ObjectiveTo investigate the relation of Treg/Th17 ratio with HBeAg loss in chronic HBV infection patients during enticarvir antiviral treatment. MethodsThe sera and peripheral blood mononuclear cells (PBMCs) were obtained from the enrolled chronic HBV infection patients and healthy controls at different time points of enticarvir antiviral treatment. The HBV markers, HBVDNA, serum alanine transaminase(ALT), the HBVspecific IL17 levels, and the frequencies of Th17, Treg cells in PBMCs were determined. ResultsHBVDNA and Treg cell frequencies were decreased and the frequency of Th17 cells was rapidly increased in all patients; the secretion of IL17 decreased upon specific stimulation with HBcAg . Therapy induced inhibition of HBV replication led to great decrease of Treg/Th17. The decrease of Treg/Th17 ratio was closely related to loss of serum HBeAg at the fourth week. ConclusionInhibition of viral replication can not only reduce the activity of Th17 cells, but also quickly decrease the Treg/Th17 ratio. The Treg/Th17 ratio at the fourth week can serve as a marker for the effect of entacavir treatment for chronic hepatitis B.