Background: Excellent long-term prognosis of penetrating corneal grafts has been explained by the immunological privilege of the cornea and the anterior chamber. In animal models the secretion of transforming growth factor beta(2) (TGF-beta(2)) into the anterior chamber and the expression of the Fas ligand on corneal endothelial cells were identified as important for the integrity of the immunological privilege.
Objective: To determine the TGF-beta(2) and soluble Fas ligand (sFasL) levels in the aqueous humor of patients after penetrating keratoplasty (PK) who have and who do not have immune reactions.
Methods: Anterior chamber puncture was performed in 13 patients who had a cataract without PK (group 1), in 31 patients after PK who did not have immune reactions (group 2), and in 12 patients after PK newly diagnosed as having endothelial immune reactions (group 3). Total TGF-beta(2) and sFasL were determined via enzyme-linked immunosorbent assay.
Results: Transforming growth factor beta(2) was detected in all patients, irrespective of the underlying condition; there was no difference in TGF-beta(2) levels between the different groups (P =.89, analysis of variance). None of the patients in group 1, 11 of 31 patients in group 2, and 8 of 12 patients in group 3 had detectable sFasL concentrations (P =.002, chi(2) test). Soluble Fas ligand averaged (mean [SD]) 20.8 (31.1) pg/mL in group 2, and 38.1 (33.2) pg/mL (P<.01, analysis of variance) in group 3.
Conclusions: It appears that total TGF-beta(2) is maintained at high steady-state levels, while the level of sFasL is up-regulated in patients who underwent PK, particularily in the advent of graft rejection.