Detection of herpes simplex virus DNA in plasma of patients with primary but not with recurrent infection: implications for transfusion medicine?

Among the family of herpes viruses, only cytomegalovirus (CMV) and, to a lesser extent, human herpes virus 8 (HHV-8) are of relevance in transfusion medicine. Due to neutropism, herpes simplex viruses (HSV) types 1 and 2 are considered to be of minor relevance. However, several reports gave evidence that a HSV DNAemia might occur and HSV could therefore be transmissible by blood products. The aim of our study was to collect data about prevalence of HSV antibodies among blood donors and to clarify whether HSV DNAemia is possible. HSV antibody states of 653 blood donors were investigated. Blood specimens of 46 patients with primary and recurrent HSV infection were tested for HSV-1 and HSV-2 DNA using TaqMan polymerase chain reaction. In 505 of the 653 blood donors HSV antibodies were detectable, most of which were HSV-1 antibodies. HSV DNA was detected in plasma, but not in peripheral blood mononuclear cells (PBMCs) of seven rather seriously ill patients with primary herpes genitalis. No HSV viraemia was detectable in otherwise healthy patients with recurrent herpes labialis. Thus, HSV DNAemia is possible, but seems to be limited to primary infections and could not be detected in the recurrent infection. Therefore, blood donors with primary herpes infection should be deferred from donation. Blood donors with recurrent HSV infection are probably not at risk of transmitting HSV, but further studies are necessary to prove this hypothesis. Detection of HSV DNA in PBMCs as described formerly could not be confirmed by this study.