Study on the distribution of CD8+ memory T cell subsets and IFN-γ level during the spontaneous clearance of hepatitis B virus in patients with chronic hepatitis B virus infection.

OBJECTIVE: To study the alteration of CD8+ memory T cell subsets under different immune statuses during the spontaneous clearance of hepatitis B virus (HBV) in Chinese patients with chronic HBV infection.

PATIENTS AND METHODS: We analyzed Chinese patients with chronic HBV infection including 10 patients with Hepatitis B surface Antigen (HBsAg) spontaneous seroconversion, 25 patients with Hepatitis B virus e Antigen (HBeAg) spontaneous seroconversion, 25 patients with chronic hepatitis B (CHB), and 25 chronic HBV carriers. The CD8+ T cells in peripheral blood were isolated, and flow cytometry was used to determine the percent change of CD8+ T memory cell subsets. ELISA was used to measure the levels of Interferon-γ (IFN-γ) secretion from CD8+ T cells.

RESULTS: (1) The percentage of CD8+ TN cells in peripheral blood was lower in the HBsAg seroconversion group than in the HBeAg seroconversion group (p<0.01), and higher in the CHB group and chronic HBV carrier group (p<0.01, 0.01); (2) The percentage of CD8+ TEM-2 memory T cells in peripheral blood was higher in the HBsAg seroconversion group than the HBeAg seroconversion group (p<0.05), CHB group, and chronic HBV carrier group (p<0.01, 0.01); (3) The percentage of CD8+ TEM-1 and CD8+ TCM cells in peripheral blood was higher in the CHB group and HBV carrier group than the HBsAg seroconversion group and HBeAg group, but there were no significant differences between groups (p>0.05); (4) IFN-γ production from CD8+ T cells in peripheral blood was higher in the HBsAg seroconversion group than the HBeAg seroconversion group (p<0.05), CHB group, and chronic HBV carrier group (p<0.05, 0.01).

CONCLUSIONS: The consistent increase of CD8+ TEM-2 cell subsets may be an important cause of spontaneous clearance of HBV. The disorder of CD8+ memory T cell differentiation may be an important mechanism of chronic HBV infection.