The natural history of human immunodeficiency virus infection in a haemophilic cohort.

112 haemophilic patients infected with HIV were followed up with clinical and laboratory assessment between 1 December 1979 and 30 November 1988. Sixty-six (59%) of the patients developed HIV-related clinical symptoms and 22 (20%) developed AIDS. Twenty (18%) of the patients developed p24 antigenaemia. Amongst the 59 patients whose date of seroconversion could be estimated the calculated 8-year cumulative incidence of AIDS was 40% (symptoms 73%). For the whole cohort of 112 patients, the median slope of linear regression of the absolute T4 lymphocyte count was steeper for those with AIDS (-0.113 x 10(9)/l per year) than for those without AIDS (-0.054 x 10(9)/l per year) (P less than 0.02). While 15 cases of AIDS developed during 58 patient-years of follow up after falling below a T4 lymphocyte count of 0.2 x 10(9)/l, only two cases occurred during 450 patient-years before reaching this count. Thus the decline of the T4 lymphocyte count to 0.2 x 10(9)/l may be an appropriate additional end-point for the assessment of new treatments for asymptomatic patients infected with HIV.