title: Serum measurement of interleukin-31 (IL-31) in paediatric atopic dermatitis: elevated levels correlate with severity scoring.
abstract: BACKGROUND
  Interleukin-31 (IL-31) is a novel T-helper-lymphocyte-derived cytokine that plays an important role in human T-cell-mediated skin diseases. When overexpressed in transgenic mice, IL-31 induces severe pruritus resembling eczema in humans. Serum IL-31 was previously found overexpressed in adults with atopic dermatitis (AD). The novelty of this study is the use of a pediatric patient group as well as comparison of IL-31 levels during flare and quiescence.
  
  
  OBJECTIVE
  This case-controlled longitudinal study was designed to determine the levels of IL-31 in serum of AD children and its associations in relation to disease activity and severity.
  
  
  METHODS
  Sera were obtained from 50 AD children and 40 healthy volunteers. IL-31 levels were measured using a sandwich ELISA. All AD patients were followed up and re-sampled for serum IL-31 after clinical remission. Serum IL-31 levels were correlated with AD disease activity and severity variables.
  
  
  RESULTS
  Serum IL-31 levels were significantly higher whether during AD flare [median, 1600; mean (SD)=1457.8±770.4 pg/mL] or quiescence (1040; 958.7±419.5 pg/mL), than those in controls (220; 197.3±91.9 pg/mL). Serum IL-31 levels were significantly higher in the high disease severity group compared with the moderate or low severity group. Moreover, serum IL-31 levels correlated positively with the calculated severity scores (LSS, SSS and SCORAD index).
  
  
  CONCLUSIONS
  The results of this study confirm the importance of IL-31 in AD pathophysiology. Serum IL-31 level is an objective reliable marker of AD severity in children. It may represent a novel target for antipruritic drug development.
authors.affiliation: Department of Pediatrics, Faculty of Medicine, Ain Shams University, Cairo, Egypt. ezzatmhm@hotmail.com
authors.forename: M H M
authors.initials: MH
authors.lastname: Ezzat
authors.forename: Z E
authors.initials: ZE
authors.lastname: Hasan
authors.forename: K Y A
authors.initials: KY
authors.lastname: Shaheen
mesh_terms: D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000097:blood* / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007378:Interleukins / Q000097:blood* / Q000502:physiology; D008137:Longitudinal Studies; D008297:Male; D012189:Retrospective Studies; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; C502187:IL31 protein, human; D007378:Interleukins