PIP: The current rate of progression of persistent generalized lymphadenopathy to acquired immunodeficiency syndrome (AIDS) was tested in a cohort of 105 homosexual men in London, UK. 5 patients were lost to follow-up, and the remaining 100 were seen every 3 months. All tested positive for the human immunodeficiency virus antibody. Previous clinical observations had shown oral candida; anemia; leucopenia; thrombocytopenia; enthrocyte sedimentation rate 15 mm in the 1st hour to be possible predictors of AIDS. 5 of the 13 patients who developed AIDS during a mean follow-up period of 22 months (range 12-32) developed Pneumocystis carinii; 5 Karposi's sarcoma; 1 both; 1 P carinii and cryptosporidiosis; and 1 cryptococcal meningitis. A life table technic calculation showed that over 3 years the probability of patients with persistent generalized lymphadenopathy progressing to AIDS was 20.9%. Of the clinical features examined, those most likely to indicate progression to AIDS were Oral candida (relative risk (RR)=12); Lymphopenia (RR=7); Erythrocyte sedimentation rate 15mm (RR=7); and anemia (RR=6). There were figures for median time before AIDS onset and the range of variation of these median times for these symptoms, e.g. oral candida, 8 months median; range of 1-24 months. Similar prospective studies performed in the US are reviewed. It is determined that a clinical examination and hematological measurements are useful in determining progression risk.