SAMHD1 knockdown in THP-1 cells results in more than 10-fold increase in HIV-1 replication [70]; in contrast to the enormous effect of Vpx in IFN-treated MDDCs, HIV-1 infection of IFN-treated THP-1 cells increases only two to three-fold in response to Vpx. The gene discussed is IFNA1; the disease is HIV-1 infection.