title: Skin cytokine expression in patients with fibromyalgia syndrome is not different from controls.
abstract: BACKGROUND
  Fibromyalgia syndrome (FMS) is a chronic pain syndrome of unknown etiology. There is increasing evidence for small nerve fiber impairment in a subgroup of patients with FMS. We investigated whether skin cytokine and delta opioid receptor (DOR) gene expression in FMS patients differs from controls as one potential contributor to small nerve fiber sensitization.
  
  
  METHODS
  We investigated skin punch biopsies of 25 FMS patients, ten patients with monopolar depression but no pain, and 35 healthy controls. Biopsies were obtained from the lateral upper thigh and lower calf. Gene expression of the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF), interleukin (IL)-6, and IL-8 and of the anti-inflammatory cytokine IL-10 was analyzed using quantitative real-time PCR and normalizing data to 18sRNA as housekeeping gene. Additionally, we assessed DOR gene expression.
  
  
  RESULTS
  All cytokines and DOR were detectable in skin samples of FMS patients, patients with depression, and healthy controls without intergroup difference. Also, gene expression was not different in skin of the upper and lower leg within and between the groups and in FMS patient subgroups.
  
  
  CONCLUSIONS
  Skin cytokine and DOR gene expression does not differ between patients with FMS and controls. Our results do not support a role of the investigated cytokines in sensitization of peripheral nerve fibers as a potential mechanism of small fiber pathology in FMS.
authors.forename: Nurcan
authors.initials: N
authors.lastname: Üçeyler
authors.forename: Susanne
authors.initials: S
authors.lastname: Kewenig
authors.forename: Waldemar
authors.initials: W
authors.lastname: Kafke
authors.forename: Sarah
authors.initials: S
authors.lastname: Kittel-Schneider
authors.forename: Claudia
authors.initials: C
authors.lastname: Sommer
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D016022:Case-Control Studies; D016207:Cytokines / Q000235:genetics*; D003863:Depression / Q000503:physiopathology; D005260:Female; D005356:Fibromyalgia / Q000235:genetics / Q000503:physiopathology*; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D012867:Skin / Q000473:pathology*
chemical_list: D016207:Cytokines