Abstract
Purpose:
Dry eye disease (DED) is a complex and multifactorial disease associated with immune and inflammatory processes. The ongoing activation of pathogenic immune cells, particularly the CD4+ T cells, plays a significant role in the pathogenesis of DED. Th17 cell, the newly discovered subset of CD4+ T cell, was reported to participate in many other ocular inflammatory diseases. This study is the first to elucidate the role of Th17 cells in the pathogenesis of DED via assessing the expression of Th17 associated cytokines, in particular interleukin-17 (IL-17) and interleukin-22 (IL-22) in tears of DED patients.
Methods:
Tear samples were collected from 20 healthy volunteers, 20 DED patients with non-Sjögren’s syndrome (NSSDE) and 20 DED patients with Sjögren’s syndrome (SSDE). Symptom questionnaires were self-administered and multiple DED-related clinical tests were performed. The expression of IL-17 and IL-22 in tears was evaluated by enzyme-linked immunosorbent assay.
Results:
Our data indicated that the expression of IL-17 and IL-22 was significantly increased in tears of DED patients compared with those of healthy controls (p<0.05). And up-regulated expression of these two proteins was also observed in SSDE patients in comparison with that of NSSDE patients (p<0.05). Moreover, the expression of IL-17 and IL-22 was positively correlated with questionnaire score and keratopathy score but negatively correlated with tear film BUT and Schirmer I test in both NSSDE and SSDE patients (p<0.05).
Conclusions:
The expression of IL-17 and IL-22 in tears was significantly increased in DED patients and associated with disease severity. Th17 cell associated cytokines, particularly IL-17 and IL-22, may play important roles in the immunopathogenesis of DED.
Keywords: 486 cornea: tears/tear film/dry eye •
555 immunomodulation/immunoregulation