Diagnosis and clinical impact of occult hepatitis B infection in patients with biopsy proven chronic hepatitis C: a multicenter study

Occult hepatitis B virus (HBV) infection in patients with chronic hepatitis C has been found associated with severe liver damage, low response to interferon treatment and increased risk of developing HCC. However, doubts remain on its clinical impact and the sensitivity and specificity of its detection. HBV-DNA was sought by PCR in plasma, peripheral blood mononuclear cells (PBMCs) and liver compartments of 89 patients with biopsy proven chronic hepatitis C, using sets of primers for core ("c"), surface ("s"), and x ("x") regions of HBV genome. Occult HBV infection was defined by the presence of HBV-DNA in at least two different PCRs in at least one compartment. Occult HBV infection was detected in 37 (41.6%) of the 89 patients investigated. It was more frequent (80.8%) in 26 anti- HBs negative/anti-HBc positive patients than in 18 anti-HBs/anti-HBc positive (61.1%, P < 0.01) and 45 anti-HBs/anti-HBc negative (11.1%, P < 0.0001), and more frequently in liver (91.9%) than in PBMCs (62.2%) and plasma (32.4%). No association was found between occult HBV infection and the degree of liver necroinflammation and fibrosis. However, considering the 52 patients without occult HBV infection, 51.4% of 35 patients with genotype 1 and 5.9% of 17 with genotype non-1 showed severe fibrosis (P = 0.003); patients with occult HBV infection did not show such difference. Instead of seeking occult HBV infection in patients with chronic hepatitis C, both anti-HBs negative/anti-HBc positive and anti-HBs positive/anti-HBc positive, in plasma alone, more reliable information can also be obtained from the liver tissue and PBMCs.