Abstract
Abstract: :
Purpose: We have previously demonstrated in a murine model of high risk corneal transplantation that the recipient bed stroma contained macrophages, neutrophils and CD4 T cells. The latter were localized to areas of vascularization. The goal of this work is to characterize the immunologic milieu of high risk human corneal recipients. Methods: Six vascularized high risk corneal beds (1–4 clock hours of vascularization) were collected at the time of corneal transplantation, snap freezed in OCT and sectioned. Immunohistochemical stains for human macrophages (CD11b), vessels (CD31) and CD4/CD8 T cells were performed. Digital images were obtained and quantification of inflammatory cells was calculated in areas of non–vascularaization and vascularization, and these were compared to normal non–vascularized control. Results: Similar to the murine model, in 6/6 high risk corneal beds, macrophages were present in the corneal stroma. In 5/6, these were not localized to areas of vascularization. All of the corneas also contained CD4 T cells, and interestingly, CD8 T cells as well. T cells mostly co–localized to areas with blood vessels. Normal control had no inflammatory cells. Conclusions: Similar to the murine high risk cornea model, human high risk vascularized corneal beds are "immunological disprivileged" as macrophages and T cells form a predominant population of inflammatory cells. T cells appear to utilize vascular channels for migration in contrast to macrophages, which do not seem as dependant on blood vessels. In contrast to the murine model, CD8 T cells are also present and seem to co–localize to vascular areas.
Keywords: transplantation • immunomodulation/immunoregulation • inflammation