Several lines of evidence indicate that microglia and macrophages play a crucial role in HIV infection and gp120-induced neurotoxicity, and we and others have shown that cell-free conditioned media of human MDM stimulated with HIVgp120 cause significant neurotoxicity when transferred into microglia-depleted cerebrocortical cell cultures of human, rat or mouse origin31, 50, 53, 54, 55, 56, 57. Here, ITIH4 is linked to HIV infectious disease.