Despite a transient increase in mRNA, type I IFN did not increase SAMHD1 protein expression in primary human dendritic cells, macrophages, or CD4+ T cells, but IFN induced SAMHD1 expression in cell lines such as HEK 293T, HeLa, and U87 malignant glioma [34,35]. Here, CD4 is linked to malignant glioma.