To investigate of the levels of serum interleukin-21 (IL-21) in the optimally treated chronic hepatitis B (CHB) patients with poor response to nucleos(t)ide analogue drugs to investigate the relationship between the the serum IL-21 levels, the dynamic changes and patients’ viral response to antiviral therapy.

The serum of a total of 25 CHB patients with a poor response to nucleos(t)ide analogue antiviral therapy was detached before and after optimally treated for 12, 24, 36, 52, 64, 76, 88 and 104 weeks, and the levels of IL-21, HBsAg, HBsAb, HBeAg, HBeAb, HBV DNA load and the liver function were dedected, respectively. And then the dynamic changes of these indicators and the correlation were analyzed. Fifteen cases of hepatitis B virus carriers and 15 cases of healthy volunteers were selected as controls.

There was no significant differences between the levels of the baseline IL-21 of the chronic hepatitis B patients poorly respond to nucleos(t)ide analogue antiviral therapy and the hepatitis B virus carriers, but they all significantly higher than the level of serum IL-21 concentration of the healthy people (P < 0.05). During the optimal therapy of the chronic hepatitis B patients poorly respond to nucleos(t)ide analogue antiviral therapy, the level of the serum HBV DNA, HBsAg, HBeAg and HBeAb all declined, and a rapid decline of HBV DNA during the first 12 weeks of treatment was observed, and the pace of the reduction of HBsAg slowed down with time. There was a moderate negative correlation between the IL-21 concentration of baseline and the logarithmic change of HBV load from 12 weeks to 24 weeks after treatment (r =-0.55, P < 0.05). A moderate negative correlation between the IL-21 concentration at week 36 and the decline of HBV load from week 36 to week 52 was also obversed (r =-0.62, P < 0.01). And the levels of IL-21 of the patients with CHB during treatment with nucleos(t)ide analogues increased at first and then declined and the peak concentration was 66.41 pg/ml, which came around at week 36 and was significantly higher than the baseline (P < 0.05), but at the 88th week and 104th week, the IL-21 declined to the levels that showed no significant differences compared with the baseline.

The levels of serum IL-21 increased in the patients with HBV infection, and after the optimal antiviral treatment with nucleos(t)ide analogue drugs, the levels of serum IL-21 of patients with CHB increased transiently, and some relevance were observed between the supression of HBV DNA, as well as the changes of the HBsAg, HBeAg and the peek concentration of the serum IL-21 of patients with CHB.