Effects of TLR4 and TLR7 genes on the immune system in COVID-19 patients

Purpose: This study aimed to investigate the effects of TLR4 and TLR7 gene polymorphisms on the immunity of COVID-19 patients. Materials and Methods: A total of 210 COVID-19 patients were divided into two groups. Group 1: COVID-19 patients experiencing severe respiratory complications requiring intensive care unit admission (n=107). Group 2: COVID-19 patients with mild SARS-CoV-2 infection who have been recovered without requiring any treatment or hospitalization (n=103). Whole blood samples (2 mL) were collected for DNA isolation and genotyping. Genotyping analyses were then conducted using the RT-PCR method to investigate the following single nucleotide polymorphisms (SNPs): TLR4 gene rs4986790 (896A/G, Asp299Gly) and rs4986791 (1196C/T, Thr399Ile), TLR7 gene rs189681811 (c.2759 G>A Arg920 Lys ) and rs149314023 (c.655G>A Val219Ile). Results: TLR7 RS189681811 and TLR7 RS149314023 gene polymorphisms were not observed in any of the study groups. However, TLR4 RS4986790 and TLR4 RS4986791 gene polymorphisms were observed in both mild and severe groups with no significant differences. Conclusion: No statistically significant differences in genotype distribution were found between the two groups for the SNPs examined. Future multicentered studies with larger sample sizes and a broader range of TLR SNPs could provide valuable insights and contribute to the existing literature.