The use of nucleoside analogues (NAs) has led to significant improvements in the treatment of chronic hepatitis B. However, NA therapy usually does not completely clear hepatitis B virus (HBV), making treatment difficult to terminate. Previous studies have shown that NA treatment can induce the production of immature viral particles, including HBV RNA in the serum of patients with chronic hepatitis B. In a new study, researchers at the School of Biomedical and Life Sciences, Hiroshima University, Japan, analyzed the association between HBV RNA titers and the rate of hepatitis recurrence after NA treatment discontinuation. They hypothesized that the presence of HBV RNA is associated with the replication activity of HBV, and that the higher the concentration, the greater the likelihood of drug resistance. Recently, their latest study suggests that serum HBV RNA concentrations can help clinical judgment of the timing of discontinuation of NA therapy. The study was published in the Journal of Gastroenterology [J Gastroenterol. 2013 Feb 9]. This cohort study included 36 patients who had discontinued NA therapy. Serum HBV DNA or DNA and RNA levels were measured using real-time quantitative PCR and statistical analysis. 24 weeks after NA treatment discontinuation, the researchers observed HBV DNA rebound in 52.8% of patients (19 cases). HBV DNA and RNA titers at 3 months of treatment were statistically significantly associated with this [P=0.043, OR: 9.474, 95% CI: 1.069-83.957]. 33.3% of patients (12 cases) experienced alanine aminotransferase (ALT) rebound, and HBeAg negativity at the end of treatment was statistically associated with this [P= 0.003, OR: 13.500, 95% CI: 2.473-73.705]. In contrast, in e antigen (HBeAg) positive patients, HBV DNA and RNA titers were only mildly correlated after 3 months of treatment (P= 0.050, OR: 8.032, 95% CI: 0.997-64.683). The authors suggest that combined monitoring of HBV DNA and HBV RNA will help predict hepatitis B relapse after NA discontinuation.