Preliminary study of normal tear complement activation in patients with seasonal allergic conjunctivitis outside the season

Purpose to determine whether there is a difference in complement activation level on the ocular surface and tear film stability between seasonal allergic conjunctivitis (SAC) patients outside the season and healthy individuals. Methods outside the ragweed season asymptomatic ragweed pollen allergic patients with the diagnosis of seasonal conjunctivitis at least during two earlier seasons (n=14, mean age 25.79 ys; 5 male, 14 female) and healthy individuals (n=19, mean age 28.05 ys; 9 male, 5 female) were recruited. We collected tear samples with glas capillaries, measured C3a complement activation product with ELISA, and determined non-invasive break-up time (NIBUT) with Keeler TearScope Plus®. Results the median (range) tear C3a levels were 9.80 (0.78–122.60) ng/ml in SAC patients, and 7.00 (2.00–35.14) ng/ml in the healthy individuals (p=n.s.). The C3a levels did not correlate with sex, age, and the number of seasonal conjunctivitis exacerbations, or NIBUT. The mean NIBUT was 21.50+/-9.41 seconds in allergic patients and 17.30+/-8.68 seconds in healthy individuals (p=n.s.). Conclusion even though a broader complement activation range was detected in seasonal allergic conjunctivitis patients outside the season compared with healthy individuals, there was no significant difference between the two groups. Outside the season the tear film stability was also similar. We assume, the repeated allergic inflammation on the ocular surface did not manifest in tear film instability or increased complement activation in the asymptomatic period.