OBJECTIVETo investigate the effects of pegylated interferon a-2a (Peg-INFa-2a) treatment on expression of CD8 and CD38 surface molecules on lymphocytes from peripheral blood of inactive hepatitis B surface antigen (HBsAg) carriers.

METHODSForty-four patients with hepatitis B virus (HBV) chronic infection (CHB) received a 48-week course of Peg-INFa-2a treatment, with 30 administered 135 mug/week and 14 administered 180 mug/week. Every 12 weeks of treatment, the subjects were assessed for HBsAg titer, presence of anti-hepatitis B e (HBe) antibody, serum alanine amino transaminase (ALT) levels, and lymphocyte surface expression of CD8 and CD38 molecules. Patients were classified as responders and non-responders according to standard parameters. Dynamic differences between the two groups over time were assessed by multivariate repeated measures ANOVA with Greenhouse-Geisser correction and differences at single time points were assessed by univariate ANOVA. Linear regression analysis was performed to evaluate the relationship of two variables.

RESULTSThe responders showed a significantly higher increase in ALT at week 12 (60.75+/-24.95 U/L vs. non-responders: 37.03+/-18.45 U/L; t = 2.905, P less than 0.01) and significantly higher proportion of CD8+CD38+ cells at week 24 (71.20+/-11.70% vs. non-responders: 56.79+/-7.72%; F = 23.941, P less than 0.01). The decline in level of HBsAg at week 24 was positively correlated with the increase in ALT level at week 12 (r = 0.386, P less than 0.01) and with expression levels of CD8 and CD38 molecules on lymphocytes at week 24 (r = 0.397, P less than 0.01).

CONCLUSIONLower baseline levels of HBsAg correlated to better Peg-INFa-2a-related HBsAg clearance. Increased expression of CD8 and CD38 on lymphocytes is suggestive of intensive cellular immunity in CHB patients and may be related to HBV-induced hepatocyte damage and may promote the HBsAg clearance.