RESUMO
An allergic response is associated by an increase in the expression and activity of the inducible nitric oxide synthase [iNOS] an inducible enzyme present endothelial cells and polymorphonuclear leucocytes [PMN] and moncytes. Vernal keratoconjunctivitis [VKC], is a recurrent or chronic ocular allergic eye disease affecting young individual living in a hot climate. This study was designed to test a hypothesis that the immune changes seen in Vernal keratoconjunctivitis during the summer or spring season is a function of the effect of hot weather on the of polymorphonuclear leucocytes [PMN] and monocytes in susceptible individuals, by evaluating the role of nitric oxide [NO] and NO-synthase [iNOS] in the pathogenesis of allergic conjunctivitis and the effect of supplementing those patients with antioxidants in order to ameliorate ocular allergic effects. 40 patients with typical VKC were divided into two groups. Antioxidants were given as a supplement to one group [n=20], while the second group did not [n=20]. Both groups were followed up periodically for clinical picture and status and were compared with a third healthy age and socio-economic matching control group. Blood samples were obtained before treatment, after one month and at the end of the whole follow up period. Blood markers of oxidative stress including: protein carbonyls, nitrite. DNA fragmentation and apoptosis in circulating lymphocytes of VKC before and after antioxidant therapy during the severity of the disease were evaluated. Also neutrophil's individual ability to express iNOS was assessed. Vernal Keratoconjunctivitis patients exhibited increased individual ability in the production and expression of nitric oxide by their stimulated neutrophils [4.5 +/- 0.05 nmol/ 10[5] cell vs. 2.5 +/- 0.09 nmol/ 10[5] cell] compared to controls. Both biochemical and clinical picture proved that a supplement of antioxidants to the traditional topical treatment would significantly improve the patients ocular allergic symptoms even after seizure of topical treatment, while recurrence of symptoms and signs occurred in group two after stoppage of the topical steroidal treatment. The antioxidant supplemented group exhibited decreased markers of oxidative stress at the end of the first month follow-up period compared to those patients that were not supplemented with antioxidants: Protein carbonyls [0.57 +/- 0.34 vs. 0.93 +/- 0.05]; Percentage of DNA fragmentation per total DNA in combined plasma and leucocytes after one month [0.7% +/- 0.09 vs. 0.93 +/- 0.05] and plasma nitrite after one month [2.4 +/- 0.5 vs. 3 +/- 0.19 nMol/ml] in VKC patients compared to controls respectively. The associated immunological and inflammatory systemic condition of VKC recommends the use of antioxidant mixture in order to emeliorate the ocular allergic effects associated with VKC. Antioxidant use proved its efficiency and prevent recurrence of VKC even after stoppage of the steroid. Also individuals with increased neutrophil's activity have higher individual susceptibility to develop VKC