Association of IL-21 cytokine with severity of primary Sjögren syndrome dry eye

Cornea. 2015 Mar;34(3):248-52. doi: 10.1097/ICO.0000000000000363.


Purpose: IL-21 plays an important role in primary Sjögren syndrome (SS) pathogenesis. The purpose of this study was to evaluate IL-21 expression in tears and the conjunctiva and to analyze the impact of IL-21 on primary SS dry eyes.

Methods: Eighty subjects were enrolled in this study: 30 patients with primary SS dry eye (30 eyes); 30 patients with non-SS dry eye (30 eyes), and 20 normal controls. Tear IL-21 levels were measured by flow cytometry, and IL-21 gene expression in the conjunctiva from impression cytology was evaluated by quantitative polymerase chain reaction. Ocular Surface Disease Index, tear film breakup time, Schirmer I test, and ocular surface staining scores were obtained for all patients.

Results: Primary SS dry eyes had significantly higher tear IL-21 levels than non-SS dry eyes and normal controls (P < 0.01). In addition, IL-21 gene expression in the conjunctiva was also higher in primary SS dry eyes than in non-SS dry eyes and normal controls (P < 0.01). However, there were no significant differences in IL-21 expression in tears and the conjunctiva between non-SS dry eyes and controls. The tear IL-21 level was significantly correlated with ocular surface stain scores (r = 0.54, P < 0.01) and Schirmer I test values (r = -0.23, P < 0.05) in primary SS dry eyes.

Conclusions: Our findings suggest that severity of primary SS dry eye is associated with IL-21.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Conjunctiva / metabolism
  • Conjunctiva / pathology
  • Dry Eye Syndromes / etiology
  • Dry Eye Syndromes / metabolism*
  • Female
  • Gene Expression Profiling
  • Humans
  • Interleukins / metabolism*
  • Male
  • Middle Aged
  • Polymerase Chain Reaction
  • Severity of Illness Index
  • Sjogren's Syndrome / metabolism*
  • Tears / metabolism


  • Interleukins
  • interleukin-21