Quantification of cfDNA and MPO-DNA Complexes

cfDNA was quantified in plasma samples using the Quanti-iT PicoGreen kit (Invitrogen) according to the manufacture’s instructions, and concentrations were calculated based on a standard curve of λ DNA (Invitrogen). MPO-DNA complex levels were quantified by ELISA using a protocol modified from (37 (link)). Briefly, a 96-well flat-bottom plate was coated with anti-human MPO antibody (Bio-Rad) overnight at 4°C and then washed 4 times with PBS-tween buffer before blocking with PBS/4% BSA. The samples were then incubated with patient plasma for 2 hours at room temperature. After 4 washes with PBS-tween, the quantity of DNA bound to captured MPO was quantified using the Quant-iT PicoGreen kit (Invitrogen) as per the manufacturer’s instructions.