Considerable progress has recently been achieved in understanding the pathogenesis of human immunodeficiency virus type 1 (HIV-1), and in improving the efficacy of antiretroviral therapies for the treatment of patients with the acquired immunodeficiency syndrome (AIDS). The pharmacological properties of new drugs are very effective in establishing a long-term suppression of HIV-1 replication, and have remarkably increased the survival period of patients with AIDS. However, current antiretroviral therapies are still far from eradicating HIV-1 from patients, and do not prevent the development of AIDS-related malignancies, which affect 40% of individuals infected by HIV-1. The malignancies that are considered AIDS-related are: Kaposi's sarcoma, non-Hodgkin lymphoma, intraepithelial cervical carcinoma and anal neoplasia. Their incidence is expected to increase as the survival period of patients with AIDS lengthens. Also, the cost of antiretroviral therapies poses a limit to the development of successful global intervention to tackle the worldwide spreading of AIDS, that, by the year 2000, will affect 40 million individuals. Some 90% of these new infections are occurring in developing countries, which can not afford the cost of antiretroviral therapies, and are not able to ensure a proper follow up of patients with AIDS. In addition, cultural and ethical problems make difficult the achievement of an adequate education of how to prevent the spreading of AIDS among populations of poorer countries. On these grounds, the field of AIDS research is evaluating alternative therapeutic approaches for the treatment and prevention of AIDS.