HBV BCP/PC mutational patterns in relation to alanine aminotransferase (ALT) and HBV DNA levels, and HBeAg negativity. Four patterns (BCP−/PC−, BCP+/PC−, BCP−/PC+ and BCP+/PC+) were determined based on positivity (+) or negativity (−) for the BCP double mutation A1762T/G1764A and the G1896A PC mutation. Association of the BCP/PC patterns with (a) serum ALT level in patients with hepatitis B-related acute-on-chronic liver failure (HB-ACLF); (b) serum ALT level in patients with chronic hepatitis B (CHB); (c) serum HBV DNA level in all patients; (d) HBeAg negative rate in all patients. Data are expressed as box plots, in which the horizontal lines illustrate the 25th, 50th and 75th percentiles for ALT level, and mean ± SD for HBV DNA level and HBeAg negative rate, respectively. *P<0.05, **P<0.01. BCP, basal core promoter; HBV, hepatitis B virus; PC, precore.