It is believed that as HIV-1 reduces its visibility to MHC-I restricted T cells by down-regulating MHC-I molecules from the surface of infected cells, it also reduces its visibility to CD1d restricted NKT cells by Nef-induced down-regulation of CD1d, both cell-types being critical for controlling the virus spread in HIV-1 infection [46]. The gene discussed is CD1D; the disease is HIV-1 infection.