THY1 and rheumatoid arthritis: Since studies in healthy murine bone marrow-derived macrophages and DCs showed that Axl expression is significantly enhanced by pro-inflammatory stimuli like LPS and TNF11, it was somehow surprising to note that, in early untreated active RA, most of the sublining cells, including both macrophages and CD90+ fibroblasts, do not express Axl on their surface; this was even further striking in the context of the DSP data showing that AXL transcript is among the genes upregulated in both lining and sublining.