Cytokine and chemokine tear levels in patients with uveitis

Abstract

Purpose: To determine whether the levels of cytokines and chemokines in tears differ in uveitis patients and healthy subjects. Methods: Ninety-two uveitis patients (mean age 46.4 years) and 157 control healthy subjects (mean age 49.5 years) were recruited. Subjects with ocular surface diseases such as dry eye were excluded from the study. Using multiplex bead-based assays, tears (4 μl) were analysed for the concentration of interleukin (IL)-1β, IL-1RA, IL-2, IL-6, IL-7, IL-8/CXCL8, IL-10, IL-12p70, IL-15, IL-17A, IL-23, epidermal growth factor (EGF), fractalkine/CX3CL1, interferon-γ, IP-10/CXCL10, monocyte chemo-attractant protein (MCP)-1/CCL2, tumour necrosis factor-α, vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-β1, TGF-β2 and TGF-β3. Tear molecule levels were compared between the groups and among the different forms of uveitis and disease severity. Results: Epidermal growth factor, IL-1RA, IL-7, IL-8/CXCL8, IP-10/CXCL10, MCP-1/CCL2, TGF-β2 and VEGF were detected in more than 75% of the samples in both groups. Statistically significant differences in percentage of detection between control and patient groups were found for IL-23, IL-1β, IL-15, EGF, fractalkine/CX3CL1 and MCP-1/CCL2. The concentrations of IL-1RA, IL-8/CXCL8, fractalkine/CX3CL1, IP-10/CXCL10, VEGF and TGF-β2 in uveitis tear samples were elevated compared to controls (p < 0.05). Significant differences in tear levels of those molecules and also EGF were also present depending on the anatomic classification of uveitis. Conclusion: There were significant differences in the levels of several cytokines and chemokines in tears of patients with uveitis compared with healthy subjects. These results can help understand the underlying pathophysiology of the uveitis and could potentially aid in diagnosis.