These results suggest that blood-borne, activated macrophages are major effectors of tissue damage during EAU.

Immediate and rapid changes in T cell and DC populations in the DLN correlate with the type of cellular infiltration in the corneal graft. The data are consistent with a model in which CD4+ T cell help for CD8+ cytotoxic T cells could be provided by sequential two-way activation of T cells and DC in the DLN. The majority of cells infiltrating the graft were macrophages and neutrophils, with fewer DC and T cells.

Background/aims-Inflammatory cells and antigen presenting cells (APC) are not present under normal circumstances in the centre of the healthy cornea. The purpose of this study was to investigate and phenotype the inflammatory cell populations, particularly with reference to T cell subpopulations and macrophages, and to localise dendritic cells (DC) and other MHC class II positive cells in three groups of grafted corneas: rejected noninflamed, rejected inflamed grafts, and control dystrophic explants. Methods-15 corneal buttons removed during keratoplasty from non-inflamed "quiet" previously grafted corneas, five inflamed corneas requiring urgent regrafting for "graft melting" (in "high risk" corneas), and 10 control dystrophic opaque corneas explanted during their first graft procedure were examined. Cryosections of corneas were immunostained with a panel of monoclonal antibodies (mAb) against CD3, CD4, CD8, CD14, CD25, CD68, HLA-DP, and HLA-DR molecules using the StreptABC method. DC were detected by dual immunostaining as CD1a+ and MHC class II+ and CD19−. Cell densities in immunostained tissue sections were evaluated using a scale from 0 to +4. Results-Immunostaining in control dystrophic corneas was negative for all antibodies. A moderate to high density of CD8+, CD14+, and CD68+ cells was observed in the majority of rejected non-inflamed as well as in rejected inflamed corneal buttons. Strong positivity for HLA-DP and HLA-DR molecules in the epithelium, stroma, and endothelium was also demonstrated. Weak positivity for CD4 and CD25 was observed in six of 15 and 11 of 15 rejected corneas, respectively. The presence of dendritic cells in the basal layer of the epithelium and in the stroma was observed in 50% of the grafts. Conclusions-A high frequency of macrophages, the presence of DC in the explants, and strong expression of HLA-DP and HLA-DR molecules on resident cells are characteristics of rejected corneal allografts, whether actively inflamed or not. The presence of DC in the stroma of the grafted cornea suggests that they may be mainly responsible for T cell activation and graft rejection since DC are known to be a 100-fold more potent than macrophages as APC. (Br J Ophthalmol 1999;83:1364-1369

Samples of iris ciliary body, choroid and retina from normal eyes and from 2 cases of sympathetic ophthalmitis (one acute and one late stage fibrosis) were examined for the expression of the VLA integrins beta 1 and alpha 1-6, and the integrin beta 3, in addition to ICAM-1, VCAM-1, ELAM-1 and CD44 using an APAAP staining technique. The expression of VLA-4, VLA-5, VCAM-1, ICAM-1, and CD44 was significantly increased and ELAM-1 was slightly increased in acute sympathetic ophthalmitis in comparison to fibrotic and normal eyes. VLA-6 was moderately increased in acute and fibrotic cases and VLA-2 VLA-3 and beta 3 were moderately expressed on all tissues examined. The differential expression of molecules known to be involved in lymphocyte activation and adhesion in acute sympathetic ophthalmitis suggests that certain adhesion molecules play a role in the pathogenesis of intraocular inflammation and may be suitable targets for immunotherapy.

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