Aim: To validate the use of tear eosinophil cationic protein (ECP) as a marker for eosinophil activation, and its pharmacological modulation, in addition to evaluating the efficacy of lodoxamide and sodium cromoglycate in the treatment of vernal keratoconjunctivitis (VKC).
Methods: Tears were collected from 30 patients affected by active mild to moderate VKC before and after therapy with disodium cromoglycate 4% (DSCG) (n = 15) or lodoxamide 0.1% (n = 15) for 10 days. Tear cytology and ECP measurement were performed, and ocular signs and symptoms evaluated.
Results: While statistically significant changes did not occur after DSCG therapy, mean tear ECP increased from 343 (SD 363) micrograms/l to 571 (777) micrograms/l due to marked elevation in six eyes. The clinical score in DSCG eyes did not improve. After lodoxamide therapy, both clinical signs and symptoms, and tear ECP levels (560 (756) micrograms/l to 241 (376) micrograms/l) decreased significantly (p < 0.0001 and p < 0.01, respectively). Compared with DSCG treatment, lodoxamide was more effective in reducing signs and symptoms (p < 0.005). ECP levels were significantly correlated with signs, symptoms, corneal involvement, and number of eosinophils in tears (p < 0.0001).
Conclusions: In patients with VKC, lodoxamide significantly reduced ECP tear levels, and thus, eosinophil activation, and was more effective than DSCG in reducing clinical signs and symptoms.