Analysis of interleukin-6 gene polymorphism and its serum levels in Indian age-related macular degeneration patients

Background: Age-related macular degeneration (AMD) is a complex condition involving multiple factors. The condition is associated with numerous inflammatory indicators, including cytokines. Single-nucleotide polymorphisms in cytokine genes can also modify gene expression, perhaps contributing to the development of the disease. The objective of the present study was to examine the correlation among IL-6 SNPs (rs1800795, rs1800796, and rs1800797) and the serum levels of IL-6 in AMD patients treated at the Regional Institute of Ophthalmology of Pt. B.D. Sharma PGIMS, Rohtak (Haryana), India. Methods: This case-control study included 131 patients diagnosed with AMD using precise ophthalmic examinations, such as slit lamp examination, fundoscopy, and ocular coherence tomography. To provide a basis for comparison, we also enlisted 100 healthy individuals as controls. Serum IL-6 protein levels were measured in both patients and controls using an enzyme-linked immunosorbent assay kit (ELISA). Genotyping IL-6 SNPs was performed using the PCR and DNA Sanger sequencing technique. Results: IL-6 serum levels were considerably elevated in individuals with AMD compared to the control group (p<0.05). Statistically significant differences were seen in the genotype frequencies of rs1800795 (p=0.027) and rs1800797 (p=0.0011) among the AMD patients and the healthy controls. Furthermore, strong correlations were observed between rs1800795 and the likelihood of developing AMD based on the heterozygous (OR=2.04; p=0.025), dominant (OR=1.80; p=0.035), and over-dominant models (OR=2.10; p=0.0094). Additionally, there were notable associations between rs1800797 and vulnerability to AMD through heterozygous (OR=3.21; p=0.009), dominant (OR=2.74; p=0.004), and over-dominant (OR=3.11; p=0.002) models. The rs1800795, rs1800796, and rs1800797 haplotypes C-G-A and G-G-A were linked to an elevated risk of AMD (p=0.005, p=0.024. respectively). Conclusions: Our findings indicated a significant elevation in IL-6 serum levels among the AMD patient group compared to the control group. The interleukin-6 gene polymorphisms rs1800795 and rs1800797 were linked to an elevated risk of AMD in our study population.