title: Acne inversa: evaluating antimicrobial peptides and proteins.
abstract: BACKGROUND
  Acne inversa is a chronic, suppurative relapsing inflammatory skin disease that primarily affects the axillae, perineum and inframammary regions. Evidence suggests that the innate immune system is involved in the pathogenesis of acne inversa.
  
  
  OBJECTIVE
  To investigate the role of the innate immune system in acne inversa.
  
  
  METHODS
  Skin biopsies were obtained from inflammatory skin lesions (n=17) and from non-lesional skin (intraindividual control, n=17) of patients with acne inversa. Additional skin lesions were taken from patients with chronic venous leg ulcers (interindividual control, n=5). Quantitative real-time reverse transcription-polymerase chain reaction was used to determine the mRNA levels of antimicrobial peptides and proteins (AMPs), including human β-defensin (hBD)-1, hBD-2 and hBD-3, LL-37 (cathelicidin) and Ribonuclease 7 (RNase 7). mRNA levels were also determined for inflammatory and anti-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), matrix metalloproteinase-1 (MMP1), interleukin (IL)-1β, IL-6, IL-8 and IL-10.
  
  
  RESULTS
  The mRNA levels of hBD-2, LL-37, IL-1β, IL-6, IL-8, IL-10 and MMP1 were significantly higher in acne inversa lesions compared to non-lesional skin (p<0.05). A significant positive correlation expression was observed between hBD-2 mRNA expression and LL-37 (ρ=0.53, p=0.03), and between hBD-2 and RNAse 7 (ρ=0.68, p=0.006). When compared to the chronic venous leg ulcer lesions, acne inversa lesions showed a significantly higher expression of RNase 7 mRNA, while IL-1 β, IL-6, IL-8, TNF-α and MMP1 mRNA expression was significantly higher in the chronic venous leg ulcer lesions (p<0.05).
  
  
  CONCLUSIONS
  The AMP, cytokine milieu and tissue proteases in acne inversa lesions differ significantly from non-lesional skin and chronic venous leg ulcers. The positively correlating up-regulation of AMPs in acne inversa indicates an important role of the innate immune system in the pathogenesis of this disorder.
authors.affiliation: Department of Dermatology, Venerology and Allergology, Ruhr-University Bochum, Bochum, Germany.
authors.forename: Falk G
authors.initials: FG
authors.lastname: Bechara
authors.forename: Michael
authors.initials: M
authors.lastname: Sand
authors.forename: Marina
authors.initials: M
authors.lastname: Skrygan
authors.forename: Alexander
authors.initials: A
authors.lastname: Kreuter
authors.forename: Peter
authors.initials: P
authors.lastname: Altmeyer
authors.forename: Thilo
authors.initials: T
authors.lastname: Gambichler