Transfusion-Associated Infections with Cytomegalovirus and Other Human Herpesviruses

Abstract

Of all human herpesviruses, human cytomegalovirus (HCMV) is the most significant cause of transfusion-associated (TA) morbidity and mortality. The problem of TA HCMV infection differs from that of other transfusion-transmitted infections in that only certain groups of patients require HCMV-free blood or blood components, i.e. seronegative pregnant women, premature infants of low birth weight who are born to seronegative mothers, seronegative recipients of allogeneic bone marrow transplants from seronegative donors, seronegative AIDS patients, and seronegative immunosuppressed patients in general. HCMV is strictly cell-associated, and transmission appears to be due to reactivation of latent virus in white blood cells. TA HCMV infec-tion in risk groups can be minimized by selection of HCMV-seronegative donors. Since transmission of HCMV from seropositive donors by blood components containing fewer than 10 7 leukocytes per unit is unlikely, leukodepletion of transfusion products by filtration is an effective alternative to the use of seronegative blood products. Other human herpesviruses causing TA infections are Epstein-Barr virus (EBV) and the human herpesviruses 6 and 7 (HHV-6, HHV-7), whereas transmissions of herpes simplex viruses (HSV-1, HSV-2) and varicella-zoster virus (VZV) by blood transfusion – if occurring at all – are extremely rare events. Frequency and clinical significance of TA infections with the human herpesvirus 8 (HHV-8) have not yet been fully elucidated. Despite the low seroprevalence of HHV-8 in Germany, its oncogenic potential merits attention, and strategies to prevent transmission and spread of HHV-8 by blood and blood products should be discussed.