TABLE 1.

Clinical characteristics of HDV infection ⁶⁴ , ⁶⁵

Infection type	Incubation (wk)	Serology	Clinical features
Acute HDV co‐infection	3–7	HDAg initially present Anti‐HDAg IgG low titre, late Anti‐HDAg IgM transient (beyond HDAg clearance) anti‐HBcore IgM high titre HDV RNA is high (initial phase, then reduces) HBV DNA variable	ALT/AST elevation Cholestatic picture with jaundice Progressive liver damage
Acute HDV super‐infection	<3	HDAg present anti‐HBcore IgM absent Anti‐HDAg IgG high titred persistent Anti‐HDAg IgM high titred persistent HDV RNA very high (initially, then reduces) HBV DNA low/undetectable	Initial high ALT/AST Rapid decrease of liver enzymes (with necrosis and reduced HDV replication) Hepatocellualr necrosis & inflammation Lymphocyte & KC portal & parenchymal infiltration Hepatocyte cytoplasmic swelling Eosinophilic degradation
Chronic HDV infection		HDAg present anti‐HDAg IgG & IgM variable titres (IgM associated with inflammation and disease progression), decrease with fibrosis progression HBeAb present anti‐HBcore IgM absent HDV RNA initially high HBV DNA low	Elevated ALT/AST Hepatocellular necrosis Portal & parenchymal inflammation Progressive fibrosis

Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; HDAg, hepatitis delta antigen; HDV, hepatitis delta virus: KC, Kupffer cells: wk, weeks