Since recovered CTLs maintained the ability to produce interferon-gamma in response to peptides, these CTLs apparently contribute to the efficacy of lamivudine therapy in patients with hepatitis B. It was reported by Boni et al [11-13] that an efficient antiviral T cell response including HBV-specific CD4+ and CD8+ cells can be restored by lamivudine treatment in CHB patients concurrently with reduction of viremia, but the restoration of HBV-specific T-cell reactivity is only transient. The gene discussed is IFNG; the disease is hepatitis B virus infection.