AICDA and infection: The low endogenous expression of AID and A1 in human cells canonically infected with HBV limits the interpretability of their contribution to hypermutation, although AID been shown to be upregulated in human hepatocytes upon infection with hepatitis C virus in vitro (Endo et al., 2007; Seeger and Mason, 2000; Uhlén et al., 2015).