Evaluation of an enzyme-linked immunosorbent assay for detection and quantification of hepatitis B virus PreS1 envelope antigen in serum samples: comparison with two commercial assays for monitoring hepatitis B virus DNA

An in-house sensitive and easy-to-use solid-phase enzyme-linked immunoassay (ELISA) was adapted for the detection and quantification of hepatitis B vi rus (HBV) PreS1 envelope antigen in serum, and compared with the HBV DNA Hy brid Capturez(TM) system from Murex and the polymerase chain reaction (PCR) Amplicor(TM) HBV Monitor assay from Roche. Twenty-five patients with chron ic hepatitis B after liver transplantation were included in this study. The sensitivity of our ELISA was found to be 50 pg of HBsAg/PreS1Ag ml(-1). Th e linearity was between 0.1 and 100 ng ml(-1). Intra-assay reproducibility was obtained with a standard deviation of < 1%. No correlation between the presence of serum PreS1 antigen and viral DNA detected by direct hybridizat ion (Murex) was observed. In contrast, there was a significant 96% correspo ndence in the presence of PreS1 antigen and viral DNA detected and quantifi ed by the PCR assay (Roche). In conclusion, the most important and reliable markers for monitoring residual HBV replication in serum were HBV DNA by t he PCR assay, and virus envelope PreS1Ag by our in-house ELISA. Thus, PreS1 Ag disappearance in serum could be used for evaluating the efficacy of anti viral therapies.