Detection of proteins encoded by the pre-S region of hepatitis B virus in the sera of HBsAg carriers: relation to viral replication.

Ibarra MZ, Mora I, Bartolomé J, Porres JC, Carreño V.

Department of Gastroenterology, Fundación Jiménez Díaz, Madrid, Spain.

In order to determine the relationship between the presence of pre-S1 and pre-S2 proteins and the level of hepatitis B virus (HBV) replication, a study of 94 HBsAg chronic carriers, 15 anti-HBe positive patients who suffered a viral reactivation and 12 HBeAg, HBV-DNA positive cases under antiviral therapy, has been carried out. Pre-S1 and pre-S2 antigens were detected by RIA using polystyrene beads coated with anti-preS1 or anti-preS2 (Dr W. Gerlich, Gottingen) and 125I-anti-HBs as tracer. The presence of pre-S1 and pre-S2 antigens was detected in 74 (79%) and 85 (90%), respectively, out of the 94 HBsAg chronic carriers included. The level of these antigens was significantly higher in HBeAg, HBV-DNA positive patients than in the other patients (p less than 0.05). Among anti-HBe positive patients suffering a reactivation, a significant increase of pre-S1 and pre-S2 levels was observed, concurring with ALT exacerbation and HBV-DNA positivity. After reactivation, the level of pre-S antigens returned to the basal values. A significant decrease in pre-S antigen levels (p less than 0.05) among patients who respond to recombinant interferon therapy was observed, while no changes were detected among non-responder cases. The detection of pre-S1 and pre-S2 antigens in serum is more frequent in those patients with high viral replication. Furthermore, among anti-HBe carriers with a viral reactivation, synthesis of pre-S antigens takes place again.