Human herpesvirus 6 (HHV-6) infected cells were detected in all lung,
lymph-node, spleen, liver, and kidney tissues obtained at necropsy fro
m an unselected series of nine patients with AIDS. This infection rate
was significantly higher than that for cytomegalovirus. Lung infectio
n with HHV-6 was extensive enough in one patient to account for fatal
pneumonitis. In other tissues increased numbers of HHV-6 infected cell
s were related to the presence of lymphocytic infiltrates or residual
lymphoid tissue, with lymphocytes being predominantly infected. Thus H
HV-6 is an important pathogen in patients with AIDS.