Time course analysis of serum ALT levels, virological parameters, and the frequency of IFN-γ-producing CD4+ T cells during the study period. (a and b) For two representative patients from group 1, an increased frequency of IFN-γ-producing CD4+ T cells preceded or coincided with HBeAg loss, without ALT flare. (c) A representative patient from group, who received ADV treatment, but had moderate reduction in viremia, remained HBeAg+ and showed no increase in the frequency of virus-specific, IFN-γ-producing T cells. IFNγ, IFN-γ; ND, not determined.