Pigment Epithelium-Derived Factor as a possible predictor of corneal transplant rejection reaction

Keratoplasty remains one of the most effective methods of restoring vision in diseases and injuries of the eye that lead to the cornea opacity. Despite the success of modern surgery, corneal transplant rejection is the most common cause of unsuccessful operations. Pigmented epithelial derivative factor (PEDF) is known for its antiangiogenic and anti-inflammatory properties, which play an important role in maintaining the immune privilege of the eye and make it one of the important regulators of the intraocular environment. Purpose of the work was to study the concentration of PEDF in the tear fluid (TF) after penetrating keratoplasty and to evaluate its role in the development of the corneal transplant rejection reaction. Material and methods. 48 patients aged 35 to 60 years (average age of 48.1 ± 5.4) including 30 men and 18 women participated in the study. Subgroup 1 (n = 35) consisted of patients who had no episodes of corneal transplant rejection during the observed period, subgroup 2 (n = 13) consisted of patients who demonstrated an episode of rejection reaction during one year after surgery. The control group included 15 healthy individuals without ophthalmological pathology. The level of PEDF (ng/ml) in the TF was determined during postoperative period using multiplex analysis on a Luminex Magpix 100 immunoanalyzer (USA) by the Bio-Rad multiplex analysis test system (USA). The graft condition was assessed using biomicroscopy and optical coherence tomography with angiography of the anterior segment. Results. In postoperative period a significant increase in the volume of vascularization with a maximum increase on day 360 in subgroup 2 was revealed. The concentration of PEDF in subgroup 1 increased to reference values on day 120, while maintaining this level at the end of the study. On the contrary, in subgroup 2, the PEDF level remained reduced until the end of the follow-up period and significantly differed from the indicator of the control group, which, along with an increase in the volume of vascularization and a progressive decrease in maximally corrected visual acuity, may indicate a violation of control over the processes of neovascularization and contribute to graft rejection. Conclusion. Given the crucial role of PEDF in curbing corneal neoangiogenesis, its decrease can be considered as a predictor of the development of a graft rejection reaction, as evidenced by the data we have obtained.

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