Abstract
Purpose: :
Allograft rejection is thought to be mediated primarily via the Th1 subset of T lymphocytes. Atopic patients demonstrate Th2–dominant immune responses which may influence graft survival. The aim of this study was to investigate the effect of perioperative allergic conjunctivitis on corneal allograft survival.
Methods: :
Three groups of female A/J mice underwent corneal allografts (full MHC and multiple minor histocompatibility antigen mismatch). 1. Naïve mice (n=9)
2. Mice that were sensitised to short ragweed pollen (SRW) by intraperitoneal injection and then challenged with topical SRW to induce allergic conjunctivitis (n=8)
3. Mice that were sensitised to SRW and challenged with topical PBS ("sensitised, unchallenged" mice.) (n=8)
Syngeneic grafts were also performed in eyes with allergic conjunctivitis (n=4). Graft survival and infiltrating cell phenotype in rejected grafts were compared between groups.
Results: :
Mice with allergic conjunctivitis (sensitised, challenged) rejected corneal allografts at a significantly faster tempo than naïve mice. Median survival time (MST) of grafts in naïve eyes was 48 days compared with 20 days in allergic eyes. Syngeneic grafts in allergic eyes survived indefinitely. Graft survival in sensitised, unchallenged mice (MST = 32) was significantly prolonged compared with that in sensitised, challenged mice. There were no significant differences, between groups, in the numbers of infiltrating CD4+ cells, CD8+ cells and macrophages at the time of graft rejection. Eosinophils were found in rejected grafts in allergic eyes only.
Conclusions: :
Active allergic conjunctivitis at the time of transplantation accelerates corneal allograft rejection. Local conjunctival inflammation appears to be an important factor in accelerating rejection. Eosinophils may act as effector cells in graft rejection in patients with allergic conjunctivitis.
Keywords: cornea: endothelium • transplantation • conjunctivitis