PLA2G2D and rheumatoid arthritis: Following the purification of two prototypic enzymes structurally related to snake venom sPLA2s (groups I and II) from pancreatic juice and rheumatoid arthritis fluid in the late 1980s, now being referred to as sPLA2-IB (encoded by Pla2g1b in mice) and sPLA2-IIA (encoded by Pla2g2a), respectively, a total of 11 mammalian sPLA2s (10 catalytically active and 1 inactive isoforms) have been identified to date and are structurally subdivided into one classical (group I/II/V/X) and two atypical (groups III and XII) branches (8–10).