CXCL12 and rheumatoid arthritis: Monocytes from RA patients with active disease lost their enhanced response to the heterocomplex when cells were treated with a JAK2 selective inhibitor, TG101348, while the migratory response to CXCL12 alone was not affected (Figure 1G), nor the migration profile of monocytes from RA patients in clinical remission (Figure 1H).