Author(s): Paunicka KJ, Mellon J, Robertson D, Petroll M, Brown JR,
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Abstract Less than 10\% of corneal allografts undergo rejection even though HLA matching is not performed. However, second corneal transplants experience a threefold increase in rejection, which is not due to prior sensitization to histocompatibility antigens shared by the first and second transplants since corneal grafts are selected at random without histocompatibility matching. Using a mouse model of penetrating keratoplasty, we found that 50\% of the initial corneal transplants survived, yet 100\% of the subsequent corneal allografts (unrelated to the first graft) placed in the opposite eye underwent rejection. The severing of corneal nerves that occurs during surgery induced substance P (SP) secretion in both eyes, which disabled T regulatory cells that are required for allograft survival. Administration of an SP antagonist restored immune privilege and promoted graft survival. Thus, corneal surgery produces a sympathetic response that permanently abolishes immune privilege of subsequent corneal allografts, even those placed in the opposite eye and expressing a completely different array of foreign histocompatibility antigens from the first corneal graft. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.
This article was published in Am J Transplant
and referenced in Journal of Clinical & Experimental Ophthalmology