Basal core promoter and precore mutations among hepatitis B virus circulating in Brazil and its association with severe forms of hepatic diseases

BACKGROUND In Brazil, few studies have investigated the prevalence of infection with the precore (PC) and basal core promoter (BCP) mutants of the hepatitis B virus (HBV). OBJECTIVES This study aimed to analyse the frequency of PC and BCP mutations among patients infected with HBV and to evaluate the association between the variants and advanced hepatic disease. METHODS A total of 161 patients infected with HBV were studied. To identify PC and BCP mutations, a 501-bp fragment of HBV DNA was amplified and sequenced. FINDINGS PC and BCP regions from HBV strains were successfully amplified and sequenced in 129 and 118 cases, respectively. PC and BCP mutations were detected in 61.0% and 80.6% of the cases, respectively. The A1762T/G1764A variant was identified in 36.7% of the patients with grade 1 and 2 liver fibrosis (29/79) and in 81.8% of the patients with grade 3 and 4 liver fibrosis (9/11) (p < 0.01); in 76.9% of the patients with cirrhosis (10/13) and in 38.1% of the patients without cirrhosis (40/105) (p = 0.01); and in 77.8% of the patients with hepatocellular carcinoma (HCC) (7/9) and in 39.4% of the patients without HCC (43/109) (p = 0.03). MAIN CONCLUSIONS A high prevalence of HBV PC and BCP mutants was found. The A1762T/G1764A variant was independently associated with advanced forms of liver fibrosis, hepatic cirrhosis, and HCC.

Interferon Treatment on HBeAg Positive Chronic Hepatitis B with HBV Precore Mutant in Liver Tissue / 대한내과학회지

BACKGROUND: This study investigates the prevalance of HBV precore mutant in chronic B hepatitis patients and whether HBV precore mutants affect hepatic inflammation and response to interferon alfa. METHODS: HBV DNA in liver tissue from 48 chronic hepatitis patients was amplified by polymerase chain reaction. The HBV precore mutants were detected by direct sequencing of amplified PCR products. Thirty-three HBeAg-positive patients (Group 1: wild- type, Group 2: mixed) were received 3-6 MU INF three times a week for 4-6 months. We did follow-ups for at least six months(mean : Group 1-11.3, Group 2- 13.7 months). A complete responder was defined as persistent(>6 months) normalization of transaminase and loss of HBeAg and/or seroconversion. RESULTS: The HBV precore mutants were found in 15 cases(31.2%) among 48 patients: 7 cases(21.2%) in 33 HBeAg-positive patients and 8 cases(53.3%) in 15 HBeAg-negative patients. The HBV precore mutants were more frequently found in HBeAg-negative patients(p= 0.043). Differences in severity of hepatic pathology were not observed in the wild-type versus mutant-type chronic hepatitis B patients(p =1.00). Initial response rate was not significantly different between two Groups(p= 0.228), but complete response rate had a lower tendency in Group 2 (p=0.073). CONCLUSION: There is a tendency for HBV precore mutants to be less responsive to INF therapy than wild type. Therefore the patients with chronic hepatitis B should be treated as early as possible in natural history of their liver disease before the emergence of HBV precore mutants.

A Study on HBV Precore Mutant in Liver Tissues of Chronic Hepatitis B Patiets / 대한간학회지

BACKGROUND/AIMS: In order to determine the relationship between the HBV precore mutant and the severity of liver disease in Korea, we performed liver biopsies in patients with HBV related chronic liver disease and compared the types of mutations and histologic findings in the same liver tissue simultaneously. METHODS: HBV DNA in liver tissues was amplified by polymerase chain reaction (PCR). The precore mutants were detected by PCR-SSCP(single strand conformation polymorphism), cloning the amplified PCR products and direct sequencing for them. RESULTS: 1. HBV DNA was detected in liver tissues of 28 cases among 30 patients with PCR. And with SSCP, the most cases were mixed type infections. 2. The HBV precore mutants were found in 12 cases among the total number of 28 cases(42.9%) and all mutations were G to A change at nucleotide 1896, creating a stop codon at codon 28. However, 10 cases among 12 mutants were associated with simultaneous another mutation at different positions or regions;9 cases at core gene region, 2 cases at nucleotide 1856(C to T change at codon 15), one case at core promoter, and one case with double mutations at nucleotide 1837 and 1846 respectively. Also, all HBV precore mutants were combined with wild type HBV sequence. 3. The relationship between HBV precore mutants and HBeAg status revealed that 4 cases from 13 HBeAg positive(30.8%) and 8 from 15 HBeAg negative or Anti-Hbe positive(53.3 %) were mutants. 4. In analysis of the types of mutants and histopathological findings of liver diseases, 6 among 15 chronic active hepatitis(40.0%), all 3 cases with hepatocellular carcinoma(100,0 %), 2 among 4 asymptomatic carriers with minimal histopathologic changes(50.0%) and a case with chronic lobular heaptitis(100.0%) showed precore region mutation. CONCLUSION: The patterns of HBV precore mutants in Korea could be summarized as followings. Firstly, most of the mutations are composed of G to A change at nucleotide 1896. Secondly, the most of the mutants at nuclmtide 1896 have been associated with simultaneous mutations at core promoter, core gene, and rarely at other positions, and manifested usua'ly mixed type viremic conditions. Thirdly, although precore mutation could be occurred in asymptomatic carrier, this type of mutation might be closely related with chronic or severe liver disease. However, it needs further investigations hereafter.