[Tear eosinophil cationic protein measurement in patients with seasonal allergic conjunctivitis].

Purpose: In the patients with seasonal allergy conjunctivitis (SAC), we investigated the concentration of tear eosinophil cationic protein (ECP) levels, the diagnosis of SAC and the usefulness of studying the disease states.
Subjects and Methods: The subjects were patients suffering from conjunctivitis seasonal allergy caused by cedar pollen and a healthy control group, and the study period was three years from 2001 to 2003. We divided the allergy group into 27 eyes of 27 patients that we measured before the pollen season and 44 SAC eyes of 44 patients that we measured during the pollen season. The healthy control group was 23 eyes of 23 healthy adults. Tears were collected by the schirmer I method. The ECP value of specimens was measured by enzyme-linked immunosorbent assay (ELISA) using samples which we eluted in buffer (0.5 M NaCl + 0.5% tris buffer saline with Tween 20) from Schirmer test paper.
Results: The measurement range of ELISA was 3.6-180 microg/l. The mean ECP value above the lower limit of ELISA in tears was 5.06 +/- 3.39 microg/l (n = 7) (mean +/- standard deviation) for the healthy control group, 9.32 +/- 6 .68 (n = 11) for the preseason group, and 54.90 +/- 117.74 (n = 29) for the pollen season group. The difference between the healthy group and the seasonal group was highly significant (p < 0.005), but there was no significant difference between the healthy group and the preseason group. We set the cut-off point at the 95th percentile (11.1 microg/l) of the healthy group and considered any value above cut-off as positive. The ECP value was positive in 2.5% (3 eyes out of 27) in the preseason group and 40.9% (18 of 44) in the seasonal group, and there was a significant difference (p < 0.01) between the seasonal group and the healthy group. When the seasonal group was divided into patients who had started treatment before the pollen season and those who began treatment during the season, we found a small ECP difference, but it was not statistically significant.
Conclusion: Measurement of the ECP value in seasonal pollen allergy sufferers may be useful for pathological ascertainment, but it dose not provide adequate diagnosis because of the large number of false negative cases.