[Human herpesvirus 6 (HHV-6): incidence in healthy blood donors and in patients with acute infections caused by other herpes viruses].

Antibodies to HHV-6 were detected by immunofluorescence in 8.04% of 460 healthy blood donors in West Austria. Testing sera from patients with acute or reactivated infections with other herpesviruses, such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), herpes simplex virus (HSV) and varicella zoster virus (VZV) we observed a remarkably higher prevalence of antibodies to HHV-6 in patients with CMV infections (75%) and also in patients with EBV infections (50%). Patients with HSV and VZV infections were positive for HHV 6 in 12.5% and 6.6% of cases, respectively. Many of the patients with CMV infection were transplant recipients. The high incidence of positive HH 6 serology in these patients could be due to new infection by HHV 6 or to the reactivation of a previous infection with HHV 6 by means of allogenic cell stimulation. Furthermore, preliminary results from our laboratory point to a serological cross-reaction between HHV 6 and CMV, which may also contribute to this result.