Survival of Second Corneal Transplants: an Experimental Model

Abstract

Abstract: : Purpose: HLA typing is not routine in corneal transplantation. Therefore a precise correlation between accelerated rejection and antigens shared by first and subsequent donors bed has not been established. Moreover local factors such as properties of host bed affect the survival of corneal grafts. We performed a second corneal graft on either the ipsilateral or the contralateral eye to investigate the effect of sensitisation or local factors on graft survival. Methods: PVG(RT1c), LEW(RT1l) or AO(RT1u) strain corneas were transplanted to PVG strain rats, followed by a LEW strain cornea in the ipsilateral or contralateral eye 6 weeks later (approximately 4 weeks after rejection of first allograft). In method controls both grafts were isografts. All animals were coded and clinical evaluation was done by a second observer. Data was evaluated ina masked fashion. Proliferation of recipient lymph node cells were tested against allogeneic, syngeneic and third party stimulator cells 13-15 days after the second transplant. Results: There was no rejection of isografts. Accelerated rejection of LEW second grafts occurred in ipsilateral and contralateral eyes after both AO and LEW strains first grafts. Furthermore, survival of second grafts in the ipsilateral eye was reduced compared with the contralateral eye. Preliminary MLR results show secondary response to third party (AO strain) in animals previously exposed to LEW strain. Conclusion: 1. Accelerated rejection of second LEW allografts in the contralateral eye after an AO graft implies sensitisation to non MHC antigens shared by the first and second donor or shared or cross reactive MHC epitopes in AO and LEW strains. 2. The trend toward earlier ipsilateral second corneal allograft rejection compared to contralateral implies that local conditions, such as development of CALT and/or vascularisation are factors in accelerated rejection.Mismatching first and second donors may not prolong graft survival. Survival Data (* -significant compared to controls)  

Keywords: 607 transplantation • 505 pathobiology • 316 animal model