Changes of costimulatory molecule CD28 on circulating CD8+ T cells correlate with disease pathogenesis of chronic hepatitis B.

Costimulatory signals are critical for antiviral immunity. The aim of this study was to evaluate the change of costimulatory molecule CD28 on circulating CD8+ T cells in chronic hepatitis B patients (CHB). Seventy CHB patients and fifty-six healthy controls were included, and forty-eight CHB patients were recruited for 52 weeks of longitudinal investigation. The proportions of circulating CD8+CD28+ and CD8+CD28- subpopulations were determined by flow cytometry, and the CD8+CD28+/CD8+CD28- T cells ratio was calculated. Compared with the subpopulation in healthy controls, high proportions of CD8+CD28- subpopulation were observed in CHB patients. Similarly, the CD8+CD28+/CD8+CD28- T cells ratio was significantly decreased in CHB patients compared with healthy controls and correlated significantly with hepatitis B virus (HBV) loads. High proportions of CD8+CD28- subpopulation and low CD8+CD28+/CD8+CD28- T cells ratio were observed in hepatitis B e antigen- (HBeAg-) positive individuals as compared with that in HBeAg-negative subjects. A significant decrease in CD8+CD28- subpopulation, increase in CD8+CD28+ subpopulation, and CD8+CD28+/CD8+CD28- T cells ratio were seen in those patients who received efficient antiviral therapy. Thus, aberrant CD28 expression on circulating CD8+ T cells and the CD8+CD28+/CD8+CD28- T cells ratio reflect the dysregulation of T cell activation and are related to the pathogenesis of chronic HBV infection.