Üveit Patolojisinde Pteridin ve Kinürenin Yolaklarındaki Olası Değişimlerin Incelenmesi

Abstract

Uveitis is an intraocular inflammation affecting the highly vascularised uveal tissue. Early recognition and appropriate therapeutic intervention of uveitis is important since it may be associated with systemic disease and undetected or untreated uveitis may lead to blindness. Neopterin is an unconjugated pteridine which is an important biomarker of cell-mediated immunity and have a potential function in the process of inflammation. In addition to neopterin release, cellular immune activation also induces indoleamine 2,3-dioxygenase (IDO) which catalyzes the rate limiting step in the tryptophan degradation. Hence, IDO activity which is expressed by the ratio of kynurenine (Kyn) to tryptophan (Trp) levels can also be used as a marker of modulation in cellular immunity, supported by immune parameters. In this thesis, it was aimed to investigate immune changes in uveitis by determination of neopterin concentrations and also tryptophan degradation. The participants were consisted of 104 uveitis patients (63, active; 41, inactive), 13 patients with Behçet's disease and 30 healthy subjects. In the uveitis patients, urinary and serum neopterin, kynurenine and Kyn/Trp were found to be statistically higher than healthy controls (all, p<0.05). When uveitis was categorized as active and inactive, it was observed that all of the measured parameters did not differ between two uveitis groups (all, p>0.05) while in both of the subgroups showed significant differences compared to controls. In both active and inactive uveitis patients with Behçet's disease, Kyn/Trp were significantly higher than Behçet's group without uveitis (p<0.05). Urinary and serum neopterin levels were positively correlated with Kyn/Trp in the uveitis patients (both, p<0.05). These results can be concluded that uveitis can cause alterations in neopterin levels and kynurenine pathway. It seems that while the measured parameters can be useful markers of cellular immune response in uveitis, they might not be used to differentiate active or inactive uveitis.