PADI4 and rheumatoid arthritis: Leukotoxin A (LtxA) is a primary virulence toxin produced by A. actinomycetemcomitans capable of inducing pore formation into the cell membrane of neutrophils, the resultant transient membrane permeability can then induce dysregulation of human PAD enzymes due to a rapid influx of calcium leading to increased endogenous citrullination, however not shown to be increased in ACPA positive population progressing to RA see Figure 1.