DISTINGUISHING BETWEEN ACUTE AND SYMPTOMATIC CHRONIC HEPATITIS-B VIRUS-INFECTION

Background/Aims: Differentiating between an acute hepatitis B (AH-B) i nfection and an acute exacerbation of a chronic hepatitis B (CH-B) inf ection can present a problem for the clinician. The only current serol ogical method of distinguishing between acute and symptomatic chronic hepatitis B virus (HBV) infection is the immunoglobulin M antibody to hepatitis B core antigen (anti-HBc) assay, which can be problematic. T herefore, in an attempt to better distinguish between acute and chroni c HBV infection, sera from 26 patients with AH-B and 53 patients with CH-B were compared in a variety of experimental immunoassays. Methods: Experimental assays have been designed to detect free antibody to hep atitis B e antigen (anti-HBe), hepatitis B e antigen (HBeAg)/anti-HBe immune complexes (ICs), and hepatitis B surface antigen (HBsAg)/antibo dy to hepatitis B surface antigen (anti-HBs) in the presence of excess antigen. An additional assay was developed to detect a novel anti-HBc specificity, designated antibody to woodchuck hepatitis virus (anti-H Bc(w)), which cross-reacts with the core antigen of the woodchuck hepa titis virus. Results: Sera from patients with CH-B showed significantl y higher levels of free anti-HBe, HBeAg/anti-HBe ICs, and HBsAg/anti-H Bs ICs compared with AH-B patient sera. Furthermore, patients with CH- B consistently produced high titer antiHBc(w), whereas patients with A H-B produced little or no anti-HBc(w) antibody. Conclusions: The serol ogy of AH-B infection and symptomatic CH-B infection can be distinguis hed using a variety of experimental immunoassays in addition to the im munoglobulin M anti-HBC assay.