Clinical and serological features of human herpesvirus-6 infection in three adults.

3 adult patients with serological evidence of human herpesvirus-6 (HHV-6) infection had mild, afebrile illnesses with nonspecific symptoms. In each case, the characteristic clinical feature was the presence of enlarged, bilateral, non-tender, anterior and posterior cervical nodes early in the illness which persisted for up to 3 months. HHV-6 IgG antibody reciprocal titres of 160 to 2560 were found during acute infection, and decreased to a titre of 10 in 1 patient 3 years later. IgM responses were detected at low reciprocal titres (10) in 2 patients and disappeared after several months.