['The contribution of cytomegalovirus (CMV) to progressive HIV infection is still controversial.', 'The occurrence of CMV DNA in the plasma of patients with advanced HIV infection was studied in relation to the development of clinical disease.', 'Plasma samples were collected every 2 weeks for 6 months. The patients have thereafter been followed clinically at least every 3 months. CMV DNA was extracted and analysed by a nested PCR.', 'CMV DNA was repeatedly detected in the plasma of five patients for more than 45 days (group 1). These patients also had very low CD4+ cell counts 51+/-41 x 10(6) /l). Three patients in group 1 developed CMV complications and CMV was the cause of death in two cases. Two patients with anti-CMV IgM responses did not develop CMV complications. All five patients died at a mean of 17 months after CMV DNA became continuously detectable by PCR. In another six patients, CMV DNA was not or only sporadically detected (group 2). In these six patients, four are still alive after more than 3.5 years and only one patient developed CMV retinitis 3 years later.'] Does continuous detection of CMV DNA in plasma of patients with advanced HIV infection imply the poorest prognosis?