Cell subpopulations in failed human corneal grafts

Abstract

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

Keratoconus: an inflammatory disorder?

“…161 However, in contrast with that investigation, two studies did not find positive results for antibody markers for CD68 in keratoconus. 162, 163 Sykakis et al 164 reported in 2012 that they identified both isolated and aggregated nuclei at sites of Bowman's breaks in keratoconic corneas, for which the origin could not be identified (they did not look for the immunohistochemical expression of anti-CD68 antibody).…”

Immunological responses in mice to full-thickness corneal grafts engineered from porcine collagen

“…Cryostat sections (5-6 mm) of the eyes were immunostained with ARTICLE IN PRESS a panel of monoclonal antibodies against T cells and myeloid cells, including CD4, CD8, CD11b, F4/80 and Gr-1, using the StreptABC method [25]. Anti-fibrinogen antibody was also included to detect fibrin in the anterior chamber postoperatively.…”

“…Six colour labelling was applied to differentiate cell subpopulations [25]. A total of 10,000 events were collected.…”

Adhesion molecule expression in local-macrophage-depleted rats bearing orthotopic corneal allografts

“…The inflammatory cells that infiltrate the corneal graft at time of rejection are T lymphocytes, neutrophils, natural killer cells, dendritic cells, and macrophages [6,7,10]. In previous studies we reported that depletion of the last-named cell type has a profound effect on the prolongation of corneal graft survival [12,13,17].…”