LPS activation of TLR4-transfected HEK293 cells (IL-8 secretion) is supported by plasma from patients with severe sepsis and septic shock but not by plasma from healthy volunteers. Healthy volunteers versus severe sepsis or septic shock, P < .001; acute rheumatoid arthritis versus severe sepsis or septic shock, P < .01; severe sepsis versus septic shock, P = NS, one-way ANOVA. Plasma from patients with acute exacerbation of rheumatoid arthritis only minimally supported LPS activation of TLR4-HEK293 cells (healthy volunteers versus acute rheumatoid arthritis, P = NS, one-way ANOVA). LPS did not activate nontransfected HEK293 cells in the presence of plasma. Plasma concentration used in this figure was 5%. Horizontal black bars represent the median.