To investigate the biologic effects of topical anti-allergic agents with H1-receptor antagonism and inhibition of histamine release from mast cells in the cultured conjunctival cells of patients with vernal keratoconjunctivitis in vitro .

Conjunctival cells of vernal keratoconjunctivitis were exposed to the anti-allergic agents SCD-P101 (Fexofenadine, Samchundang, Korea), Patanol® (Alcon, USA), Zaditen® (Novartis, USA), and Azelan® (Taejoon, Korea). Efficacy of the topical antihistamine/mast cell stabilizers was evaluated using the MTT assay, measuring the concentration of procollagen and inflammatory cytokines. Cell damage was determined using the lactate dehydrogenase (LDH) assay with dilution rates of 10, 20, and 30% and compared with the balanced salt solution-treated group. Cellular morphologic results were examined by inverted light microscopy and transmission electromicroscopy.

Metabolic activity of conjunctival cells decreased at higher concentrations and longer exposure durations, except for the SCD-P101 agent. The procollagen, laminin, IL-6 and IL-8 titers tended to be lower than that of the control in the eyes exposed to all the anti-allergic drugs tested in this study, but the concentration of TNF-β was similar to that of the control group. Zaditen® and Azelan® tended to show a greater LDH titer and edema, as well as cytoplasmic and nuclear degeneration of the conjunctival cells than did SCD-P101 or Patanol®.

Cellular metabolic activity was the highest in the new anti-allergic agent SCD-P101. SCD-P101 and Patanol® caused marginally less damage to cultured conjunctival cells than did Zaditen® and Azelan®.