A FLOW CYTOMETRIC STUDY ABOUT THE IMMUNOPATHOLOGY OF VERNAL KERATOCONJUCTIVITIS

Background: Vernal keratoconjunctivitis (VKC) is a bilateral seasonal conjunctival inflammation. Exact pathogenesis of the disease is unknow n, but some evidences suggest T-H lymphocyte-mediated immune reactions . Objective: The aim of this study was to investigate the role of the T lymphocyte and its subsets in the pathogenesis of VKC. Methods: We o btained tear samples from patients with VKC and normal volunteers duri ng active (spring) and quiescent (winter) periods, The patients' recor ds were also obtained for assessment of symptom scores, The percentage s of CD4/29+, CD4/45RA+, CD4+, and CD8+ in tear samples were establish ed by using Bow cytometry, and the results of all three groups were co mpared with each other by using the Wilcoxon matched-pair signed-rank test and the Mann-Whitney U test. Results: The percentages of CD4/29and CD-If cells in tears of patients with VKC increased significantly in the active period and decreased to normal levels in the quiescent s tage. In contrast, the percentages of CD4/45RA+ and CD8+ cells in tear s of patients with VKC did not show any significant change between spr ing and winter, The patients' symptoms were significantly lower in the quiescent period (winter) compared with the active stage (spring). Co nclusion: We propose that increased numbers of CD-IC and CD4/29+ cells in tears may be exacerbating the disease during the spring season.