Using Mendelian randomization analysis to explore the immune cells involved in myocarditis(MC).

Genome-wide association study (GWAS) was used to mine the data, and the exposure factors were 731 immune cell traits, and the outcome factor was myocarditis. Regression models such as Inverse-Variance Weighted method (IVW), MR-Egger, Simple Mode, weighted median and Weighted Mode were used for Mendelian randomization analysis. At the same time, heterogeneity tests, horizontal multiple validity analyses, and sensitivity analyses were also conducted. Multivariate Mendelian randomization analysis of the relevant immune cell traits was performed by Inverse-Variance Weighted method (IVW) to correct the effect of seven positive immune cell traits on the outcome.

(1)The results of Mendelian randomization showed that there was a causal relationship between 7 immune cell traits that include CD39+resting Treg %resting Treg (OR=1.237, 95%CI:1.039-1.474), CD4+CD8dim %leukocyte (OR=0.737, 95%CI:0.543-0.100), CD28-CD8dim AC (OR=0.868, 95%CI:0.753-0.100), CD28-CD8br AC (OR=1.398, 95%CI:1.097-1.780), CD20 on CD20-CD38- (OR=1.295, 95%CI:1.012-1.659), CCR2 on monocyte (OR=1.010, 95%CI:1.000-1.208), CD11b on basophil (OR=0.852, 95%CI:0.727-0.998) and MC.(2)The results of multivariate Mendelian randomization showed that CD39+ resting Treg %resting Treg (OR=1.228, 95%CI:1.059-1.423), CD28-CD8dim AC (OR=0.629, 95%CI:0.428-0.924), CCR2 on monocyte (OR=0.661, 95%CI:0.488-0.895) were correlated with MC.(3)The results of reverse Mendelian randomization did not find a causal relationship between 7 positive immune signatures and MC.

This study confirm the close relationship between immune cells and MC through genetics, which will provide a reference for future research.