A novel stop codon mutation in HBsAg gene identified in a hepatitis B virus strain associated with cryptogenic cirrhosis

Variants of hepatitis B virus surface antigen observed during therapy with nucleic acid polymer REP 2139-Ca have no influence on treatment outcome and its detection by diagnostic assays

The treatment of patients suffering from HBeAg-positive chronic hepatitis B with REP 2139-Ca resulted in potent reductions in HBsAg and HBV DNA, seroconversion to anti-HBs and the establishment of functional control of infection. In this cohort of 12 patients, we investigated whether differences between HBsAg sequences might explain the lack of response to REP 2139-Ca observed in 3 of 12 patients. We also assessed if the reduction or complete loss of HBsAg in serum observed during therapy were caused by mutations in the "a" determinant preventing the detection of HBsAg by standard diagnostic assays. The complete pre-S/S open reading frame (ORF) was sequenced and pre-S1, pre-S2 and S amino acid sequences were analysed. We found no major differences between pre-S1, pre-S2 and S sequences in responders and nonresponders correlated with low reduction in HBsAg. In addition, we found no mutations in the "a" determinant that would significantly affect the reactivity of HBsAg in diagnostic assays. These results demonstrate that the amino acid sequence of complete pre-S/S ORF has no direct influence on response to REP 2139-Ca therapy.

Indications of Liver Biopsy in the Era of Noninvasive Assessment of Liver Fibrosis

BACKGROUND

Liver biopsy (LB) has been used as diagnostic modality in liver diseases (LD). Over last two decades, there has been remarkable improvement in understanding of natural history, molecular diagnostics of viral hepatitis, genetic of LD, and also limitations of LB. There is current trend in avoiding LB in the management of various LDs.

AIM

To determine utility of LB in clinical practice.

MATERIAL AND METHODS

In a prospective study, 2413 patients of LD were followed up, 219 (9%) were acute, and remaining 2194 (90.9%) were chronic LD. Patients were evaluated by biochemical parameters, virological studies, and imaging endoscopy as and when required. LB was performed in 176 (7.2%) patients when no conclusion could be drawn from the noninvasive workup. Patients with platelet count <50,000/cm(2), ascites, and overt bleeding were excluded. Patients with international normalization ratio (INR) more than 1.5 were not excluded. No prophylactic use of fresh frozen plasma and platelet transfusion was done. There was no major complication related to the procedure. Indications for LB were as follows: cryptogenic LD 38 cases, hepatitis B infection 35, suspected autoimmune hepatitis 30, mass lesion in the liver and lymphoma 29, evaluation of portal hypertension 15, elevated liver enzymes 11, hepatitis C infection 9, and drug-induced LD 4, and miscellaneous 5 cases which were primary biliary cholangitis, primary sclerosing cholangitis, cholestatic LD, sarcoidosis, and amyloidosis.

RESULTS

LB changed the diagnosis in 55 (31.2%). These were cryptogenic LD in 24 cases, portal hypertension 15, elevated liver enzymes 11, and 5 others. In remaining, LB confirmed clinical diagnosis and helped in making management decisions.

CONCLUSION

LB was required in 7.2% of patients with chronic LD. In 31.2% cases, LB changed the diagnosis. LB was a safe procedure even in presence of low platelet count and abnormal INR.

Surface gene mutations of hepatitis B virus among high-risk patients with occult hepatitis B virus infection

Surface gene mutants of hepatitis B virus (HBV) have been reported in a variety of patient groups. Because of limited data regarding these mutations in patients with occult HBV infections; we aimed to determine these mutations among high-risk patients with occult HBV infection. The presence of HBV-DNA was determined in patients with isolated anti-HBc by real-time polymerase chain reaction (PCR). Then, surface gene region was amplified by nested PCR and mutations were analyzed after sequencing. The mutations that resulted in nonfunctional hepatitis B surface antigen (HBsAg) were insertion of single nucleotide in 2 cases, which causes frameshift and single-nucleotide replacement, and premature stop codons at Leu15 and Gly10 in the other 2 cases. Amino acid substitution at amino acid position 207(S207N) was found in the other isolates. Our study suggested that "a" region mutations did not play a major role in HBsAg detection, and other genetic and nongenetic factors may be responsible for failure to detect HBsAg by routine laboratory tests.

