The Impact of TLR4 rs41426344 Polymorphism on Ankylosing Spondylitis Disease Activity: A Study in Turkish Patients

Ankylosing spondylitis (AS) is a chronic inflammatory disease primarily affecting the axial skeleton and sacroiliac joints, with both genetic and environmental factors playing a role in its pathogenesis. Toll-like receptor 4 (TLR4) has been implicated in immune response and inflammation, but its genetic variations have not been extensively studied in AS. This study investigates the association between the TLR4 rs41426344 polymorphism and AS susceptibility and disease activity in a Turkish population. A total of 200 participants (100 AS patients and 100 healthy controls) were recruited. Genotyping of the TLR4 rs41426344 (G/C) polymorphism was performed using real-time PCR melting curve analysis. Disease activity was assessed using Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score with C-reactive protein (ASDAS-CRP) scores. Statistical analyses were conducted to determine the association between genotypes and disease risk. The CC genotype was significantly associated with AS susceptibility, with an odds ratio (OR) of 10.000 (95% CI: 4.091-24.431, p < 0.0000001), indicating a strong genetic risk factor. Additionally, CC genotype carriers exhibited higher BASFI, BASDAI and ASDAS-CRP scores, suggesting greater disease severity and inflammation levels. A statistically significant difference (p < 0.05) was observed in ASDAS-CRP scores between CC and GC genotypes This is the first study to investigate the TLR4 rs41426344 polymorphism in AS, and our findings indicate a strong association with both disease susceptibility and severity in the Turkish cohort. These findings reinforce the role of innate immunity in AS pathogenesis and suggest that TLR4 polymorphisms may serve as potential genetic markers for AS risk assessment and disease activity monitoring.