The causal relationship between immune cells and ankylosing spondylitis: a bidirectional Mendelian randomization study

Background Ankylosing spondylitis (AS) is one of several disorders known as seronegative spinal arthritis (SpA), the origin of which is unknown. Existing epidemiological data show that inflammatory and immunological factors are important in the development of AS. Previous research on the connection between immunological inflammation and AS, however, has shown inconclusive results. Methods To evaluate the causal association between immunological characteristics and AS, a bidirectional, two-sample Mendelian randomization (MR) approach was performed in this study. We investigated the causal connection between 731 immunological feature characteristic cells and AS risk using large, publically available genome-wide association studies. Results After FDR correction, two immunophenotypes were found to be significantly associated with AS risk: CD14 - CD16 + monocyte (OR, 0.669; 95% CI, 0.544 similar to 0.823; P = 1.46 x 10(-4); P-FDR = 0.043), CD33dim HLA DR + CD11b + (OR, 0.589; 95% CI = 0.446 similar to 0.780; P = 2.12 x 10(-4); P-FDR = 0.043). AS had statistically significant effects on six immune traits: CD8 on HLA DR + CD8 + T cell (OR, 1.029; 95% CI, 1.015 similar to 1.043; P = 4.46 x 10(-5); P-FDR = 0.014), IgD on IgD + CD24 + B cell (OR, 0.973; 95% CI, 0.960 similar to 0.987; P = 1.2 x 10(-4); P-FDR = 0.021), IgD on IgD + CD38 - unswitched memory B cell (OR, 0.962; 95% CI, 0.945 similar to 0.980; P = 3.02 x 10(-5); P-FDR = 0.014), CD8 + natural killer T %lymphocyte (OR, 0.973; 95% CI, 0.959 similar to 0.987; P = 1.92 x 10(-4); P-FDR = 0.021), CD8 + natural killer T %T cell (OR, 0.973; 95% CI, 0.959 similar to 0.987; P = 1.65 x 10(-4); P-FDR = 0.021). Conclusion Our findings extend genetic research into the intimate link between immune cells and AS, which can help guide future clinical and basic research.