Prevalence of human herpesvirus 6A and 6B during pregnancy

Cooperative activation of the human herpesvirus 6B U79/80 early gene promoter by immediate-early proteins IE1B and IE2B

The human herpesvirus 6B (HHV-6B) U79/80 gene belongs to the early gene class and appears as early as 3 hr postinfection. It is one of the most abundantly expressed transcripts and a useful diagnostic marker for viral reactivation. However, the expression mechanisms of the U79/80 gene remain unclear. To identify the viral factor(s) that activates the U79/80 promoter along with other HHV-6B core early gene promoters, p41, DNA polymerase, and U41, we examined the activities of U79/80 and other early gene promoters. In HHV-6B-infected MT-4 cells, U79/80 promoter activity was the highest among early gene promoters. In addition, we identified that HHV-6B immediate-early (IE)2B protein is one of the viral proteins involved in the activation of the U79/80 and other early gene promoters. Although the IE2B could independently activate these early gene promoters, the presence of IE1B significantly augmented the activities of early gene promoters. We also found that IE2B bound three human cytomegalovirus IE2-binding consensus, cis repression signal (CRS), within the U79/80 promoter. Moreover, the U79/80 promoter was activated by cellular factors, which are highly expressed in MT-4 cells, instead of HeLa cells because it was upregulated by mock infection and in the absence of IE2B. These results suggested that the activation mechanism of the U79/80 gene differs from other HHV-6B core early genes, apparently supporting its rapid and abundant expression. Therefore, the U79/80 early gene is an actually suitable biomarker of HHV-6B reactivation.

[Acute herpesviridae hepatitis during pregnancy: A review]

Viral hepatitis are well defined during pregnancy, including hepatitis A, B, C, D or E. In contrast, viral hepatitis called non-alphabetic, like viruses Herpesviridae family hepatitis [cytomegalovirus (CMV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV) or herpes simplex virus (HSV)] are rarely described. The aim of this article is to make a focus on the care of these viral herpesviridae hepatitis during pregnancy. Herpes hepatitis is more common during pregnancy, with a neonatal risk at peripartum period. VZV infection can cause disease to the fetus, with possible vertical transmission, and induce congenital or neonatal varicella. While EBV infection during pregnancy seems benign, the CMV is a high risk of birth defects. The management of these patients therefore depends on the gestational age, but especially the type of virus involved. The diagnosis is therefore essential to adapt treatment and obstetrical care.