DETECTION OF HBS-ANTIGEN IN ANTI-HBC ALONE POSITIVE SERA

The immunoserological finding ''anti-HBc alone'' is often observed in defined groups of individuals, such as patients with inflammatory hepa topathies, patients on hemodialyses or with organ transplants, i.v. dr ug users and homosexuals, but it also occurs in up to 1% of Swiss bloo d-donors. In order to gain further information about whether ''anti-HB c alone'' reflects late immunity or points to an ongoing or a recently passed hepatitis B virus infection, 153 serum samples were tested for immune-complex-dissociated HBs-antigen, using acid treatment for comp lex dissociation. Of the samples tested 31% contained complexed HBsAg, the highest rates being found in individuals with hepatopathies (up t o 80%), in i.v. drug users (up to 63%) and in hemodialysis patients (4 0%). The 153 sera were also tested for HBV-DNA by nested PCR. Sixty (3 9%) probes yielded positive results, comprising 29 (48%) of 60 sera wi th immune-complexed HBsAg but only 18 (19%) of 93 probes without compl exed HBsAg. The results point to the possibility that at least some of the individuals with ''anti-HBc alone'' still have an ongoing HBV-inf ection. (C) Journal of Hepatology.