258 Analysis of the Hepatic Microenvironment Before and After Direct-Acting Antiviral (DAA) Therapy for Viral Hepatitis C

OBJECTIVES/GOALS: The effect of the Direct-Acting Antiviral (DAA) on hepatic histopathological features from patients treated for HCV has not been thoroughly evaluated. The goals of this retrospective study were to determines differences between the liver biopsies collected before and after DAA treatment and correlated the histopathology with clinical outcome. METHODS/STUDY POPULATION: Spectral imaging was used to evaluate differences in intrahepatic macrophage (CD68, CD14, CD16, MAC 387, and CD163) and T cell (CD3, CD4, CD8, CD45, and FoxP3) phenotypes in paired liver biopsies collected from the same patient before (n=10) and after (n=10) achieving SVR (Figure 1). Imaging analysis and machine learning algorithms were used to evaluate changes in these key immune cells. We also compared differential gene expression of over 700 genes using RNA isolated from liver biopsies with NanoString. RESULTS/ANTICIPATED RESULTS: Multispectral imaging analysis showed a significant increase of proinflammatory/M1-like (e.g., CD14+) and anti-inflammatory/M2-like macrophage (e.g., CD163+) phenotypes in pre-treatment versus post-treatment biopsies, respectively. Gene expression analysis revealed enrichment of inflammatory (HLA-B, STAT1, CXCL10) and interferon induced-antiviral (ISG15, OAS3, MX1 and IFIT1) genes in the pre-treatment vs the post-treatment group. Cell deconvolution analysis also showed a significant increase of M1-like macrophages in the pre-treatment group when compared to the post-treatment group or controls. Upregulation of genes associated with cell proliferation and differentiation (c-KIT and Fos) was observed in the post-treatment biopsies of patients with persistent inflammatory infiltrates. DISCUSSION/SIGNIFICANCE: Protein and gene expression profiles observed in patients before DAA therapy showed a strong macrophage-mediated inflammatory response against HCV infection in the liver that shifted significantly to a tissue remodeling microenvironment after treatment.