MPO and systemic lupus erythematosus: Since this quantification was performed on 20X images in an area showing NETs, we performed the same quantification on 2X images that are non-subjective and cover most of the plasma-smeared area and obtained similar results (Figure S5).To compare the quantitative results of our newly developed smear assay with data obtained from DNA-MPO-CitH3 ELISA, a two-tailed correlation analysis was computed using matched data across healthy and SLE patient samples (Figure 7).