In the present study, we measured the soluble (s) ectodomains sMer and sAxl in the circulation of SLE patients and matched healthy individuals with the aim of investigating how these molecules relate to clinical, laboratory and immunological profiles of SLE; how they are related to each other and to the TAMR ligands growth arrest–specific 6 (Gas6) and reduced free Protein S (ProS); and under what immunological conditions they are produced. The gene discussed is PROS1; the disease is systemic lupus erythematosus.