Conclusion: Placentas of HCV-seropositive mother-child dyads demonstrate frequent CD8+ T cells that specifically target HCV epitopes. In particular, the placenta has an enrichment of the TSCM memory phenotype and relatively low frequency of naïve CTLs. The expansion of primordial memory population with enhanced self-renewal and multipotency likely contributes to anti-HCV immunity and

limits HCV transmission. Further characterization of these mechanisms might provide a broader application for novel immunotherapeutic approaches for HCV infection. Disclosures: Michael R. Narkewicz – Consulting: Vertex; Grant/Research Support: BTK inhibitor Novartis, Vertex; Stock Shareholder: Merck The following people have nothing to disclose: Rachel McMahan, Christine

Waasdorp Hurtado, Lucy Golden-Mason, Mona Krull, Hugo R. Rosen Background: The FIB-4 index is a simple SAHA HDAC formula using age, aspartate aminotransferase(AST), alanine aminotransferase (ALT), and platelet counts to evaluate liver fibrosis. We investigated the use of the FIB-4 index in predicting the incidence of hepatocellular carcinoma (HCC) in hepatitis C virus carriers with normal ALT levels. Methods: A total of 516 patients with ALT levels persistently less than or equal to 40 IU/L during the observation period over 3 years were included. None of the patients received antiviral therapy. Factors associated with the cumulative incidence of HCC were determined. Results: HCC developed in 60 of 51 6 patients (1 1.6%). The rates of HCC at 5 and 10 years were 2.6% and 17.6%, respectively. When patients were categorized based

on the FIB-4 index: <2.0 (n=226), >2.0 and <4.0 (n = 169), and >4.0 (n=121), the cumulative incidences Thymidylate synthase of HCC at 5 years were 0.5%, 1.3%, and 8.0%, and those at 10 years were 2.8%, 25.6%, and 37.1 %, respectively. The patients with FIB-4 index > 4.0 was at a highest risk for HCC development (p<0.0001). Factors that were significantly associated with the incidence of HCC by mul-tivariate analysis were FIB-4 index >2.0 (hazard ratio: 7.690 [95% confidence interval, 2.636–22.438]; p<0.001) and FIB-4 index >4.0 (8.991 [3.088–26.178] ; p<0.001), α-fetopro-tein(AFP) >5 ng/ml (2.742 [1.497–5.023] ; p<0.001) and AFP>10ng/ml (4.915 [2.353–10.267] ; p<0.001), and total bilirubin >1.2 mg/dl (2.142 [1.115–4.117]; p=0.022).There were no significant correlation between FIB-4 index and tumor markers(AFP, AFP- Lens culinaris agglutinin-reactive (L3) and des-gamma -carboxyprothrombin (DCP)). Conclusions: The FIB-4 index is closely associated with the risk of HCC in hepatitis C virus carriers with normal ALT levels.