Increase in CD45RO+ T cells and activated eosinophils in chronic allergic conjunctivity

We assessed the infiltration of CD45RO+ cells in conjunctival biopsies of fifteen subjects affected by seasonal allergic conjunctivitis by means of immunohistochemistry. Correlations between infiltration of CD45RO+ cells and serum and mucosal indices of eosinophilic activation were investigated. The study was performed in autumn and all selected patients showed <<red eyes>> also in absence of sensitising pollens. Fifteen healthy subjects were used as controls. The semi-quantitative count of CD45RO+ cells in biopsy specimens demonstrated that positive cells were higher in allergic patients than in controls (p < 0.001) and EG2+ eosinophils were present only in biopsies of allergic patients. Furthermore, a statistically significant positive correlation (r = 0.73; p < 0.001) between CD45RO+ lymphocytes and EG2 positive eosinophils, was observed in the biopsies of allergic patients. Total serum IgE significantly correlated with CD45RO+ cells (r = 0.61; p < 0.02) and EG2+ eosinophils (r = 0.67; p < 0.01) in the conjunctiva. On the other hand serum ECP did not correlate with any histological and immunohistochemical parameters in the conjunctival biopsies. The present study shows that mild symptoms in SCA patients out of pollen season are associated with inflammation of the conjunctiva as shown by an increased number of CD45RO and EG2 positive cells.