Identification of dendritic cells in ePTFE grafts explanted from humans

Following implantation different cell types interact with synthetic vascula r prostheses resulting in a complex immune-inflammatory response. Dendritic cells are responsible for activating the primary T-lymphocyte immune respo nse in various pathological conditions by their role as antigen-presenters. This study aimed at examining whether dendritic cells accumulate within sm all diameter expanded polytetrafluoroethylene (ePTFE. Goretex(R)) grafts ex planted from humans. Segments of expanded polytetrafluoroethylene were expl anted from 11 patients (6 male, 5 female), aged between 60 and 83 years (me an 70.7 years) at secondary or revision bypass operation. The graft implant duration varied from 4 months to 12 years (mean 40.5 months). Dendritic ce lls were identified immunohistochemically using S-100 antibody, as well as by electron microscopy. Immunohistochemical examination showed that all 11 explanted synthetic grafts contained S-100(+) cells colonising both the syn thetic matrix itself, and the adjacent perigraft tissue. Electron microscop ic analysis confirmed the presence of cells with a characteristic dendritic cell morphology within the grafts. Dendritic cells which accumulated withi n synthetic grafts were found to co-localise with T-lymphocytes. Based on t hese observations, we speculate that dendritic cells may be involved in the immune-inflammatory responses following the implantation of synthetic vasc ular prostheses through their interaction with T-lymphocytes. (C) 2000 The International Society for Cardiovascular Surgery. Published by Elsevier Sci ence Ltd. All rights reserved.