Results of the inhibition assays. (a) Statistically significant differences (P < 0.001) were seen in all three concentrations between C-reactive protein (CRP) and monomeric CRP (mCRP) considering the ability to inhibit anti-CRP binding, indicating that anti-CRP autoantibodies are targeted to the monomeric form of the acute-phase protein. (b) Increasing concentrations of soluble DNA–histones showed a dose-dependent decrease in anti-nucleosome antibody reactivity. Statistically significant differences (P < 0.001) between each concentration of DNA–histones were seen. OD, optical density.