Although several epidemiological studies, including our study have been demonstrated the link between HCV and B-cell non-Hodgkin's lymphoma (NHL), the direct evidence of the HCV-associated-NHL remains uncertain. Direct antiviral agents (DAA) have been shown to have a higher cure rate, less side effects, and a shorter duration of therapy for chronic HCV infection. Whether DAA treatment can cure HCV-associated indolent B-cell NHL remains unclear? If yes, a direct evidence of HCV-associated lymphomagenesis will be approved. Because DAAs are more potent and efficient than pegylated (Peg) interferon plus ribavirin and well-tolerated for the treatment of HCV infection, it is reasonable to use DAAs as the frontline treatment for HCV-positive patients with indolent B-cell NHL, such as MZL, LPL, and low-grade FL, who do not require immediate cytoreductive therapy. The aim of this proposal is to assess whether Harvoni® (ledipasvir and sofosbuvir) could eradicate HCV and lead to durable complete remission of HCV-associated indolent B-cell NHL.