Toll-like Receptor (TLR) 2, TLR4 and CD4+CD25+CD127low/-regulatory T Cells Correlate with Hepatitis B Virus Infection Y. Zhang 1 , J.Q. Lian 1 , C.X. Huang 1 , X. Wei 1 , J.P. Wang 1 , P.Z. Wang 1 , X.F. Bai 1 1 Center of Infectious Diseases, Tangdu Hospital, The 4th Military Medical University, Xi'an, China Background: TLRs play a crucial role in sensing and initiating innate antiviral response and Tregs actively suppress immune response, contributing to viral persistence and chronic tissue damage. In this study, we determined TLR2 and 4 expression and Treg frequency, as well as their function in the effect of HBV infection. Methods: TLR2 and TLR4 expression on monocytes and circulating CD4 + CD25 + CD127 low/-Tregs were determined by flow cytometry in 16 AHB, 42 CHB, 22 AsC and 20 NC. Spearman correlation was performed to investigate associated variables on Treg or TLRs. PBMCs were stimulated with HBeAg or HBcAg and the TLRs profile was examined. Result: TLR2 expressions were up-regulated in CHB and AsC, while TLR4 were increasingly expressed in AHB and AsC. Treg frequency in CHB was significantly higher than that in NC. In CHB, the increased TLR2 negatively correlated with HBV DNA loads and Treg frequency negatively correlated with TLR4 expressions. TLR2 was up-regulated after HBeAg stimulation in both NC and CHB. Conclusion: Increased Tregs may be associated with CHB and there might be possible interactions between HBeAg, TLR signaling and the innate immune response, which may partially explain the mechanism of HBV infection induced immuno-tolerance. (6.7±1.35) . HBV-DNA was quantitatively determined by polymerase chain reaction (PCR) technique, and HBV genotype was determined by PCR microwave gene chip technique. Antiviral efficacy was assessed using measuring the following scales: the ALT normalization rate, HBV-DNA negative conversion rate and the HBeAg/anti-HBe seroconversion rate. Results: Among 55 serum specimen, HBV genotype distribution was 38 genotype C, 14 genotype B, and 3 genotype non-B or C respectively. In genotype B, ALT normalization rate was 78.57%(11 cases), HBV-DNA negative conversion rate was 35.71%(5 cases) and the HBeAg/anti-HBe seroconversion rate was 14.28%(2 cases). In genotype C, ALT normalization rate was 76.31% (29 cases), HBV-DNA negative conversion rate was 47.37%(18 cases) and the HBeAg/anti-HBe seroconversion rate was 18.42%(7 cases). The efficacy of adefovir dipiroxil showed no significant differences between genotype B and C in the treatment of chronic hepatitis B P>0.05 . Conclusion: Adefovir dipiroxil is an effective antiviral drug. HBV genotype is irrelevant to the antiviral efficacy of adefovir dipiroxil in treatment of patients with chronic hepatitis B.