Mendelian randomization study of inflammatory cytokines and Bell's palsy

Background: Current research suggests inflammation as a cause of Bell's palsy. However, a large number of patients have not fully recovered even after combined antiviral and glucocorticoid treatment. Consequently, the relationship between inflammation and Bell's palsy remains uncertain. Methods We employed a two-sample Mendelian randomization approach using genetic variances of Bell's palsy from the UK Biobank (626cases and 361,141 controls of European ancestry) and inflammatory cytokines from a GWAS summary containing 8,293 healthy participants. We took a series of rigorous quality control steps to select eligible instrumental SNPs closely related to the exposure. In order to make the conclusion more robust and reliable, we employed several robust analysis methods including inverse variance weighted, weighted median, MR-Egger regression, each based on different assumptions in two-sample MR Analysis. We also performed sensitivity analyses, such as MR-Egg regression, MR-PRESSO and leave-one-out, to mitigate concerns of horizontal pleiotropy and heterogeneity. Results Our two-sample mendelian randomized study indicates a positive association between tumor necrosis factor-related apoptosis-inducing ligand(TRAIL), interleukin 2(IL-2 ) with Bell's palsy, while revealing a negative correlation between interleukin 12(IL-12)and Bell's palsy. Conclusions At the genetic level, IL-2 and TRAIL appear to be potential risk factors for Bell’s palsy. Conversely, IL-12 seems to have a diminishing effect on Bell's palsy, yet the evidence is insufficient and warrants further investigation.