Objective: The purpose of the study is to compare tear fluid concentrations of interleukin-1alpha (IL-1alpha), tumor necrosis factor-alpha (TNF-alpha), and epidermal growth factor (EGF) in ocular rosacea with those in control subjects and to examine the relation between tear functions, such as production and clearance rate, and the concentrations of cytokines in tear fluid.
Participants and intervention: Fourteen patients with severe meibomian gland disease, facial rosacea, and symptoms of ocular irritation were examined for ocular surface disease, tear production, and tear clearance rate (TCR). Twelve control subjects, frequency-matched for age, and 15 ideal normal subjects with no ocular symptoms and normal tear function were assessed using the same parameters. Minimally stimulated tear samples (20 microl) were drawn from each subject and analyzed using a sandwich enzyme-linked immunosorbent assay to detect IL-1alpha, TNF-alpha, and EGF.
Results: Tear IL-1alpha concentration was significantly higher in patients with rosacea than in age-matched (P = 0.003) and ideal control subjects (P < 0.001). Tumor necrosis factor-alpha was not detected in patients or control subjects, indicating levels of less than 10 pg/ml. Epidermal growth factor was not significantly higher in patients with rosacea than in age-matched control subjects. Tear turnover LN(TCR) was lower in patients with rosacea than in both age-matched (P = 0.048) and ideal control subjects (P = 0.002). Schirmer I scores were statistically lower in patients with rosacea than in ideal control subjects (P = 0.013), but not age-matched control subjects. Interleukin-1alpha was correlated inversely with LN(TCR) (r= -0.58, P < 0.0001) and Schirmer I (r = -0.39, P = 0.012).
Conclusions: Concentrations of IL-1alpha are present in normal tears but are elevated in ocular rosacea, whereas TNF-alpha is not present in either case. The reduced tear turnover, LN(TCR), its inverse correlation with IL-1alpha, and the absence of TNF-alpha in the tears of these patients suggest that the increased concentration of IL-1alpha observed may be largely because of clearance failure of cytokine normally produced at the ocular surface.