title: Exaggerated IDO1 expression and activity in Langerhans cells from patients with atopic dermatitis upon viral stimulation: a potential predictive biomarker for high risk of Eczema herpeticum.
abstract: BACKGROUND
  Atopic dermatitis (AD) is a heterogenous and highly complex disease characterized by an increased microbial colonization. For unknown reasons, a subgroup of patients with AD develops Eczema herpeticum (EH), a severe viral complication due to spreading of herpes simplex virus (HSV). Indoleamine 2,3-dioxygenase (IDO1) is a tryptophan (Trp)-catabolizing enzyme which is assumed to be instrumental in the antibacterial and antiviral defence mechanisms.
  
  
  METHODS
  Comparative investigation of the IDO1 expression and activity in freshly isolated monocytes, plasmacytoid DC (pDC) and in vitro-generated Langerhans cells (LC) obtained from AD patients with HSV infections and EH and nonatopic controls.
  
  
  RESULTS
  We demonstrate an increase in Trp degradation in the serum of patients during acute EH episodes. Circulating pDC from patients with history of EH display an increased IDO1 expression. An increased Trp degradation is detected in the supernatants of circulating monocytes from AD patients with acute EH. Mature LC from AD patients with history of EH and with acute EH display an increased IDO1 expression and activity, respectively. In LC from patients with history of EH, viral signals induce an exaggerated IDO1 expression and activity.
  
  
  CONCLUSIONS
  IDO1 expression and activity in LC seem to be involved in the pathophysiology of EH in AD and could represent a predictive biomarker for patients with risk to develop EH and other viral complications.
authors.affiliation: Department of Dermatology and Allergy, Friedrich-Wilhelms-University, Bonn, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Staudacher
authors.affiliation: Department of Dermatology and Allergy, Friedrich-Wilhelms-University, Bonn, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Hinz
authors.affiliation: Department of Dermatology and Allergy, Friedrich-Wilhelms-University, Bonn, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Novak
authors.affiliation: Department of Dermatology, Albert-Ludwigs University, Freiburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: von Bubnoff
authors.affiliation: Department of Dermatology and Allergy, Friedrich-Wilhelms-University, Bonn, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Bieber
mesh_terms: D000328:Adult; D015415:Biomarkers; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D003876:Dermatitis, Atopic / Q000150:complications / Q000209:etiology*; D018450:Disease Progression; D005260:Female; D015870:Gene Expression; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase / Q000235:genetics* / Q000378:metabolism; D007617:Kaposi Varicelliform Eruption / Q000209:etiology; D007801:Langerhans Cells / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology / Q000378:metabolism; D018139:Simplexvirus; D014364:Tryptophan / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; C576710:IDO1 protein, human; D007074:Immunoglobulin G; D050503:Indoleamine-Pyrrole 2,3,-Dioxygenase; D007073:Immunoglobulin E; D014364:Tryptophan
keywords: Eczema herpeticum; Langerhans cells; atopic dermatitis; biomarker; herpes simplex virus; indoleamine 2,3-dioxygenase