Eosinophil cationic protein as a marker for assessing the efficacy of tacrolimus ophthalmic solution in the treatment of atopic keratoconjunctivitis

PURPOSE To examine the clinical efficacy and anti-inflammatory effects of tacrolimus eye drops; we studied the changes in clinical ocular findings and measured tear eosinophil cationic protein (ECP) levels of atopic keratoconjunctivitis (AKC) patients before and after the treatment. METHODS Nine eyes of 9 patients (8 males, 1 female; mean age: 16.9 ± 11.4 years; range: 6-44 years) diagnosed with moderate or severe AKC disease were enrolled in this prospective study and treated with tacrolimus. All patients received 0.1% tacrolimus eye drops 2 times a day for 1 month. Tear samples were taken before and after treatment and ECP concentrations were obtained. Corneal fluorescein staining and conjunctival injection, edema, and papillary formation were graded on the recruitment day and one month later. Analysis of pre- and post-treatment findings was done using the Wilcoxon signed test. The ECP concentrations were correlated with the clinical signs using Spearman correlation tests. RESULTS Post-treatment tear ECP levels were significantly reduced compared to the pre-treatment level. Clinical corneal scores also improved significantly after one month treatment with tacrolimus eye-drops. The mean conjunctival injection and conjunctival edema scores were significantly (p<0.05) decreased after the drug therapy. Strong positive linear correlations between ECP values and clinical signs were observed. Patients did not present side effects during the treatment with tacrolimus. CONCLUSIONS In this pilot study, tacrolimus eye drops were found to reduce signs of AKC. ECP proved to correlate well with clinical signs of AKC.