Hepatic Serology

Question 1

what is serology

in the context of hepatitis how is it used

Answer 1

Serology: the study of blood serum; regarding the immune system and pathogenic substances

in hepatic serology: focused on understanding the antigen and antibody presence

Question 2

Antigen v antibody

immunoglobin

Answer 2

Antigen: a toxin or forgein substance which triggers an immune response, the production of anti-bodies
- can be from toxins, viruses, bacteria or chemicals
- body tissue cells (and cancer cells) have their own antigens too, so that could induce an immune response too
- the antigen is only present during an active infection

Antibody: produced from B cells within the adaptive or humoral immune system (not the innate)
- the antibody is produced and binds to an antigen within th ebody to neutralize it
- pathologic response of antibodies to self-antigens within the body can occurs and create autoimmune diseases

antibodies are otherwise known as immunoglobins

Immunoglobins (5 types within the body)

IgA: found in mucosa
IgM: attached or free floating: these act as the first responder to an antigen
- IgM appear 5-7 days after expsoure
- last for approx. a few weeks
IgG: from plasma cells, cross placenta later phase response & stick around
- develop AFTER IgM, within 10 days to 2 weeks after expsoure and last for months/years
IgD: basophil and mast cells
IgE: parasite and allergic reactions

Question 3

Hepatitis B (blood, born with it as baby)

HepBsAg

anti-HBc

anti-HBs

Answer 3

HepBsAg = surface antigen of Hep B
- will be + if there is an ACTIVE and ONGOING infection
- as long as the virus is present, the antigen of the surface will be present

anti-HBc= antibody for the Hep B core
- this will only be POSITIVE IF THEY HAVE BEEN INFECTED with the Hep B virus
- this will NOT be positive if they have only had the vaccine
- because it is an antibdoy - this will linger after they have “cleared” the infection – thus a marker for a previous infection

anti-HBs = antibody for the Hep B surface
- this will be postive if you mount an IMMUNE RESONSE TO THE SURFACE: EITHER THE VACCINE OR AN INFECTION
- if they are + surface antibdoy and - core antibody; they have had the vaccine but never been infected
- if actively infected: the surface antigen wont be produced until months after the infection

Question 4

Inturpret the Following Serologies

HBsAg = -
anti-HBc = -
anti-HBs = -

HBsAg = -
anti-HBc = -
anti-HBs= +

HBsAg = -
anti-HBc = +
anti-HBs = +

HBsAg = +
anti-HBc = +
IgM anti-HBc = +
anti-HBs = -

HBsAg = +
anti-HBc = +
IgM anti-HBc = -
anti-HBs = -

Answer 4

first group: not infected, never infected, not vaccinated therefore succeptible to the disease

second one: not infected, never infected, but vaccinated

third one: not acteively infected, was infected at some point with the virus

fourth one: actively infected, acutely infected (igM = immediate), but the surface antibody wont appear for some time

fifth one: actively infected, antibody produced against the core, but not IgM, so chornic infection (properly IgG postive) but havent CLEARed the infection yet, so surface antibody not + yet

Question 5

Other Hep B serologies

Hepatitis B e antigen

Hepatitis B e antibody (anti-Hbe)

Serum HBV DNA

Answer 5

Hep B e antigen
- from the pre-core
- early antigen (e), not the envelope
- marker of early infectivity & associated with high levels of HBV DNA

Hep B e antibody
- a seroconversition of this antibody occurs usually early within the acute infection
- this process can be delayed in chronic, thus a good marker to see where in the infectious process they are

HBV DNA
- the HBV replication

Question 6

Hepatitis C Serology

Hep C Antibody

Hep C viral RNA

Answer 6

Hep C antibody
- indicates a prior infection (either they cleared it or were treated)
- may take some time to develop in early phases of an acute infection (8-11 weeks)

Hep C RNA
- used to confirm the presence of the infection or not
- if the antibody is + and the antigen - = a prior infection!