Apoptosis observed in peripheral T lymphocytes from patients with chronic hepatitis B.

Background & Aims: Activation-induced cell death is involved in regulating peripheral T-cell function. Understanding the kinetics of these T cells is important to elucidate the pathogenesis of chronic hepatitis B, which is mediated by cellular immune mechanisms.

Methods: Subtle apoptotic cells in CD3+ cells were discriminated by flow-cytometric assay using freshly obtained and in vitro recombinant hepatitis B core antigen-stimulated peripheral lymphocytes from patients with chronic hepatitis.

Results: The ratio of apoptotic cells in freshly obtained CD3+ cells was significantly higher during the decreasing phase than increasing phase of serum alanine aminotransferase activity in each patient, and apoptosis of CD3+ cells was induced by stimulation with recombinant hepatitis B core antigen.

Conclusions: Activation-induced cell death in peripheral T cells was found in chronic hepatitis B virus infection, similar to some other viral infections. The apoptosis in T cells during the decreasing phase of serum alanine aminotransferase activity results in a vast amount of T-cell deletion that may weaken T-cell function of cytotoxicity over hepatitis B virus-infected hepatocytes. Thus, activation-induced cell death is considered an important modulator in down-regulating the "burst" of responding T cells in patients with chronic hepatitis B.