Alterations in the hepatic microenvironment following direct-acting antiviral therapy for chronic hepatitis C

Background and aims. The first direct-acting antivirals (DAAs) to treat the viral hepatitis C (HCV) became available in 2011. Despite numerous clinical studies of patient outcomes after treatment, few have evaluated changes in the liver microenvironment. Despite achieving sustained virologic response (SVR), patients may still experience adverse outcomes like cirrhosis and hepatocellular carcinoma. By comparing gene and protein expression in liver biopsies collected before and after treatment, we sought to determine whether specific signatures correlated with disease progression and adverse clinical outcomes. Methods. Biopsies were collected from 22 patients before and after DAA treatment. We measured [~]770 genes and used multispectral imaging with custom machine learning algorithms to analyze phenotypes of intrahepatic macrophages (CD68, CD14, CD16, MAC387, CD163) and T cells (CD3, CD4, CD8, CD45, FoxP3). Results. Before DAA treatment, patients showed two distinct gene expression patterns: one with high pro-inflammatory and antiviral gene expression and another with weaker expression. Patients with adverse outcomes exhibited significantly (p<0.05) more inflammatory activity and had more advanced fibrosis stages in their baseline biopsies than those with liver disease resolution. Patients who achieved SVR had significantly decreased liver enzymes, reduced inflammatory scores, and restored type 1 interferon pathways similar to controls. However, after DAA treatment, patients with persistently high gene expression (67%, pre-hot) still had significantly worse outcomes (p<0.049) despite achieving SVR. A persistent lymphocytic infiltrate was observed in a subset of these patients (76.5%). After therapy, anti-inflammatory macrophages (CD16+, CD16+CD163+, CD16+CD68+) increased, and T cell heterogeneity was more pronounced, showing a predominance of helper and memory T cells (CD3+CD45RO+, CD4+CD45RO+, CD3+CD4+CD45RO+). Conclusions. Patients who have more inflamed livers and more advanced fibrosis before DAA treatment should be closely followed for the development of adverse outcomes, even after achieving SVR. We can enhance patient risk stratification by integrating gene and protein expression profiles with clinical data. This could identify those who may benefit from more intensive monitoring or alternative therapeutic approaches, inspiring a new era of personalized patient care. Lay SummaryDirect-acting antiviral (DAA) therapy has dramatically improved the treatment of chronic HCV, making it curable for most people. This study determined gene and protein expression differences in the liver before and after treatment of HCV. These results will lead to a deeper understanding of the changes in the hepatic immune microenvironment with and without the virus present in the liver in hopes of improving patient surveillance, prognosis, and outcome in the future.