Hepatitis B virus its causes of transmission,its complication and newest line of treatment

”      HBsAg

–       serologic hallmark of HBV infection

–       appears in serum 1-10 weeks after acute exposure

–       appears 2-6 weeks before hepatitis symptoms

–       persistence greater than 6 months implies chronicity

      Anti-HBs

–       Marks recovery from hepatitis B

–       Often not detectable until after “window period”

     
Anti-HBc (IgM)

–       First antibody to be detected (within one month after appearance of HBsAg)

–       Sole marker of HBV infection during window period

–       Usually an indicator of acute infection

–       May remain detectable up to two years after acute infection

–       Low-titer IgM may persist in chronic HBV infection

      Anti-HBc (IgG)

–       persists along with anti- HBs in patients who recover from acute infection and those who progress to chronic infection

–       Isolated presence with absence of HBsAg and anti-HBs

      During window period (although predominantly IgM)

      Many years after recovery from acute infection when anti-HBs has fallen to undetectable levels

      Many years of chronic infection when HBsAg titer has fallen to undetectable levels

      Clinical significance is unclear       

HBeAg

–       Marker of HBV replication and infectivity

–       Appears shortly after appearance of HBsAg

–       Higher rate of transmission when positive

–       Most have detectable HBV DNA

      Anti-HBe

–       May persist for years after resolution of acute episode

–       Seroconversion usually associated with disappearance of HBV DNA and remission

–       Small proportion of patients still have active disease

      HBV DNA

–       Can be detected 1 week after appearance of HBsAg

      Hybridization assays

–       PCR can detect it up to 2-3 weeks before HBsAg

–       Major role is in chronic infection to assess HBV replication and possibility of antiviral therapy

–       High DNA levels are less likely to respond to interferon therapy

–       May be checked in pts with isolated anti-HBc IgG to rule out low level chronic HBV infection