title: Serum IL-21 levels are elevated in atopic dermatitis patients with acute skin lesions.
abstract: BACKGROUND
  Interleukin (IL)-21 is a member of the type I cytokine family and plays a role in the pathogenesis of T helper type 2 allergic diseases. It has been reported that IL-21 expression is upregulated in acute skin lesions in atopic dermatitis (AD) patients; however, little is known about the serum IL-21 levels of AD patients. The aim of this study was to quantify the serum IL-21 levels of AD patients and to evaluate the relationships between the serum IL-21 level and disease severity, laboratory markers, and eruption type in AD patients.
  
  
  METHODS
  We measured the serum IL-21 levels of adult AD patients and healthy control subjects using an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  The adult AD patients exhibited significantly higher serum IL-21 levels than the healthy control subjects. A comparison of the patients' serum IL-21 levels based on the clinical severity of their AD revealed that the patients with severe AD demonstrated significantly higher serum IL-21 levels than those with mild AD and the healthy control subjects. The serum IL-21 levels were significantly correlated with the skin severity score, and especially with the degree of acute lesions such as erythema and edema/papules. The serum IL-21 level was not associated with laboratory markers, such as the serum IgE level, the serum thymus and activation-related chemokine level, blood eosinophilia, and the serum lactate dehydrogenase level.
  
  
  CONCLUSIONS
  These results suggest that IL-21 might be involved in the pathogenesis of AD, especially the development of acute skin lesions.
authors.affiliation: Departments of Dermatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Mizutani
authors.affiliation: Departments of Dermatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. Electronic address: risat@koto.kpu-m.ac.jp.
authors.forename: Risa
authors.initials: R
authors.lastname: Tamagawa-Mineoka
authors.affiliation: Departments of Dermatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Naomi
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: Departments of Dermatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Masuda
authors.affiliation: Departments of Dermatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Norito
authors.initials: N
authors.lastname: Katoh
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D016022:Case-Control Studies; D003876:Dermatitis, Atopic / Q000097:blood* / Q000175:diagnosis*; D018450:Disease Progression; D004797:Enzyme-Linked Immunosorbent Assay; D004804:Eosinophils; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D007378:Interleukins / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology*; D055815:Young Adult; D000098546:Interleukin-21
chemical_list: D015415:Biomarkers; D007378:Interleukins; D007073:Immunoglobulin E; D000098546:Interleukin-21
keywords: Atopic dermatitis; Atopy; Cytokine; Interleukin 21; T helper 2