Peptidylarginine deiminase 4 (PAD4), encoded by PADI4, plays critical roles in the immune system. The pathological roles of PAD4 were investigated in lupus model mice. PAD4-regulated pathways were identified by RNA-sequencing of WT and Padi4 KO neutrophils. Overall design: Neutrophil mRNA profiles of 8 week-old wild type and Padi4-/-, in response to TLR7 agonost (R848), were generated.