CALCR and rheumatoid arthritis: As CD14 (Park et al., 2016) and CD68 (Bresnihan et al., 2009) have both been proposed as biomarkers for the therapeutic response in patients with RA, our findings of increased Cd14 and Cd68 expression levels in Calcr−/− CAIA mice, suggest a mechanistic involvement of the CTR in controlling the overexpression of these monocyte/macrophage surface markers.