RESUMO
As most published studies on precore mutants have been carried out on isolates from patients with liver diseases, and it is unclear whether HBsAg carriers with viraemia in the absence of HBeAg are also generally infected by such mutants, it was decided to sequence the precore region in some HBV-DNA isolated from HBsAg-positive carriers. Precore sequences of HBV-DNA from 43 HBsAg carriers in Malaysia were studied. Three HBV subtypes were identified according to the nucleotide sequence of the precore region. Most of the carriers were found to be infected by the subtype adr. Mutations were detected in the precore regions. The most common conserved mutation was a silent mutation involving conversion from T to C (CCT to CCC) at position 1858 at codon 15 (proline). It was found that 4/43 (9.3%) had a mutation at the penultimate codon where TGG was changed to TAG. All 4 isolates with the TAG mutation had nt T at position 1858. Of the 4 carriers who were infected by these mutant viruses, 2 were coinfected with the wild type, 1 was infected only by a variant with the mutation at position 1896, while another was infected by a variant with mutations at positions 1896 and 1899. Three of the 4 were anti-HBe positive while 1 was HBeAg positive. Alanine aminotransaminase activities in all 4 carriers were normal. This study therefore demonstrated that variants with stop codons at the penultimate codon could be found in asymptomatic carriers in Malaysia.
Assuntos
Portador Sadio/virologia , DNA Viral/genética , Vírus da Hepatite B/genética , Adolescente , Adulto , Sequência de Bases , Códon de Terminação , Análise Mutacional de DNA , DNA Viral/isolamento & purificação , Feminino , Antígenos de Superfície da Hepatite B/sangue , Antígenos E da Hepatite B/sangue , Humanos , Malásia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , MutaçãoRESUMO
HBV-DNA were analysed in 330 HBsAg-positive carriers in Malaysia by dot-blot hybridization and polymerase chain reaction. Seventy-three (22.12%) were positive for the virus. Of these, 65 (89%) were males and 8 (11%) were females. Statistically, there was no significant difference (P = 0.13). No significant decline in HBV-DNA with age in the Malay and Chinese males was observed (P = 0.2). Prevalence of HBV-DNA was higher in the Chinese carriers than in the Malay carriers for most age groups in both sexes. Sixty-one HBV-DNA-positive carriers were also positive for HBeAg. However, three individuals were positive only for anti-HBe, one was positive for both HBeAg and anti-HBe, and eight were negative for both HBeAg and anti-HBe. Fifty-seven were positive for HBeAg but negative for HBV-DNA. No relation was observed between raised alanine aminotransaminase and aspartate aminotransaminase levels and the presence of HBV-DNA (P = 0.4).
Assuntos
Portador Sadio/epidemiologia , Antígenos de Superfície da Hepatite B/sangue , Hepatite B/epidemiologia , Adolescente , Adulto , Fatores Etários , Sequência de Bases , Portador Sadio/etnologia , DNA Viral/isolamento & purificação , Feminino , Hepatite B/etnologia , Hepatite B/transmissão , Vírus da Hepatite B/genética , Humanos , Immunoblotting , Malásia/epidemiologia , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Prevalência , Fatores SexuaisRESUMO
The incidence of HBsAg in random blood donors was found to be twice that of the prisoner population. The anti-HBe however, was about twice that in the prisoners when compared with the random blood donors. Both the random blood donors and the prisoners had similar incidence of HBeAg. The percentage frequency of HBsAg positivity with anti-HBe positivity was also similar in both groups. The 18 normal non-blood donors did not have HBsAg, HBeAg or anti-HBe.
