Precision of conjunctival provocation tests in right and left eyes

Abstract

Background: Conjunctival provocation tests (CPTs) are used for assessing the efficacy of antiallergic treatments, but their reproducibility is not well characterized. A study was carried out to assess the reproducibility of CPTs and the release of mediators during CPTs. Methods: Both eyes of 30 grass-pollen-allergic patients were challenged with threefold increasing concentrations of a standardized orchard grass pollen extract. The positivity of the CPT was assessed by a cumulative symptom score. The release of mediators was examined by means of histamine (radioimmunoassay), prostaglandin D 2 and leukotrienes C 4 and D 4 (enzyme immunoassay). Results: There was a significant correlation between the concentrations of allergen inducing a positive CPT in both eyes ( p < 0.0001, Spearman). All but one patient had a significant release of at least one mediator. After allergen CPT there was a significant release in both eyes in 13 of 20 patients for prostaglandin D 2, 11 of 19 for leukotrienes C 4 and D 4 and 15 of 18 for histamine. The correlations between the levels of mediators released during diluent and allergen challenges in both eyes were significant for prostaglandin D 2 (diluent and allergen challenges) and leukotrienes C 4 and D 4 (allergen challenge). Conclusion: Considering the whole group of patients, CPT is reproducible in both eyes, but the results are less satisfactory when patients are examined individually.