Expression of L-selectin by rheumatoid and age/sex-matched control leucocytes. (a) Baseline expression of L-selectin on peripheral leucocytes in patients with rheumatoid arthritis (RA) and control volunteers. Correlation of neutrophil (b) and monocyte (c) L-selectin and erythrocyte sedimentation rate (ESR). Linear regression of the relationship between resting neutrophil L-selectin expression and the ESR showed a significant correlation. Equation statistics are presented in the graph. In addition, Pearson's correlation also confirmed this finding (r = -0.54, p < 0.05; n = 15). Trends were also shown between monocyte L-selectin expression and ESR (0.1 > p > 0.05). (d) Neutrophil L-selectin was shed rapidly on TNF-α stimulation. MESF, milliequivalents of soluble fluorescein.