[Markers of type B viral hepatitis]

Abstract

The discovery of Australian antigen (HBsAg) has led to an increasing deal of knowledges about the virus of type B hepatitis (HBV); several markers of HBV have been detected and are becoming disposable for clinical and epidemiological purposes. The HBsAg is carried by 3 types of particulate structures discovered by electron microscopy as small spherical particles having diameter around 22 nm, long filaments and spherical particles having an overall diameter of the 42 nm (Dane-particle) with an electron-dense core. Dane-particle core contains circular double-stranded DNA molecules and an enzyme, the DNA polymerase. At present, Dane-particle is thought to represent the HBV, having properties consistent with those of a complete virus. Four antigen/antibody systems related to viral type B hepatitis have been discovered; they have been designated with the following nomenclature: HBsAg/anti-HBs, HBcAg/anti-HBc, HBeAg/anti-HBe, epilon antigen/anti epilson. The availability of the HBV markers for clinical purposes will permit a better understanding of the sequence of the biological reactions as well as of the clinical and epidemiological features concerning this viral infection: incubation period, acute disease, resolution, chronic carrier state, actively or passively immunized subject, persistent or subsided infectivity, prognosis.