Testing for human immunodeficiency virus (HIV-1) antigens in haemophiliacs positive for HIV antibody

Sera collected from 28 haemophiliacs during the 2 years from 1985 to 1987 were examined for the presence of human immunodeficiency virus (HIV-1) antigen by two different methods using commercially available test kits. Of 28 patients, 18 had been positive for HIV antibody since at least 1985 and their HIV infection by blood products went back 3–6 years. Of these 18 antibody-positive patients, 8 were positive for HIV antigen according to one or both antigen tests on one or more occasions. The longest period of antigen expression was 21 months in two patients, one being in perfect health, the other showing AIDS-related complex (ARC) for the last 9 months. The detection of antigen expression was highly variable between the two tests used. Both positive and negative antigen-test results must therefore be used with great caution in clinical practice.