Figure 5

Elevated serum levels of NET components in RA patients have potential clinical utility. (A) Cell-free DNA levels in plasma and serum from healthy matched blood donors (n = 41) and patients with RA (n = 32) determined with real-time PCR. (B) Cell-free nucleosome levels in plasma and serum from healthy donor controls and patients with RA, determined with ELISA. (C) Determination of NE protein concentrations in plasma and serum from healthy donors and patients with RA, as assessed with sandwich ELISA. (D) MPO concentrations in plasma and serum from healthy donors and patients with RA, as determined with sandwich ELISA. (E) NET-associated MPO/DNA complexes quantified by using a modified capture ELISA. In contrast to the serum levels, none of the plasma levels of these NET components attained statistical significance (Figure  5A to E). (F) ROC analysis of cell-free nucleosomes in serum of patients with RA and healthy controls. (G) Detail of cell-free nucleosome ROC curve with groups of ACPA + and ACPA- RA cases and (H) scatterbox and whisker plots with individual values for control, ACPA + and ACPA- groups. The ROC curve analysis of other NET components, cell-free DNA (I), NE (J), and MPO (K), was not as conclusive as that for cell-free nucleosomes. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001; n.s., statistically not significant.