A. Optimal microscopy and flow cytometry was used to determine the percent of monocytes that underwent forward transendothelial migration (TEM) in collagen gel coated with HUVEC endothelial cells after 1 hour exposure to pooled plasma from healthy study participants as indicated in methods. The compared groups were nonsmokers (NS, light grey) (n=21), electronic-cigarette vapers (ECIG-vapers, grey)(n=21) and tobacco cigarette smokers (TCIG-smokers, dark grey)(n=18). Two different approaches were utilized to dissect the proatherogenic properties of circulating factors in plasma compared to cells. B. Gating flow cytometry strategy in macrophages isolated from collagen gels. C. Representative data of % transmigrated CD45+CD11b+ macrophages isolated from collagen gels among compared groups. D. % TEM migration among compared groups (Approach A) expressed relatively to the mean of the non-smoker group. Autologous plasma and cells were used for the atherogenesis assay. E. % TEM migration among compared groups (Approach B) expressed relatively to the mean of the non-smoker group. Patient plasma and pooled PBMCs from NS were used for the atherogenesis assay. F. % TEM migration among ECIG groups who were ex smokers versus never smokers. Summary data are shown as box and whisker plots with minimum, median, interquartile range (IQR) and maximum values. Mann Whitney test was used to compare 2 groups.