LPS activation of HUVECs, human circulating leukocytes, calcitriol-differentiated THP-1 cells, and TLR4-transfected HEK293 cells. (A) LPS activation (IL-8 secretion) of HUVECs is significantly increased by plasma from patients with severe sepsis and septic shock compared with plasma from healthy volunteers. Healthy volunteers versus severe sepsis or septic shock, P < .05, one-way ANOVA. Horizontal black bars represent the median. (B) LPS activation (IL-8 secretion) of human circulating leukocytes from healthy volunteers is decreased by plasma from patients with severe sepsis and septic shock compared with plasma from healthy volunteers (1 experiment of 3 similar experiments, P = NS between groups, one-way ANOVA). (C) LPS activation (IL-8 secretion) of calcitriol-differentiated THP-1 cells is decreased by plasma from patients with severe sepsis and septic shock compared with plasma from healthy volunteers (1 experiment of 3 similar experiments, P = NS between groups, one-way ANOVA). (D) LPS activation of TLR4-transfected HEK293 cells (IL-8 secretion) is supported by plasma from patients with ARDS with severe sepsis and septic shock and by undiluted lung edema fluids. In 4 septic patients with ARDS (patients no. 1-4) and in 2 patients with congestive heart failure (CHF; no. 1 and no. 2), plasma samples were taken at the same time as edema fluid. White bars indicate cell activation in the absence of LPS; black bars, cell activation in the presence of LPS; PL, plasma; EF, lung edema fluid. Mean ± 1 SD of triplicates, 1 representative experiment of 2 similar experiments. Neither plasma nor edema fluid supported LPS activation of untransfected HEK293 cells above basal levels (not shown).