CD14 and TLR4-mediated effects. (a) ELISA assays were performed to analyse levels of soluble CD14 (sCD14) in sera from patients with ankylosing spondylitis (AS) (n = 50) and healthy controls (CO) (n = 23). The Mann-Whitney test was used to determine the statistical differences between the group of patients and the control group. **P < 0.01. A blocking antibody (Ab) directed against (b) CD14 and (c) TLR4 or an isotype control were added to peripheral blood mononuclear cells from patients with AS maintained in 5% autologous serum. After 1 hour, lipopolysaccharide (LPS) stimulation at a concentration of 10 μg/ml for 16 hours was started. Box blots show percentages of perforin-producing CD4+CD28null T cells from seven independent experiments. Differences were tested for significance using the Wilcoxon test. **P < 0.01.