Spontaneous regression of highly immunogenic Molluscum contagiosum virus (MCV)-induced skin lesions is associated with plasmacytoid dendritic cells and IFN-DC infiltration

J Invest Dermatol. 2011 Feb;131(2):426-34. doi: 10.1038/jid.2010.256. Epub 2010 Aug 26.


Molluscum contagiosum virus (MCV) infection induces self-limiting cutaneous lesions in an immunocompetent host that can undergo spontaneous regression preceded by local inflammation. On histology, a large majority of MCV-induced lesions are characterized by islands of hyperplastic epithelium containing infected keratinocytes and surrounded by scarce inflammatory infiltrate. However, spontaneous regression has been associated with the occurrence of a dense inflammatory reaction. By histology and immunohistochemistry, we identified MCV-induced lesions showing a dense inflammatory infiltrate associated with cell death in keratinocytes (inflammatory Molluscum contagiosum (I-MC)). In I-MC, hyperplastic keratinocytes were highly immunogenic as demonstrated by the expression of major histocompatibility complex class I and II molecules. Immune cell infiltration consisted of numerous cytotoxic T cells admixed with natural killer cells and plasmacytoid dendritic cells (PDCs). Accordingly, a type I IFN signature associated with PDC infiltration was demonstrated in both keratinocytes and inflammatory cells. Among the latter, a cell population resembling IFN-DC (CD123(+)CD11c(+)CD16(+)CD14(+)MxA(+)) was identified in proximity to islands of apoptotic keratinocytes. In vitro-generated IFN-DCs expressed a strong cytotoxic signature, as demonstrated by high levels of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas ligand (FasL). This study establishes a previously unreported model to underpin the role of innate immune cells in viral immune surveillance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Biopsy
  • CD11c Antigen
  • Cell Communication
  • Dendritic Cells / metabolism
  • Dendritic Cells / pathology*
  • Fas Ligand Protein / metabolism
  • Humans
  • Immunity, Innate
  • Inflammation / metabolism
  • Inflammation / pathology
  • Interferon Type I / metabolism*
  • Interleukin-3 Receptor alpha Subunit
  • Keratinocytes / metabolism
  • Keratinocytes / pathology
  • Molluscum Contagiosum / pathology*
  • Molluscum Contagiosum / virology*
  • Molluscum contagiosum virus / isolation & purification*
  • Skin / metabolism
  • Skin / pathology*
  • Skin / virology
  • TNF-Related Apoptosis-Inducing Ligand / metabolism


  • CD11c Antigen
  • Fas Ligand Protein
  • Interferon Type I
  • Interleukin-3 Receptor alpha Subunit
  • TNF-Related Apoptosis-Inducing Ligand
  • TNFSF10 protein, human