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Human herpesvirus 8 (HHV-8) “in vitro” infection of human placental histocultures


Most human Herpesvirus infect placental cells and may be harmful in pregnancy, leading to obstetrical and/or neonatal complications. Although a correlation between human herpesvirus 8 (HHV-8) infection and abortion or low birth weight in children has been reported [1, 2] presently no information has been published regarding HHV-8 tropism for placenta.

Materials and methods

In this study, a placenta histoculture system was used to evaluate the susceptibility of placental cells to “in vitro” HHV-8 infection. Quantitative detection of HHV-8 was performed by real-time PCR, and virus expression was evaluated by immunohistochemistry for latent and lytic HHV-8 antigens.


Increasing amounts of HHV-8 DNA were detected in placental tissues and culture supernatants and immunohistochemistry analyses demonstrated that both cyto- and syncitiotrophoblasts, as well as placental endothelial cells, expressed latent (see Figure 1) and lytic antigens. In addition, relevant apoptotic phenomena were observed in infected histocultures.

Figure 1

Immunohistochemical detection of the HHV-8 LANA protein in placental histocultures. Specific reactivity was visualized with immunoperoxidase staining using anti-LANA-1 monoclonal antibodies with a DAB developer (brown colour) and haematoxylin counterstaining. (A) HHV-8-infected CRO-AP/3 cells showed a strongly positive nuclear immunostaining. (B) HHV-8-infected placental histocultures showed positive immunostaining in cytotrophoblasts (yellow arrow), syncytiotrophoblasts (blue arrow) and endothelial cells (white arrow). (C) Mock-infected placental histocultures. Original magnifications, X100.


We here demonstrated for the first time that HHV-8, like other human herpesviruses, may productively infect placental cells in vitro, thus providing evidence that this phenomenon might influence vertical transmission and pregancy outcome in HHV-8-infected women.


  1. 1.

    Gaye-Diallo A, Toure AT, Gessain A, Gueye-Ndiaye A, Ndour AN, et al: Preliminary study of human Herpesvirus type 8 infection in pregnant women in Dakar (Senegal). Bull Soc Pathol Exot. 2001, 94: 231-234.

  2. 2.

    Sarmati L, Ticconi C, Santangelo R, Montano M, Rezza G, et al: Does the risk of abortion increases in women with high human herpesvirus-8 antibody titers?. J Infect Dis. 2003, 188: 173-174. 10.1086/375830.

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This work was supported by grants from Istituto Superiore di Sanità (grant n. 50G.3, MLC; grant n. 50G.29, JRF) and from Associazione Italiana per la Ricerca sul Cancro (MLC). MB was the recipient of a fellowship from Associazione Italiana per la Lotta contro le Leucemie, Linfomi e Mieloma (AIL).

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Correspondence to Mariantonietta Di Stefano.

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  • Endothelial Cell
  • Birth Weight
  • Culture Supernatant
  • Immunohistochemistry Analysis
  • Vertical Transmission