Figure 1.

E-cigarette use associated alterations in immunomodulatory protein levels in saliva, sputum, and plasma. A: inflammatory markers were assessed in the saliva of nonsmoking nonvaping healthy controls (n = 11; blue circles) and e-cigarette users at baseline (n = 17; solid red squares), with lower levels of IL-1RA identified in the oral airways of e-cigarette users. B: IL-1RA remained low in e-cigarette users after 2 wk of reduced e-cigarette usage (n = 14; hollow red squares). C: sputum demonstrated reductions in both GRO and IL-1RA in the lower airways of e-cigarette users vs. healthy controls. D: GRO and IL-1RA remained low in lower airway samples after 2 wk of reduced e-cigarette usage. E: plasma samples demonstrated elevations in TNFβ and VEGF in the circulation of e-cigarette users vs. controls. F: after 2 wk of reduced e-cigarette use, plasma levels of TNFβ and VEGF were persistently elevated. Data are represented as individual data points with the geometric mean. Statistical analysis was conducted with two-way ANOVA with correction for multiple comparisons by controlling the false discovery rate, using the two-stage step-up method of Benjamini, Krieger, and Yekutieli. *P < 0.05, **P < 0.01, and ****P < 0.0001.