Immunological analysis of a patient with hepatitis B virus (HBV) reactivation after bone marrow transplantation.

Patients with resolved hepatitis B virus (HBV) infection undergoing chemo- or immunosuppressive therapy are at potential risk for HBV reactivation. To determine whether the host immune response contributes to liver injury, we performed an immunological analysis of a patient with HBV reactivation. Consistent with the detection of HBV DNA in the sera, the number of polyclonal HBV-specific cytotoxic T lymphocytes (CTLs) gradually increased; however, the number of CD4(+)CD25(+) regulatory T cells (Treg) decreased. The interaction between HBV-specific CTLs and CD4(+)CD25(+) Treg is an important determinant of liver injury during HBV reactivation. Therefore, monitoring the number of these cells might be a useful modality for the diagnosis of acute hepatitis resulting from HBV reactivation.