CXCL1 and gout: We supplemented our in vitro assays with an in vivo peritoneal model of acute gout flare where we studied the impact of Prg4 expression on the peritoneal influx of inflammatory classical monocytes (CMs), anti-inflammatory non-classical monocytes (NCMs) and neutrophils as well as IL-1β and CXCL1 levels (24, 27).