To determine the pathological role of tumor necrosis factor alpha (TNF-alpha) in ocular surface disorder of patients with Sjögren syndrome (SS), TNF-alpha in the tears of patients with SS were analyzed. In addition, the relationship between TNF-alpha levels in the tear samples and the severity of the corneal epithelial disorder was evaluated.
Tear samples were obtained from the 60 eyes of 30 patients with primary SS and the 60 eyes of 30 normal subjects. Tear samples were analyzed using a sandwich enzyme-linked immunosorbent assay to detect TNF-alpha. Corneal epithelial cell damage was examined with a slit-lamp biomicroscope and scored by the van Bijsterveld scoring system.
TNF-alpha was detected in the tears of patients with SS at concentrations ranging from 8 to 1,500 pg/ml in 33 of the 60 eyes of the patients. In contrast, TNF-alpha was not detected in the tears of normal controls. The concentration of TNF-alpha was significantly higher in the tear samples from patients whose clinical scores were two or three points compared with patients whose scores were zero or one point (Mann-Whitney U test: p < 0.03).
TNF-alpha was detected in the tears of patients with SS, and tear TNF-alpha levels showed a significant correlation with the grade of corneal epithelial damage, suggesting that TNF-alpha is a potent mediator in keratoconjunctivitis sicca.