Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.2 (alanine aminotransferase)
 26,722 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the relations between HBV heterogeneity and different phases of HBV infection and disease in 145 HBsAg-positive carriers followed-up for 28 months (range 24-60 months). Viraemia was characterized for the relative prevalence of wild-type and HBeAg minus HBVs after HBV-DNA amplification by PCR using an oligonucleotide hybridization assay. HBeAg minus HBV was detected in 27% of immunotolerant HBV carriers, in 67% of patients with chronic hepatitis B (immunoelimination phase) and in 17% of HBsAg carriers with latent infection. Serum HBV-DNA and IgM anti-HBc became undetectable and ALT levels normalized, either spontaneously or after interferon therapy in 12 (36.3%) of 33 patients with an exclusive wild-type viraemia, but only in two (5.7%) of 35 patients with homogeneous HBeAg minus HBV (p = 0.005). An HBeAg minus viraemia higher than 20% was associated, in both HBeAg- and anti-HBe-positive patients, with HBV-induced liver disease and an unfavourable outcome of hepatitis. These findings suggest that surgence of HBeAg defective HBV is a virus strategy to survive under peculiar conditions dictated by the interplay between HBV and the host's immune system. The HBeAg/anti-HBe serological status is determined not only by the extent of virus replication and integration of HBV-DNA into cellular DNA but also by heterogeneity of HBV. The study of HBV heterogeneity in baseline sera of patients undergoing antiviral therapy appears to have a predictive value of the outcome of HBV infection in the single patient.
 ...
PMID:'e' antigen defective hepatitis B virus and course of chronic infection. 182 19

Three clinicopathological phases of chronic hepatitis B virus (HBV) infection are identified. First, is immune tolerance of HBV. High levels of viraemia are associated with normal alanine aminotransferase (ALT) levels and minimal histological lesions. More than 30-40% of hepatocytes have the hepatitis B core antigen (HBcAg), predominantly in their nuclei. Maternally derived hepatitis B e antigen (HBeAg) crossing the placenta may result in the elimination of T helper cells responsive to HBeAg/HBcAg. This phase can last for periods ranging from a few weeks to 10 or more years until the immune tolerance is lost. Second, is the immune clearance of HBV. Intermediate levels of viraemia are associated with fluctuating ALT levels and active and ongoing hepatitis. Approximately 20-30% of hepatocytes have HBcAg, predominantly in their cytoplasm. Expression of pre-core defective HBV mutants during chronic HBV infection may lead to a reduction in the secretion of HBeAg and may trigger the beginning of the immuno-elimination phase. The mechanism of intrahepatic shift of HBcAg from the nucleus to the cytoplasm and the decreased levels of viraemia in this phase may be, at least in part, secondary to liver damage and regeneration. Third, is latent infection with residual integrated HBV. Undetectable viraemia is associated with normal ALT levels and no virus-induced liver damage. With regard to hepatocyte expression of HBsAg in chronic HBV infection, membrane staining of HBsAg on hepatocytes has been shown to correlate well with the presence of viraemia. The degree of cytoplasmic hepatitis B surface antigen (HBsAg) expression inversely correlates with the level of viraemia. Therefore, HBsAg carriers with high levels of viraemia have low levels of cytoplasmic hepatitis B surface antigen (HBsAg) expression, while those with low levels of viraemia have high levels of cytoplasmic HBsAg expression. However, several exceptions have been identified. High levels of viraemia associated with high levels of cytoplasmic HBsAg expression were recognized in patients with fibrosing cholestatic hepatitis. In contrast, low levels of viraemia associated with low levels of cytoplasmic HBsAg expression were recognized in patients with hepatitis C virus but not hepatitis D virus superinfection.
 ...
PMID:Natural history of chronic hepatitis B virus infection: an immunopathological study. 940 40

Primary infection with Epstein-Barr virus (EBV) often occurs subclinically during childhood, resulting in a latent infection of B lymphocytes. In this report, a chronic hepatitis B case who presented with a serologic profile mimicking acute hepatitis B virus (HBV) infection and exhibiting transient autoantibody positivities because of the polyclonal activation of B cells due to EBV reactivation has been presented. The test results of 56 years old male patient who suffered from fatigue and pain on the right upper quadrant, revealed high levels of liver enzymes (AST: 187 U/L, ALT: 569 U/L), positivity of HBsAg, anti-HBc IgG and anti-HBe, and negativity of anti-HBc IgM, HBeAg and anti-HBs. Since HBV-DNA level was found 405,974 copies/mL by quantitative real time polymerase chain reaction (PCR), the patient was taken into follow-up. At the 6th month AST and ALT levels further elevated (352 U/L and 609 U/L, respectively), and anti-HBc IgM and anti-HBs became positive in addition to the previous positive markers of HBV. With the suspicion of superinfection, further laboratory investigations yielded negative results in CMV-IgM and Paul Bunnel test, while positive results in EBV anti-VCA IgM and IgG, anti-EBNA IgM and IgG, anti-p22 IgM and IgG and anti-EA IgM. In the follow-up period high levels of autoantibody positivities [rheumatoid factor (42.200 U/ml), anti-nuclear antibody (1/100) and anti-Ro-52] together with increased levels of total IgG, IgM and IgA were detected. In the following months, the levels of transaminases, total immunoglobulins and HBV-DNA have distinctively decreased, and in the 20th month the previous HBV profile regained (HBsAg, anti-HBc IgG and anti-HBe positive, anti-HBc IgM and anti-HBs negative, HBV-DNA: 6984 copies/ml) and the other pathological test results returned to normal. As a result, ALT increases seen during the course of chronic hepatitis B should not always be considered as HBV manifestations and the unusual serologic patterns should be evaluated as a consequence of superinfection with various viral agents.
 ...
PMID:[Polyclonal activation due to Epstein-Barr virus superinfection in a case with chronic hepatitis B]. 1817 82