Genetic Variations in TLR7 and Their Role in Systemic Lupus Erythematosus: A Systematic Review and Meta-analysis

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease with multi-systemic involvement. It is characterized by the excessive production of auto-antibodies and immune complex deposition which occurs due to improper functioning of TLR7 (toll-like receptor 7). This systematic review and meta-analysis aims to study the genetic polymorphism in TLR7 and its risk to the development of SLE. PubMed, Scopus and Cochrane central were searched for articles published till August 2023 that examined TLR7 polymorphism in SLE. Case-control, cohort, and cross-sectional studies reporting clear data on genotype frequency were selected. Odds Ratio (OR) and 95% confidence interval was calculated for each study, and publication risk was calculated using Egger's test. Although we started with 8 (single nucleotide polymorphism) SNPs for systematic review, meta-analysis was done on 3 SNPs based on the inclusion criteria. A total of 10 studies involving 10,917 cases and 10,945 controls for rs3853839, rs179008, and rs179010 were included in our meta-analysis. The pooled analysis showed no association of TLR7 gene polymorphism and SLE susceptibility for rs3853839, rs179008, and rs179010 in all models including allelic, homozygous, heterozygotes, dominant, and recessive models. Notably no heterogeneity was reported for rs179008. In contrast allelic, homozygous, dominant and recessive models of rs3853839 showed significant heterogeneity of p < 0.05. Overall, our meta-analysis suggests that these TLR7 genetic variants do not influence the development of SLE.