A case-control study on IL-8 gene polymorphisms and serum IL-8 levels in patients with age-related macular...

Age-related macular degeneration (AMD) is a leading cause of vision loss, with inflammatory and genetic factors contributing to its development. This study examined the association of IL-8 polymorphisms (rs4073, rs2227306, rs2227543) and serum IL-8 levels in a North Indian AMD cohort. A case-control study involving 160 AMD patients and 100 controls was performed. AMD was confirmed through detailed clinical evaluation and diagnostic imaging. Genomic DNA was extracted and genotyped using PCR followed by Sanger sequencing, and serum IL-8 concentrations were determined by ELISA. Statistical analyses were conducted using SPSS v22.0 and SNPstats. AMD patients exhibited significantly higher serum IL-8 levels than control (p < 0.001). ANCOVA adjusting for age and smoking confirmed elevated IL-8 in AMD (adjusted mean: 63.52 pg/ml vs. 41.23 pg/ml in controls; p < 0.001), with higher levels in wet AMD than dry AMD (67.75 pg/ml vs. 54.32 pg/ml; p = 0.043). The IL-8 rs4073 AA genotype and A allele were more frequent in AMD patients (p = 0.006 and p = 0.011, respectively). Multivariate logistic regression showed strong associations between rs4073 AA genotype and AMD risk under codominant (adjusted OR = 2.68; 95% CI: 1.17-6.15; p = 0.025), recessive (adjusted OR = 2.68; 95% CI: 1.27-5.67; p = 0.0067), and log-additive (adjusted OR = 1.50; 95% CI: 1.02-2.20; p = 0.036) models. No significant associations were observed for rs2227306 or rs2227543. Among all participants, AA carriers had significantly higher serum IL-8 levels than TT and AT genotypes (p = 0.018 and p < 0.001). The IL-8 rs4073 AA genotype and elevated serum IL-8 levels may serve as potential markers for AMD susceptibility in the North Indian population.