Evaluation Serum Levels of Aggrecan, Fibulin-1, Lubricin, and β-Defensin 3 in Females with Rheumatoid Arthritis

Background: Rheumatoid Arthritis (RA) is a chronic, systemic autoimmune inflammatory disease primarily affecting the joints. Despite the availability of diagnostic tools, identifying novel biomarkers that reflect joint pathology remains crucial for the accurate evaluation of RA.Objective: To assess the serum levels of novel joint-related biomarkers (aggrecan, fibulin-1, lubricin, and human beta-defensin 3 [HBD-3]) in females with RA, and to determine their diagnostic performance compared to healthy controls (HC).Materials and methods: This case-control study included 60 female RA patients and 60 age-matched HC. Serum concentrations of aggrecan, fibulin-1, lubricin, HBD-3, and anti-citrullinated protein antibody (ACPA) were determined using ELISA kits. Erythrocyte sedimentation rate (ESR) was measured via the standard Westergren method.Results: Serum levels of aggrecan, fibulin-1, lubricin, and HBD-3 were significantly increased in RA patients compared to HC (P-value = 0.0001). For predicting disease status, the biomarkers yielded the following area under the receiver operating characteristic (AUROC) curve values: aggrecan (0.947, cut-off > 15.80 ng/mL), fibulin-1 (0.885, cut-off > 7.975 ng/mL), HBD-3 (0.885, cut-off > 325.2 pg/mL), and lubricin (0.719, cut-off > 169.4 pg/mL). Additionally, these biomarkers showed significant positive correlations with each other and with ACPA levels.Conclusion: Serum aggrecan, fibulin-1, lubricin, and HBD-3 are significantly elevated in RA patients, indicating strong disease association and high diagnostic potential. Future longitudinal studies are required to establish definitive clinical utility in monitoring disease activity.