Abstract
Purpose:
To measure a panel of tear cytolkines/chemokines and mRNA expression of a panel of inflammatory molecules and their receptors in conjunctival cells in atopic keratoconjunctivitis (AKC) and to correlate their levels with AKC-related features and extraocular atopic disorders.
Methods:
22 AKC patients and 18 age and sex-matched controls were evaluated after 20 min in a controlled environment chamber (45% relative humidity, 22°C, 930 mb). Patients were medically controlled and had discontinued medications for one week before examination. Symptom questionnaires were answered by patients and controls. Unstimulated tears were collected from most symptomatic eye. Levels of 19 molecules (EGF, IL-1RA, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-17A, IP-10, eotaxin 1, fractalkine, IFN-γ, VEGF, TNF-α and RANTES) were measured by multiplex bead assay and correlated with clinical parameters. Conjunctival epithelial cells were collected by impression cytology in upper bulbar conjunctiva and gene expression of 84 inflammatory molecules was determined by RT2-PCR in pooled cDNA samples.
Results:
IL-5 tear levels were decreased (p=0.0121) in AKC compared to controls. IL-6 and IL-1β tear levels were increased in AKC tear samples near to statistical significance (p=0.0509; p=0.0713). AKC patients with active atopic dermatitis (AD) had increased IFN-γ and TNF-α tear levels (p=0.0104, p=0.0176) compared to non-active AD. AKC patients with concomitant asthma had decreased tear IL-2 (p=0.0282). Several molecule tear levels correlated with clinical signs. All molecules were detected, except IL-17A and eotaxin 1. Expression of 45 genes was detected in AKC conjunctival epithelial cells: 10 genes (IFNγ, CXCL2, CXCL3, CCL11, CCL24, CCL26, CCR2, CCR3, IL-17C, and NAMPT) were ≥ 2 fold upregulated and 5 genes (CCL5, CXCR1, IL27, LTA, and LTB) were ≥ 2 fold dowregulated.
Conclusions:
IL-5 tear levels were decreased in AKC patients compared to healthy individuals, probably related to the absence of proliferative lesions, as described. Interestingly, the addition of active AD correlated with 2 highly inflammatory molecules, IFN-γ and TNF-α, in tears. In spite of the fact that these patients had mild inflammation, the expression of several inflammatory genes was altered in their conjunctival cells. These results add further knowledge to the search for potential biomarkers in AKC.
Keywords: 490 cytokines/chemokines •
557 inflammation •
474 conjunctiva