CD244, also known as 2B4, was firstly described as an inhibitory receptor highly expressed on exhausted CD8+ T cells in line with PD-1 in chronic LCMV infection and chronic HBV infection in mice.27, 59 Subsequently, Jung et al.26 addressed CD244 as an important inhibitory molecule on HBV virus-specific CD8+ T cells by providing evidence that in chronic HBV-infected patients, these cells expressed higher levels of CD244 coincidence with an increased expression of PD-1 both in the peripheral blood and hepatic tissue compared with acute and resolved infection. This evidence concerns the gene PDCD1 and infection.