Defective hepatitis B virus DNA is not associated with disease status but is reduced by polymerase mutations associated with drug resistance.
Defective hepatitis B virus DNA (dDNA) is reverse-transcribed from spliced hepatitis B virus (HBV) pregenomic messenger RNA (pgRNA) and has been identified in patients with chronic HBV (CH-B). The major 2.2-kb spliced pgRNA encodes a novel HBV gene product, the hepatitis B splice protein (HBSP) via a deletion and frame shift within the polymerase. Although spliced RNA and HBSP expression have been associated with increased HBV DNA levels and liver fibrosis, the role of dDNA in HBV-associated disease is largely undefined. Our aims were to (1) compare the relative proportions of dDNA (% dDNA) in a range of HBV-infected serum samples, including patients with human immunodeficiency virus (HIV)/HBV coinfection and HBV-monoinfected persons with differing severities of liver disease, and (2) determine the effect of mutations associated with drug resistance on defective DNA production. Defective DNA was detected in 90% of persons with CH-B. There was no significant difference in the relative abundance of dDNA between the monoinfected and HIV/HBV-coinfected groups. We also found no association between the % dDNA and alanine aminotransferase, hepatitis B e antigen status, HBV DNA levels, fibrosis levels, compensated or decompensated liver cirrhosis, genotype, or drug treatment. However, the % dDNA was significantly lower in individuals infected with lamivudine-resistant (LMV-R) HBV compared with wild-type HBV (P < 0.0001), indicating that antiviral drug resistance alters the balance between defective and genomic length DNA in circulation. Experiments in vitro using HBV encoding LMV-R mutations confirmed these results.


CONCLUSIONS
Our results identified no association between dDNA and parameters associated with disease status and suggested that the relative abundance of dDNA is largely dependent on the integrity of the HBV polymerase and is unrelated to the severity of liver disease.
Victorian Infectious Diseases Reference Laboratories, Research and Molecular Development, North Melbourne, Victoria, Australia.
Scott
S
Preiss
Margaret
M
Littlejohn
Peter
P
Angus
Alex
A
Thompson
Paul
P
Desmond
Sharon R
SR
Lewin
Joe
J
Sasadeusz
Gail
G
Matthews
Gregory J
GJ
Dore
Tim
T
Shaw
Vitini
V
Sozzi
Lilly
L
Yuen
George
G
Lau
Anna
A
Ayres
Chloe
C
Thio
Anchalee
A
Avihingsanon
Kiat
K
Ruxrungtham
Stephen
S
Locarnini
Peter A
PA
Revill
D000410:Alanine Transaminase / Q000097:blood; D000998:Antiviral Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D004279:DNA, Viral / Q000097:blood / Q000235:genetics*; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D016368:Frameshift Mutation / Q000235:genetics*; D015684:Gene Products, pol / Q000235:genetics*; D005838:Genotype; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000097:blood / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014162:Transfection
D000998:Antiviral Agents; D004279:DNA, Viral; D015684:Gene Products, pol; D006513:Hepatitis B e Antigens; C066027:P protein, Hepatitis B virus; D000410:Alanine Transaminase