occult hepatitis b virus infection in patients with chronic hepatitis c treated with antiviral therapy

background occult hepatitis b virus infection (obi) is defined as the presence of hepatitis b virus (hbv) dna in the liver and/or in the serum of patients with negative results of hepatitis b s antigen (hbsag) test with or without serological markers of previous viral exposure. the impact of obi in patients with chronic hepatitis c (chc) is still unclear. objectives the aim of this study was to assess obi prevalence and its potential implications on treatment outcome in a cohort of patients with chc underwent standard antiviral therapy. patients and methods baseline serum samples from 137 hbsag-negative chc patients treated with pegylated-interferon and ribavirin (73 responders/74 non responders),were retrospectively analyzed for hbv status. results seventy-three patients (53.3%) showed markers of previous exposure to hbv. hbv dna was detected in 2 of 137 serum samples (1.5%), both carrying hbv antibodies. liver biopsies and post-therapy sera were available for 35 patients (12 responders/23 non responders). hbv dna sequences were found in 13 of 35 specimens (37.1%), all of patients with hbv dna negativity in basal and post-therapy serum samples. among obi-positive patients, 5 (38.5%) carried serological markers of hbv infection. regarding therapy outcome, in the obi-positive group there were 5 of 13 (38.5%) sustained virological responders (svr) compared to 7 of 22 (31.8%) in the obi-negative one. conclusions despite the high prevalence rate of liver hbv dna in patients with chc, svr was not affected by occult hbv infection.