1 The epidemiology of AIDS.- 2 Transfusion-associated AIDS.- 3 The human retroviruses causing AIDS.- 4 Effects of HIV infection on the immune system.- 5 T cell phenotyping in the diagnosis and management of AIDS and AIDS related disease.- 6 The immunosuppressive effects of blood.- 7 Serological tests.- 8 Donor screening for HIV in the United States.- 9 Blood donor screening for HIV infection: introduction in the United Kingdom and Europe and its impact on transfusion medicine.- 10 Asymptomatic infection with human immunodeficiency virus.- 11 Psychological and ethical implications of HIV screening.- 12 The future.