Galectin-3, Tryptophan, and AADAT as Linked Biomarkers in Rheumatoid Arthritis

Objective: This study aims to evaluate serum levels of Galectin-3, Tryptophan (TRP), and kynurenine/alpha-aminoadipate aminotransferase (AADAT) in patients with rheumatoid arthritis (RA), and to investigate their potential diagnostic and prognostic implications. Methods: This was an original experimental study. The study population consisted of individuals followed up at the Rheumatology Polyclinic of Selçuk University Faculty of Medicine, Konya, Türkiye. Between April 2025 and July 2025, 45 RA patients diagnosed according to the ACR/EULAR 2010 criteria and 45 healthy control subjects were included in the study. Statistical analyses included t-test, Mann–Whitney U, correlation analyses, and ROC curve evaluation. Serum levels of Galectin-3, TRP, and AADAT were measured by ELISA. Disease activity was assessed using DAS-28 scores. Results: TRP levels were significantly lower in RA patients compared to controls (p < 0.001), whereas Galectin-3 levels were significantly higher (p < 0.001). AADAT levels did not differ significantly between groups (p = 0.61). Galectin-3 and TRP showed strong diagnostic performance (AUC = 0.84 and 0.76, respectively). Significant correlations were observed among Galectin-3, TRP, and AADAT, as well as with hematological indices. Conclusions: Elevated Galectin-3 and reduced TRP levels are associated with RA pathogenesis, whereas AADAT levels remain comparable between patients and controls. These findings suggest Galectin-3 and TRP as potential biomarkers for early diagnosis of RA.