An indication that consumption of complement in SLE serum influenced ROS production after stimulation of PMNs with MPs and LPS came from the finding that the SLE:NHS ratio for ROS production tended to correlate positively with the C3 content in the patients’ serum (rs =0.75, p = 0.066) (Fig. 2b). This evidence concerns the gene C3 and systemic lupus erythematosus.