Genetically Supported Causality Between Immune Cells Traits and Low Back Pain: A Bi-Directional Two-Sample Mendelian Randomization Study.

Prior studies have suggested that immune cells play a crucial role in Low Back Pain (LBP). We employed a bi-directional Mendelian randomization (MR) study to investigate the causal relationship of immune cells with the risk of LBP. Single Nucleotide Polymorphisms (SNPs) that had a significant genetic association with immune cells were used as instrumental variables (IVs). The inverse variance weighted (IVW) method was used as the primary approach for MR analyses. To assess the robustness, sensitivity analyses were further performed using MR-Egger and MR-PRESSO. The MR analysis revealed a causal relationship between six types of immune cells and LBP (P < 0.05), including CD4 Treg AC (OR, 0.925; 95% CI, 0.878-0.974; P = 0.003), CD19 on CD20- CD38- (OR, 0.938; 95% CI, 0.898-0.979; P = 0.003), CD4 on HLA DR+ CD4+ (OR, 0.947; 95% CI, 0.909-0.987; P = 0.010), CD25 on CD39+ CD4+ (OR, 0.954; 95% CI = 0.922-0.988; P = 0.008), CD14 on CD33br HLA DR+ CD14dim (OR, 0.950; 95% CI = 0.916-0.985; P = 0.006), and CD4RA on TD CD4+ (OR, 1.030; 95% CI, 1.012-1.048; P = 0.001). Reverse MR analysis found no evidence of potential causal effects of genetically predicted LBP on the six types of immune cells. This study has demonstrated a close genetic connection between immune cells and LBP, providing valuable insights for future clinical research.