Virological differences between patients infected with subtypes Ba and Bj of hepatitis B virus genotype B.
BACKGROUND
Hepatitis B virus (HBV) genotype B is classified into subtype Ba with the recombination with genotype C in the precore region plus core gene and subtype Bj without recombination. Virological and clinical differences between infections with subtypes Ba and Bj, however, are yet to be determined.


METHODS
During 1976 through 2001, 224 patients visited Toranomon Hospital in Tokyo, Japan who were infected with HBV genotype B. Subtypes of genotype B were determined by sequencing HBV-DNA recovered from sera for detecting recombination with genotype C.


RESULTS
Subtype Ba was detected in 53 patients (24%) and Bj in 167 (75%); subtypes were not able to be determined in the remaining four (1%). The only virological difference was that detection of hepatitis B e antigen at the presentation was more frequent in the patients infected with subtype Ba than those with Bj (63% vs 33%, P = 0.016). There were no differences in the distribution of liver disease of various forms between the patients infected with subtypes Ba and Bj at presentation. No differences were noted, either, in the development of liver cirrhosis or hepatocellular carcinoma, or the loss of hepatitis B surface antigen from serum, between the patients infected with subtypes Ba and Bj during follow up of up to 26 years.


CONCLUSIONS
Although there were some virological differences between the patients infected with subtypes Ba and Bj of HBV genotype B, they do not seem to influence the long-term clinical outcome.
Kobayashi
Mariko
M
Research Institute for Hepatology, Toranomon Hospital, Tokyo, Japan. vj7m-kbys@asahi-net.or.jp
Suzuki
Fumitaka
F
Akuta
Norio
N
Tsubota
Akihito
A
Ikeda
Kenji
K
Arase
Yasuji
Y
Suzuki
Yoshiyuki
Y
Saitoh
Satoshi
S
Kobayashi
Masahiro
M
Hosaka
Tetsuya
T
Someya
Takashi
T
Matsuda
Marie
M
Sato
Junko
J
Miyakawa
Yuzo
Y
Kumada
Hiromitsu
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000956:Antigens, Viral / Q000235:genetics*; D016009:Chi-Square Distribution; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000821:virology*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric
D000956:Antigens, Viral