Alpha-1-antitrypsin in aqueous humour from patients with corneal allograft rejection

Purpose: To investigate the presence and concentration of alpha 1-antitrypsin in aqueous humour at the time of corneal rejection and to compare results obtained from patients with reversible and irreversible rejection. Methods: Samples of aqueous humour were obtained from 17 patients with acute corneal endothelial allograft rejection. The presence of alpha 1-antitrypsin in aqueous humour was confirmed by immunoblotting and measured employing a sandwich ELISA. Total protein concentrations in aqueous humour were measured using Bradford's method. The outcome of corneal rejection episodes was determined 1 month after diagnosing corneal rejection and described as reversible or irreversible rejection. Results: alpha 1-antitrypsin was detected in aqueous humour. Patients with reversible rejection had significantly higher alpha 1-antitrypsin concentration than patients with irreversible rejection (p = 0.044). There was no significant difference in total protein concentrations (p = 0.745), and no correlation was found between alpha 1-antitrypsin and total protein concentrations (p = 0.368). Conclusions: alpha 1-antitrypsin in aqueous humour seems to signal a favourable outcome of corneal rejection. The possible mechanism is discussed.