Anti-retroviral effects of interferon-alpha in AIDS-associated Kaposi's sarcoma.

21 patients with AIDS and Kaposi's sarcoma were enrolled in an open therapeutic trial to determine the in vivo anti-retroviral activity of recombinant interferon-alpha (IFN-alpha). 8 (38%) showed a complete or partial anti-tumour response. The mean pretreatment CD4 count for the responders was 399 cells/microliter vs 154 cells/microliter for the non-responders. All 5 of the patients with more than 400 CD4 cells/microliter pretreatment showed a significant reduction in tumour, whereas none of the 7 patients with under 150 CD4 cells/microliter had any response. 5 of the 6 complete or partial responders with greater than 50 pg/ml of human immunodeficiency virus (HIV) p24 before IFN therapy showed a 75% or greater reduction by 12 weeks of therapy, with 3 patients having persistently negative HIV cultures. The anti-viral effects were also most pronounced in the patients with the highest CD4 counts. These data demonstrate the potential benefits, both anti-tumour and anti-retroviral, of treatment with IFN-alpha in the early stages of HIV infection and Kaposi's sarcoma.