Proteomics Screening of Differentially Expressed Cytokines in Tears of Patients with Graves' Ophthalmopathy

Background: The current study aimed at exploring the cytokine profile in the tears of patients with Graves' ophthalmopathy (GO).

Methods: Tears were sampled from the eyes of 7 patients with active GO and 7 healthy volunteers using filter paper. Then the levels of up to 34 cytokines in the tears of each subject were detected using high-throughput protein microarray technology in line with the introduction.

Results: The results of cytokine protein microarray screening showed that 10 proteins, namely, CD40, CD40 Ligand, GITR, IL-12p70, IL-1 beta, IL-2, IL-21, IL-6, MIP-3 alpha and TRANCE, were overexpressed (with fold change >1.20) and 3 proteins, namely, GM-CSF, IL-1 sRI and IL-13 were downregulated (with fold change < 0.83) in GO patients. In addition, the protein levels of CD40 and CD40 ligand (CD40L) were significantly different between GO patients and healthy controls (P=0.028 and 0.011, respectively). Further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of differently expressed proteins showed that these proteins were involved in biological functions including biological processes (positive regulation of cytokine production, JAK-STAT cascade and leukocyte proliferation), molecular functions (cytokine and growth factor receptors binding and cytokine activity), and other important pathways (cytokine-cytokine receptor interaction, JAK-STAT signaling pathway, IL-17 signaling pathway, NF-kappa B signaling pathway, Th17 cell differentiation, and intestinal immune network for IgA production), all of which might be involved in the pathology of GO.

Conclusion: Our cytokine protein microarray analysis indicated that several proteins were differentially expressed in GO patients, which provides potential targets for GO prevention.