Virus-specific CD8 + T cells obtained from a patient cohort of 51 previously untreated chronically infected patients undergoing IFN-free therapy with a combination of faldaprevir ( a protease inhibitor ) and deleobuvir ( a non-nucleoside polymerase inhibitor ) with or without ribavirin were analysed ex vivo and after in vitro expansion at baseline , wk4 , wk 12 , and after treatment .