Mechanisms and comparison of anti-allergic efficacy of topical lodoxamide and cromolyn sodium treatment in vernal keratoconjunctivitis

Purpose: To explore the mechanism of action of topical lodoxamide and cromo lyn sodium treatment in vernal keratoconjunctivitis (VKC) and to compare th e efficacy of these drugs to each other. Design: Single-investigator, masked, randomized, clinical trial. Participants: Twenty male and 10 female patients between the ages of 6 and 19 years, who were diagnosed as having active VKC, were enrolled in this st udy. Interventions: The patients were randomly divided into two equal groups (gr oups A and B). Group A patients received topical lodoxamide ophthalmic solu tion 0.1% (LOS); topical cromolyn sodium ophthalmic solution 4% (CSO) was p rescribed to group B patients in a dose of two drops four times daily. Main Outcome Measures: The eye symptom severity scores and clinical signs o f the patients were evaluated both in the pre- and post-treatment periods. In addition to the clinical data, conjunctival impression cytologic specime ns were obtained from patients both before and after treatment. Impression cytologic specimens were stained using immunohistochemical methods to detec t the percentages of CD4(+), CD8(+), CD45RA(+), and CD23(+) cells. Statisti cal analyses were performed within and between groups. Results: The percentages of CD4(+) and CD23(+) cells in tear samples of pat ients in groups A and B were significantly higher in the pretreatment stage than post-treatment stage. In the post-treatment stage, group A patients h ad significantly lower CD4(+) and CD23(+) cell values compared with group B patients. Patient symptom scores and clinical signs were at a significantl y lower level after treatment with either LOS or CSO in both groups A and B compared with their pretreatment values. Moreover, group A patients had si gnificantly lower symptom scores and clinical signs than group B patients i n the post-treatment stage. Conclusions: Clinical superiority of LOS over CSO may be linked to its grea ter effect on the CD4(+) cells, because CD4(+) cells plays a pivotal role i n the pathogenesis of VKC. (C) 2000 by the American Academy of Ophthalmolog y.