Low CD4 T cell counts in HIV-infected individuals are directly associated with the incidence of KS, which can spontaneously regress with immune reconstitution through highly active antiretroviral therapy (HAART) (Lebbe et al., 1998; Jones et al., 2000; Cattelan et al., 2001; Pellet et al., 2001; Wilkinson et al., 2002; Casper et al., 2004a; Mocroft et al., 2004). Here, CD4 is linked to Kaposi's sarcoma.