Molecular hybridization techniques in current diagnosis of chronic hepatitis B in childhood.

Following the cloning and sequencing of the hepatitis B virus genome, molecular hybridization techniques have been established to detect hepatitis B virus (HBV) DNA in serum and liver tissue. Analyses can be performed by dot blot, Southern blot and in situ hybridization. HBV DNA is regarded to be the most sensitive marker of viral replication and infectivity which was previously related to the presence of hepatitis B e antigen in serum and hepatitis B core antigen in liver cells. In liver tissue different molecular patterns can be recognized as free viral DNA and integrated sequences. Furthermore, introduction of the polymerase chain reaction allows the detection of very small amounts of viral DNA and has markedly improved diagnostic sensitivity. Thus the study of HBV DNA has become a valuable part of the routine diagnosis in chronic hepatitis B, providing a more reliable evaluation of virus replication and infectivity, and facilitating more precise statements about course and prognosis of the disease.