Decreased active TGF-beta2 levels in the aqueous humour during immune reactions following penetrating keratoplasty

Abstract

Purpose: The secretion of transforming growth factor (TGF)-beta (2) into the aqueous humour is important for maintaining the immunological privilege of the anterior ocular segment that promotes corneal allograft survival. Levels of total TGF-beta (2), however, were similar in eyes with and without immune reactions following penetrating keratoplasty (PK). In this study, we tested the hypothesis whether the activated form of TGF-beta (2) is decreased in eyes with immune reactions following PK.

Methods: Anterior chamber puncture was performed in 38 cataract patients without PK (group I), in 10 patients without immune reaction following PK (group II), and in 10 patients following PK with newly diagnosed endothelial immune reaction (group III). About 0.05-0.1 ml of aqueous humour were harvested from each patient. Analysis of active TGF-beta (2) was started via ELISA within 3 h following puncture.

Results: Average active TGF-beta (2) concentration was 38.9 pg/ml+/-24.3 in group I, 47.4 pg/ml+/-23.1 in group II, and 12.7+/-26.0 pg/ml in group III. The differences between groups I and III (P=0.005) and groups II and III (P=0.008) were statistically significant.

Conclusion: The lowest levels of active TGF-beta (2) were measured in eyes with newly diagnosed endothelial immune reactions. This suggests that TGF-beta (2) has a protective effect on corneal grafts following PK. Further (prospective) studies are being carried out to discover whether active TGF-beta (2)--determined prior to PK--might serve as a predictive parameter for the occurrence of immune reactions.