Fig. 1

PMN ROS production and degranulation induced by autologous MPs and/or LPS. Leukocytes from 20 SLE patients and 10 healthy controls were incubated with (a) autologous MPs, (b) LPS, (c) a combination of autologous MPs and LPS or (d) PMA for 30 min in the presence of autologous serum and DHR, a probe for H₂O₂ production. Fluorescent oxidation product rhodamine 123 contained in PMNs staining positive for CD15 and negative for the dead cell marker near infrared was measured by flow cytometry and expressed as median fluorescence intensity (MFI) units. (e) Increase in ROS production after addition of MPs or MPs in combination with LPS. PMN production of ROS after stimulation with (f) MPs or (g) PMA, adjusted for background activity (of unstimulated cells), is shown for healthy controls and SLE patients with high and low levels of circulating complement C3, respectively. (h) Concentration of the primary granule protein myeloperoxidase (MPO) released into the cell supernatants. HC healthy control, LPS lipopolysaccharide, MP microparticle, ROS reactive oxygen species, SLE systemic lupus erythematosus, Unstim unstimulated