Serum Neopterin, Biopterin, Tryptophan, and Kynurenine Levels in Patients with Fabry Disease

ABSTRACT

Background: Fabry disease is characterized by the accumulation of globotriaosylceramide. Substrate accumulation in lysosomes is thought to trigger an inflammatory response and is responsible for progressive organ damage through the induction of autoimmunity. The levels of pteridine and kynurenine pathway metabolites increase when immune activation is observed and are employed to monitor several diseases and determine prognosis. Aims: To elucidate the effects of immune activation on the pathophysiology of Fabry disease and to investigate the potential utility of pteridine and kynurenine metabolites. Study Design: A prospective case-control study. Methods: In this study, 33 patients with Fabry disease and 33 age-and sex-matched healthy controls were included. Blood pteridine and kynurenine metabolites were studied in both groups. Organ involvement in Fabry disease and its correlation with the pteridine and kynurenine pathways were also investigated. Results: The patients' neopterin and biopterin levels and the tryptophan/kynurenine ratio were statistically higher than those of the healthy control group (p < 0.05). A statistically significant association was found between neopterin levels and hypertrophic cardiomyopathy, cardiac arrhythmias, and GFR values (p = 0.044, p = 0.021, and p = 0.030, respectively), tryptophan and corneal verticillate, hearing loss and tinnitus (p = 0.010, p = 0.009 and p = 0.046, respectively), and kynurenine levels and valvular heart disease (p = 0.020). Conclusion: From the onset of the disease, patients with Fabry disease exhibited elevated levels of inflammation and immune activation. Furthermore, inflammation and immune activation markers can be used as early disease biomarkers.