Abstract P113: Associations of Immune Cell Subsets with Coronary Artery Calcium Incidence and Progression in the Multi-Ethnic Study of Atherosclerosis

Introduction: Coronary artery calcium (CAC) and its progression strongly associates with incident cardiovascular disease (CVD). Although immune dysregulation and related inflammation are important causes of coronary artery disease, few data exist on associations between specific immune cell subsets and CAC presence and progression. Hypothesis: We hypothesized innate & adaptive immune cell subsets are associated with longitudinal CAC changes Methods: In the Multi-Ethnic Study of Atherosclerosis (MESA), we examined associations of immune cell subsets (measured at baseline in peripheral blood by flow cytometry) with incident CAC and CAC progression. Of 975 participants sampled who had CAC and immune cell subsets measured at baseline (2000-02), 378 had CAC 0 at baseline and were used to examine incident CAC from MESA exam 2 (2002-04) through 5 (2010-12); the remaining 597 participants were included to analyze CAC progression from exam 1-5. Incident CAC analyses (N=378) used Weighted Cox regressions to determine hazard ratios of incident CAC, adjusted for age, gender, race, MESA site, education, smoking status, blood pressure, body-mass index, diabetes status, cholesterol, HDL cholesterol, statin use, and antihypertensive medication. CAC progression analyses among individuals with nonzero CAC at baseline (N=597) used weighted multivariable-adjusted linear mixed models to investigate associations of baseline immune cell subsets with CAC progression, with Benjamini-Hochberg correction for multiple comparisons. Results: Among 378 participants with CAC 0 and immune cell subsets measured at baseline, 149 had incident CAC between MESA examination 2-5. Of 19 subsets measured, natural killer (NK) cells (CD3-CD16+CD56+) were associated with an elevated risk of incident CAC (hazard ratio (HR) 1.26 per standard deviation (SD) higher NK cells; 95% confidence interval (CI) 1.03-1.56, p=0.03). Two CD4+ T cell subsets, Th1 (HR 0.81, 95% CI 0.66-0.99, p=0.04) and Th2 (HR 0.80, 95% CI 0.64-0.99, p=0.04) were associated with a borderline lower risk for incident CAC. In analyses of CAC progression for participants with nonzero CAC at baseline (N=597), CD19+ B-cells were associated with CAC progression (beta-coefficient=53.1 Agatston units per SD higher B-cells proportion, 95% CI 2.0-104.2, p=0.04), while intermediate monocytes (CD14+CD16+) (beta = -71.6 Agatston units per SD higher, 95% CI -134.9 - -8.3, p=0.03) and higher T-regulatory cells (CD4+CD25+CD127-) (beta = -71.6 Agatston units per SD higher, 95% CI -119.1 - -4.8, p=0.03) were negatively associated with CAC progression. Conclusions: Among individuals with CAC 0 at baseline, NK cells were associated with incident CAC. In individuals with nonzero CAC at baseline, T-regulatory cells and intermediate monocytes were negatively associated with CAC progression, whereas B-cells were positively associated with CAC progression.