Aim: Occult HBV infection (OBI) is characterized by the detection of HBV DNA in low levels in serum and peripheral blood mononuclear cells and/or in the liver, in the absence of detectable hepatitis B surface antigen (HBsAg). The prevalence of OBI varies among patient populations tested and the sensitivity of the assay employed. Also OBI can be a source of virus contamination in both blood and organ donations. In this study, we evaluated the presence of occult HBV infection in patients diagnosed with viral hepatitis B infection.
Material and methods: All samples were investigated for serological markers of HBV, HCV, and HDV by ELISA (AxSYM and Architect i2000SR, Abbott, USA) and also examined for the presence of HBV DNA by Real-time PCR in the clinical microbiology laboratory between 2001-2015. Also, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were evaluated.
Results: We detected HBsAg negativity in the sera of 105 (2.6%) of 4036 patients having positive HBV DNA. The minimum and maximum DNA levels were 1x101-1.7x108 copies/mL. Among the 105 patients, 31 (29.5%) were positive for only anti-HBc total, 3 (2.8%) were positive for anti-HBs, and 16 (15.2%) were positive for both anti-HBs and anti-HBc. Thirteen (12.3%) of the 105 patients were negative for serological markers of HBV infection. Nineteen (18%) patients were immunocompromised individuals.
Conclusion: Especially in immunocompromised individuals, occult HBV infection can reactivate and cause liver damage. Also OBI should be carefully assessed in particular clinical contexts: HBV infection transmission, liver disease progression, hepatocellular carcinoma onset, and HBV reactivation.