DKK3 and rheumatoid arthritis: As shown in Fig. 3h, the signature for HLA-DRAhigh sublining fibroblasts (SC-F2), a proinflammatory subset associated with leukocyte-rich synovial infiltration in RA, was significantly higher in responders (P = 0.027) as opposed to CD34+ sublining fibroblasts (SC-F1) and, in particular, to the newly described DKK3+ sublining fibroblasts (SC-F3), both increased in refractory patients (P = 0.036 and 0.00055, respectively).