Viral Sequence Analysis of Occult HBV Infection and Its Reactivation in Immunosuppressed Patients

Mechanisms associated with reactivation of hepatitis B virus (HBV) in patients with occult HBV infection (OBI) remain unclear. In some cases immunosuppression is an enhancer of viral replication. However, not all patients with OBI who undergo immunosuppression experience reactivation. This study explores the role of viral heterogeneity as a determinant of occult HBV reactivation. HBV genotype, mutation patterns and quasispecies were assessed by sequencing the PreS/S region of 16 patients with OBI undergoing chemotherapy, 3 of whom experienced a OBI reactivation. The latter were also assessed at the time of reactivation. Phylogenetic analysis identified low nucleotide and amino acid diversit…