Thursday, 7 August 2014

Serology of Hepatitis

1) HBsAg— considered to be infected ( can be acute/chronic or carriers)
Persistence of HBsAg is used to differentiate acute from chronic infection.
Presence of the antigen longer than 6 months after initial exposure indicates chronic infection.
2) anti-HBs—
implies either active or passive immunization that usually persists for life.
3) Anti-HBc— (NOTE:- HbcAg is not detectable in serum)
first detectable antibody
IgM anti-HBc indicates acute infection. ( most reliable marker of acute hepatitis infection) only serologic marker detectable during the “window period “ .
IgG anti-HBc indicates previous or ongoing infection.
4) HbeAg
High infectivity and active disease higher rates of viral transmission marker of viral replication and infectivity ( HbeAg----produced only during replication of the virus)
5) anti-HBe:
low infectivity.
Loss of HBeAg and appearance of anti-HBe in serum is called “seroconversion”
Indicates clinical improvement (=remission of the disease)
6) HBV DNA (quantitative viral load) indicates viral burden and viral replication assess recovery from infection and candidacy for antiviral therapy to differentiate between inactive carrier state
and chronic active hepatitis in chronic HBV infection. cutoffs for consideration for antiviral therapy
A) HbeAg-positive patients with chronic hepatitis -----100,000 copies/mL (or 20,000 IU/mL)
B) HbeAg-negative patients---10,000 copies/mL ( or 2,000 IU/mL )
A) imp info :-
1) Qualitative marker of HBV-replication -----HbeAg
2) Quantitative marker of HBV-replication:- Definitive is HBV-DNA >HBV-DNA polymerase
Refers to HBeAg-negative with normal serum ALT levels and low (< 2000 IU/mL) or undetectable HBV DNA.
C) precore or basic core mutant HBV also referred to as HBeAg-negative, or anti- HBe-positive HBV
HBeAg-negative and anti-HBe-positive patients with high serum HBV-DNA levels (>10000 copies /ml) and persistent or intermittent elevations in alanine aminotransferase (ALT) activity represents severe and progressive form of liver disease associated with frequent development of cirrhosis and HCC.

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