NETs analysed by novel calprotectin-based assays in blood donors and patients with multiple myeloma or rheumatoid arthritis: A pilot study.

Two novel enzyme-linked immunosorbent assays (ELISAs), designed to detect complexes containing DNA, leucocyte calprotectin and S100A12 proteins, were generated for improved specificity and rapid measurement of neutrophil extracellular traps (NETs). The assays were applied on plasma and serum samples from blood donors for establishment of reference values, and from patients with multiple myeloma (MM) or rheumatoid arthritis (RA) in order to examine putatively increased values in the two different inflammatory conditions. Although NETs were hardly detectable in healthy individuals, NET levels were as expected highly and statistically significantly increased in RA patients. The detection of statistically significantly increased NET levels in MM is a novel finding.