Soluble Mer is released by M2c monocytes/macrophages and correlates with circulating levels of soluble CD163 in systemic lupus erythematosus, and soluble CD163, like soluble Mer, correlates with Systemic Lupus Erythematosus Disease Activity Index score. Levels of soluble Mer (sMer) (A) and soluble Axl (sAxl) (B) were measured in supernatants of monocytes/macrophages cultured for 3 days in the presence of medium alone (resting M0), interferon γ (IFN-γ), granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin 17 (IL-17) (classically activated and/or proinflammatory M1 and M17), IL-4, transforming growth factor β (TGF-β), IL-10, macrophage colony-stimulating factor (M-CSF), dexamethasone (Dex), alone or in combination (alternatively activated and/or regulatory M2a and M2c cells). In 40 consecutive patients in our cohort, potential correlations between plasma levels of sMer (C) or sAxl (D) and soluble CD163 (sCD163) were examined. Levels of sCD163 were also analyzed according to circulating autoantibodies (E) and disease activity (F). αchrom., antichromatin; SLEDAI, Systemic Lupus Erythematosus Disease Activity Index. *P < 0.05; **P < 0.01; n.s., not significant.