Paper II
Question
Changes in serum markers and liver histology in Hepatitis B infection
Answer
Serum markers in Hepatitis B infection
Acute infection
- HBsAg (Hepatitis B surface antigen): First marker to appear, indicates active infection (acute or chronic)
- HBeAg (Hepatitis B e antigen): Indicates active viral replication and high infectivity
- IgM anti-HBc (core antibody): Indicates recent/acute infection — the key marker distinguishing acute from chronic infection during the “window period” (when HBsAg has disappeared but anti-HBs has not yet appeared)
- HBV DNA: Direct measure of viral replication/load
Resolution/immunity
- Anti-HBs (surface antibody): Indicates recovery and immunity (also the marker induced by vaccination)
- IgG anti-HBc: Indicates past exposure (persists lifelong)
- Anti-HBe: Appears with seroconversion, indicates reduced viral replication
Chronic infection
- Persistence of HBsAg beyond 6 months defines chronic infection
- Continued presence of HBeAg/HBV DNA indicates high-replicative, more infectious chronic disease
Liver histology
Acute hepatitis
- Diffuse hepatocyte swelling (ballooning degeneration)
- Individual hepatocyte necrosis with acidophil (Councilman) bodies — apoptotic hepatocytes
- Mixed inflammatory infiltrate in portal tracts and lobules (mononuclear cells predominant)
- Kupffer cell hyperplasia, cholestasis may be present
Chronic hepatitis
- Portal and periportal inflammation (predominantly lymphocytic), with interface hepatitis (piecemeal necrosis) — inflammation extending beyond the portal tract limiting plate into the adjacent parenchyma
- Ground-glass hepatocytes (finely granular eosinophilic cytoplasm) — characteristic of HBsAg accumulation in the endoplasmic reticulum, best highlighted by immunohistochemistry
- Progressive fibrosis (bridging fibrosis in advanced disease), which can progress to cirrhosis
- Increased risk of hepatocellular carcinoma with long-standing chronic infection