Changes in serum levels of Th1 /Th2 cytokines in HBeAg- positive pregnant women with HBV infection after telbivudine treatment

Objective To evaluate the changes in serum levels of Th1 /Th2 cytokines in pregnant women with chronic hepatitis B virus ( HBV) infection after telbivudine treatment and to investigate the immune mechanism by which telbivudine blocks the mother- to- infant transmission of HBV. Methods Fifty- four HBeAg- positive pregnant women with chronic HBV infection were enrolled from April 2008 to September 2012, and they were divided into two groups based on their alanine aminotransferase ( ALT) levels: immune active group ( n =18) and immune tolerant group ( n = 36) . Telbivudine was administrated at a dose of 600 mg per day during the second or third trimester.Before treatment and prior to delivery, the serum levels of ALT, total bilirubin ( TBil) , HBV DNA, and HBV markers were routinely measured, and the levels of Th1 cytokines ( interleukin- 2 ( IL- 2) , interferon- γ ( IFNγ) ) and Th2 cytokines ( interleukin- 4 ( IL- 4) , interleukin- 6 ( IL- 6) ) were determined by enzyme- linked immunosorbent assay. SPSS 18. 0 was used for statistical analysis. Results After treatment, HBV DNA level was reduced significantly ( P < 0. 01) , while there were no significant changes in serum ALT and TBil and no HBeAg seroconversion. Compared with the healthy population, before treatment and prior to delivery, both treatment groups showed higher expression of IL- 2 ( healthy control < 4 pg /ml) and IFNγ ( healthy control < 15 pg /ml) but lower expression of IL- 4 ( healthy control< 10 pg /ml) and IL- 6 ( healthy control < 5 pg /ml) . Furthermore, there were no significant differences in IL- 2, IFNγ, IL- 4, and IL-6 levels between the two groups ( P > 0. 01) . Prior to delivery, IL- 4 level was elevated in immune active group ( P = 0. 014) , but within the limits of normal range, while IL- 2, IFNγ, and IL- 6 levels showed no significant changes ( P = 0. 182, 0. 259, and 0. 710, respectively) ; the levels of IL- 2, IFNγ, IL- 4, and IL- 6 in immune tolerant group showed no significant changes ( P = 0. 651, 0. 839, 0. 650, and 0. 542, respectively) . Conclusion Th1 cytokines are highly expressed while Th2 cytokines are lowly expressed in the second or third trimester among HBV- infected pregnant women. Short- term telbivudine treatment has limited influence on Th1 /Th2 balance in HBV- infected pregnant women, indicating that other mechanisms might be recruited for interfering with the mother- infant transmission of HBV.