CALCA and systemic lupus erythematosus: Other soluble biomarkers that can be used to differentiate infectious disease from exacerbation of SLE include reduced expression of soluble Fc gamma receptor III; elevated levels of granulocyte colony-stimulating factor; and elevated levels of sCD14, sICAM-1, sE-selectin [9, 10], and procalcitonin (PCT) [11].