A new core promoter mutation and premature stop codon in the S gene in HBV strains from Iranian patients with cirrhosis

In order to define hepatitis B virus (HBV) mutational patterns in Iran, nucleotide sequences obtained from 91 patients and encompassing the precore, basal core promoter (BCP) and surface (S) regions, were compared. The patients were grouped as asymptomatic carriers, chronic active hepatitis or cirrhotic patients. Genotypes and mutations were determined by sequencing and phylogenetic analysis. All strains belonged to genotype D, and most of them to subgenotype D1. All but two strains specified ayw2, one ayw3 and one adw2 determinants. Two deletions of 8- or 20-bp were found in the X region in eight strains, six from patients with chronic active hepatitis. Eight of 21 strains from patients with cirrhosis harboured unusual mutations such as a stop codon at position 69 in the S region or a previously not described mutation in the BCP region ((1761)TC/ATTTG(1766)). All patients infected by strains with the stop codon mutation had detectable HBsAg and high viral load. The accumulation of mutations found in the BCP and S regions in HBV strains from patients with chronic active hepatitis and cirrhosis may predict disease progression in Iranian HBsAg carriers.

Detection of a premature stop codon in the surface gene of hepatitis B virus from an HBsAg and antiHBc negative blood donor

BACKGROUND

In blood donors, HBV infection is detected by the presence of serum hepatitis B surface antigen (HBsAg). However, some mutations in the surface gene region may result in altered or truncated HBsAg that can escape from immunoassay-based diagnosis. Such diagnostic escape mutants pose a potential risk for blood transfusion services.

RESULTS

In the present study, we report a blood donor seronegative for HBsAg and antiHBc, but positive for antiHBs who was HBV DNA positive by PCR. Sequencing of the HBsAg gene revealed presence of a point mutation (T-A) at 207th nucleotide of the HBsAg ORF, which resulted in a premature stop codon at position 69. This results in a truncated HBsAg gene lacking the entire 'a' determinant region. However, follow-up of the donor after 2 years revealed clearance of HBV DNA from the serum.

CONCLUSION

The case illustrates an unusual mutation, which causes HBsAg negativity. The finding emphasizes the importance of molecular assays in reducing the possibility of HBV transmission through blood transfusion. However, developing more sensitive serological assays, capable of detecting HBV mutants, is an alternative to expensive and complex amplification-based assays for developing countries.

HBV reactivation with fatal fulminating hepatitis during rituximab treatment in a subject negative for HBsAg and positive for HBsAb and HBcAb

A 51-year-old man who was hepatitis B surface antigen (HBsAg)-negative and positive for anti-hepatitis B surface antigen (anti-HBs) and anti-hepatitis B core antigen (anti-HBc), during rituximab therapy for chronic Lymphocytic leukemia, developed reactivation of hepatitis B virus (HBV) infection with hepatitis that proceeded towards hepatic failure and death in spite of lamivudine therapy. HBsAg remained persistently negative, notwithstanding a high HBV-DNA titer. Our observation, following other cases of fatal reactivation of HBV infection in patients receiving rituximab, suggests that, in all patients with previous markers of HBV infection, lamivudine prophylaxis should be considered during rituximab therapy.

Construction and expression of eukaryotic vector bearing fusion gene of HBV PreS2S and Fc fragment

AIM: To construct and express a recombinant eukaryotic expression vector bearing fusion gene of HBV S2S and Fc fragment.

METHODS: The technique of splicing by overlapping extension and twice PCR were used, and fusion gene fragment was obtained and cloned into pGEM-T Easy TA cloning vector to get suited enzyme sites. Recombinant eukaryotic expression vector pcDNA3 S2S/Fc was constructed by double adhesive terminal ligation. Then the recombinant vector was transferred into SP2/0 cells by using Lipofectamine.

RESULTS: The recombinant vector was identified by digestion with restriction enzymes and confirmed by DNA sequencing analysis. And the vector bearing fusion gene could be expressed in eukaryotic cells detected by indirect immunofluotescence technique.

CONCLUSION: The relative efficient expression of the fusion gene in SP2/0 cells may provide an experimental basis for specific immunotherapy for HBV infection.

Effect of HBeAg on the hepatitis B virus vertical transmission in neonates

AIM: To investigate the effect of HBeAg on the hepatitis B virus vertical transmission in neonates.

METHODS: HBsAg positive pregnant women were enrolled,and ELISA or Abbott was employed to detect the HBeAg and HBsAg in the peripheral blood of neonates and their mothers.

RESULTS: Fifty-seven HBsAg positive pregnant women were reconfirmed as HBsAg positive. Fifteen of them were detected as HBeAg positive. Eleven of 16 neonates born to 15 HBeAg positive mother were detected as HBeAg positive. Three neonates diagnosed as HBsAg positive by ELISA or Abbott reagents were detected as HBeAg positive. Statistic analysis indicated that HBeAg in newborns was an important risk factor.

CONCLUSION: HBeAg in neonates played an important role during HBV vertical transmission.