CCR1 and arthritic joint disease: During autoantibody-induced arthritis, the recruitment of neutrophils in the inflamed joint requires a cascade of cytokines and chemokines (LTB4, IL-1β, CCR1, and CXCR2 ligands) produced by endothelial cells, synovial cells, and neutrophils themselves (Chen et al, 2006; Kim et al, 2006; Chou et al, 2010; Sadik et al, 2011).