Inflammatory markers in the tears of patients with ocular surface disease

To determine the concentration of interleukins (IL-1beta and -6) and matrix metalloproteinase 9 (pro-MMP-9) in the tears of patients with different ocular surface diseases and to examine the possible relationship between the disorders and molecular inflammation.

77 patients diagnosed as having different ocular surface disorders and 18 normal control subjects were studied. Patients were routinely examined and separated into 5 groups: (1) control, (2) blepharitis, (3) ocular allergic disease, (4) dry eye and (5) conjunctivochalasis. Ten microliters of tears were collected by a Weck cell sponge. The concentrations of IL-1beta, IL-6 and pro-MMP-9 were measured by enzyme-linked immunosorbent assay, and the MMP-9 activity was evaluated with gelatin zymography.

Levels of IL-1beta and IL-6 in tear fluid were significantly higher in conjunctivochalasis (p = 0.0062 and p = 0.0134) than in the control group. Pro-MMP-9 levels were significantly elevated in blepharitis (p = 0.013), in allergic eye disease, in dry eye and in conjunctivochalasis (all p < 0.001), in comparison to controls.

Pro-MMP-9 levels in tears are elevated in all of the studied pathologies especially in ocular allergy and conjunctivochalasis. However, IL-1beta and IL-6 were only found to be overexpressed in conjunctivochalasis. These findings illustrate the selective implication of different molecules in each disorder.