AbstractSuppressor T‐cell activity and allogeneic T‐cell response to concanavalin A (ConA) were investigated in 46 patients chronically infected with hepatitis B virus (HBV). Thirty‐eight patients had chronic active hepatitis, seven of whom were superinfected with Delta virus, and eight were healthy chronic HBV carriers. T‐cell suppressor activity was in the normal range in healthy carriers and in patients negative for serum HBV‐DNA, independent of the e antigen status. In contrast, the group of patients positive for HBV‐DNA exhibited a significant reduction in suppressor activity. Longitudinal studies in patients who cleared serum HBV‐DNA demonstrated that suppressor T‐cell activity became normal thereafter. These results suggest a relationship between suppressor T‐cell function and the stage of viral replication in individuals with chro