliation: Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; Deparment of Medical Microbiology and Parasitology, Ladoke Akintola University of Technology, Ogbomosho, Nigeria.

ABSTRACT

Background: Occult hepatitis B virus infection (OBI) characterized by the absence of detectable HBsAg remains a potential threat in blood safety. We investigated the actual prevalence, viral factors and genotype of OBI infections in Nigerian blood donors.

Methods: Serum collected from two blood banks were reconfirmed as HBsAg seronegative by ELISA. Forty HBsAg positive samples were employed as controls. HBV-DNA was amplified from all donors and viral loads were determined using quantitative real-time PCR. Antibodies to the HBV core, surface and HBe antigen (anti-HBc,anti-HBs,HBeAg) were measured. The PreS/S and PreC/C regions of the HBV genome were sequenced.

Results: Of the 429 blood donors, 72(17%) were confirmed as OBI by DNA detection in different reference labs and excluded the concern of possible contamination. Of the 72 OBI samples, 48(67%) were positive for anti-HBc, 25(35%) positive for anti-HBs, and 2(3%) positive for HBeAg. Of the 72 OBI samples, 31(43%) were seropositive for either anti-HBc, anti-HBs or HBeAg, 21 (30%) positive for both anti-HBc and anti-HBs,one positive for both anti-HBc and HBeAg. None of the OBI samples were positive for all three serological markers. The viral load was <50copies/ml in the OBI samples and genotype E was predominant. The L217R polymorphism in the reverse transcriptase domain of the HBV polymerase gene was observed significantly higher in OBI compared with HBsAg positive individuals (P<0.0001).

Conclusion: High incidence of OBI is relevant in high endemic areas worldwide and is a general burden in blood safety. This study signifies the high prevalence of OBI and proposes blood donor samples in Nigeria should be pre-tested for OBI by nucleic acid testing (NAT) and/or anti-HBc prior to transfusion to minimize the HBV infection risk.

No MeSH data available.


Related in: MedlinePlus