Human lupus netting neutrophils induce endothelial damage, infiltrate tissues and expose immunostimulatory molecules. Homo sapiens

Our group has proposed that low-density granulocytes (LDGs) play an important role in lupus pathogenesis, as they can damage endothelial cells and synthesize increased levels of proinflammatory cytokines and type I interferons. LDGs have a heightened capacity to synthesize neutrophil extracellular traps (NETs). NETs from LDGs display increased levels of bactericidal and immunostimulatory proteins, such as the cathelicidin LL37 and externalize double-stranded DNA (dsDNA). Lupus netting LDGs have increased capacity to kill endothelial cells and expose IL-17. Through NETosis, lupus neutrophils stimulate plasmacytoid DCs to synthesize IFN-α. Our results further expand the potential pathogenic role of aberrant lupus neutrophils through a NET-mediated effect. We used microarrays to analyze the gene expression of neutrophils in healthy and lupus patients, and of low-density granulocytes in lupus patients. Overall design: Human neutrophils and LDGs were isolated from PBMCs. RNA from healthy neutrophils, lupus neutrophils and lupus LDGs was extracted and processed for hybridization on Affymetrix microarrays.