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

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<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<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.