Serum IL-21 levels are elevated in atopic dermatitis patients with acute skin lesions

Allergol Int. 2017 Jul;66(3):440-444. doi: 10.1016/j.alit.2016.10.010. Epub 2016 Nov 22.


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.

Keywords: Atopic dermatitis; Atopy; Cytokine; Interleukin 21; T helper 2.

MeSH terms

  • Adolescent
  • Adult
  • Biomarkers
  • Case-Control Studies
  • Dermatitis, Atopic / blood*
  • Dermatitis, Atopic / diagnosis*
  • Disease Progression
  • Enzyme-Linked Immunosorbent Assay
  • Eosinophils
  • Female
  • Humans
  • Immunoglobulin E / blood
  • Immunoglobulin E / immunology
  • Interleukins / blood*
  • Leukocyte Count
  • Male
  • Middle Aged
  • Severity of Illness Index
  • Skin / pathology*
  • Young Adult


  • Biomarkers
  • Interleukins
  • Immunoglobulin E
  • interleukin-21