CXCL9 and macrophage activation syndrome: We have identified a cut off value for each biomarker in MAS (CXCL9 900 pg/ml, CXCL10 260 pg/ml, neopterin 5.0 ng/ml, IL-18 82996 pg/ml) and sHLH (CXCL9 2145 pg/ml, CXCL10 270 pg/ml, neopterin 7.1 ng/ml).