On the other hand, the lower expression of CD71 transferrin receptor on CD57+ memory and conventional NK cells is in line with the progressive decrease of proliferative potential during NK differentiation (28); CD71 was reported to play an important role in the MCMV-driven adaptive NK cell expansion and in vivo protection (66); similarly, iron deficiency was shown to impair NK cell activation, metabolism, and antiviral function in vivo (69). This evidence concerns the gene TFRC and Iron deficiency anemia.