infection

The present authors have recently reported that inoculation with human herpesvirus-6 (HHV-6) ren-ders CD4MT lymphocytes susceptible to apoptosis in vitro. In order to confirm that apoptosis of CD4M T lymphocytes also occurs in HHV-6 infection in vivo, apoptosis of lymphocytes isolated from nine patients with exanthem subitum and from an adult patient with severe HHV-6 infection was examined. Peripheral blood mononuclear cells were cultured for 3 days and apoptosis of lymphocytes was then examined by flow cytometry of propidium iodide-stained DNA. The percentages of hypodiploid DNA, indicating apoptosis, in lymphocytes from 10 pa-tients with HHV-6 infection were significantly higher than those from five infant patients with non