Efficacy of long-term lamivudine monotherapy in patients with hepatitis B e antigen-negative chronic hepatitis B.

We evaluated the safety and efficacy of long-term lamivudine monotherapy in a group of 25 patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. Lamivudine was administered in a daily dose of 150 mg for a mean of 26 +/- 7 months and was well tolerated. No patient lost hepatitis B surface antigen (HBsAg). The rate of initial biochemical response increased from 88% at 6 months to 96% at 12 months of therapy, but it progressively decreased thereafter; the biochemical remission rate was 68% at 18 months, 59. 5% at 24 months, and 42.5% at >/=30 months. Alanine transaminase (ALT) increased to higher than the baseline levels in 8 of the 11 patients with a biochemical breakthrough reaching acute hepatitis levels in 6 of them. Acute icteric hepatitis developed in one patient. The virologic remission rate assessed by a sensitive quantitative polymerase chain reaction (PCR) assay was 68% at both 6 and 12 months, decreasing thereafter to 52% at 18 months and to 41. 6% at both 24 and >/=30 months. Virologic breakthroughs were always persistent and preceded ALT elevations by a median of 4 (3-24) months. YMDD mutants were detected in all patients with a virologic breakthrough. In conclusion, in patients with HBeAg-negative chronic hepatitis B, long-term lamivudine therapy is safe and is associated with high biochemical and virologic response rates at the end of the first year. However, response rates tend to decrease with time and breakthroughs due to YMDD mutants accumulate. ALT activity during breakthroughs often exceeds the baseline and may reach even acute hepatitis levels.

Absence of the negative strand of GBV-C/HGV RNA from the liver.

BACKGROUND/AIMS: The pathogenic role of the human virus GBV-C/HGV remains unclear as information on tissue specific tropism and sites of replication of GBV-C/HGV is limited and controversial. The aim of this study was to determine whether the liver is the site of GBV-C/HGV replication. METHODS: We utilized the strand-specific Tth RT-PCR assay to investigate the presence of the positive- and negative-strand of GBV-C/HGV RNA in liver and serum samples from 12 patients with chronic GBV-C/HGV infection; four were infected with GBV-C/HGV alone, six were coinfected with HCV and two with HBV. A control group of six patients infected with HCV alone was included. The presence of the positive- and negative-strand of HCV RNA was also investigated in the same samples. RESULTS: All liver specimens were negative for the presence of the replicating negative-strand of GBV-C/HGV RNA. Positive-strand GBV-C/HGV RNA was found in 6 of the 12 liver samples and was detectable only at low levels, most probably reflecting serum contamination. By contrast, the negative strand of HCV RNA was detected in high titers in the liver of all HCV-infected and -coinfected subjects with less than a 100-fold difference from the positive strand. In serum samples only the positive strands of GBV-C/HGV and HCV RNA were detected in comparable titers. CONCLUSIONS: The results of this study suggest that GBV-C/HGV is not replicating in the liver and, taken together with the bulk of evidence against hepatopathogenicity, they argue against the new agent being a hepatotropic virus. We suggest that the acronymic term of this agent GBV-C/HGV is used with the understanding that it is not a hepatitis virus.

HBeAg-negative hepatitis B in a previously thalassemic patient during immunosuppressive therapy for chronic GVHD.

We report the case of a 15-year-old previously thalassemic girl who, 15 months after allogeneic BMT, developed HBeAg-negative hepatitis B (variant with mu-1896). In the absence of another route of transmission, HBV reactivation is postulated. The time of emergence of the HBV variant (with mu-1896) is probably related to the development of anti-HBe immunity. This mutant strain is associated with fulminant hepatitis. The patient achieved complete remission and HBV eradication despite having moderate GVHD and receiving immunosuppressive therapy.

Incidence and clinical significance of hepatitis B virus precore gene translation initiation mutations in e antigen-negative patients.

Hepatitis Be antigen (HBeAg)-negative chronic hepatitis B (CHB) is associated with hepatitis B virus (HBV) variants harbouring changes in the precore region. Most commonly, a G to A point mutation at nucleotide 1896 (m1896) creates a novel translation stop codon that prevents HBeAg production. In the Mediterranean region the m1896 mutation prevails in greater than 98% of HBeAg-negative CHB patients. In this study the prevalence of additional mutations in the precore region was investigated among patients with chronic HBV infection. Precore sequences were determined by sequencing serum HBV DNA amplified by polymerase chain reaction (PCR) with primers flanking the precore/core region. Thirty-one HBeAg-negative and five HBeAg-positive individuals were studied. All HBeAg-negative patients (100%) harboured the m1896 mutation and 20 (64.5%) also had a G to A mutation at nucleotide 1899 (m1899). Additional mutations affecting the translation initiation of the precore gene were found in seven (22.5%) patients, all with active liver disease, five of whom had episodes of HBV reactivation. HBeAg-positive patients had no mutations in these positions and neither did any of the five BHeAg-negative patients with normal levels of liver enzymes, representing the healthy carrier state of HBV infection. Serial sample analysis from one patient revealed that the initiation codon mutation developed following HBeAg seroconversion and the appearance of m1896. During periods of high HBV replication, the ratio of mutant to wild-type ATG was found to increase in parallel with HBV DNA levels. These data show that a significant proportion of HBeAg-negative patients who already harbour the 1896 stop codon mutation may subsequently develop precore translation initiation mutations, which appear to be associated with enhanced HBV replication and severe liver disease.

Human immunodeficiency virus type 1 Tat-mediated trans activation correlates with the phosphorylation state of a cellular TAR RNA stem-binding factor.

Protein kinase C (PKC) is involved in the mitogenic stimulation of cell proliferation and has recently been reported to be essential for Tat-mediated trans activation. We have determined that RNA binding of a cellular factor which specifically interacts with the trans-activation response region (TAR) is blocked in cells depleted of PKC activity by chronic phorbol myristate acetate stimulation. We also show that nuclear extracts can be depleted of the cellular TAR-binding factor by in vitro treatment with purified protein phosphatase 2A. Furthermore, TAR RNA-binding activity can be partially restored to depleted nuclear extracts in vitro by addition of PKC. Chimeric constructs in which the Tat protein is artificially tethered to viral RNA show PKC independence for Tat-mediated trans activation. Specific mutations in the TAR RNA stem region which cause reduced binding of host cell factor in vitro also cause reduced Tat-mediated trans activation in vivo. Together, these results suggest that phosphorylation-dependent binding of a cellular cofactor to TAR RNA is an essential step in Tat-mediated trans activation. Deciphering the regulation of Tat-mediated trans activation by phosphorylation will be critical in fully understanding the regulation of human immunodeficiency virus type 1 activation.