Download marker - Cat`s TCM Notes

MARKER
HBsAg (envelope protein of virion)also
known as hepatitis B 's' or surface
antigen
ACUTE INFECTION
Present during acute infection.
CHRONIC INFECTION
GENERAL NOTES
Always present in chronic Indicates person is potentially infectious.
infection.
Useful for diagnosis of HBV infection.
Can be detected for several weeks before symptoms of acute
infection.
Used in vaccines to elicit a protective antibody response.
Anti-HBs (antibody to HBsAg) also
known as HBsAb or 'surface antibody'
HBcAg (nucleocaspid of virion) also
known as hepatitis B 'c' or core antigen
Anti-HBc
(antibody to core antigen)
Appearance 1-4 months after start of symptoms indicates
recovery and subsequent immunity to hepatitis B virus
infection.In people who are recovering from acute hepatitis B
virus infection, surface antibody usually appears after surface
antigen has disappeared.
Can neutralise hepatitis B virus. Protects against reinfection.
Marker of immunity against hepatitis B virus (is used to
assess response to vaccination).
Not detectable in serum so is detected indirectly via presence of core antibody.
Usually anti-HBc IgM indicates recent infection.Appears
soon after surface antigen and may be only marker of infection
in 'window period' after surface antigen disappears and before
Two classes: anti-HBc IgM, and anti-HBc surface antibody appears.
IgG
also known as HBcAb or 'core antibody'
HBeAg (water-soluble form of core
Detectable in early phase of hepatitis B virus infection, shortly
protein - secreted by cells infected with after surface antigen appears. At this early stage it indicates an
hepatitis B virus)also known as hepatitis active acute infection, at its most infectious period.
B 'e' antigen
Anti-HBe (antibody to HBeAg)
Indicates infection is likely to resolve spontaneously.
also known as HBeAb or 'e antibody
Never detectable in
chronic infection.
Anti-HBc IgG is always
present in chronic
infection. Anti-HBc IgM is
not present.
Anti-HBc indicates past or present infection i.e. the person
has been in contact with the virus. Anti-HBc testing identifies
all previously infected people but does not differentiate
between carriers and non-carriers.
Positivity in chronic infection Treatment for e antigen positivity aims to convert to e antigen
is always associated with
negativity.
high levels of virus.
In chronic infection its
presence usually (but not
always) indicates that the
level of virus is likely to be
low.
Transition from e antigen to e antibody positivity usually
indicates that virus production has decreased significantly.
But e antibody may be associated with low or high viral DNA
levels (usually low). e antibody positivity with high viral DNA
levels is likely to require treatment.