Cytokine and chemokine levels in tears from healthy subjects

Abstract

ABSTRACT.Purpose: There is growing evidence for the existence of an 'immune tone' in normal tears. The aim of this study was to determine the levels of a large panel of cytokines and chemokines in tears obtained from healthy subjects. These levels can then serve as baseline values for comparison with patients suffering from ocular surface diseases. Subjects and Methods: Nine healthy subjects participated in this study, and normal ocular surface health was documented by the results of a dry eye questionnaire, Schirmer strip wetting, and vital staining of the cornea. Four microliters of tears were collected from each eye and analysed separately with multiplex bead-based assays for the concentration of 30 cytokines and chemokines. Results: Twenty-five cytokines ⁄ chemokines were detected. CCL11 ⁄ Eotaxin1, GM-CSF, G-CSF, IFN-c, IL-2, IL-3, IL-4, IL-5, IL-10, IL-13, IL-12p70, IL-15, CX3CL1 ⁄ Fractalkine, TNF-a, epidermal growth factor, and CCL4 ⁄ MIP1b were present at 5-100 pg ⁄ ml. IL-1b, IL-6, IL-7A, CXCL8 ⁄ IL-8, and CCL2 ⁄ MCP-1 were present at 100-400 pg ⁄ ml. IL-1Ra, CXCL10 ⁄ IP-10 and vascular endothelial growth factor were present at more than 1000 pg ⁄ ml. Conclusion: Multiplex bead-based assays are convenient for cytokine ⁄ chemokine detection in tears. Fracktalkine has been detected in human healthy tears for the first time. The knowledge of cytokine ⁄ chemokine concentrations in tears from normal subjects is an important reference for further comparison with patients suffering from ocular surface diseases. Variability in their levels can reflect a phenomenon of potential importance for the understanding of the ocular surface cytokine pattern.

Graves' Orbitopathy Results in Profound Changes in Tear Composition: A Study of Plasminogen Activator Inhibitor-1 and Seven Cytokines

“…These findings indicate that tear cytokines are regulated differently, and the appearance of proinflammatory cytokines in the tears of patients with GO, but not in those with GD without orbitopathy, is not the result of the thyroid disease but the orbitopathy itself. Sources of cytokines and chemokines in tears may include the main and accessory lacrimal glands, the corneal and conjunctival fibroblasts, and the immunovigilant cells normally present in the ocular surface (44).…”

Cytokine Profiles in Tears Accompanying the Secondary Conjunctival Responses Induced by Nasal Allergy

“…39,40 Finally, because the appearance of cytokines in tears during the secondary forms of CR to NPTs has not yet been investigated, our results cannot be compared with other data.…”

Inflammatory mediator profiles in tears accompanying keratoconjunctival responses induced by nasal allergy

“…Even, little amount of data that is available on the mediator and cytokine profiles in the tears of the healthy subject can be used as reference values 23 24. Data dealing with appearance and concentration changes of the mediators and cytokines in tears during the secondary forms of keratoconjunctival response to NPTs are, however, lacking.…”