Although a previous in vitro study documented suppression of miR-122 expression by IFN-β [11], and interferon repression of miR-122 in the liver was suggested from clinical observations of interferon-treated patients with chronic hepatitis C [21], the association between decreased miR-122 and increased genomic expression of IFN-α and IFN-β in the studied chimpanzees was not found. This evidence concerns the gene IFNB1 and chronic hepatitis C virus infection.