VSIG4 and arthritic joint disease: It is noteworthy that the phagocyte population involved in the pathogenesis of arthritis expresses complement receptor for C3b and iC3b (CRIg) (also designated VSIG4 or Z39Ig) [39, 40], which is selectively expressed on tissue macrophages, mainly on KCs [3, 4], and the expression increased according to the severity of the arthritis [40].